ATOMIC ENERGY §?S& L'ENERGIE ATOMIQUE OF CANADA … · A Waste Heat Utilization forking Party was...

AECL-5109

ATOMIC ENERGY § ? S & L'ENERGIE ATOMIQUEOF CANADA LIMITED ^ f i S 9 DU CANADA LIMITEE

AN ASSESSMENT OF THE UTILIZATION OF

WASTE HEAT IN GREENHOUSES

by

STUART L. IVERSON, DANIEL R. PROWSE and JOSEPH D. CAMPBELL

Whiteshel l Nuc lear Research Establishment

Pinawa, Man i toba

January 1976

ATOMIC ENERGY OF CANADA L I M T E D

AN ASSESSMENT OF THE UTILIZATION DFWASTE MEAT IN GREENHOUSES

by

1 2S t u a r t L. I v e r s o n , D a n i e l R. P r o w s e a n d J o s e p h 0. Cam;) be

1. E n v i r o n m e n t a l R e s e a r c h B r a n c h , W!!RE

2 . C h e m i c a l Technolociy B r a n c h , W N R E

3. D e p a r t m e n t o f P l a n t S c i e n c e , U n i v e r s i t y o f M a n i t o b a ,W i n n i p e g , M a n i t o b a

W h i t e s h e l l N u c l e a r R e s e a r c h E s t a b l isiimentA t o m i c E n e r g y of C a n a d a L i m i t e d

P i n a w a , M a n i t o b a R O E 1 L 0

J a n u a r y 1 9 7 6 A H . I

Evaluation de l ' u t i l i sa t ion en serres de la chaleur perdue

par

Stuart L. Iverson, Daniel R. Prowse et Joseph D. Campbell*

*Département d'Horticulture, Université du Manitoba, Winnipeg, Manitoba

Résumé

On a f a i t une étude de fa isabi l i té économique de l'emploi de la chaleurperdue provenant du circuit du modérateur du réacteur CANDU G-2 pour chaufferles serres. Trois systèmes de récupération de la chaleur perdue ont étécompares à un système classique alimenté par gaz. Chaque système derécupération de la chaleur perdue comprend la recirculation de l'eau légèretiède provenant des échangeurs thermiques modifiés du modérateur, au moyend'un système de distribution amenant cette eau tiède à des échangeursthermiques à tubes munis d'ai lettes dans les serres. Le système de distributionétait destiné à une entreprise de culture de légumes en serres devant couvrirde 8 à 10 hectares (20-25 acres) en bordure de la zone d'exclusion du réacteurmesurant 914 m. Deux configurations de serres ont été évaluées, l'uneconsistant en serres individuelles reliées par un corridor pour former desunités9de 4047 m (1 acre) tandis que l'autre é ta i t une serre unique couvrant4047 m\

Les plus bas coûts calculés pour le chauffage et la ventilation dessystèmes de récupération de la chaleur perdue étaient de $9.55 par an parmètre carré de surface de récolte sous le climat de Winnipeg, Manitoba. Uneserre classique chauffée par du gaz naturel à raison d'environ $1.50 parmille pieds cubes donnerait l ieu aux mêmes frais annuels de chauffage.

Trois améliorations possibles du système d 'ut i l isat ion de la chaleurperdue ont été étudiées. Chaque amélioration pourrait rendre le systèmeéconomiquement compétitif aux prix courants du gaz naturel. Etant donnéque l'on s'attend à une nouvelle augmentation du coût du gaz naturel etétant donné qu ' i l existe au Canada une demande pour les légumes produitssous vi t res, le concept de l ' u t i l i sa t ion en serres de la chaleur perduemérite un développement plus poussé.

L'Energie Atomique du Canada, LimitéeEtablissement de Recherches Nucléaires de Whiteshell

Pinawa, Manitoba, ROE 1L0

Janvier 1976

AECL-5109

AN ASSESSMENT OF THE UTILIZATION OF

WASTE HEAT IN GREENHOUSES

by

S t u a r t L. I v e r s o n , D a n i e l R. P r o w s e a n d J o s e p h D. C a m p b e l l *

A B S T R A C T

T h e e c o n o m i c f e a s i b i l i t y o f u t i l i z i n n w a s t e h e a t f r o mt h e m o d e r a t o r c i r c u i t o f t h e C A N D U G -2 r e a c t o r to h e a t g r e e n h o u s e sw a s e x a m i n e d . T h r e e w a s t e h e a t r e c o v e r y s y s t e m s w e r e c o m p a r e d toa c o n v e n t i o n a l g a s - f i r e d s y s t e m . E a c h w a s t e h e a t r e c o v e r y s y s t e mi n v o l v e d t h e r e c i r c u l a t i o n o f w a r m l i g h t w a t e r f r o m m o d i f i e dm o d e r a t o r h e a t e x c h a n g e r s t h r o u g h a d i s t r i b u t i o n s y s t e m to f i n n e d -t u b e h e a t e x c h a n g e r s in t h e g r e e n h o u s e s . T h e d i s t r i b u t i o n s y s t e mw a s a s s u m e d t o s e r v i c e an 8 o r 1 0 h e c t a r e ( 2 0 - 2 5 a c r e ) g r e e n h o u s ev e g e t a b l e i n d u s t r y l o c a t e d i m m e d i a t e l y o u t s i d e t h e 9 1 4 m r e a c t o re x c l u s i o n z o n e . T w o g r e e n h o u s e c o n f i g u r a t i o n s w e r e e v a l u a t e d , o n ec o n s i s t i n g o f i n d i v i d u a l h o u s e s c o n n e c t e d b y a c o r r i d o r t o f c n r4 0 4 7 ;n^ (1 a c r e ) u n i t s w h i l e t h e o t h e r w a s a s i n g l e r o o f c o v e r i n g4 0 4 7 m 2 .

( T h e l o w e s t c a l c u l a t e d h e a t i n g a n d v e n t i l a t i o n costr, f orw a s t e h e a t s y s t e m s w e r e $ 9 . 5 5 p e r y e a r p e r s q u a r e m e t e r o f q r o w i n ns u r f a c e f o r t h e c l i m a t e o f W i n n i p e g , M a n i t o b a . A c o n v e n t i o n a lg r e e n h o u s e h e a t e d by n a t u r a l g a s at a b o u t $ 1 . 5 0 p e r 1 0 0 0 s t a n d . i n !c u b i c f e e t w o u l d e x p e r i e n c e t h e s a m e a n n u a l h e a t i n g c o s t s .

T h r e e p o t e n t i a l i m p r o v e m e n t s to t h e w a s t e h e a t u t i 1 i za t i o'is y s t e m w e r e d i s c u s s e d , e a c h o f w h i c h w o u l d m a k e t h e s y s t e me c o n o m i c a l l y c o m p e t i t i v e a t c u r r e n t n a t u r a l q a s p r i c e s . S i n c e thep r i c e o f n a t u r a l g a s ^ r. e x p e c t e d to i n c r e a s e a b o v e its c u r r e n t l e v e la n d s i n c e a n u n f i l l e d , e x p a n d i n g d e m a n d f o r g r e e n h o u s e - g r o w n p r o d u c ee x i s t s in C a n a d a , t h e c o n c e p t o f w a s t e h e a t u t i l i z a t i o n in g r e e n -h o u s e s m e r i t s f u r t h e r d e v e l o p m e n t .

* D e p a r t m e n t o f P l a n t S c i e n c e , U n i v e r s i t y o f M a n i t o b a , VJ i nn i i'°'i,M a n i t o b a

A t o m i c E n e r g y o f C a n a d a L i m i t e dW h i t e s h e l l N u c l e a r R e s e a r c h E s t a b l i s h m e n t

P i n a w a , M a n i t o b a , R O E 1 1 0

January 1976 M en

F O R E W O P D

R . T . S . P o b e r t s o n

D i r e c t o r - A d v a n c e d P r o j e c t s ,n t e s h e l l N u c l e a r R e s e a r c h E s t a b l i s h m e n t

A t o m i c E n e r g y o f C a n a d a L i m i t e dPi n a w a , M a n i t o b a

A g r o u p a t W h i t e s h e 11 N u c l e a r R e s e a r c h E s t a b l i s h m e n t( W N R E J h a s b e e n e x a m i n i n g u s e s f o r n u c l e a r r e a c t o r s o t h e r t h a nt h e g e n e r a t i o n o f e l e c t r i c i t y . O n e a s p e c t o f t h i s e x a m i n a t i o nh a s been a n i n v e s t i g a t i o n o f p o s s i b l e a p p l i c a t i o n o f t h e r e a c t o r ' sl o w - g r a d e w a s t e h e a t i n f o o d p r o d u c t i o n . T h e s o u r c e o f t h i sw a s t e h e a t i s t h e c o o l i n g w a t e r d i s c h a r g e d f r o m t h e t u r b i n ec o n d e n s e r s a n d m o d e r a t o r c i r c u i t s o f o u r C A N D U - P H W * r a a c t o r s .

T h e u s e o f l o w - g r a d e w a s t e h e a t f o r f o o d p r o d u c t i o nr e q u i r e s m o r e t h a n t h e n u c l e a r e n g i n e e r i n g a n d b i o l o g i c a lc o m p e t e n c e a v a i l a b l e w i t h i n A t o m i c E n e r g y o f C a n a d a L i m i t e d . Ita l s o r e q u i r e s e x p e r t i s e i n a g r i c u l t u r e a n d a o u a c u l t u r e . S u c he x p e r t i s e i s r e a d i l y a v a i l a b l e i n t h e P l a n t S c i e n c e D e p a r t m e n t ,U n i v e r s i t y o f M a n i t o b a a n d t h e E n v i r o n m e n t C a n a d a F r e s h w a t e rI n s t i t u t e i n W i n n i p e g ; s c i e n t i s t s i n t h e s e i n s t i t u t e s a r a k n o w nt o b e i n t e r e s t e d i n w a s t e h e a t u t i l i z a t i o n f o r f o o d p r o d u c t i o n .

A W a s t e H e a t U t i l i z a t i o n f o r k i n g P a r t y w a s f o r m e d t oi n v e s t i g a t e t h e p o s s i b i l i t y o f u s i n g n u c l e a r w a s t e h e a t f o rf o o d p r o d u c t i o n b y m e a n s o f i n t e n s i v e a g r i c u l t u r e a n d a n u a c u l I'jre,a n d t o p r e p a r e s p e c i f i c p r o p o s a l s f o r s u c h u s e s . D r . J . E . G u t h r i eE n v i r o n m e n t a l R e s e a r c h B r a n c h , W M R E , c h a i r e d t h e W o r k i n g P a r t yw h i c h c o n s i s t e d t o t w o s u b - c o m m i t t e e s : A g r i c u l t u r e a n d A a u a c u l t u rT h e m e m b e r s o f t h e s u b - c o m m i t t e e s w e r e :

A g r i c u l t u r e

D r . S . L . I v e r s o n

D r . J . D. Campbe l l

D r . D. R. Prowse

E n v i r o n m e n t a l R e s e a r c h B r a n c hWNRE - C h a i r m a n

D e p a r t m e n t o f P l a n t S c i e n c e ,U n i v e r s i t y o f M a n i t o b a

C h e m i c a l T e c h n o l o g y Bv-anch,WNRE

*Canada Deuter ium Uranium - Pressur ized Heavy Water

_ '1' l.ln"e

?r. J. E. Guthrie E n v i r o n m e n t a l Research B r a n c h ,WNRE - C h a i r m a n

Dr. D. P. S c o t t * E n v i r o n m e n t C a n a d a ,F r e s h w a t e r I n s t i t u t e

'Jr. D. R. rrowse Chemical T e c h n o l o g y B r a n c h ,WNRE

Dr. Prowse's p a r t i c u l a r c o n c e r n in both s u b - c o m m i t t e e s was theheat t r a n s f e r and e n g i n e e r i n g aspects of the i n v e s t i g a t i o n .The e x p e r i e n c e of the P l a n t S c i e n c e D e p a r t m e n t in g r e e n h o u s eh o r t i c u l t u r e was made a v a i l a b l e to the a g r i c u l t u r e s u b - c o m m i t t e ethrough Dr. C a m p b e l l . The v a r i o u s a s p e c t s of fish b i o l o g yr e p r e s e n t e d in the F r e s h w a t e r Institute w e r e provided by Dr. Scott

The basic guide lines given to the Working P a r t y w e r e :

a) the studies s h o u l d identify the m a r k e t s for a g r i c u l t u r e( g r e e n h o u s e ) and a q u a c u l t u r e p r o d u c e in C a n a d a , ande x a m i n e the e c o n o m i c s of p r o d u c i n g p r o d u c e for thesem a r k e t s using n u c l e a r waste heat

b) the source of heat should be the c o o l i n g w a t e r fromthe turbine c o n d e n s e r s , or from the m o d e r a t o r c i r c u i tof a 600 M W ( e ) C A N D U - P H W n u c l e a r p o w e r r e a c t o r

c) the r e f e r e n c e c l i m a t e should be t h a t of the p r a i r i e s

d^ the research and d e v e l o p m e n t r e q u i r e d to a s s u r e thes u c c e s s of a c o m m e r c i a l a g r i c u l t u r a l or a q u a c u l t u r a lv e n t u r e u t i l i z i n g n u c l e a r w a s t e h e a t should bei denti fi ed

e) the WR-1 r e a c t o r should be c o n s i d e r e d as the s o u r c eof heat for ( d ) .

The Waste Heat U t i l i z a t i o n W o r k i n g Party s t u d i e s aredescribed in two d o c u m e n t s :

1. An A s s e s s m e n t of the U t i l i z a t i o n of Waste H e a t inG r e e n h o u s e s by S.L. I v e r s o n , D.R. Prowse andJ.D. C a m p b e l l . A t o m i c Energy of Canada L i m i t e dr e p o r t no. A E C L - 5 1 0 9 . 1 9 7 5 .

Dr. S c o t t submitted a proposal to use the c o n d e n s e r c o o l i n gw a t e r from the Douglas P o i n t N u c l e a r G e n e r a t i n g S t a t i o n fora q u a c u l t u r e as early as 1 9 6 2 .

A n A s s e s s m e n t o f N u c l e a r P o w e r P l a n t W a s t e H e a tU t i l i z a t i o n f o r F r e s h w a t e r F i s h F a r m i n g byJ . E . G u t h r i e , D . R . P r o w s e a n d D . P . S c o t t . A t o m i cE n e r g y o f C a n a d a L i m i t e d r e p o r t n o . A E C L - 4 9 2 4 .1 9 7 5 .

T h e s e d o c u m e n t s e x a m i n e t h e s h o r t - a n d l o n g - t e r m p r o s p e c t s o fp r o d u c i n g f o o d i n g r e e n h o u s e s h e a t e d w i t h t h e w a t e r d i s c h a r g e df r o m t h e m o d e r a t o r c i r c u i t o f a C A N D U r e a c t o r , 1 by i n t e n s i v ea q u a c u l t u r e ( f i s h f a r m i n g ) u s i n g t h e r e a c t o r ' s c o n d e n s e r e f f l u e n t

PREFACE

T h i s d o c u m e n t w a s w r i t t e n f o r t w o p u r p o s e s :

1. T o a s s e s s t h e e c o n o m i c f e a s i b i l i t y o f u t i l i z i n g a s p e c i f i cs o u r c e o f w a s t e h e a t i n g r e e n h o u s e s f o r t h e p r o d u c t i o n o fv e g e t a b l e s in C a n a d a .

2 . T o e x a m i n e s o m e o f t h e e c o n o m i c , h o r t i c u l t u r a l a n de n g i n e e r i n g p r o b l e m s w h i c h w i l l g o v e r n t h e u s e o fw a s t e heat, in t h e g r e e n h o u s e i n d u s t r y .

S e c t i o n t w o d e m o n s t r a t e s t h a t t h e r e is a s i z e a b l e nwn-U't.i n C a n a d a f o r t r a d i t i o n a l g r e e n h o u s e v e g e t a b l e s . S e c t i o n fiv< j

i d e n t i f i e s s p e c i f i c h e a t s o u r c e a n d g r e e n h o u s e c o m b i n a t i o n s t tui ta r e , o r w i l l s o o n b e c o m p e t i t i v e w i t h g a s h e a t e d s y s t e m s . S u i t inns i x c o n c l u d e s b y p o i n t i n g o u t s o m e o f t h e r e s e a r c h a n d d e v e 1 onr, v n •t h a t is r e q u i r e d b e f o r e a c o m m e r c i a l l y s i z e d s y s t e m c a n b e b u i l t .T h e r e m a i n d e r o f t h e r e p o r t p r e s e n t s a n d d i s c u s s e s g e n e r a l b a c k -g r o u n d i n f o r m a t i o n a n d d e t a i l s t h a t c l a r i f y a n d s u p p o r t t h e m a j o rt h e m e .

T h r e e p o t e n t i a l i m n r o v e m e n t s t o t h e w a s t e h e a tu t i l i z a t i o n s y s t e m w e r e d i s c u s s e d , e a c h o f w h i c h w o u l d m a k e t n es y s t e m e c o n o m i c a l l y c o m p e t i t i v e a t c u r r e n t n a t u r a l g a s p r i c e s .S i n c e t h e p r i c e o f n a t u r a l g a s is e x p e c t e d t o i n c r e a s e a b o v e it.:,c u r r e n t l e v e l , a n d s i n c e a n u n f i l l e d , e x D a n d i n q d e m a n d f o rg r e e n h o u s e - g r o w n p r o d u c e e x i s t s in C a n a d a , t h e c o n c e p t o f w a s re-h e a t u t i l i z a t i o n in g r e e n h o u s e s m e r i t s f u r t h e r d e v e l o p m e n t .

.CJ)NJ.E_N_T_S_

1. INTRODUCTION 1

1.1 SCOPE OF THE kEPORT .... 2

1.2 VEGETABLES PRODUCED IN GREENHOUSES 2

1.3 THE GREENHOUSE INDUSTRY IN CANADA .1

2. THE CANADIAN MARKET 7

2.1 PROBABLE MARKET FOR TOMATOES 7

2.2 PROBABLE MARKET FOR CUCUMBERS 7

2.3 PROBABLE MARKET FOR OTHER VEGETABLES 0

2.4 FUTURE PRICES AND MARKETS 'J

3. CHARACTERISTICS OF THE HEAT SOURCES ANDTHE GREENHOUSE HEATING SYSTEM IK

3.1 WASTE HEAT SOURCES IN CANDU REACTORS 18

3.2 PRELIMINARY CONSIDERATIONS 20

3.3 GREENHOUSE STRUCTURE 21

3.4 AIR CIRCULATION 23

3.5 HEATING SYSTEM REQUIREMENTS 23

4. VEGETABLE YIELD IN GREENHOUSES 3;

4.1 COMPARISON OF GROWTH CONDITIONS IN WASTE

HEAT AND CONVENTIONAL GREENHOUSE 3'J

4.2 PRODUCTION SCHEDULING 34

4.3 EXPECTED YIELDS OF TOMATOES V)

5. DESCRIPTION OF COMMERCIAl GREENHOUSE

SYSTEMS EVALUATED 3r'

5.1 HEAT SUPPLY SYSTEMS

5.1.1 Waste Heat Systems 4 15.1.1.1 Two Reactors 4?5.1.1.2 One Reactor With Fossil-

Fired Standby 4 ;>5 . 1 . 1 . 3 One R e a c t o r With F o s s i l -

Fired P e a k i n g ^ '<

'J . 1 . ?. Gas H e a t i n q S y s t e m "•'

5.2.1 Individual Houses 46

5.2.2 Block Houses 46

6. L'CCKJOMC ANALYSIS OF THE COMMERCIAL SYSTEMS 47

6.1 COSTS OF THE HEAT RECOVERY SYSTEMS 48

6.2 COSTS OF THr GREENHOUSE HEATING SYSTEMS 48

6.3 TOTAL ANNUAL COSTS 52

6.4 AREAS OF POTENTIAL SAVING 57

7. GENERAL DISCUSSION 59

3. LITERATURE CITED 62

APPENDICES

APPENDIX A - DESCRIPTION AND COST SUMMARY OF COMMERCIALGREENHOUSE SYSTEMS 65

A.I PRELIMINARY CONSIDERATIONS 65

A.2 THE GREENHOUSE FACILITY 67

A.2.1 Introduction 67

A.2.2 Design of Individual GreenhouseOperating Unit 70

A.2.2.1 Air Circulation, Heatingand Coolinn Systems 71

A.2.3 Design o': Single Roof GreenhouseOperatin. Unit 74

A.2.3.1 Air Circulation, Heatingand Cooling System 74

A.2.4 Commercial Greenhouse Facilities 75

A.2.5 Capital Cost Estimate 75

A.3 DISTRIBUTION SYSTEM WITHIN THE GREENHOUSE

FACILITY 78

A.3.1 System Description 78

A.3.2 Capital Cost 78

A.4 MODERATOR HEAT EXCHANGE AND WARM WATER

SUPPLY SYSTEM 80

A.4.1 System Design 80

A.4.2 Capital Cost of Heat Supply Systems 87

A.5 NATURAL GAS GREENHOUSE HEATING SYSTEfi 87

A. 5.1 Description 38

A.5.2 Capital Cost 88

A.6 MAINTENANCE AND OPERATING COST SUMMARY 90

APPENDIX B - STRUCTURE OF WASTE HEAT GREENHOUSEINDUSTRY 93

APPENDIX C - HEAT EXCHANGER COSTS FOR THEMODIFIED MODERATOR CIRCUIT 98

LIST OF TABLES

TABLE 1. Production of greenhouse tomatoes andcucumbers in Canada 5

TABLE 2. Value of greenhouse vegetable productionby provinces in 1972 6

TABLE 3. Estimate of additional greenhouse areapossible for tomato production in eightCanadian provinces 8

TABLE 4. Estimate of additional greenhouse ireapossible for cucumber production ineight Canadian provinces 10

TABLE 5. Additional greenhouse area possible forCanadian production of four vegetables 11

TABLE 6. Waste heat sources from CANDU fi-2nuclear power stations 19

TABLE 7. Factors affecting the yield of a givengroup of plants 31

TABLE 8. Production characteristics of potentialgreenhouse crops 35

TABLE 9. Design parameters of the four heatingsystems 43

TABLE 10. Back-up systems of the four heatingsystems 44

TABLE 11. Design parameters and capital costcomparison of the moderator waste heatrecovery systems 49

TABLE 12. Yearly operating cost comparison:moderator waste heat delivery systems 50

TABLE 13. design parameters and capital cost ofthe cjreenliDiise heating systems 53

TABLE 14. Operating cost comparison of qreenhouseheating and ventilation systems exclusiveof the cost of delivered heat andfossil fuel 54

TABLE 15. Total annual heating and ventilation costsfor the various systems at two fuel costsbased on a yearly system heat load of94 x 10 6 kWh and a boiler efficiency of 7555 ... 55

TABLE 16. The effect of various modifications on thetotal annual cost of heating 10 ha of blockgreenhouses with warmed water from themoderator circuits of two reactors 58

TABLE A-l Design parameters and capital cost summaryof warm water greenhouse heating andventilation systems 73

TABLE A-2 Systems specifications and capital costsummary of greenhouse warm waterdistribution systems 79

TABLE A-3 Design parameters and capital costsummary of moderator heat exchange systems .... 85

TABLE A-4 Design parameters and capital cost summaryof main supply piping, pumphouse, andstandby heating systems 86

TABLE A-5 Capital cost summary of natural gas

heating and ventilation systems 89

TABLE A-6 Maintenance cost summary 91

TABLE A-7 Utility operating cost summary 92TABLE B-l Five possible organizations of an industry

utilizing waste heat for greenhousevegetable production 95

TABLE C-l Design specifications and calculated costsfor moderator heat exchanger 100

LIST OF FIGURES

FIGU?: i. Effect of retail price differential betweenimported and greenhouse tomatoes on percentconsumer selection 13

FIGURE 2. Weekly wholesale quotations for freshtomatoes in Toronto, 1967 14

FIGURE 3. Retail price index for tomatoes inCanada 1971-1974 17

FIGURE 4.

FIGURE 5.

FIGURE 6.

FIGURE 7.

FIGURE S.

FIGURE 9.

FIGURE 10.

FIGURE 11.

FIGURE 12.

FIGURE 13.

FIGURE 14.

FIGURE A-l

FIGURE k-Z

FIGURE A-3

FIGURE A-4

FIGURE A-5

FIGURE A-6

FIGURE A-7

Comparison of possible locations for thereturn air duct in a waste heat greenhouse ... 24Schematic diagram of reference sincleunit greenhouse 25Heat loss from greenhouse structures undernighttime conditions 27

Typical daily variation in heating andcooling load requirements for a double-layer plastic covered greenhouse 28

Calculated heat load curve for a double-layer plastic covered greenhouse 29

Some relationships between factors affectingyield of tomatoes 32Two indices of solar energy available forplant growth in southern Ontario andWinnipeg 36

Greenhouse production schedules currentlyin use or proposed 37Layout of greenhouse facility 40

Operating cost of moderator waste heatdelivery systems versus cost of fossilfuel 51

Comparison of total operating costs forgreenhouse heating and ventilation systemsversus cost of fossil fuel 56

Schematic diagram of an operating unitbased on individual greenhouses 68Schematic diagram of an operating unitbased on single roof greenhouse 69Layout of operating units and warm waterdistribution system, based onindividual greenhouses 76

Layout of operating units and warm waterdistribution system based on singleroof greenhouse 77

Existing moderator heat exchange systemfor G-2 CANDU reactors: design temperaturesshown "'Modified moderator heat exchanqe system andwarm water supply system for singleunit station '-?Modified moderator heat exchange and warmwater supply system for multi-unit powerstation H'i

- 1 -

1. I N T R O D U C T I O N

A t p r e s e n t , a n d in t h e f o r e s e e a b l e f u t u r e , a p p r o x i m a t e l y

2 . 4 kW o f w a s t e h e a t a r e d i s s i p a t e d to t h e e n v i r o n m e n t f o r e a c h

k i l o w a t t o f e l e c t r i c i t y g e n e r a t e d in a C A N D U * p o w e r s t a t i o n . ALio.it

9 5 p e r c e n t o f t h i s h e a t is d i s s i p a t e d t o n a t u r a l w a t e r s n e a r t h e

r e a c t o r a s a s l i g h t l y w a r m e d w a t e r s t r e a m w i t h a m a x i m u m t e m p e r a t u r e

o f 3 2 ° C .

A b o u t 5 0 0 0 M W o f was; t e h e a t a r e o r e s e n t l y b e i n n d i s ? , ' ' ^ i t n d

f r o m o p e r a t i n g n u c l e a r s t a t i o n s in C a n a d a . H o w e v e r , by t h e y e a r

2 0 0 0 ^ ' , it is e s t i m a t e d t h a t a b o u t 3 0 0 , 0 0 0 M W o f w a s t e tied*-, w i l l

h a v e t o b e d i s s i p a t e d , o r a l t e r n a t i v e l y w i l l b e p o t e n t i a l l y

a v a i l a b l e a s a h e a t s o u r c e . T h e w a s t e h e a t d i s c h a r g e d in c o o l i n n

w a t e r r e p r e s e n t s a s i g n i f i c a n t l o s s o f a v a l u a b l e r e s o u r c e - e n e r a v .

H o w e v e r , i t i s v e r y l o w - g r a d e e n e r g y a n d m u s t b e c a r e f u l l y m a t c h e d

w i t h p o t e n t i a l u s e s .

T o t a l s a l e s f r o m C a n a d i a n g r e e n h o u s e p r o d u c t i o n ', n 1 9 7 3

w a s v a l u e d a t $ 8 3 , 3 3 4 ,454.^ 2 ^ . O f t h a t a m o u n t $1 3 , 0 0 2 , 9 3 5 . w a s

f r o m p r o d u c t i o n o f v e g e t a b l e s . E v e n s o , in 1 9 7 2 , i m p o r t s a c c o M i t o d

f o r o v e r 7 5 p e r c e n t o f t h e C a n a d i a n c o n s u m p t i o n o f 6 k i n d s o f

v e g e t a b l e s t h a t c o u l d b e r a i s e d i n g r e e n h o u s e s . T h e v a l u e t f

t h e s e i m p o r t s w a s $61 , 1 4 8 , 0 0 0 ' . A p r i m a r y c o m p o n e n t , 3 0 t o

5 0 p e r c e n t , o f t h e c o s t o f v e g e t a b l e p r o d u c t i o n in C a n a d i a n

g r e e n h o u s e s i s t h e c o s t o f e n e r g y . G r e e n h o u s e a g r i c u l t u r e u s e s

e n e r g y p r i m a r i l y f o r s p a c e h e a t i n g : a f o r m o f e n e r q y u s e n o t

i n c o m p a t i b l e w i t h w a s t e h e a t u t i l i z a t i o n .

T h e p r o b l e m o f u t i l i z i n g w a s t e h e a t f r o m C A N D U r e a c t o r s

f o r p r o d u c t i o n o f g r e e n h o u s e v e g e t a b l e s is e s s e n t i a l l y o n e o f

m a t c h i n g t h e c h a r a c t e r i s t i c s o f t w o c o m p l e x a n d d e m a n d i n n s y s t e m s :

* C A N a d a D e u t e r i u m U r a n i u m

- 2 -

the e'ectrical generation system of a nuclear reactor and the plant

production system of a greenhouse. The question 1s not whether it

can be done, but whether it can be done at a cost that will allow

the greenhouse product to compete in the market, and in a manner

that will not decrease the efficiency of either generator station

or greenhouse operations. Realities dictate that if, by utiliza-

tion of waste heat, reactor operations are made more complex, unsafe

or expensive, the utility will not be interested in providing heat

to a greenhouse operation. Of equal importance, however, if green-

houses heated with waste heat do not consistently produce crops

comparable in quality and yield to those grown in conventional

systems, the grower will not be interested.

1 .1 SCOPE OF THE REPORT

This report does not review the literature of either

waste heat utilization or greenhouse vegetable production, but

does examine:

1. Potential Canadian markets for greenhouse vegetables.

2. Yields of produce to be expected from a weste heatsystem as compared to those from a conventionalsystem.

3. An economic comparison of waste heat and conventionalheating systems.

We have considered only the use of greenhouses to raise

vegetables and not the broad area of cut flowers, potted plants,

bedding plants, nursery stock or vegetables for transplanting.

However, a greenhouse capable of maintaining an optimum environ-

ment for vegetables could also be used for raising flowers or

other plants. We have also not considered soil warming with

waste heat as a means of increasing agricultural production.

Although such applications might be feasible in some locations^ '

they require a separate analysis.

- 3 -

The essence of this study is the comparison of the

heating costs and production potential of waste heat and

conventional greenhouses. It has been assumed that if produce

from the waste heat system can compete with that from the

conventional system, it will be able t? compete with imported

vegetables. However, the major economic analyses of the green-

house vegetable industry^ s ' 8 ' have been outdated by recent

economic changes and an analysis of the entire industry should

be conducted, and the economics of the industry reassessed.

Such a study would contain the data necessary to determine if

greenhouse produce could compete successfully with imported

vegetables.

The questions of possible radionuclide contamination

and public acceptance of the produce have not been examined in

detail Lut it is clear that the probability of any contamination

would be extremely low. Numerical values could be calculated

once the system was designed in detail. Public acceptance of

the produce would be partially dependent on the marketing system,

but it is not expected to be a major problem.

I.2 VEGETABLES PRODUCED IN GREENHOUSES

On a world-wide b a s i s , a large variety of vegetables

are raised in greenhouses: tomatoes, c u c u m b e r s , lettuce, gherkins,

strawberries, green peppers, c h i l i , pumpkins, eggplant, kohlrabi,

horseradish, cauliflower, green beans, squash, okra, c a b b a g e ,

Chinese c a b b a g e , melons, and green salad o n i o n s . The most

important of these are tomatoes and cucumbers but it has been

suggested that green peppers, green beans and strawberries show

promise as greenhouse vegetables and, where adequate heat is no(9)problem, eggplar J:, okra and sweet corn might have possi bi 1 i ties .

- 4 -

A study of waste neat utilization* ' projected that cucumbers

and leaf lettuce would produce maximum returns, followed by

tomatoes and radishes. Strawberries, squash, eggplant and peppers

would produce lower returns Der square meter yearv . Although

mosc vegetables can be raised in the greenhouse environment, only

a few - primarily tomatoes and cucumbers - are profitable crops

in North America.

1 .3 THE GREENHOUSE INDUSTRY IN CANADA

In 1972, 131 ha (323.7 acres) of greenhouses were used

to produce tomatoes and cucumbers valued at $13,023,765. Annual

production of tomatoes has increased at a rate of about 7 percent

per year from 1956 to 1962 and about 4.5 percent per year from

1962 to 1972 (Table 1 ) . Cucumber production was almost the same

in 1972 as in 1962, but peaked in 1967 at a much higher level,

and was at a lower level in 1970 (Table 1 ) . Lettuce is the third

most important vegetable crop but accounted for only 1 percent of

total receipts in 1966' . Other vegetables such as radishes,

parsley and Chinese greens have been raised by a few growers in

Canada*6*.

The distribution of vegetable production in Canada

(Table 2) has been determined by several factors. Fuel costs are

a major part of greenhouse operations, so production has concentra-

ted in the warmer parts of Canada (Southern Ontario, Vancouver,

Victoria, the Annapolis Valley) or where fuel is very cheap

(Medicine Hat)* '. Proximity to large markets and a concentration

of grower expertise are also factors in the location of the

industry^ '. Other factors affecting the suitability of an area

include sunlight intensity, airborne pollution, frequency of

violent weather, summer humidity and supply of water low in

chlorides^ "'.

- 5 -

TABLE 1

Production of Greenhouse Tomatoes andCucumbers in Canada^ 0' '

1956

1962

1963

1964

1965

1966

1967

1968

1969

1970

1971

1972

Tomatoes(kg x 10 6 )

2.68

6.08

7.30

8.16

8.61

9.99

9.37

10.05

11 .08

1.2.36

12.45

13.60

Cucumbers(kg x 10 6 )

4 . 5 0

9.36

12.52

12.83

14.16

14.14

15 .10

12 .68

10.77

7.55

8 .54

9.16

- 6 -

TABLE 2

(12)Value of Greenhouse Vegetable Production by Provinces in 1972

1972 Value of % ofProduction Canadian(Dollars) Total

Newfoundland andPrince Edward Island 11,445 0.1

fiova Scotia

(primarily Annapolis Valley) 609,531

Mew Brunswick 8,450

Quebec 117,903

O n t a r i o

( p r i m a r i l y Essex County) 10 ,656 ,614

Manitoba 11,942

Saskatchewan 4 ,754

Alberta(primarily near Medicine Hat) 484,310 3.7British Columbia(primarily near Vancouverand Victoria) 1 ,113,151 8.5

TOTAL 13,023,765

4

0

0

81

0

.7

.1

.9

.8

.1

- 7 -

2. THE C A N A D I A N M A R K E T

2.1 P R O B A B L E M A R K E T FOR T O M A T O E S

The C a n a d i a n g r e e n h o u s e t o m a t o is a high quality p r o d u c t

that is a v a i l a b l e o n l y on a seasonal b a s i s . Its c h i e f c o m p e t i t i o n

is from imported t o m a t o e s of lower q u a l i t y and p r i c e , and

r e l a t i v e l y c o n s t a n t a v a i l a b i l i t y . In Ontario and Nova S c o t i a ,

a p p a r e n t c o n s u m p t i o n of g r e e n h o u s e t o m a t o e s is equal to 30 p e r c e n t

or m o r e of total annual unloads (Table 3 ) . A s s u m i n g that m a r k e t s

in o t h e r p r o v i n c e s could be i n c r e a s e d to the same l e v e l , an

a d d i t i o n a l 110 ha of g r e e n h o u s e s could be used to raise tomatoes

in C a n a d a . Most of this additional g r e e n h o u s e area would be

l o c a t e d in Quebec and the four w e s t e r n p r o v i n c e s .

2.2 P R O B A B L E M A R K E T FOR C U C U M B E R S

Two types of g r e e n h o u s e c u c u m b e r s , the w h i t e spined and

the s e e d l e s s , are r a i s e d in C a n a d a . The white spined v a r i e t i e s

h a v e b e e n the m o s t c o m m o n , p a r t i c u l a r l y in O n t a r i o . They do not

have a q u a l i t y a d v a n t a g e over i m p o r t e d field c u c u m b e r s , but are

not as p e r i s h a b l e as t o m a t o e s , can be stored l o n g e r and shipped

m o r e e a s i l y . S e e d l e s s c u c u m b e r s h a v e been raised e x t e n s i v e l y in

B r i t i s h Columbia and have been i n t r o d u c e d into O n t a r i o . They have

a m o r e d e l i c a t e f l a v o u r and should command a p r e m i u m on the m a r k e t

once they have been a c c e p t e d by the c o n s u m e r . S e e d l e s s c u c u m b e r s

are m o r e p e r i s h a b l e and do not s t o r e or ship as well as the w h i t e

s p i n e d v a r i e t i e s . S t a t i s t i c s Canada does not d i f f e r e n t i a t e b e t w e e n

the two t y p e s ; t h e r e f o r e the p r o d u c t i o n of each of the two

v a r i e t i e s r.annot be d e t e r m i n e d .

TABLE 3

Estimate of Additional Greenhouse Area Possible for Tomato Productionin Eight Canadian Provinces (data from 1972)

N o v a N e w Bi i ti shS c o t i a B r u n s w i c k Q u e b e c O n t a r i o M a n i t o b a S a s k a t c h e w a n A l b e r t a C o l u m b i a

G r e e n h o u s e p r o d u c t i o n ' '

(Tei 540.7 14.C 99.3 11,869.4 11.3 4.5 160.1 382.3

Net interprovi r.cial flowof greenhouse tomatoes*"

(Te) +0 .4 +48.1 + 3 , 1 3 0 . 1 - 4 , 0 0 3 . 0 +56.7 - +41.7 - 2 7 . 7

Apparent consumption ofCanadian greenhousetomatoes (Te) 541.1 62.6 3,529.5 7,866.3 68.9 4.5 201.8 854.6

Total tomato unloads'^'(Te) 1,603.9 956.2 39,595.7 25,580.3 6,100.0 3,615.2 9.644.4 13,528.2

Apparent consumption ofijreenhou;« tomatoes asa percent of unloads 33.7 6.5 8.9 30.8 1.1 0.1 2.1 6.3

Additional greenhousetomatoes requi-ed tofill market to 30%

(Te) - 253.4 8,354.9 - 1,762.9 1,080.9 2,690.8 3,206.0

Greenhouse arearequired (ha) at15.7 kg/m2 - 1.6 53.2 - 11.2 6.9 17.1 20.4

*Te - 1000 kilogrammes

- 9 -

The p r o j e c t e d m a r k e t for g r e e n h o u s e c u c u m b e r s is mucii

s m a l l e r than t h a t for tomatoes (Table 4 ) , p r i m a r i l y because tr.5

total m a r k e t is s m a l l e r . T a b l e 4 indicates that an a d d i t i o n a l

20 ha of c u c u m b e r s could be r a i s e d which is a p p r o x i m a t e l y 19

p e r c e n t of the p r o j e c t e d a c r e a g e of t o m a t o e s .

2 . 3 P R O B A B L E M A R K E T FOR O T H E R V E G E T A B L E S

G r e e n h o u s e v e g e t a b l e s o t h e r than c u c u m b e r s and t o m a t o e s

h a v e not been r a i s e d in large e n o u g h q u a n t i t i e s to be r e p o r t e d

s e p a r a t e l y by S t a t i s t i c s C a n a d a . Table 5 s h o w s the q u a n t i t i e s

of p e p p e r s , l e t t u c e , o n i o n s , r a d i s h e s imported in 1 9 7 2 . T h e i r

y i e l d s were d e r i v e d from r e s e a r c h conducted in g r e e n h o u s e s in

K e x i c o during the w i n t e r

for C a n a d i a n c o n d i t i o n s .

K e x i c o during the w i n t e r s e a s o n ' and would have to be v e r i f i e d

P e p p e r s have been e x a m i n e d as a p o t e n t i a l g r e e n h o u s e

c r o p in O n t a r i o but it was found that they y i e l d e d a lower r e t u r n[13]

than t o m a t o e s ^ '. Lettuce y i e l d s w e l l , but w o u l d need a SDecialm a r k e t i n g e f f o r t s i n c e the g r e e n h o u s e types are l e a f , or small

h e a d e d , v a r i e t i e s , in c o n t r a s t to the large headed imported tyDes

O n i o n s and r a d i s h e s should be e a s i l y grown and m a r k e t e d , but the

r e t u r n s are not k n o w n . S i n c e l a r g e m a r k e t s a p p e a r to exist for

t h e s e v e g e t a b l e s , they w a r r a n t f u r t h e r i n v e s t i g a t i o n .

2.4 F U T U R E P R I C E S AND M A R K E T S

In this s e c t i o n , m u c h of the general d i s c u s s i o n d r a w s

s p e c i f i c data f r o m tomato m a r k e t s but it is e x p e c t e d that

s i m i l a r f o r c e s w o u l d control the prices of o t h e r p r o d u c e . The

p r i c e of g r e e n h o u s e produce is d e t e r m i n e d by the price of

c o m p e t i n g p r o d u c e d e l i v e r e d to the m a r k e t and the Drice d i f f e r -

e n t i a l the c o n s u m e r is w i l l i n g to pay for the hiaher q u a l i t y

TABLE 4

E s t i m a t e o f A d d i t i o n a l G r e e n h o u s e A r e a P o s s i b l e f o r C u c u m b e r P r o d u c t i o nin E i g h t C a n a d i a n P r o v i n c e s ( d a t a f r o m 1 9 7 2 )

Net Interprovincialflow of(cucumbers(3)

Apparent consumptionof Canadian cucumbers

Apparent consumptionof cucumbers as apercent of unloads

Additional cucumbers

Greenhouse arearequired (ha) at22.4 kg/n,Z

Scotia

352.0

41.4

Brun!wick Quebec Ontario Manitoba Saskatchewan Alberta

13-8

".1

95.3 5,106.2

-7

3,280.3

38 6 9

^ ^ + ^ ^ ^ . 1 > 8 Z 6. 6 +513.9 *245.4

^ g ^ } g g g 3 3 > 2 7 9. 5 5 ? 4.4 248.6

834.2 318.4 ,1.195.8 8,487.3 1,756.3 968.0

25 7

142.2 H9.1

5

BritishColumbia

-HI.6

689.5

2,917.1

23.3

1-9

-84.8

877.3

3,409.3

25.7

428.8 419.4

I-9

- 11 -

TABLE 5

Additional Greenhouse Area Possible for Canadian Productionof Four Vegetables (data from 1972)

Peppers L e t t u c e ^ Onions R a d i s h e s ^ 0 '

Imported*3* (Te) 14,470 116,710 8,550 4,390

Y i e l d H )(kg.nf2/year) 8.40 42.40 29.90^ ; 29.90

Area required(ha) 172 275 32 16

(a) Converted at 0.23 kg per head.

(b) Yield unknown, assumed to be the same as radishes.

(c) Converted at 0.23 kg/bunch.

grecnho.ise p r o d u c t . S o m e g r e e n h o u s e v e g e t a b l e s , such as p e p p e r s ,

o n i o n s , r a d i s h e s and w h i t e s p i n e d c u c u m b e r s , w h e r e the q u a l i t y

d i f f e r e n c e is n e g l i g i b l e and p r o d u c t d i f f e r e n t i a t i o n d i f f i c u l t ,

are sold at or n e a r the s a m e p r i c e as c o m p e t i n g p r o d u c e . O t h e r

vt}qetables s u c h as t o m a t o e s , s e e d l e s s c u c u m b e r s and l e t t u c e c a n be

d i f f e r e n t i a t e d f r o m field g r o w n c r o p s and so c o m m a n d a p r e m i u m

p r i c e due to s u p e r i o r q u a l i t y .

C o n s u m e r s can be g r o u p e d into t h r e e t y p e s : 1 ) t h o s e

t h a t are v e r y q u a l i t y c o n s c i o u s and w i l l i n g to nay a high p r e m i u m

f o r g r e e n h o u s e p r o d u c e , 2 ) t h o s e t h a t buy t h e c h e a p e s t p r o d u c e ,

and 3 ) the g r o u p of p r i m a r y i n t e r e s t to g r e e n h o u s e v e g e t a b l e

o r o d u c e r s - t h o s e t h a t p r e f e r g r e e n h o u s e p r o d u c e but a r e a l s o p r i c e

c o n s c i o u s ( F i g . 1 ) . A g r e e n h o u s e i n d u s t r y t h a t is s m a l l , r e l a t i v e

to the total m a r k e t , can c o m m a n d a h i g h e r p r i c e d i f f e r e n t i a l t h a n

o n e t n a t is l a r g e .

In M a n i t o b a , w h i c h has a small g r e e n h o u s e i n d u s t r y , the

v e g e t a b l e m a r k e t i n q board s e t s and a t t e m p t s to m a i n t a i n a c o n s t a n t( 1 4 )

p r i c e for t o m a t o e s t h r o u g h o u t the s e a s o n ^ . H o w e v e r , in T o r o n t o

w h e r e the s u p p l y is l a r g e r e l a t i v e to the m a r k e t , the p r i c e v a r i e s

t h r o u g h o u t the s e a s o n ( F i g . 2 ) . A l a r g e i n d u s t r y in M a n i t o b a w o u l d

be s u b j e c t to a p r i c e s t r u c t u r e m o r e like t h a t of T o r o n t o w h e r e the

p r i c e of g r e e n h o u s e t o m a t c e s d e c r e a s e s w i t h i n c r e a s i n g s u p p l y in

"lay t h r o u g h J u l y . The low p r i c e in O c t o b e r is d u e p a r t i a l l y to the

low p r i c e of i m p o r t s , but a l s o to the e x t r e m e l y low p r e m i u m p a i d

f o r g r e e n h o u s e t o m a t o e s . T h e r e a s o n f o r t h e low p r e m i u m is n o t

k n o w n , b u t it do>js not a p p e a r to be d u e to l o w q u a l i t y '. In

M a n i t o b a it w o u l d a p p e a r to be p o s s i b l e to m a r k e t g r e e n h o u s e t o m a t o e

t h r o u g h o u t the f i e l d t o m a t o s e a s o n . Local f i e l d t o m a t o e s are

p r o d u c e d in q u a n t i t y only d u r i n g A u g u s t a n d S e p t e m b e r a n d a c c o u n t fc

less than n a i f of the u n l o a d s ^ ' in t h o s e m o n t h s . In T o r o n t o the

- 13 -

0.60

en

0.40

ccCD

o

5

0.20

(NO PREFERENCE)

50PERCENT. PREFERENCE

100

FIGURE 1. Effect of retail price differential !)<• tweor.and greenhouse tomatoes on pet ":en1 •-•' rt';'j" -• r

1.40 -

1.20 -

0-80 -

0.60 -

0.40 -

0.20 _

N D

FIGURE I. WctHy wholesale quotations for freToronto, 1967(7).

- 15 -

f i e l d t o m a t o s e a s o n e x t e n d s f r o m J u l y t h r o u g h O c t o b e r , and in A u g u s t

a n d S e p t e m b e r n e a r l y a l l t h e u n l o a d s a r e f i e l d g r o w n . T h e s a l e s of

C a n a d i a n f i e l d g r o w n t o m a t o e s o n t h e M o n t r e a l m a r k e t a r e s i m i l a r to

t h o s e in T o r o n t o w h i l e t h e A l b e r t a , S a s k a t c h e w a n a n d B r i t i s h C o l u m b i a

m a r k e t s are s i m i l a r t o W i n n i p e g .

T w o f u t u r e t r e n d s c o u l d a f f e c t t h e r e l a t i o n s h i p b e t w e e n

m a r k e t p e n e t r a t i o n a n d p r i c e d i f f e r e n t i a l . A c o n s u m e r e d u c a t i o n

p r o g r a m m e , a d v e r t i s i n g , d i s t i n c t i v e p a c k a g i n g , e t c . w o u l d m a k e

m o r e p e o p l e a w a r e o f t h e h i g h e r q u a l i t y of a r e e n h o u s e p r o d u c e ,

m o v i n g t h e c u r v e ( F i g . 1 ) to t h e r i g h t , and i n c r e a s i n g t h e n u m b e r o f

p e o p l e w i l l i n g to p a y a g i v e n d i f f e r e n t i a l . A c o n t i n u e d i n c r e a s e in

t h e t r u e s t a n d a r d o f l i v i n g w o u l d e n a b l e m o r e p e o p l e to p a y f o r a

q u a l i t y p r o d u c t , a n d t e n d to m o v e t h e c u r v e u p w a r d . T h e r e f o r e , if t h e

s t a n d a r d o f l i v i n g c o n t i n u e s to i n c r e a s e , a n d i f g r e e n h o u s e p r o d u c e

is m a r k e t e d a g g r e s s i v e l y , t h e m a r k e t v o l u m e at a n y g i v e n p r i c e

d i f f e r e n t i a l s h o u l d e x p a n d a t a m o r e r a p i d r a t e t h a n d o e s t h e

p o p u l a t i o n o f C a n a d a .

C o m p e t i n g f i e l d g r o w n p r o d u c e c o m e s f r o m t h r e e m a j o r

s o u r c e s : C a n a d a , t h e U . S . a n d M e x i c o . D u r i n g t h e i r f i e l d s e a s o n

( p r i m a r i l y J a n u a r y t h r o u g h M a y ) M e x i c a n v e g e t a b l e s a p p e a r to s e t

t h e m a r k e t p r i c e , w h i l e t h e U . S . g r o w n v e g e t a b l e s s e t t h e m a r k e t

p r i c e b e t w e e n t h e n a n d t h e C a n a d i a n f i e l d g r o w n s e a s o n . I n d i r e c t l y ,

a l l w i n t e r v e g e t a b l e p r i c e s a r e c o n t r o l l e d by t h e c o s t of p r o d u c t i o n

in t h e s o u t h e r n U n i t e d S t a t e s , s i n c e a l a r g e c a p a c i t y f o r p r o d u c t i o n

e x i s t s w h i c h w o u l d b e u s e d if t h e p r i c e i n c r e a s e d s u f f i c i e n t l y . It

is in t h e i n t e r e s t o f t h e M e x i c a n p r o d u c e r s to m a i n t a i n t h e i r p r i c e

j u s t b e l o w t h e l e v e l a t w h i c h a d d i t i o n a l U . S . c a p a c i t y f o r p r o d u c t i o n

w o u l d b e u t i l i z e d . B e c a u s e o f t h e s e m a r k e t f o r c e s , v e g e t a b l e p r i c e s

w i l l p r o b a b l y e s c a l a t e w i t h U . S . p r o d u c t i o n c o s t s .

- 16 -

U.S. and Mexican field crop production costs are

sensitive to increases in transportation c o s t , while greenhouse

crops are more sensitive to interest rates, oil and construction

costs. Both crops are sensitive to labour costs. Recent increases

in the cost of transportation and oil may be reflected in the higher

prices paid by consumers for tomatoes in 1974 (Fiq. 3 ) . Since the

U.S. and Canada are subject to similar economic forces, it is

probable that U.S. field production costs will escalate at

approximately the same rate as Canadian field and greenhouse produc-

tion costs. The economic situation is essentially unanalyzable ,

however, since any one of the following factors could change it

rapidly:

1. Change in the U.S.-Canadian exchange rate.

2. Different rates of inflation in the U.S. and Canada whichwould increase costs of production in one relative to theother.

3. Changes in tariffs or import regulations. Increases inCanadian tariffs, or tightening of import regulationswould obviously help the local industry, but increasesin the U.S. tariffs on Mexican produce would make Canadaa relatively better market and put more pressure on localproducers .

4. A breakthrough in field vegetable production. Since muchof the labor and cost of field vegetable production isinvolved in picking, efforts are being made to developmechanical pickers and suitable vegetable varieties.Success could decrease the costs of field producevegetables .

5. A large increase in vegetable producing acreage in Mexico.Land and water are available in M e x i c o * 6 ) for producingmore vegetables which might be marketed by decreasingtheir price relative to those produced in the U.S. andCanada.

6. The development of a large greenhouse industry in the U.S.based on waste heat. Since many of the power stations tobe built in the U.S. will require cooling towers, there isinterest in developing a greenhouse agriculture system todissipate part of the heat. Since part of the greenhousecosts could be written off against the generating station,vegetable production costs could be low.

- 17 -

TC

C•H

I/)

o

en

os

a)u

O incvi

qcvi

( O ' l = L 9 6 1 ) X 3 Q N I 3 D I b d

- 1.

Iii summary, an unfilled expanding market exists in

Canada for greenhouse produce that can be sold at' premium p r i c e ,

such as tomatoes. The size of this market is dependent on the

Dremium required to yield a reasonable return. Large markets also

exist for vegetables such as lettuce and peppers that are not sold

at a premium. The profitability of these latter vegetables should

be re-examined in the light of changing economic factors.

3. CHARACTERISTICS OF THE HEAT SOURCES AND

THE GREENHOUSE HEATING SYSTEM

The search for uses of waste heat has been generally

frustrated by the relatively low temperature of the waste heat

s o u r c e , or, when a promising high temperature source has been

available, by the low total energy available from that s o u r c e .

These characteristics are to be anticipated, both now and in the

f u t u r e , since nuclear power stations are designed and operated to

maximize electrical energy production and, t h e r e f o r e , to m i n i m i z e

loss of energy.

3 .1 WASTE HEAT SOURCES IN CANDU REACTORS

The largest source of waste heat from nuclear stations

is low-grade thermal energy from the condenser cooling circuit

(Table 6 ) , and several uses for this source are currently under

evaluation^ ' or direct experimental i n v e s t i g a t i o n ^ 8 ' 1 9 ' . Of

the heat transfer systems considered which could use this s o u r c e ,

wet contact heat exchange appeared to be the only one that was

TABLE 6

Waste Heat Sources from CANDU G-2 Nuclear Power Stations(600 MW(e))

Stati onSystem

Turbi ne

Moderator

Primary

Description ofHeat Source

Saturated steam fromlow pressure turbine

Liquid heavy waterfrom calandria

Liquid heavy waterfrom purificationsystem

Des i gnTemperature of

Heat Source

29(a)

43-71

>100

Avai1ableHeat

(MW/Reactor)

1400

118

25

Des i gnTemperature of

Heat Sink

15-32(b)

15-32^5

j2(b)

(a) Design condensation temperature during winter operation.

(b) Maximum allowable discharge temperature of cooling water.

- 20 -

economically feasible. H o w e v e r , use of this system would result

in a water-saturated e n v i r o n m e n t in the g r e e n h o u s e s . B e c a u s e of

the humidity and condensation control d i f f i c u l t i e s associated

with such a s y s t e m , but primarily because of adverse plant growth

c o n d i t i o n s v , this heating system was e l i m i n a t e d from f u r t h e r

consideration. Extensive research may p e r m i t its use in the

future. C o n s e q u e n t l y , although a large amount of energy is

available in the condenser cooling w a t e r , its temperature appears

to bo too low to permit e c o n o m i c utilization in a g r e e n h o u s e

heating system under Canadian climatic c o n d i t i o n s .

It has been assumed in this study that the i n t e r m e d i a t e -

grade waste heat sources identified in CANDU stations will be

available. The heat source investigated was the m o d e r a t o r cooling

circuit. This study evaluates the cost involved in m o d i f y i n g this

circuit to supply a water stream at 55°C.

3.2 PRELIMINARY C O N S I D E R A T I O N S

The primary c h a r a c t e r i s t i c of w a s t e heat from nuclear

reactors is its low t e m p e r a t u r e . In t h e o r y , a maximum t e m p e r a t u r e

of 70°C could be obtained from the m o d e r a t o r cooling c i r c u i t .

H o w e v e r , since it would be impractical to pump heavy w a t e r from

the calandria to a greenhouse heating s y s t e m , an i n t e r m e d i a t e

heat transfer agent (assumed to be light w a t e r ) is r e q u i r e d .

Practical considerations limit the maximum temperature of this

transfer agent to about 6 0 ° C .

Several heating systems were initially c o n s i d e r e d which

could use w a t e r in the a v a i l a b l e temperature range to s a t i s f y the

requirements of a greenhouse heating system. These w e r e :

1. Dry heat exchange e m p l o y i n g forced air c i r c u l a t i o nover a finned tube heat e x c h a n g e r .

2. Dry heat exchange employing natural convectionai r heaters .

3. Contact heat exchange between greenhouse air andwarm water in an evaporative pad with forced aircirculation system.

4. Heat pumps in conjunction with dry heat exchange.

Of these systems, contact heat exchange was the leastexpensive. However, for reasons previously discussed, thissystem was not considered ûrther. A visit to an operating

(19)systenr ' which employs direct contact exchange appeared tosupport this decision.

Systems that included heat pumps had very high capitalcosts and will not be considered further at this time.

Of the two remaining dry contact systems, the forced aircirculation system appeared to have several distinct advantagesover the natural convection system. First, a forced air systemcan be designed in which the circulation fans satisfy the heatingsystem requirements, and also the requirements of a greenhousecooling system. Such a combination of fan d u t i e s , which resultsin a reduced capital expenditure for forced air systems, was notpossible in a natural convection heating system. Second, theforced air system offers horticultural advantages such as evenheat distribution, constant air movement for CO2 dispersion,good control of humidity and freedom from pipes in the growingarea. Therefore, a forced air circulation system was chosen forfurther evaluation.

3.3 GREENHOUSE STRUCTURE

Greenhouses are designed to control light intensity,carbon dioxide levels, temperature and moisture so as to assureoptimal growth of plants. Because high levels of light are

- 22

required for photosynthesis, qreenhouses are constructed of

materials (glass, plastic) which transmit 80 to 90 percent of

incident sunlight. Traditionally, greenhouses have been

constructed of single-layer glass, fiberglass, or single- or

double-layer polyethylene supported on a suitable framework.

In this study, double-layer plastic covered areenhouses

were chosen for evaluation for the followinq reasons:

1. The capital costs of constructing double-layer housesare Itss than the costs of glass or rigid fiberglassconstruction.

2. Double-layer greenhouses require only two-thirds tofive-eights of tha heating load of a single-layergreenhouse.

3. Because double-layer greenhouses are more airtightthan glass greenhouses, growth is promoted by moreefficient and economic utilization of carbon dioxideenri chment.

Disadvantages of double-layer greenhouses include the

requirement of mor.e elaborate heating and ventilation equipment

to overcome humidity and condensation, and the necessity to

replace the plastic cover every few years because of deteriora-

tion.

Greenhouses may be constructed as separated units

joined by a central corridor, or as connected units forming a

single roof over the growing area. Although the single roof

construction has a lower heat loss per unit of growing surface,

the separated unit is preferable in terms of disease control

and crop production scheduling. Consequently, both types were

evaluated. Specifically, unit greenhouses constructed of a

double-layer polyethylene skin over a supporting erch structure

were chosen. Such greenhouses have performed successfully under

winter conditions in Manitoba.

- 23 -

3.4 AIR C I R C U L A T I O N

In c o n v e n t i o n a l , f o r c e d air c i r c u l a t i o n s y s t e m s , the

d i f f e r e n c e b e t w e e n the t e m p e r a t u r e of the g r e e n h o u s e air ( 2 1 n C )

and the air f r o m the h e a t i n g u n i t is t y p i c a l l y 30 to 4 0 ° C , To

a c h i e v e the s a m e t e m p e r a t u r e i n c r e a s e in a i r f r o m a w a r m w a t e r

s y s t e m ( 5 5 ° C ) w o u l d r e q u i r e u n e c o n o m i c a l l y l a r g e h e a t t r a n s f e r

s u r f a c e s and s p e c i a l fans to o v e r c o m e the p r e s s u r e drop a s s o c i a -

ted w i t h a i r f l o w t h r o u g h the h e a t t r a n s f e r c o i l . C o n s e q u e n t l y ,

r a t h e r than h e a t a small v o l u m e of air to h i g h t e m p e r a t u r e s and

d i s t r i b u t e t h a t a i r t h r o u g h d u c t s , it is m o r e e c o n o m i c a l to h e a t

a l a r g e v o l u m e of air o v e r a s m a l l e r t e m p e r a t u r e r a n g e (5 to 7 ° C )

p r o v i d e d t h a t t h e air c i r c u l a t i o n s y s t e m c a n d i s t r i b u t e t h a t a i r

w i t h a low p r e s s u r e d r o p . To d o t h i s , a v e r y l a r g e air r e t u r n

d u c t to the h e a t i n g coil m u s t be p r o v i d e d .

T h r e e p o s s i b l e l o c a t i o n s for s u c h a d u c t a r e : 1 ) in tne

a t t i c of the g r e e n h o u s e ^ ' ° , 2 ) in the b a s e m e n t of the g r e e n h o u s e ,

a n d 3 ) t h r o u g h t h e g r o w i n g a r e a o f an a d j a c e n t g r e e n h o u s e . T h e s e

p o s s i b i l i t i e s a r e s h o w n in F i g u r e 4 t o g e t h e r w i t h a s u m m a r y of

t h e i r a d v a n t a g e s and d i s a d v a n t a g e s . The r e f e r e n c e c o n c e p t ( F i g . 5)

u s e s the a t t i c r e t u r n s y s t e m s i n c e it is l o w e s t in c o s t and c a n

be e x t r a p o l a t e d e a s i l y to l a r g e o p e n area h o u s e s . The a i r

c i r c u l a t i o n s c h e m e (Fig. 5 ) i n c l u d e s p r o v i s i o n f o r an e v a p o r a t i v e

p a d c o o l i n g s y s t e m and u s e s t h e s a m e c i r c u l a t i o n fans f o r b o t h

h e a t i n g and c o o l i n g s y s t e m s . D e t a i l s on the c o n s t r u c t i o n of the

r e f e r e n c e g r e e n h o u s e are g i v e n in A p p e n d i x A,

3.5 H E A T I N G S Y S T E M R E Q U I R E M E N T S

H e a t l o s s from a g r e e n h o u s e d e p e n d s u D o n : 1) the

c o v e r i n g m a t e r i a l , 2) the s u r f a c e area of b o t h the g r o w i n g s u r f a c e

a n d the s t r u c t u r e , 3) the o r i e n t a t i o n and l o c a t i o n , 4 ) the

t e m p e r a t u r e d i f f e r e n t i a l b e t w e e n the i n s i d e of the h o u s e and the

ATTIC

END VIEW

R I: TURNDUCT

BASEMENT

END VIEW

•I -V 1 -'. .\ *

••.ROW: v

APIA

CONSTRUCTIONCOST LOW HIGH INTERMEDIATE

AIR CIRCULATIONCOST

INTERMEDIATE HIGH LOW

DECREASEDLIGHT IN

GROWING AREA

SOME NONE NONE

EASE OFEXTRAPOLATION

TO LARGE-SCALEGREENHOUSES

EASY EASY HARDER

FIGURE 4. Comparison of possible locations for the return airduct in a wa.ite heat greenhouse.

- 25 -

TOP VIEW

FINNEDCOILS

EVAPORA' IV[

PAD

SIDE VIEW

SUMMER

EXHAUST

FANS ATTIC

MOTORI/l [)LOUVERS

FIGURE 5. Schematic diagram of ref orervj'j u i:.r It

- 26 -

;.^b!eit e n v i r o n m e n t , and 5) t h e a v e r a g e c l o u d c o v e r . H e a t i n g

svstei'is "vjst be d e s i q n e d to a c c o m m o d a t e t h e m a x i m u m h e a t l o s s

d u r i n g n i g h t - t i m e c o n d i t i o n s . For d o u b l e - l a y e r p o l y e t h y l e n e

c o v e r e d g r e e n h o u s e s , a h e a t l o s s c o e f f i c i e n t of 3.4 to 4 . 0

W / ( m L " . ' C ) is e m p l o y e d ( F i g . 6 ) .

Tne h o u r l y h e a t l o a d r e q u i r e m e n t s of a g r e e n h o u s e v a r y

s i g n i f i c a n t l y d u r i n g the d a y , and t h r o u g h o u t the y e a r . In

W e s t e r n C a n a d a d u r i n g m i d - w i n t e r , a h e a t i n g s y s t e m o p e r a t e s

c o n t i n u o u s l y . H o w e v e r , at all o t h e r t i m e s of the y e a r , o p e r a t i o n

of bot.1 h o a t i n q and c o o l i n g s y s t e m s m a y be r e q u i r e d in a g i v e n

day (Fig. 7 ) . In s u m m e r , the c o o l i n g load r e q u i r e d to m a i n t a i n2

s a t i s f a c t o r y g r e e n h o u s e t e m p e r a t u r e s can e x c e e d 631 W / m g r o w i n g

s u r f a c e , '.e. a b o u t 2.34 x 10 W for a 1 2 . 2 by 3 0 . 5 m g r e e n h o u s e

at miri-dav. By c o m p a r i s o n , m a x i m u m h e a t i n g l o a d s d u r i n g w i n t e r

m o n t h s will r a r e l y e x c e e d 1.61 :

c o v e r e d h o u s e of the s a m e s i z e .

m o n t h s will r a r e l y e x c e e d 1.61 x 10 W f o r a d o u b l e - l a y e r p l a s t i c

G r e e n h o u s e s a r e a t t r a c t i v e to h e a t s u p p l i e r s b e c a u s e of

t n e i r high h e a t c o n s u m p t i o n p e r unit land a r e a . S u c h a h i g h

d e n s i t y s y s t e m has l o w e r d i s t r i b u t i o n c o s t s p e r MM of d e l i v e r e d heat(17 1A t y p i c a l d o m e s t i c h e a t i n g s y s t e m in an u r b a n n e i g h b o r h o o d v '

has a h e a t c o n s u m p t i o n d e n s i t y b e t w e e n 0 . 3 0 and 0 . 4 0 M W / h a . In

c o m p a r i s o n , g r e e n h o u s e f a c i l i t i e s h a v e p e a k c o n s u m p t i o n d e n s i t i e s

of a b o u t 1 . 9 0 M W / h a , a v a l u e w h i c h is a p p r o a c h e d o n l y in t h e c e n t r a l

c o r e a r e a s o f m o s t c i t i e s ' .

A p e r t i n e n t f a c t o r in the e v a l u a t i o n of a g r e e n h o u s e

H e a t i n g s y s t e m is the y e a r l y h e a t i n g l o a d f a c t o r * . L i k e o t h e r

b u i l d i n g h e a t i n g s y s t e m s in C a n a d a , g r e e n h o u s e s y s t e m s h a v e a

m a x i m u m h e a t i n g load f a c t o r of a b o u t 0 . 3 0 ( F i g . 8 ) . T h e c a l c u l a -

tion of t h i s load f a c t o r , h o w e v e r , a s s u m e s c o n t i n u o u s o p e r a t i o n

y e a r l y h e a t i n g load f a c t o r = ( a c t u a l y e a r l y h e a t 1 o a d ) / ( y e a r l yh e a t l o a d e v a l u a t e d at m a x i m u m g r e e n h o u s e d e s i g n c o n d i t i o n s )

- ? • / -

0.30 -

0.25

CVJ0.20

0.15

UJa:

0.10

0.05

-60

\

O COTTER AND WALKER ( 1 1 )

• COTTER AND WALKER ( 1 1 )

O * PROWSE

\

WIND VELOCITY = 24 km/hRADIATION LOSS AS GIVENBY KONDRATYEV (21)

•40 -20 0 20OUTSIDE AIR TEMPERATURE (°C)

40

FIGURE 6. Heat loss from greenhouse structuresconditi ons.

- 28 -

too

50

0

-50

-100

-150

-POO

l

-

-

-

i

APWI1224

\

\

\

1

RILN N I P E G.2 x 30

km/h

\

1

1 1

AREA.5 m GREENHOUSEWIND

/

/

/

/

\ /

1 |

1

-

-

1

0400 0800 1200T I M E O F D A Y ( H )

1600 2000

V. Typical dally var ia t ion in heating and cooling loadrequirement f f t r a .iouble-layer p l a s t i c covered

- 29 -

o

12.2 m x 30.5 m GREENHOUSEWINNIPEG AREA24 km/h PREVAILING WINDEXCLUDES INFILTRATION LOSS

0 i i i i I 1 1

J F M A M J J A S O N D

FIGURE 8. Calculated heat load curve for a 1plastic covered greenhouse.

- 30 -

of the g r e e n h o u s e t h r o u g h o u t the y e a r . In f a c t , b e c a u s e of

re d u c e d l i g h t i n t e n s i t y and high fuel c o s t s , some c o m m e r c i a l

g r e e n h o u s e o p e r a t o r s do n o t o p e r a t e t h e i r g r e e n h o u s e s d u r i n gloo)

December, January or February v ' which further reduces the

heating load factor to between 0.22 and 0.25.

4. VEGETABLE YIELD IN GREENHOUSES

The factors affecting yield can be divided into two

categories: 1) those that affect the yield of a given group of

plants as they complete the cycle from seed to fruit, and2

2) those that pertain m o r e to yield per m /a. Examples of the

latter a r e : when the crop should be planted to take advantage

of high light levels and high prices, when the mature plants

should be removed to allow planting of young more vigorous plants,

etc. This category is called production scheduling.

4.1 COMPARISON OF GROWTH CONDITIONS IN WASTE H E A TAND CONVENTIONAL G R E E N H O U S r

Factors in category 1 (those affecting the yield of a

given group of plants) are listed in Table 7, and some of their

relationships with yield are shown in Figure 9. The increased

air flow in the reference greenhouse, in comparison with most

conventional houses, should have a beneficial influence on plant

yield. If the design of the house is such that a m a j o r portion

of the air flow is through the plant c a n o p y , and there are no

areas of extremely low velocity, the temperature variation betwee

plants will be low and the partial pressures of C 0 2 and H 2 0 at th

leaf surfaces will be similar throughout the house. When plants

- 3 1

T A B L E 7

F a c t o r s A f f e c t i n g t h e Y i e l d o f e. G i v e n G r o u n o f P l a n t s

1 a r a m e t e rP a r a m e t e rC o n t r o l

u e n e 1 1 c p o t e n t i a lof v a r i e t y

H i s t o r y of the p l a n t

Soil e n v l r o n m e n t

Aera ti on

Nutrient levelsand balances

Root space

M o i s t u r e l e v e l s

Tempera t u r e

S o i l bo rne d i s e a s e s

A e r i a l e n v i r o n m e n t

T e m p e r a t u r e

Hutni d i t y

L i g h t

C 0 o

v a r i e t y s e l e c t i o n

h o r t i c u l t u r a l u r a c t u :

s e l e c t i o n or m o d i f i c a t i o nor r o o t i n g m e d i u m

ferti1i z a t i o n

plant S D a c i n q androot m e d i u m v o l u m e

w a t e r i n g

soil h e a t i n g

s t e r i l i z e r o o t i n a ri;edi iri s o l a t e root z o n e

heat or e v a p o r a t i v e cool

venti1 a te

b u i l d i n g d e s i g n , o r i e n t a t i o nand m a t e r i a l s , r e f l e c t i v eground c o v e r , p l a n t s p a c i n a

add by b u r n i n g h y d r o c a r b o r ' ;

; i f t',_• r i ' M i •• : • • » . . , -

|- <• 1 , r I. I (_ r

0 n v v n r i w .: - ' • •

>:. n .

r. M r -•

"line

n o n "

dec re(i s<

T h e t e m p e r a t u r e , h u m i d i t y a n d C O 2 l e v e l s o f i m p o r t a n c e are t h r i v e •< t 1l e a f s u r f a c e . T h e r e f e r e n c e s y s t e m r e q u i r e s q r e a t e r a i r f l o w s f o r '<.•t r a n s f e r a n d t h u s m a y g i v e m o r e o p t i m a l t e m p e r a t u r e s , h u m i d i t y a n d • 'l e v e l s a t t h e l e a f s u r f a c e s .

- 32 -

s \

3ONV1S

i v . ? n

- 3 3 -

are a c t i v e l y t r a n s p i r i n a , C O ; ; i s t a k e n u n a n d w a t e r i c q

C o n s e q u e n t l y t h e a i r s u r r o u n d i n g t h e l e a v e s b e c o m e s s a t u r a t e d v i t ' i

w a t e r v a p o r a n d d e p l e t e d i n C O ? . H i g h h u m i d i t y e n c o u r a q e s tlu-

d e v e l o p m e n t o f f u n g a l d i s e a s e s a n d t h e l a c k o f C D ? c a n l i m i t o r o w i ;

G o o d a i r f l o w t h r o u g h t h e c a n o p y s h o u l d i n c r e a s e g r o . v t h a n d <ir:- r /• :

p r o b l e m s w i t h f u n g a l d i s e a s e s b u t t h e e f f e c t o n y i e l d , a 1 t h o u • : < :

p r e d i c t e d t o b e p o s i t i v e , c a n n o t b e e s t i m a t e d .

T h e r e f e r e n c e g r e e n h o u s e d e s i g n i n c l u d e s a n a t t i c f. > •

c i r c u l a t i o n . T h e m a j o r d i s a d v a n t a g e o f t h i s s y s t e m i s t i v s t t » ; .

a t t i c l i m i t s t h e a m o u n t o f l i g h t a v a i l a b l e t o t h e p l a n t s . T h e < j f f '

o f t h i s d e c r e a s e o n y i e l d w i l l d e p e n d o n i t s r a i n i t u d e a n d h•.*..- i,f .

i n p r a c t i c e , l i g h t i s t h e l i m i t i n g f a c t o r f o r p l a n t n r o w t . h . 7

a t t i c f l o o r c a n b e e x p e c t e d t o a b s o r b u p t o 1 0 p e r c e n t o f t h e

i n c i d e n t l i g h t a n d w i l l a l s o c a u s e l o s s b y r e f l e c t i o n . B e c a j ^ * f

t h e c o m p l e x g e o m e t r y o f t h e r e f e r e n c e g r e e n h o u s e , r e f l e c t i o n ^ c •-?

i s d i f f i c u l t t o e s t i m a t e .

D u r i n g s o m e p a r t s o f t h e y e a r ( ' i o v e m b e r t h r o u < n J a n u a r y )

l i g h t i s p r o b a b l y t h e prjc-tiai l i m i t i n g ' ' n c l o r t o u r e e n h c u s e

p r o d u c t i o n . D u r i n g S e p t e m b e r , O c t o b e r , F e b r u a r y ? n d ' \ a r c h ,

p r o d u c t i o n i s u s u a l l y l i m i t e d b y d i s e a s e , n u t r i t i j n , f t c . b u t litjh

w o u l d s t i l l b e l i m i t i n g i f t h e o t h e r f a c t o r s w e r e r e m o v e d . P u r in':

t h e r e m a i n d e r o f t h e y e a r a m p l e l i g h t i s a v a i l a b l e a n d p r o d u c t i o n ,

i n t h e d u s e n c e o f d i s e a s e a n d p o o r n u t r i t i o n , w o u l d b e l i m i t e d L y

t h e g e n e t i c p o t e n t i a l o f t h e p l a n t . I f t h i s i s t h e c o r r e c t

i n t e r p r e t a t i o n , t h e d e c r e a s e d l i g h t i n t e n s i t y w o u l d h a v e o n l y a

m a r g i n a l e f f e c t o n y i e l d s . N e v e r t h e l e s s , a l l p r a c t i c a l s t e p s t o

m a x i m i z e l i g h t , s u c h a s m i n i m i z i n g t h e s i z e o f o v e r h e a d s t r u c t u r a l

m e m b e r s , a n d i n c r e a s i n g t h e r e f l e c t i v i t y o f t h e g r e e n h o u s e f l o o r ,

m u s t b e t a k e n . S i n c e t h e f i n a l c r i t e r i o n i s y i e l d , r e s e a r c h i n d

g r e e n h o u s e i s r e q u i r e d t o d e t e r m i n e t h e e c o n o m i c p e n a l t y a s s o c i a t e

w i t h t h e a t t i c r e t u r n s y s t e m .

- 3 4 -

4 . 2 P R O D _ U r n O _ N _ S C H E D U L I N G

P r o d u c t i o n s c h e d u l e s in t h e C a n a d i a n g r e e n h o u s e i n d u s t r y

hsve o v o l v e d in r e s p o n s e t o f o u r f a c t o r s . T h e m i d w i n t e r

o c c u r r e n c e o f m a r g i n a l l i g h t l e v e l s a n d p e a k h e a t i n g l o a d s c a u s e

t h e f a l l c r o p to be t e r m i n a t e d in e a r l y D e c e m b e r a n d t h e s p r i n g

c r o p to b e p l a n t e d o u t in m i d - J a n u a r y o r l a t e r . In J u l y a n d A u g u s t ,

h i g h t e m p e r a t u r e s m a y c a u s e f r u i t m a l f o r m a t i o n s , p o o r p o l l i n a t i o n

a n d p o o r v i g o r T h e s e f a c t o r s a n d c o m p e t i t i o n f r o m f i e l d g r o w n

t o m a t o e s e n c o u r a g e t e r m i n a t i o n o f t h e s p r i n g c r o p a n d s u b s e q u e n t

p l a n t i n g o f t h e f a l l c r o p .

In t h e r e f e r e n c e g r e e n h o u s e m u c h o f t h e c o s t o f h e a t

a p p e a r s as a f i x e d c o s t ( S e c t i o n 6 ) . T h e r e w i l l , t h e r e f o r e , b e

l i t t l e m o t i v a t i o n to c l o s e d o w n t h e g r e e n h o u s e d u r i n g m i d - w i n t e r .

In s u m m e r , t h e p r o v i s i o n o f e v a p o r a t i v e c o o l i n g w i l l b e m u c h

c h e a p e r t h a n f o r a c o n v e n t i o n a l h o u s e s i n c e t h e r e f e r e n c e d e s i g n

is e q u i p p e d w i t h f a n s , l o u v e r s , e t c . t o h a n d l e l a r g e v o l u m e s o f

a i r . T h u s p r o d u c t i o n s c h e d u l e s in w a s t e h e a t g r e e n h o u s e s w i l l b e

d e t e r m i n e d by t h e a n n u a l c y c l e in l i g h t a v a i l a b i l i t y , m a r k e t f o r c e s

a n d a d e s i r e to e v e n - o u t d e m a n d s o n l a b o r a n d c r i t i c a l f a c i l i t i e s .

T h e p r o d u c t i o n c h a r a c t e r i s t i c s o f p o t e n t i a l c r o p s a r e

s h o w n in T a b l e 8 , a n d t h e a n n u a l c y c l e o f l i g h t a v a i l a b i l i t y is

g i v e n in F i g u r e 1 0 . A v a i l a b i l i t y o f l i g h t in W i n n i p e g is s l i g h t l y

h i g h e r in N o v e m b e r a n d D e c e m b e r a n d s l i g h t l y l o w e r i n J a n u a r y a n d

F e b r u a r y t h a n in s o u t h e r n O n t a r i o . It t h e r e f o r e a p p e a r s l i k e l y

t h a t p r o d u c t i o n s c h e d u l e s s i m i l a r t o s o u t h e r n O n t a r i o ( F i g . 1 1 )

c a n b e e m p l o y e d .

It a p p e a r s t h a t g r e e n h o u s e t o m a t o e s c o u l d b e m a r k e t e d

s u c c e s s f u l l y in c o m p e t i t i o n w i t h f i e l d g r o w n c r o p s in W e s t e r n ,

b u t n o t in C e n t r a l C a n a d a ( S e c t i o n 2 ) . In W e s t e r n C a n a d a ,

t h e r e f o r e , i t a p p e a r s t h a t i f it p r o v e s t o b e p o s s i b l e t o r a i s e

TABLE 8

Production Characteristics of Potential Greenhouse Crops

CropLight

Requi rementTemperatureRequi rement

GreenhouseConfi gurati on Market

Economi cReturn

Lenqthof cropcvcl e

Cucumber

Pepper

Tomato

Lettuce

Radi sh

Oni on(salad onion'(green onion

high

high

m e d - high

1 ow

1ow - med

1 ow

high

high

med

1 ow

1 o w

prob 1ow

raised beds good

total surface good

raised beds good

total surface unknown

tota1 s urface qood

total surface good

good

lower thancucumbers& tomatoes

good

unknown

unknown

unk nown

long*

long*

long*

30-90days

about30 days

about30 days

* fiese crops will continje to produce for as much as a year

• 36 -

1 r

500

B.

os

UJzX

z01t -IamUL

O

oI

500

4 0 0

3 0 0

2 0 0

100

OL

• _ WINNIPEG

0 - - SOUTHERN ONT (GUELPH)

j i I I

• • - WINNIPEG

O - SOUTHERN ONT (HARROW)

1 L I I I I I I I I _|_F M A M J J A S O N I

MONTHS

1! ' . Two i n d i " t > o . or" s o l a r e n e r g y a v a i l a b l e r o r n l a n t p.i'owtfin s r . i t h e r n O n t a r i o a n d W i n n i p e g . I n c i d e n t r a d i i t i o nw.i;; ";OiiS\ii't"! <;n ,i h o r i z o n t a l s u r f a c e ' ' .

ONTARIOCROP SYSTEM

MANITOBASYSTEM

OHIOINTERCROPSYSTEM

ON!ARIOFULL YEARSYSTEM

PROPOSEDSYSTEM y

ALTERNATIVE1 _^^-

ALTERNATIVE y

1

Ji

F

. "" SPRING CROP /(TOMATOES OR CUCUMBERS) /

^ ^ ^ ^ U T E SPRING CROP (TOMATOES) ^ ^

^ ^ LETTUCE ^ ^ /^ ^ -^ TOMATOES /

FULL YEAR CROP (TOMATOES)

SPRING CROP (TOMATOES OR CUCUMBERS) S*y

^-^^ SPRING CROP (TOMATOLS)

C;:JG CROP (TOM'T'^S, C U' L-Mf.£ Kb , F E F ^ E R S ) / ^ /

1 1 I 1 1 1

M A M J J A

FALL CROP (TOMATOES)

/FALL CROP (TOMATOES) /

/ FALL CROP (TOMATOES)

/ /

' FALL CROP (TOMATOES)

^^--^^-^TLTT^^^^^"^ RAD I

^ F A L L C R O P S ( L E T T U C E , R A D I S H E S )

I I 1 1

S 0 N D J

uctSHES

i

MONTHS

P"

- 3 8 -

•.jjdlity g r e e n h o u s e t o m a t o e s in D e c e m b e r , a p r o d u c t i o n s c h e d u l e

s u c h .is t h e o n e s h o w n in f i g u r e 11 c a n b e u s e d . If m i d - w i n t e r

p r o d u c t i o n is n o t p o s s i b l e , a s c h e d u l e s u c h a s a l t e r n a t i v e ! c o u l d

b e c o n s i d e r e d . In C e n t r a l C a n a d a , i t a p p e a r s t h a t g r e e n h o u s e

t or.?. f o e s c a n n o t be m a r k e t e d in a n y v o l u m e i, /> . g u s t o r S e p t e m b e r

a n d a s c h e d u l e s i m i l a r t o t h e c u r r e n t O n t a r i o s c h e d u l e w o u l d b e

u s e d .

In a m a r k e t s u c h a s W i n n i p e g , w h e r e t h e r e is a n u n f i l l e d

d e m a n d f o r g r e e n h o u s e t o m a t o e s , t h e t w o t o m a t o c r o p p e r y e a r

s c h e d u l e w o u l d p r o b a b l y b e m o s t p r o f i t a b l e . As t h e m a r k e t f o r

t o m a t o e s ( a n d c u c u m b e r s ) a p p r o a c h e s s a t u r a t i o n a n d p r i c e s d e c r e a s e ,

s c n e d u l e s s u c h as a l t e r n a t i v e s 1 and 2 w o u l d b e c o m e m o r e p r o f i t a b l e .

In s u m m a r y , i t a p p e a r s t h a t i n c r e a s e d a i r f l o w a n d t h e

a v a i l a b i l i t y o f i n e x p e n s i v e h e a t in t h e m i d d l e o f t h e w i n t e r a n d

e v a p o r a t i v e c o o l i n g in t h e s u m m e r s h o u l d i n c r e a s e y i e l d s . D e c r e a s e d

l i g h t in t h e g r o w i n g a r e a , d u e t o t h e l o c a t i o n o f t h e r e t u r n a i r

d u c t , w o u l d t e n d t o d e c r e a s e y i e l d s . U n d e r W e s t e r n C a n a d i a n

c l i m a t e a n d m a r k e t c o n d i t i o n s , t h e r e f e r e n c e s y s t e m s h o u l d

s i g n i f i c a n t l y o u t - y i e l d t h e c o n v e n t i o n a l h o u s e , w h i l e u n d e r s o u t h e r n

O n t a r i o c o n d i t i o n s t h e y m a y b e a b o u t e q u a l .

4 . 3 E X P E C T E D Y I E L D S O F T O M A T O E S

A v e r a g e m a r k e t a b l e y i e l d s o b t a i n e d b y 2 3 t o m a t o p r o d u c e r s

in E s s e x C o u n t y , O n t a r i o , in 1 9 6 5 a n d 1 9 6 6 w e r e 1 2 . 8 5 k q / m i n t h e2

s p r i n g a n d 4 . 4 4 k g / m f o r t h e f a l l c r o p f o r a t o t a l o f 1 7 . 2 9

k g / m . a ^ '. S p r i n g c r o p y i e l d s o f 1 8 . 7 k g / m in T h o m p s o n a n d

1 3 . 8 k q / m in W i n n i p e g h a v e b e e n r e c o ^ d e d ^ ' i n d i c a t i n g t h a t t h e

p o t e n t i a l y i e l d in M a n i t o b a is a t l e a s t e q u a l t o t h a t o f O n t a r i o .

A n o r t h e r n a r e a w i t h h i g h y i e l d s is t h e I s l e o f G u e r n s e y , w h e r e

s o m e g r o w e r s r e g u l a r l y p r o d u c e 2 0 . 2 - 2 2 . 4 k g / m 2 in a h a r v e s t p e r i o d

t h a t e x t e n d s f r o m A p r i l t o N o v e m b e r ^ '. T h e h i g h p o t e n t i a l

- 39 -

p r o d u c t i v i t y o f t h e t o m a t o i s i l l u s t r a t e d !,v a r, ••> • e r i i v n '2

N e w J e r s e y w h i c h p r o d u c e d 2 3 . 4 5 k g / m i n a t ; r e c P i O ' U ; p i ih ,

h a r v e s t p e r i o d ^ . I n t h i s s t u d y , r i n g a n d t r o u g h c..:! t:j->j •,••:•!

u s e d t o c o n t r o l s o i l b o r n e d i s e a s e s , a n d a i r m o v e m e n t t-d

v e n t i l a t i o n c o n t r o l l e d a i r b o r n e d i s e a s e s . C o l d t r e a t r . d r i t an<'

l i g h t r e f l e c t i v e g r o u n d c o v e r w e r e a l s o u s e d b u t C 0 ? e n i H ' i ; , ^

w a s n o t u s e d . G i v e n t h e g o o d d i s e a s e c o n t r o l a c h i e v e d in t n i .

• s t u d y , p l u s C 0 9 f e r t i l i z a t i o n ^ , l i g h t m o d u l a t e d iiMnp'ird t •. r •{21 \ t ? f\ \

c o n t r o l , g a m m a r a y s t i m u l a t i o n o f s e e d s • , a ^ d t'iv t 4 " -•' 2 9 ^

p r o d u c t i o n s c h e d u l i n g a l l o w e d b y g r o w i n g r o c t e c l i n i Q i ô

a n n u a l y i e l d s u p t o 3 4 k g / m m a y b e a c h i e v a b l e . A n i n t ^ j s t ' ' •2

a n n u a l a v e r a q e o f 1 8 k g / m w o u l d b e r e a l i s t i c a n H , k ]'<-><h

s h o u l d s u r p a s s 2 2 k g / m o n a l a r g e s c a l e . I t m u s t '- :• -c= * 1 i.- •''•

h o w e v e r , t h a t a s d i s e a s e i s c o n t r o l l e d m o r e s u c c e s s r u l ' y .;n;i

a d v a n c e d h o r t i c u l t u r a l t e c h n i q u e s a r e a p p l i e d , lifj'tt w i l l

o f t e n b e c o m e t h e l i m i t i n g f a c t o r w h i c h w i l l D r e v e n t th.-_ .j t : • (.

d e s i g n f r o m p r o d u c i n g t h e s a m e y i e l d a s a c o n v e n t i o n a l d G •: i'.; n .

5. DESCRIPTION OF COMMERCIAL G P E E N u. 0 L ' L5YSTEMS _E_VALu_ATE_D ~

T o d e t e r m i n e t h e f e a s i b i l i t y o f h e a t i n g q r e e r ^ i j s o s •-•

n u c l e a r w a s t e h e a t , f o u r d i f f e r e n t h e a t s u n p 1 y s y s t e m s J n d t w •'•

g r e e n h o u s e c o n f i g u r a t i o n s w e r e e v a l u a t e d . Ti;e s y s t e m .i s-. u\w.<*.' •

w e r e :

1 . t h a t t h e g r e e n h o u s e f a c i l i t y c o u l d b e l o c a t e d o n tr,•• •e d g e o f , b u t n o t w i t h i n , t h e 9 1 4 m e x c l u s i o n z o n e ^c

a C A N D U p o w e r s t a t i o n ( F i g . 1 2 ) . T h i s i s a c o n s e r v a -t i v e a s s u m p t i o n s i n c e i t m a y b e p o s s i b l e i n s o w "c i r c u m s t a n c e s t o l o c a t e i n s i d e t h e e x c l u s i o n z o n t j .

2 . t h a t a g r e e n h o u s e f a c i l i t y o f 8 - 1 0 h e c t a r e s o f a r o w i ns u r f a c e r e p r e s e n t s a r e a s o n a b l e c o m p r o m i s e b e t w e e n t hl o w h e a t d i s t r i b u t i o n c o s t s p o s s i b l e w i t h a v e r y 1 d r ' ? 's y s t e m , a n d t h e p r o b l e m s o f f u n d i n g a n d m a r k e t i n g th. 1

p r o d u c e f r o m s u c h a s y s t e m .

- 4 0 -

LAKE OR R I V E R

2 _J

>- z:1 OL

D_ =>C- I—

i/i a:

INUCLEARSTATION

I

I II S T A T I O N F A C I L I T I E S |

Q PUMPHOUSE 914 m E X C L U S I O N L I M I T

"ann

i ii iii

• • • •• • • •• • • •

GREENHOUSEF A C I L I T Y

100 m

FIGU'KL 12. Layout of greenhouse facility.

- 41 -

'; . M i fit. t h e ? a r e e n h o u s e f a c i l i t y w o u l d s.p <.;il n i v i d t ^ ' - to p e r a t i n g u n i t s o f 0 . 4 h a g r o w i n g s u r f a c e e a c h ' op e r m i t f a m i l y - s i z e d o p e r a t i o n s ( A p p e n d i x B ) . T h r

a l s o i s a c o n s e r v a t i v e a s s u m p t i o n s i n c e t h e - N - n d L ' M ,i n t h e i n d u s t r y i s t o w a r d l a r g e r o p e r a t i n g u n - ; - s .

T u s i m p l i f y c o m p a r i s o n s , a l l f o u r h e a t i n g s y s t e m s w e r e s i ? e ;

p r o v i d e 3 5 M W ( t h e d e s i g n h e a t l o a d ) . T h i s c a p a c i t y i s <-..,{<-,, ,. •

t o m a i n t a i n a l l g r e e n h o u s e s a t 2 1 J C w i t h a n o u t s i d e t e r r H ? r . i :•.••••

o f - 4 0 ° C a n d a w i n d s p e e d o f 2 5 k m / h . A l t h o u g h 3 b "V; c r v . l d

o > t a i n e d f r o m t h e m o d e r a t o r c i r c u i t o f a s i n g l e r e a c t o r , , .;.•

s y s t e m w o u l d o n l y h a v e a n a v a i l a b i l i t y o f a b o u t 9 5 p e r - , e n i ''

o n c u r r e n t e x p e r i e n c e . T h e r e f o r e a b a c k - u o n e a t s & ; ; r - v. i

i n c l u d e d i n a l l w a s t e h e a t s y s t e m s . T h e b a c k - u p s v b t e - w o ~ ,

t o p r o v i d e 2 6 M W ( t h e s u r v i v a l h e a t l o a d ) w h i c h w o u l d • • a : n t r - " v

g r e e n h o u s e t e m p e r a t u r e s a t 7 ° C a n d p r e v e n t d a m a o e t o t • c r , ; >

w i t h a n o u t s i d e t e m p e r a t u r e o f - 4 0 ° C a n d a w i n d s o e e u :•:"..

A t e n v i r o n m e n t a l t e m p e r a t u r e s a b o v e - 2 0 c C , t h e b a r k - ; p ;. , .-

w i l l m a i n t a i n 2 1 ° C i n t h e g r e e n h o u s e .

A l l o f t h e w a s t e h e a t s y s t e m s d e l i v e r n ^ t -;> •••.-•

g r e e n h o u s e s v i a w a r m e d l i g h t w a t e r , r e c i r c u ~>. •;. t e d i n ..c'• i ^ ; . '.',• • •..

s c h e d u l e 1 0 , c a r b o n s t e e l p i p e . F l o w i n t h e sy •• t<z i s i o i n t ^ i ' i e

b y f o u r 7 5 k W p u m p s l o c a t e d i n a p u m p h o u s e ( F i g . 1 2 ) , • <> >-. ••< i o

h o u s e s t h e f o s s i 1 - f u e l e d b o i l e r s i n t h e s y s t e m s u s i n g a c- i r, r-. i . - .

m o d i f i e d r e a c t o r . A m o r e c o m p l e t e d e s c r i p t i o n o f t h e - H i r t r i L ; • i .••;•

s y s t e m i s g i v e n i n A p p e n d i x A . 4 .

5.1 HEAT SUPPLY SYSTEMS

5.1.1 Waste Heat Systems

Details of the design of these systems -;r«

Appendix A.4.

- 42 -

;•• . i . I . 1 T w o '•>-o u : to_r_s

In t h i s s y s t e m , h e a t e x c h a n g e r s a r e a d d e d t o t h e

;;v a e-\i t o r c i r c u i t s of t w o r e a c t o r s ( F i q . A . 7 ) e a c h o f w h i c h can

s u p p l y 'idlf ( 1 7 . 5 M W ) t h e d e s i g n l o a d u n d e > n rmal o p e r a t i n q

•;ondi t i o n s . The t o t a l s u p p l y of h e a t is f r o m the r e a c t o r s , and

M e load f a c t o r is 0 . 3 0 7 ( T a b l e 9 ) . W h e n o n e of the r e a c t o r s is

>-:.it .icn.'n, f l o w to the r e m a i n i n g h e a t e x c h a n q e r is i n c r e a s e d and

r.••>£' o u t l e t t e m p e r a t u r e a l l o w e d to d e c r e a s e f r o m 54 to 3 5 ° C .

- d e c t n e s e c o n d i t i o n s , t h e r e m a i n i n g e x c h a n q e r is c a p a b l e of

" e o t ; n ; ' t-i e s u r v i v a l h e a t l o a d (26 M W ) a n d m a i n t a i n i n q t h e

•iroeniiojses it o r a b o u t 7 " C. C u r r e n t e x p e r i e n c e i n d i c a t e s t h a t

tic; g r e e n h o u s e s w i l l o p e r a t e f o r an a v e r a q e of 5 d a y s p e r w i n t e r

jt t h i s r e d u c e d t e m o e r a t u r e ( T a b l e 1 0 ) . T h e p r o b a b i l i t y of

c o i n c i d e n t r e a c t o r s h u t d o w n s ( T a b l e 1 0 ) , a l t h o u q h c u r r e n t l y n o t

n i g h , is e x p e c t e d to d e c r e a s e as n u c l e a r o p e r a t i n q e x p e r i e n c e

is qair.ed. It is e s t i m a t e d that, o n c e e v e r y 14 y e a r s h e a t to the

( i r e e n n o u s e s w i l l be l o s t a t s o m e t i m e d u r i n g t h e w i n t e r s e a s o n

( T a b l e 1 0 ) . T h e m a x i m u m p r o d u c t i o n l e s t f r o m s u c h an e v e n t w o u l d

l.e 2-3 m o n t h s h a r v e s t w h i l e t h e a v e r a g e l o s s s h o u l d b e m u c h l e s s

s i n c e t h e c r o D S are n o r m a l l y r e p l a n t e d d u r i n g t h e D e c e m b e r -

J a n u a r y p e r i o d .

5 . 1 . 1 . 2 O n e R e a c t o r W i t h F o s s i l - F i r e d S t a n d b y

In t h i s s y s t o m t h e m o d e r a t o r c i r c u i t s of a s i n g l e

r e a c t o r a r e m o d i f i e d to p r o v i d e a c a p a c i t y o f 23 KW w h i c h is

s u f f i c i e n t to m e e t 9 5 p e r c e n t o f t h e a n n u a l h e a t l o a d . T h e

r e m a i n i n g 5 p e r c e n t of t h e a n n u a l h e a t l o a d , a n d t h e s u r v i v a l

h e a t l o a d w h e n t h e r e a c t o r is s h u t d o w n , is m e t by a 2 6 MW f o s s i l

f i r e d s y s t e m . The n u c l e a r p a r t o f t h e s y s t e m o p e r a t e s w i t h a

load f a c t o r of 0 . 4 4 3 w h i l e t h e f o s s i l - f i r e d s t a n d b y h a s a lo a d

factor of 0.021 (Table 9).

C

- 43 -

re

:E

i-

o• A IS:

c

o

o

CD

O

\ z = -

O)

1—

T3

c

4 -

o*->ca>uwo

Q_

a;

—

~-

TJ

,—

CC

^-

o

ot3

U -

-o03O

_J

cV-

••L

13

<Di—

cc

o

' - • > '

\

E :

oo

l_

<ca;

1—

/ u a A O D t yJ O ; e j s p o , .

TAULi' 10

s y s t e m s of tlie ' o u r H o a t i n n Sv<: U-is

Two' 1 o d i f i e rtReactor, ,

Hci t ' ti'i Sy> ton1

One " o d i f i c d H e <> c t o r

5 1 . 1 n ij I • v

f o s s i l

back-up system

M i n i m u m t e n p e r a t u r e ( C )in greenhouse under designconditions on Lack-upsys tern

Days per v/inter' a' onback-up system

Most probable cause oftemperatures below C C l t ) )

Probability per winter(i4ov . - Kar . )

Other . tor

Coi nci dentReactor Shutdown;

0.07 (a)

l f i r-fd B m

Loss of11ectric itv

"i 1 ! • r e d i!oi '< e r

Loss ofElectricity

ione

L o s s o f G a 1 .o r E l e c t r i c i t y

( a ) B a s e d o n 2 4 w i n t e r r e a c t o r m o n t h s o p e r a t i o n o f P i c k e r i n q U n i t s 1 - 4 .

(t>) D e f i n e d a s f a i l u r e o f h e a t i n g s y s t e m f o r l o n n e r t h a n 3 0 m i n u t e . .

- 4 5 -

5 . 1 . 1 . - 5 O n e k e a c t o r W i t h F o s s i'i-Ki r e d P e a k i n_o

E x c e p t f o r t n e l o w e r d e s i g n e d c a p a c i t y o f tn<> •'•ni-

h e a t e x c h a n g e r s , t h i s s y s t e m i s th<? s a m e a s t h e o n e descr-i:,-

a b o v e . T h e m o d e r a t o r c i r c u i t s o f a s i n g l e r e a c t o r ,>re ' ^ l i

t o p r o v i d e a c a p a c i t y o f 1 7 . 2 M W w h i c h is s u f f i c i e n t t o ';v:'

8 5 p e r c e n t o f t h e a n n u a l h e a t l o a d . Thr- r e m a i n i n n 1 b :;er (.<.*;

t h e a n n u a l h e a t l o a d a n d t h e s u r v i v a l h e a t lo.'d w h e n *•;!<• •<"•

i s s h u t d o w n i s m e t t;v a 2 6 f /W f o s s i l - f i r e d s y s t o m . T .••,<

m o d i f i c a t i o n s i n c r e a s e t h e l o a d f a c t o r o f t h e n u c l e a r : •-> i •. •

s y s t e m t o 0 . 5 3 2 a n d t h e f o s s i l p a r t t o 0 . G 6 2 ( 7 a ' H e

5 . 1 . 2 G a s H e a t i n g S y s t e m

A s a n e x a m p l e o f c u r r e n t n r e e n h o i . s e p r a c t i c e , •>

a i r n a t u r a l g a s s y s t e m w a s a l s o e v a l u a t e d . T h i s s v s t e > r '

t o m e e t t h e s a m e t o t a l h e a t l o a d a s t h e wft>r.K: b o a t .v ';;

b a s e d o n g a s - f i r e d f u r n a c e s l o c a t e d i n e a c h h o u s e . - ;-u ^

f u r n a c e u n i t s a r e s m a l l , t h e f a i l u r e o f i n d i v i d u a l u; t

t o l e r a t e d a n d b a c k - u p c a p a b i l i t y h a s n o t b e e n p r o v i d e d .

d e s c r i p t i o n o f t h i s s y s t e m i s g i v e n i n A p p e n d i x A . 5 .

5 . 2 G R E E N H O U S E S

D e t a i l e d d e s c r i p t i o n s o f f a c i l i t i e s b a s e d o n t w o --<.

h o u s e d e s i q n s , i n d i v i d u a l h o u s e s a n d b l o c k h o u s e s , d r e .•liven

A p p e n d i x A . 2 . B o t h d e s i q n s u t i l i z e d o u b l e p l j i t i t . c u v - t , t c

m i n i m i z e h e a t l o s s . F o r c e d a i r r e c i r c u 1 a ti o n , w i t h o n ,\ 11- i c

r e t u r n s y s t e m a n d f i n n e d - t u b e h e a t e x c h a n q e r s , i s c o ^ n u . n t n t > o 1.

d e s i g n s . T o f a c i l i t a t e c o m p a r i s o n a m o n g h e a t i n n s y s t e m : . , th>-

g r e e n h o u s e f a c i l i t y b a s e d o n e a c h d e s i g n w a s s i z e d t o ; t i l w <

i

- 46

^ ' ^ v t h e i n d i v i d u a l L o u s e s n a v e h i g h e r m a t l o o s e s ':e»-

s u r f a c e j r o a , t n e f a c i l i t y h a s e d o n t h i s , 1 o s i n n h a s H 15

i'-1 M i r f a c e c o m p a r e d t o 1 0 h a f o r t h e b l o c k h o u s e d e s i q n

co

In t h i s d e s i n n , 11 . i r e e n h o u s e s e a c h 1 2 . 2 m b y 3 0 . 5 m ,

o n n e c t e d b y a c o r r i d o r t o f o r m a 0 . 4 0 h a (1 a c r e ) o p e r a t i n g

n ' t . ' h e f a c i l i t y is c o m p o s e d o f 2 0 s u c h o p e r a t i n q u n i t s w i t h a

:. t a " o r o w i n q ire.i o f R h a . T h e l a y o u t o f t h e h c a t i n q a n d a i r

. i re 11 a t i or. s y s t e m in a n i n d i v i d u a l h o u s e i s s h o w n i n F i q u r e 0 .

T n e a d v a n t a g e s o f t i n s d e s i g n a r e t n a t p r o d u c t i o n s c h e d u l i n gf ; o x i :>-; 1 1 t y i s m a x i m i z e d a n d p o s s i b i l i t i e s f o r d i s e a s e t r a n s m i s -

•5 i •• >. a r e ' n i r s i r r i z e d .

-' • •'- • ? '-' 1 c f. H 0 u s e s

In t h i s d e s i q n , e a c h o p e r a t i n q u n i t is c o m p o s e d o f 6

o u s t s 6-5.5 m i o n g c o n n e c t e d by g u t t e r s t o f o r n a c o n t i n u o u s r o o f

V' r the 0.4 ha c r o w i n g a r e a . T h i s d e s i q n h a s a l o w e r heat, l o s s

use îaare m e t e r of grov/ing a r e a and p r o v i d e s m o r e g r o w i n g a r e a

per a c r e of la.'... u c c u p i e d , t h e r e b y m i n i m i z i n g w a r m w a t e r d i s t r i b u -

t i o n c o s t s . T h e f a c i l i t y is c o m p o s e d o f 2 5 o p e r a t i n q u n i t s w i t h

•:• total g r o w i n g a r e a of 10 h a .

4 7 -

AL S

A d e t a i l e d b r e a k d o w n o f i n d i v i d u a l s y s t e m coirwi'ip

c o s t s is p r e s e n t e d in A p p e n d i x A . T h e m a j o r 3 S s . i T i ' . i n r r <•.:'

a r r i v i n g a t t h e c o s t s w e r e :

1. t h a t a u t i l i t y w o u l d c o n s t r u c t , m a i n t a i n anr) : • • r •t h e m o d e r a t o r h e a t e x c h a n g e s y s t e m a n d t h e nr i;•'o >• /w a r m w a t e r d i s t r i b u t i o n n e t w o r l ' t o , a n d •.•; i t ' " . .ic o n u a e r c i a l g r e e r . h o u s e f a c i l i t y ( A p n t ' ; d i ; •:] ,

? . t h a t t h e u t i l i t y w o u l d r e c o v e r i t s cotr> tf'itt ' -ri .m a i n t e n a n c e a n d o p e r a t i n g c o s t s t h r o j c h : r1-,:- : > f.t h e q r e e r i h o u s e o p e r a t o r s b u t viould n o t ;r-•'• > :a d d i t i o n a l c h » r a e f o r t h e h e a t , a n d

3. t h a t t h e c o s t e s t i m a t e s f o r c o n s t r u c t i o n o f J '! 4'.:o p e r a t i n g u n i t c a n b e l i n e a r l y e x t r a n o 1 > t ao ' '.•:.•c o s t o f c o n s t r u c t e d 2 0 - 2 5 s u c h u n i t s .

T o s i m p l i f y c o m p a r i s o n s , a l l f o s s i l f u p ] -trices ':-.

b e e n c a l c u l a t e d in m $ / k W h a l t h o u g h in s o m e c a s e c t h e n ; n v a

o r i c e f o r n a t u r a l g a s in $ / h s c f f\d^ b e e n o i v e n f c i i 1 u s i•-,•

p u r p o s e s .

In g e n e r a l , t h e g r e e n h o u s e i n d u s t r y r M > :Si. : ••''..:<<

q o s o r f u e l o i l d e p e n d i n g o n a v a i l a b i l i t y a n d p r i c e . ',<.'••:

o c a k i n g s y s t e m s , s u c h a s h y p o t h e s i s e d h e r e , m a y b e rcj-;.,i rvrj

u s e f u e l o i l f o r r e a s o n s o f a v a i l a b i l i t y ever- t h o u g h

c u r r e n t l y m o r e e x p e n s i v e o n a h e a t e q u i v a l e n t , b a s i s .

T o f u r t h e r s i m p l i f y c o m p a r i s o n s , a l l c o s t s w ? r e

c a l c u l a t e d in 1 9 7 4 d o l l a r s a n d n o a l l o w a n c e f o r e s c a 1 A t * >••') h<

b e e n m a d e .

1

- 43 -

6.1 COSTS OF THE HtAT RECOVERY SYSTEMS

The capital costs of the three waste heat recovery

systems are shown in Table 11. These include the cost of the

punphouse and main supply system piping U D to the boundary between

the nuclear station exclusion area and the greenhouse complex.

The two-unit station has the highest capital cost while the sinqle-

•.in it station with fossil-fired peak hoating has the lowest.

To calculate annual operating costs for the three

systems, two prices for fossil fuel were used. The lower price,

4.44 m$/kwh ($1.30 M s c f ) , represents approximately what the

growers in Essex County were paying for natural gas in March

1 9 ? 5 ( 3 ° ) . Tne higher price, 6.83 m$/kWh ($2.00 M s c f ) , may be

e x p e c U ' before 1980^ 3 1 ^ .

Delivered heat costs (Table 1 2 ) , based on an annual

heat load of 94 x 1 0 6 kWh, ranged from 3.0 to 4.1 m$/kWh. The

two-unit station had the lowest delivered heat cost followed by

tne one-unit station with standby. The one-unit station with

peaking was the most expensive. This relationship is true at

ill fossil fuel prices above about 2.0 m$/kWh (Fig. 1 3 ) .

6.2 COSTS OF THE GREENHOUSE HEATING SYSTEMS

The capital costs of the two types of greenhouses

heater* by warm water, including the cost of the distribution

system within the greenhouse complex are shown in Table 13. The

capital cost of the block house heated by natural gas is also

shown, but the cost of Individual houses heated by natural gas

was not calculated. It would be higher than costs for the block

house since the higher heat loss would require more heatino

equipment. On a square nieter basis, the capital outlay for

TABLE

Design Parameters and C a p i t a l C j s t Comparison or" theModera to r Waste Heat Recovery Systems

MODERATOR WASTE HEAT DELIVERY SYSTEMS

Design Specifications

rioderator Heat Recovery (t'W)

Standby Heating System (?'W)

O n e - U n i t S t a t i o n

Standby Heating Peakinq Heating

23

26

17.2

26

T v o i'ni t S t a t ion

35

CaDital Cost (i)

In-Reactor fioderator HeatExcnanger System

Main Supply System Pipirwiand Pumphouse

Cil M > e d Standby HeatintjSystern

f, 10,000

'.'. 4 0.000

TO'-H

4

i -

1 . E

75,

00 ,

30 ,

<•*( -

<• -' .

.100

00 0

} ,200,100

1 , 7 3 0 ,

TABLE 12

Y e a r l y O p e r a t i n g C o s t C o m p a r i s o n : M o d e r a t o r W a s t e H e a t D e l i v e r y S y s t e m s

Cap i ta l Charge Recovery

(30 year Cap i ta l Recoveryat 10" I n t e r e s t )

Heat De l i ve ry System

Maintenance

U t i l i t y Costs

E l e c t r i c i t y (15 m$/kWh)

Heavy Water Pumping*a '

L i g h t Water Pumping

Foss i l Fuels (75% B o i l e r E f f i c i e n c y )

(a) 4.44 m$/kWh

(b) 6.83 n$/kWh

Total Operating Cost ($/a)

Delivered Heat Cost(b' (m$/kWh)

One-Unit Stati_on

Standby Heati ng Pea kj_n_g_ Jl&a.t_i.f'3

Two Unit Stati or

181,000

60,300

20,000

20,250

159,000

54,550

20,000

20,250

27,840 83,470

42,820

309,390 337,270

324,370

3.29 3.59

3.45

128,400

382,200

4.06

188,500

54,400

20,000

20,250

283.150

3.01

(a) Based on incomplete data

(b> Based on yearly system heat load of 94 x 10 kWh

- 51 -

00oo

•a

500-

-50

400-

-4.0

300-

200-

100-

E

• 3 0

-2.0

-10

ASSUMPTIONS

75% BOILER EFFICIENCY

94 x 10b kW-h YEARLY HEAT LOAD

IO0 200h

1.0 2.0 30 4.0 5 0 6 0 7.0

COST OF FOSSIL FUEL

SINGLE UNITSTATION

TWO-UNITSTATION

($ /10 6 BTU)

(m$/kW-h)

FIGURE 13. Operating cost of moderator w-ir;t'systems versus cost of los.Al '.<:•

- 52 -

t!e noatirui and v e n t i l a t i o n system in the qas heated block house

is a p p r o x i m a t e l y naif that required for the warm w a t e r heated

•jluck h o u s e . Individual houses heated by warm w a t e r are tiie most

costly o p t i o n . A s i m i l a r r e l a t i o n s h i p is seen in o p e r a t i n g c o s t s ,

excluding the cost of heat (Table 1 4 ) , with the natural pas

systen costing a p p r o x i m a t e l y half as m u c h as the c o m p a r a b l e warm

water s y s t e m .

6•3 TOTAL ANNUAL C O S T S

Total annuc,1 costs for the c o m b i n a t i o n s of systems are

shown in Table 15 for two fuel c o s t s , and as a f u n c t i o n of fossil

fue 1 costs in Figure 1 4 . In the s y s t e m s involvinq o n e modified

r e a c t o r , the f o s s i 1 - f u e l e d standby s y s t e m is less e x p e n s i v e than

tne peakinci system at all fossil fuel costs above a p p r o x i m a t e l y

2 m $ / k W h . Since prices below this level are not e x p e c t e d in the

f u t u r e , and since the p e a k i n g system o f f e r s no a d v a n t a g e in terms

of r e l i a b i l i t y , it will not be c o n s i d e r e d f u r t h e r . G i v e n the

choice between the t w o - u n i t station and the single u n i t with

f o s s i l - f i r e d s t a n d b y , it is apparent that the t w o - u n i t station

is less e x p e n s i v e at all probable fossil fuel c o s t s . The

d i f f e r e n c e is only 3-5 p e r c e n t , h o w e v e r , so if only a single

nuclear unit is a v a i l a b l e , the s t a n d b y system is not ruled o u t ,

p a r t i c u l a r l y if greater reliability of such a system is

cons i dered .

The warm w a t e r system with two m o d i f i e d r e a c t o r s is not

c o m p e t i t i v e with a natural gas system at a fuel p r i c e of 4.4 m $ / k W h

($1.30 M s c f ) . It breaks even at a b o u t 4.58 m$/kWh and is

a p p r o x i m a t e l y 20 p e r c e n t less e x p e n s i v e at a fuel p r i c e of6.83 m $ / k W h ( $ 2 . 0 0 ) .

- 53 -

T A B L E 13

D e s i g n P a r a m e t e r s and Captial Cost ofthe G r e e n h o u s e H e a t i n g S y s t e m s

Warm Water System

Individual BlockHouse House

'.i6 t<i ft!

Bloc*.

?JL^ ]JLn_ . l y f i cati ons

Growing Surface

Hectares

Acres

Design Heat Load (!

8

20

35

10

25

35 31;

Capital Cost ($)

Distribution System 923,COO 820,000

Heating and VentilationSystem 2,060,000 2,500,000

TOTAL S 2,983,000

?5.0')0-

| , - , b ; > . ;•;•;

(1) See Reference 22

- 54 -

TABLE 14

Ope r a t i n g Cost C o m p a r i s o n of G r e e n h o u s e Heating and V e n t i l a t i o nS y s t e m s E x c l u s i v e of the Cost of D e l i v e r e d Heat and Fossil Fuel

i ! , ji'OW wlrj Si r f ;1C e

Warm Water System

I n d i v i d u a lHouse

BlockHouse

10

Natura l GasH £_at i ng Sys tern

BlockHouse

10

A t i Mj^ - O 1 ! t : S : 'J| )

C i f - i t j i ; . h a r q e R e c o v e r y

,'M <; t r i t .i t i in Sy1^ ten'30 yertrs at 10 interest rate)

Heating and Ve n t i l a t i o n System( 1 0 y e a r s a t 1 0 i n t e r e s t r a t e )

";i i o tend m e

• lCi tricjl Pumpinq Costs

Elei. trici ty (15 m$/kWh )

Vent i1 a t i o n

98

337

96

,000

,000

,560

88

406

HO

,000

,000

,500

4

249

77

,000

,000

.000

43

15

590

7

,500

,000

,000

.38

49

18

671

6

,i?0U

.150

,850

.72

24,600

18,150

372,750

3.73

1 J y t? a r p e r i o d

TABLE 15

Total Annual Heating and Ventilation Costs for the Various Systems at Two Fuel CostsBased on a Yearly System Heat Load of 94 x 10^ kWh and a Boiler Efficiency of 75,'

Fossil Fuei at 4.44

TwoModif iedReactors

! One Modified Reactor

|Fossil Fueled I Fossil Fueledj Standby

Two

1ndi vidua I ;House

8 ha

Operating $

Heat $

TotalAnnual S

S/m2

nct House!

1 C >•• a

O p e r a t i n g S

Heat 5Tc td 1."• r n „ a I S

590 ,060

283 ,150(; 873 ,210

I

i 10.91 I' i

H J_l 6 / : , R 5 0 !

j 2 8 3 , 1 5 0 •

• ? t 5 , 0 J 0 ;

' 9 . bb

1 Reactors

590,060

309,390

899,450

11 .24

6 7 1 , 8 5 0

3 0 9 , 3 9 0

981 , 2 4 0

9 . 8 1

F o s s i l Fuel a t 6 .83 nS/kWh

One Modified Reactor

M o d i f i e d I F o s s i l F j e l e d j F o s s i ' • Fue led

1

Standby

1 1 . 5 9

i, 7 I , 8 5 .1

3 3 7 . ^ 7 0

1.009,12

10.09

590,060

283,150

873,210

10.91

372.750 ! 671.R501 I

' 5 5 6 , 4 6 5 | 2 8 3 . 1 5 0

2 9 , 2 1 5

9 . 29

9 5 5 . 0 0 0 j

9.5 5

590,060

324,370

914,430

11 .43

671 ,850

3 2 4 , 3 7 0

9 9 6 , 2 2 3

? . 96

PeaHnq

590,060

382.200

972,260

12.15

671 ,850

3E2.200

1 ,054,050

10.54

Natur.i lGas

372,7501

855,799 |

1,228,599

12.2ft

- 56 -

inoo

2LUQuO

UJt—CO

to

120

100

8.0

6.0

4.0

2.0

0

<••

- >

V

/

-

10 2.0 30. i l l

^ / 2 i H 2 S 2 - ^ J J [ O B v SINGLE-UNIT

— • y TWO-UN I T

/ TWO-UNIT STATION

WITH POTENTIAL IMPROVEMENTS

ASSUMPTIONS

10 HA OF GREENHOUSE AREA75* FURNACE EFFICIENCY94 x 106 kW-h YEARLY HEAT LOAD

4 . 0 5 0 6.0 7 0 (m$/kW-h)

1.00

COST OF FOSSIL FUEL

2.00 ($/106 BTU)

1GUKL l.U. C . mparison of total operating costs for greenhouseheating and ventilation systems versus cost otfossil fuel.

57 -

6 .4 A R E A S O f P O T E N T I A L S A V I N G

S e v e r a l a r e a s o f p o t e n t i a l s a v i n g s in t h - v,an: w a t . •s y s t e m c a n b e i d e n t i f i e d :

1 . P l a t e - t y p e h e a t e x c h a n g e r s f o r u s e in n u c l e a r oyster•••are b e i n g i n v e s t i g a t e d b y A E C L a n d h a v e t h e p o t e n t i a lf o r r e d u c i n g t h e c o s t o f t h e i n - r e a c t o r m o d e r a t o r I;.:e x c h a n g e r s y s t e m ( T a b l e i l ) by 7 5 p e r c e n t ( k . H . Re t ^ i .p e r s o n a l c o m m u n i c a t i o n ) . T h i s r e d u c t i o n w n j d d t c r e at o t a l a n n u a l c o s t s b y a p p r o x i m a t e l y 1 3 n e r c c n t ( T j b u -

c . It may a l s o be p o s s i b l e to locate the qreenm.ujxe u ; '.<•<•e x c l u s i o n a r e a . T h e e f f e c t o n t o t a l c o s t <,i.,--f;ri v-ym o v i n g t h e g r e e n h o u s e c o m p l e x t o w i t h i n ',61; r of t-n<"-r e a c t o r s i s s h o w n in T a b l e 1 6 .

3 . It h a s b e e n e s t i m a t e d t h a t c o s t s o f t h e varn; w a t e rd i s t r i b u t i o n s y s t e m w i t h i n t h e g r e e n h o u s e c o m p l e xc o u l d b e d e c r e a s e d b y o n e - t h i r d if p l a s c i c r a t h e r t-idfs t e e l p i p e were u s e d . T h e e f f e c t o f s u c h a c o s t r p d u i :••••:-is s h o w n i n T a b l e 1 6 .

T h r e e p o i n t s s h o u l d b e n o t e d r e g a r d i n g t h e r e s u l t s

t a b u l a t e d in T a b l e 1 6 .

1 . A n y o n e o f t h e s u g g e s t e d c h a n g e s w o u l d ivjlc '.!:•:. t w o -r e a c t o r w a r m w a t e r s y s t e m c o m p e t i t i v e i n p r i o . w i t ht h e g a s h e a t e d g r e e n h o u s e s a t t o d a y ' s f u e l c u 3 i > .

2 . If a l l t h r e e o f t h e c o s t s a v i n g s c o u l d b e i m p l e m e n t e d ,t h e h e a t i n g a n d v e n t i l a t i o n c o s t s w o u l d b e 16 p e r c e n tb e l o w c u r r e n t c o s t s f o r g a s h e a t e d s y s t e m s .

3 . A s n o t e d i n T a b l e s 1 5 a n d 1 6 , a p p r o x i m a t e l y t w o - t h i r do f t h e t o t a l a n n u a l o p e r a t i n g c o s t s a r e w i t h i n t h eg r e e n h o u s e c o m p l e x . If p l a t e - t y p e h e a t e x c h a n q c r s c a n .b e u s e d , t h e i n - r e a c t o r m o d i f i c a t i o n s " a n d m a i nd i s t r i b u t i o n s y s t e m m a k e u p o n l y 24 p e r c e n t o f t h ea n n u a l c o s t s , w h i c h i n d i c a t e s t h a t t h e l a r g e s t n o t e n t i a lf o r s a v i n g s is in t h e g r e e n h o u s e c o m p l e x .

It s h o u l d b e n o t e d t h a t a d e t a i l e d e c o n o m i c o p t i m i z a t i o n

o f t h e p r o p o s e d s y s t e m t o o b t a i n m a x i m u m d e l i v e r e d e n e r g y c o s t s

h a s n o t bec*n m a d e . S u c h a n o p t i m i z a t i o n is p o s s i b l e a n d s h o u l d b e

d o n e s i n c e t h e v a r i a t i o n in s y s t e m p a r a m e t e r s c a n b e d e f i n e d w i t h

s u f f i c i e n t c o n f i d e n c e t o a l l o w s u c h a s t u d y . H o w e v e r , it s h o u l d

TABLE 16

The Effect of Various M o d i f i c a t i o n s on the Total Annual Cost of Hea t i n g 10 ha of BlockG r e e n h o u s e s with Warmed W a t e r from the M o d e r a t o r C i r c u i t ? of Two Rea c t o r s

Block House

10 ha

Operating $

Heat 3

Total

$/m2

AsDescri bed

671 ,850

283,150

955,000

9.55

Plate TypeHeat

Exchanges

671 ,850

160,930

832,780

8.33

LocateInside

Exd us i onArea

671 ,850

253,090

924,940

9.25

Bo

471,

130,

802,

9.

th

850

690

540

03

PlasticPi pe In

GreenhouseArea

642,759

283,150

925,908

9.26

Al 1

642,758

130,690

773.448

7.73

t

enCO

- 59 -

not be expected that such a study would result in a draiatir

r e d u c t i o n in d e l i v e r e d energy c o s t . P r e l i m i n a r y studies on tne

e f f e c t of p a r a m e t e r v a r i a t i o n s on system cost indicate t h a t ,

a l t h o u g h the a s s u m e d system m a y not be o p t i m a l , it appears to

be a close a p p r o x i m a t i o n to such a system.

7. G E N E R A L D I S C U S S I O N

Given our a s s u m p t i o n s , this study indicators t h i t , a

a natural gas p r i c e of about 4.6 m $ / k W h ($1.35 fiscf), m o d e r a t o r

h e a t will be c o m p e t i t i v e for g r e e n h o u s e h e a t i n g . Since n-is

p r i c e s above that level are f o r e c a s t for the n e a r f u t u r e , it

a p p e a r s that this problem w a r r a n t s further c o n s i d e r a t i o n , since

a large m a r k e t e x i s t s in Canada for g r e e n h o u s e p r o d u c e . Howeve- ,

an i n c r e a s e in the cost of fossil f u e l s , or use of waste h e a t ,

m u s t r e s u l t in an increase in r e t u r n s for p r o d u c e if the n r e e n -

h o u s e industry is to be p r o f i t a b l e . At a h e a t i n g and v e n t i l a t i o n2

c o s t of >9.55/m .a and the 1973 a v e r a g e p r o d u c t i o n cost in Fssex

C o u n t y ^ 3 2 ' ( e x c l u s i v e of heat and v e n t i l a t i o n ) of $10.92 m ^ . a ,2

and a s s u m i n g an a v e r a g e yield of 18 kg/m . a , the cost of

p r o d u c t i o n would be $ 1 . 1 4 / k g . A l l o w i n g the g r e e n h o u s e o p e r a t o r

a r e t u r n of 15 p e r c e n t on his i n v e s t m e n t would bring the price to

$ 1 . 2 4 / k g compared to the c u r r e n t W i n n i p e g price of $1.10/kg. If2

the heating costs could be d e c r e a s e d to $7.7 3/rn .a as was d i s c u s s e din S e c t i o n 6, the cost of p r o d u c t i o n would be $1.04/kq and the

p r i c e required to y i e l d a 15 p e r c e n t return w o u l d be $ 1 . 1 5 / k g .

S i n c e the size of the m a r k e t is highly d e p e n d e n t uDon p r i c e ,

e f f o r t s must be m a d e to d e c r e a s e heating cost or increase

p r o d u c t i o n per m .

- 60 -

The area, of t h e study w h e r e t h e least c o n c r e t e2

c a l c u l a t i o n s can be m a d e is y i e l d s / m . a . The p r o d u c t i o n p r a c t i c e s

that m a x i m i z e e c o n o m i c r e t u r n in f o s s i l - f u e l h e a t e d g r e e n h o u s e s

have b e e n o p t i m i z e d by a c o m b i n a t i o n of r e s e a r c h a n d e x p e r i e n c e .

G r e e n h o u s e s h e a t e d by w a s t e heat w i l l r e q u i r e n e w p r a c t i c e s , w h i c h

will a l m o s t c e r t a i n l y i n c r e a s e y i e l d s b e c a u s e they w i l l i n v o l v e

v e a r - r o u n d p r o d u c t i o n , but there a r e no d a t a to e s t i m a t e w h a t2

tr.ese y i e l d s m i o h t b e . If t o m a t o y i e l d s of 22 k g / m .a can be

r o u t i n e l y a c h i e v e d , as t h e y are in G u e r n s e y , e v e n h e a t i n g c o s t s

of 5 9 . 5 5 / m .a w o u l d a l l o w a r e t u r n of 15 p e r c e n t to the o p e r a t o r

at c u r r e n t W i n n i p e g p r i c e s for g r e e n h o u s e t o m a t o e s . S i n c e the

G u e r n s e y c r o p s e a s o n is c o n s i d e r a b l y l e s s than a y e a r , it m a y be

p o s s i b l e to equal or s u r p a s s t h e i r y i e l d s . A p r o g r a m m e of

p r o d u c t i o n r e s e e r c h o r i e n t e d t o w a r d g r e e n h o u s e s h e a t e d w i t h w a s t e

heat is r e q u i r e d to p r o v i d e data w i t h w h i c h to a s s e s s t h e

p r o f i t a b i l i t y of the i n d u s t r y at a n y g i v e n h e a t i n g c o s t .

In a d d i t i o n to a p r o g r a m m e of p r o d u c t i o n r e s e a r c h and

the o p t i m i z a t i o n s t u d y s u g g e s t e d e a r l i e r , v a r i o u s o t h e r d e v e l o p -

m e n t s t e p s s h o u l d be t a k e n . A E C L is i n t e r e s t e d in p l a t e - t y p e

heat e x c h a n g e r s as a m e a n s of d e c r e a s i n g p o w e r s t a t i o n c o s t s

( A p p e n d i x C ) and so t h e i r p o t e n t i a l w i l l br i n " ? s t i g a t e d r e g a r d -

less of the w a s t e heat i m p l i c a t i o n s . T h e t ^ e s t i o n of w h e t h e r the

g r e e n h o u s e f a c i l i t y s h o u l d be l o c a t e d w i t h i n the e x c l u s i o n a r e a ,

as a m e a n s of d e c r e a s i n g c o s t s , is d e p e n d e n t u p o n t h e s p a c e

a v a i l a b l e , as well as m a n y o t h e r c o n s i d e r a t i o n s . T h i s can best

be d e t e r m i n e d at a t i m e w h e n a c o m m e r c i a l o p e r a t i o n is being

c o n s i d e r e d for a p a r t i c u l a r s i t e . G r e e n h o u s e d e s i g n , h e a t i n g and

d i s t r i b u t i o n s y s t e m c o s t s can be i n v e s t i g a t e d o n l y by c o n s t r u c t i n g

and o p e r a t i n g a test g r e e n h o u s e . S u c h a g r e e n h o u s e s h o u l d a l s o

be o p e r a t e d to p r o v i d e p r o d u c t i o n d a t a .

- 6 1 -

T h e c o s t c a l c u l a t e d f o r u t i l i z a t i o n o f gorier,) t o r -i • •> ' •

t h i s s t u d y is m u c h h i g h e r t h a n t h o s e f o u n d in a r e c e n t s t u d y ,11.

t h e U n i v e r s i t y o f G u e l p h ^ '. M u c h o f t h e d i f f e r e n c e a r i s e "

b e c a u s e t h e G u e l p h s t u d y d i d n o t i n c l u d e t h e c o s t s o f m o d i f i e d 1

to t h e m o d e r a t o r c i r c u i t .

A l t h o u g h s o m e o f t h e q u e s t i o n s r a i s e d b y t h i s s t u d y c m

b e a n s w e r e d b y f u r t h e r a n a l y s i s , t h e c o n c e p t s a n d e s t i m a t e s • ; •

b e t e s t e d in t h e f i e l d . C o n s i d e r i n g t h a t t h e u n o p t i m i z e d L I T .

h e a t i n g s y s t e m f o r q r e e n h o u s e s i s c o m p e t i t i v e w i t h t h e est.ib ',•:,.<

t e c h n o l o g y o f t h e f o s s i l - f u e l h e a t i n g s y s t e m , it w o u l d a p p e a r *- ••• ."

w h i l e t o d o s o .

T h e u t i l i z a t i o n o f w a s t e h e a t f o r g r e e n h o u s e a q r i C J 1 *•;

d o e s n o t h o l d o u t t h e p r o m i s e o f " f r e e " h e a t . H o w e v e r , it d o t s

a p p e a r to b e a p r e m i s i n g c o n c e p t in t i m e s o f r i s i n g c o s t s for n

a n d e n e r g y .

8. LITERATURE CITED

1. Mooradian, A.J. and O.J.C. Runnalls. 1974. CANDU-EconomicAlternative to the Fast Breeders. Atomic Energy ofCanada Limited report AECL-4916.

Statistics Canada. 1975. Greenhouse Industry 1972-T973.Catalogue 22-202 Annual.

"?. Department of Agriculture. 1973. Annual Unload Report,Fresh Fruits and Vegetables on 12 Canadian Markets,1972. Information Canada, Ottawa Cat. No. A71-7/1972.

4. Statistics Canada. 1973. Imports, merchandise trade1970-1972. Catalogue 65-203 Annual.

5. Gill ham, R.W. 1974. The Feasibility of Using Waste Heatin the Ontario Agricultural Industry: Technical andEconomic Considerations, University of Guelph.

6. Tariff Board. 1969. Greenhouse vegetables. ReferenceMo. 14G, The Queen's Printer, Ottawa.

7. Blum, H. 1969. Marketing of Ontario's Greenhouse Productsin Competition with Imports from Mexico. FarmEconomics, Co-operatives and Statistics Branch, OntarioDepartment of Ajriculture and Food. Toronto, Ontario.

8. Fisher, G.A. and P. Hedlin. 1971. Greenhouse VegetableProduction in rssex County. Farm Economics,Co-operatives and Statistics Branch, Ontario Departmentof Agriculture and Food, Toronto, Ontario.

9. Dal ryir.ple, D.G. 1973. Controlled Environment Agriculture;a Global Review of Greenhouse Food Production. U.S.Department of Agriculture Report No. 89.

10. Yee, W.C. 1972. Agricultural and Aquacultural Uses ofWaste Heat. Oak Ridge National Laboratories reportO R I N L - 4 7 9 7 .

11. Wittwer, S.H. and S. Honma. 1969. Greenhouse Tomatoes.Guidelines for Successful Production. Michigan StateUniversity P r e s s , East Lansing.

I?. Statistic-, Canada. 1974. Greenhouse Industry 1971-1972.Catalogue 22-202 Annual.

13. Personal communication from Dr. Gordon Ward, AgricultureCanada, Experiment Station, Harrow, Ontario.

- 63 -

1 4 . P e r s o nal c o m m u n i c a t i o n f r o m J. P i a n t j e , M a n i t o b a Veqeta' !P r o d u c e r s M a r k e t i n g B o a r d , W i n n i p e g , M a n i t o b a .

1 5 . L a r z e l e r e , H . E . and R.R. D e d o l p h . 1 9 6 2 . C o n s u m e r sA c c e p t a n c e of G r e e n h o u s e Crown and S o u t h e r n F i e l d - G r o w nT o m a t o e s . M i c h . A g r . E x p . S t a . Q u a r t e r l y B u l l e t i n4 4 : 5 5 4 - 5 5 8 .

1 6 . S t a t i s t i c s C a n a d a . 1 9 7 4 . P r i c e s and P r i c e I n d e x e s .C a t a l o g u e 6 2 - 0 0 2 M o n t h l y .

17. G u t h r i e , J . E . D.R. P r o w s e and D.P. S c o t t . 1 9 7 6 . AnA s s e s s m e n t of N u c l e a r P o w e r Plant. W a s t e HeatU t i l i z a t i o n for F r e s h w a t e r Fish F a r m i n g . Atomic.E n e r g y of Canada L i m i t e d report A E C L - 4 9 2 4 .

1 8 . F u r l o n q , W . K . , L.V. W i l s o n , M . I . Lundin and i^.M. Yr-ro-^.1 9 7 3 . U s es of W a s t e Heat C o v e r i n g O R N L " c 11 v i r. i e sT h r o u g h D e c e m b e r 3 1 , 1 9 7 2 . :«.- the J o i n t A EC (GkNL ; -TVA P r o g r a m ; A c t i v i t i e s R e p o r t , O R N L - T M - 4 1 9r., J ^ n e .

1 9 . T r i m m e r , R.M. 1 9 7 4 . Lake W a b a m u n Thermal W a t e r Proj<3 •" t .Resume" and P r o g r e s s R e p o r t , Plant I n d u s t r y Divisio'i,A l b e r t a D e p a r t m e n t of A g r i c u l t u r e , S e p t e m b e r 9.

2 0 . L y o n , R . B . and R.O. S o c h a s k i . 1 9 7 5 . N u c l e a r Power forD i s t r i c t H e a t i n g . A t o m i c Energy of C a n a d a Liinitocr e p o r t A E C L - 5 1 1 7 .

2 1 . K o n d r a t y e v , K . Y a . 1 9 6 9 . R a d i a t i o n i n t h e 'U•<•.:••,,',,>;;>•,•'.>.A c a d e m i c P r e s s , New Y o r k .

2 2 . B e a t o n , N . J . , J.D. C a m p b e l l and J.S. T o w n s e n d . \'in.E c o n o m i c and T e c h n i c a l A s p e c t s of G r e e n h o u s e Tom,-**:P r o d u c t i o n in M a n i t o b a . D e p a r t m e n t of Plant Scienc;.-.A g r i c u l t u r a l E c o n o m i c s and A g r i c u l t u r a l trig i neer i m i ,U n i v e r s i t y of M a n i t o b a .

2 3 . E n v i r o n m e n t C a n a d a . 1 9 7 4 . M o n t h l y R e c o r d , Meteorol oq i C-J <O b s e r v a t i o n s in C a n a d a .

2 4 . C a m p b e l l , J . D . 1 9 7 4 . G r e e n h o u s e P r o d u c t i o n of Tomato'•-and C u c u m b e r s . T w e n t i e t h Annual P r o g r e s s R e p o r t ,A g r i c u l t u r a l R e s e a r c h E x p e r i m e n t a t i o n , and F> terr, ;-.•!•work c o n d u c t e d by the F a c u l t y of A g r i c u l t u r e ,U n i v e r s i t y of M a n i t o b a , p p . 1 0 9 - 1 1 0 .

2 5 . W i t t w e r , S.H. 1 9 6 0 . O b s e r v a t i o n s of the M o d e r n f<iro;.>•.»<.G r e e n h o u s e V e g e t a b l e I n d u s t r y . Annual report of '. LnV e g e t a b l e G r o w e r s A s s o c i a t i o n of A m e r i c a , IT>- ()-<:>-

2 6 . J e n s e n , M . H . 1 9 6 8 . I n c r e a s e d Y i e l d s T h r o u g h the 1:se ofP l a s t i c s for G r e e n h o u s e T o m a t o P r o d u c t i o n Pro f "t-t i' :of the E i g h t h N a t i o n a l A g r i c u l t u r a l P l a s t i c C o n f e r s -•p p . 5 1 - 5 8 .

- 64 -

iijnd, J.W. and R.W. Soffe. 1971. Light-ModulatedTemperature Control and the Response of GreenhouseTomatoes to Different CO2 Regimes. J. Hort. Sci.46:381-396.

Berezina, N.M. 1964. Presowing Irradiation of Seeds ofAgricultural Plants. Atomizdat, Moscow. Translatedby M.W. Gerrard and P.S. Baker, ORNL. Contract No.W-7405-eng-26.

:i\- M e c t r i c i t y C o u n c i l . 1 9 7 2 . G r o w i n g R o o m s , A G u i d e tot h e P r a c t i c a l D e s i g n o f I n s t a l l a t i o n s . G r o w e l e c t r i cH a n d b o o k N o . 1 , 3 0 Mi 11 b a n k , L o n d o n .

!'"v'-,nnal c o m m u n i c a t i o n f r o m R . P . S t o n e , O n t a r i o M i n i s t r ynf Agriculture and Food, Essex County.

i'-i•"."••<il communication from V.R. Puttagunti. , WhiteshellNuclear Research Establishment, Pinawa, Manitoba.

is'if, u."\. 1973. Greenhouse Vegetable Production Costsand Returns "in Ontario, 1973. Economics Branch,Ontario Ministry of Agriculture and Food, Chatham,'.) n t a r i 0 .

- 65

APPENDIX A

DESCRIPTION AND COST SUMMARY OF COMMERCIAL GRL!

T h e c o m m e r c i a l o r e e n h o u s e s y s t e m jv.ui'iod, i •. ..:

o f tiiree i n t e r c o n n e c t e d s y s t e m s : 1) t h r> i n - r e a i : t n r :<•

h e a t e x c h a n g e a n d w a r m w a t e r s u p p l y s y s t e m f o r t.i' ' ; I T I " / H

f a c i l i t y , 2 ) t h e w a r m w a t e r d i s t r i b u t i o n s y s t e m w i t h i •

q r e e n h o u s e f a c i l i t y , and 3 ) t h e n r e e n h o u s e a i r di ,t.ri: . :

h e a t i n g a n d c o o l i n q s y s t e m s . E a c h of t h e d e s i g n v i r i •.: . •',

t h e s e t h r e e s y s t e m s , t o g e t h e r w i t h a c a p i t a l , o p e r a t i . ' : ••

m a i n t e n a n c e c o s t s u m m a r y , w i l l b e d e s c r i b e d in V v folio,-

s u b s e c t i o n s . A s w e l l , a c a p i t a l c o s t e s t i m a t e of a ridtu

h e a t e d g r e e n h o u s e f a c i l i t y h a s b e e n p r e p a r e d . B e f o r e tkv;<

t h e s e s y s t e m s , s o m e of t h e p r e l i m i n a r y c o n s i d e r a t i o n s uiii'

r e s u l t e d in t h e f i n a l d e s i g n o f e a c h s y s t e m w i l l t;e nr-.jMM

A•] P R E L I M I N A R Y C O N S I D E R A T I O N S

T h e e s s e n t i a l s y s t e m a n d e c o n o m i c a s s u m p t i o n ' . w;,

d e t e r m i n e d t h e l a y o u t of t h e c o m m e r c i a l sv«;ten w o r ' 1 : •-1':<'

p r e v i o u s l y ( S e c t i o n 5 ) . G i v e n t h e s e a s s u m p t i o n s , s'.v •> i :

p a r a m e t e r s c o m m o n to all s y s t e m s r e m a i n e d to ho tix(;<':

1. T h e d e s i g n of t h e g r e e n h o u s e a i r circul.it.iM',h e a t i n g a n d c o o l i n o s y s t e m .

2 . T h e d e s i g n h e a t i n g l o a d f o r the qrcenhnu'.'•s t r u c t u r e .

3. T h e w a r m w a t e r s u p p l y a n d r e t u r n t e m p e r a

4 . T h t m a x i m u m d e s i o n p r e s s u r e and prev..; r*.1

in t h e w a t e r d i s t r i b u t i o n and r e t u r n '. y•>*'.• r.

- 66 -

T h e r e a s o n s f o r s e l e c t i n g a d r y c o n t a c t h e a t e x c h a n g e

s y s t e m a n d an a t t i c r e t u r n d u c t f o r r e - c i r c u l a t i n q a i r w e r e

d i s c u s s e d p r e v i o u s l y ( S e c t i o n s 3 . 2 a n d 3 . 3 ) . T h e e v a l u a t i o n o f

e a c h q r e e n h o u s e s t r u c t u r e , t h e p l a c e m e n t o f t h e f i n n e d c o i l ,

m o t o r i z e d l o u v e r s , e v a p o r a t i v e p a d a n d f a n s w e r e d i c t a t e d

p r i p . i r i l y b y the n e c e s s i t y to u s e c i r c u l a t i o n f a n s f o r b o t h

' l a t i n o a n d c o o l i n q . C o n s e q u e n t l y , r e - c i r c u l a t i o n f a n s w e r e

l o c a t e d a t t h e o p p o s i t e e n d o f t h e q r e e n h o u s e f r o m w h i c h o u t s i d e

a i r b o w l d b e d r a w n . T h e f i n a l a r r a n g e m e n t o f h e a t i n q c o i l ,

e v i p o r a c i v e c o o l i n g p a d a n d r e c i r c u l a t i o n f a n s is c o m p a r a b l e

to do e x p e r i m e n t a l d e s i g n b e i n g e v a l u a t e d at O a k R i d g e N u c l e a r( 1 8 )

L a - o r a t o r y

T h e d e s i g n h e a t i n q l o a d f o r e a c h q r e e n h o u s e s t r u c * re

w a s b a s e d o n an e x t r e m e e n v i r o n m e n t a l c o n d i t i o n o f - 4 0 ° C e x t e r i o r

a i r t e m p e r a t u r e a t n i g h t w i t h a p r e v a i l i n g w i n d s n e e d o f 2 4 k m / h .

Y e a r l y h e a t l o a d c a l c u l a t i o n s w e r e b a s e d o n m o n t h l y a v e r a g e a i r

t e m p e r a t u r e s a n d r a d i a n t h e a t f l u x e s a t W i n n i p e g , M a n i t o b a , a n d

i n c l u d e d a n a d d i t i o n a l 2 0 p e r c e n t h e a t l o a d t o p r o v i d e f o r a i r

i n f i l t r a t i o n , c o r r i d o r h e a t i n q a n d d i s t r i b u t i o n s y s t e m h e a t l o s s e s .

T w o d i f f e r e n t q r e e n h o u s e s t r u c t u r e s a n d g r e e n h o u s e

l a y o u t s w e r e c o n s i d e r e d . H o w e v e r , i r r e s p e c t i v e o f e i t h e r s t r u c t u r e

of l a y o u t , t h e d e s i g n h e a t l o a d s o f t h e r e s u l t i n g f a c i l i t y m a y b e

summarized as:

1. Maximum heat load of 35 MW du r i n g extreme w e a t h e rconditions to m a i n t a i n g r e e n h o u s e t e m p e r a t u r e s at2I"C.

2 . S u r v i v a l h e a t l o a d o f 26 MW d u r i n g e x t r e m e w e a t h e rc o n d i t i o n s t o m a i n t a i n q r e e n n o u s e t e m p e r a t u r e s a t7 ° C .

3 . Norma l n e a t l o a d o f 23 MW d u r i n g t h e c o l d e s t m o n t h o ft h e y e a r ( J a n u a r y ) t o m a i n t a i n g r e e n h o u s e t e m p e r a t u r e sa t 2 T C

The c a l c u l a t e d y e a r l y h e a t l o a d o f t h e g r e e n h o u s e

f a c i l i t y was 04 x 10 kW h / a .

- 6 7 -

Tiie m a x i m u m d e s i g n p r e s s u r e o f t h e h e a t i n w •„,,(•.

i m p o r t a n t d e s i q n p a r a m e t e r b e c a u s e o f m a t e r i a l a n d c o m n o n e t t

a s s o c i a t e d w i t h h i q h p r e s s u r e d e l i v e r y s y s t e m s . T o m i n i n« i :•>

c o s t s , a m a x i m u m s y s t e m p r e s s u r e o f 6 2 0 k P a ( 7 5 p s i q ) w.-i s

s p e c i f i e d . W h e n c o m b i n e d w i t h l o w w a t e r t e m p e r a t u r e s (-6!'"'< )

l o w p r e s s u r e s y s t e m p r e s e n t s t h e p o s s i b i l i t y o f u:;inu L ! K - a •.-••••

p i p i n g m a t e r i a l s , s u c h a s p l a s t i c o r a s b e s t o s c e m e n t . M o w , ' .

t h i s p o s s i b i l i t y w a s n o t e x p l o i t e d i n t h e f i n a l s y s t e m d e s i <••

w h i c h e m p l o y s c o n v e n t i o n a l s t e e l p i p e s y s t e m s .

T h e m o s t i m p o r t a n t d e s i g n p a r a m e t e r s t o b e s n - c i r

i n t h i s s t u d y w e r e t h e w a r m w a t e r s u p p l y t e m p e r a t u r e t o , <;r.-!

r e t u r n t e m p e r a t u r e f r o m , t h e g r e e n h o u s e f a c i l i t y . O n c e t.i;-.-

w e r e f i x e d , a l l i n d i v i d u a l s y s t e m s i n t h e c o m m e r c i a l f d i i ' i * ,

c o u l d b e d e s i g n e d . S e v e r a l c o m b i n a t i o n s o f s u p p l y a r m n > •

t e m p e r a t u r e s w e r e a s s e s s e d i n a p r e l i m i n a r y s c r e e n i n g . <;« >•

t h e c o m b i n a t i o n o f 5 4 ° C s u p p l y a n d 3 7 ° C r e t u r n t e m p e r s t;r<-

a p p e a r e d t o b e t h e m o s t s u i t a b l e c o m p r o m i s e b e t w e e n r.tic- >c><.:>td e m a n d s o f t h e g r e e n h o u s e h e a t i n g s y s t e m , trie i n - r c i c t o r '<•• •'

e x c h a n g e s y s t e m , a n d t h e w a r m w a t e r d i s t r i b u t i o n - / - i . • .

A . 2 T H E G R E E N H O U S E F A C I L I T Y

A . 2 . 1 I n t r o d u c t i o n

T w o d i f f e r e n t m e t h o d s o f g r e e n h o u s e c o n ' ; t n n . t i o n

l a y o u t w e r e a s s e s s e d i n t h i s s t u d y . In t h e f i r s t , i n d i v i d •. •

g r e e n h o u s e s w e r e s e p a r a t e l y c o n s t r u c t e d a n d t h e n j o i n e d *'.-•

b y a c o m m o n c o r r i d o r ( F i g . A - l ) . I n a l l , e l e v e n s r n o r .i t e I

i n t e r c o n n e c t e d g r e e n h o u s e s w e r e r e q u i r e d t o p r o v i d e (in i ' '

u n i t o f 0 . 4 h a . I n t h e s e c o n d l a y o u t , t h e a r e e n h n • > >. .tt .•

w a s m o d i f i e d t o e n c l o s e t h e o p e r a t i n g u n i t u n d e r a •>; n " i e r

T o f a c i l i t a t e a n a l y s i s , t h e r e s u l t i n g s t r u c t u r e c o n ' , i .'• i •

e n d g r e e n h o u s e s a n d 8 c e n t r a l g r e e n h o u s e s ( F i n . " ' )

- 68 -

TOP VIEW

SERVICEAREA

CENTRAL ACCESS CORRIDOR

SIDE VIEW

TO m

; K i' .ic diagram of an operating unit based oniual greenhouses.

- 69 -

TOP VIEW

1

1

1

1111

11

111

11111

11

11111

J. _

111

11t11

11

11111

_ l _

11

11111

t1

11111

._ X

1

11

11111

CORRIDOR

SIDE VIEW

10 in

FIGURE A-2. Schematic <iiagram o:single; roof

a n

- 70 -

E a c h l a y o u t has its s p e c i f i c a d v a n t a g e s . F o r the

i n d i v i d u a l n r o e n h o u s e l a y o u t , p l a n t d i s e a s e , t e m p e r a t u r e c o n t r o l

and p r o d u c t i o n s c h e d u l i n g Arc f a c i l i t a t e d . H o w e v e r , t h e s i n g l e

roof l a y o u t r e q u i r e s l e s s land and has a l o w e r h e a t l o s s per u n i t

of g r o w i n g s u r f a c e . For e x a m p l e , 10 ha of g r o w i n g s u r f a c e m a y

Le h e a t e d in the s i n g l e r o o f l a y o u t u s i n g the s a m e h e a d load as

is r e q u i r e d by 8 ha of g r o w i n g s u r f a c e o f the i n d i v i d u a l g r e e n -

house l a y o u t . F u r t h e r , s i n c e the s i n g l e r o o f l a y o u t is m o r e

c o m p a c t , the w a r m w a t e r d i stri b>i ti on s y s t e m b e t w e e n o p e r a t i n g

u n i t s is s h o r t e r than f o r the i n d i v i d u a l g r e e n h o u s e l a y o u t .

A. 2.2 D e s i g n of I n d i v i d u a l G r e e n h o u s e O p e r a t i n g U n i t

I n d i v i d u a l g r e e n h o u s e s ( F i g . 5 ) in t h i s o p e r a t i n g u n i t

are c o m p a r a b l e to a g r e e n h o u s e p r e s e n t l y o p e r a t i n g a t t h e

u n i v e r s i t y of M a n i t o b a . E a c h g r e e n h o u s e c o n s i s t s of a d o u b l e -

p l a s t i c l a y e r s u p p o r t e d on a s e r i e s (0.91 m s p a c i n g ) of 2.5 cm

g a l v a n i z e d p i p e a r c h e s . F o r s t r u c t u r a l r i g i d i t y , the a r c h e s a r e

j o i n e d by 2 x 4 r a f t e r s a n d f a s t e n e d to e n d p l a t e s on a iight

r e i n f o r c e d c o n c r e t e f o u n d a t i o n . The f o u n d a t i o n c o n s i s t s of a

I'D en g r a d e b e a m s u p p o r t e d every 2 m by 1 m r e i n f o r c e d c o n c r e t e

: i e r s . The end w a l l s of t h e g r e e n h o u s e a r e 2 x 4 s t u d c o n s t r u c t i o n

c o v e r e d w i t h f i b e r g l a s s . The f l o o r a r e a o f the g r e e n h o u s e is

b u i l t up to a b o u t 20 cm a b o v e g r a d e w i t h c o m p a c t e d e a r t h and is

c o v e r e d w i t h 10 cm of a g g r e g a t e . A w e e p i n g t i l e d r a i n a g e s y s t e m

and a r e f l e c t i v e p l a s t i c f l o o r c o v e r i n g a r e a l s o p r o v i d e d .

T h e d o u b l e l a y e r p l a s t i c c o v e r i n g c o n s i s t s o f a two mil

p o l y e t h y l e n e i n s i d e l a y e r and a m o r e d u r a b l e and e x p e n s i v e o u t e r

c o v e r i n g , s u c h as F a b r e n e or L o r o t e x . I n d i v i d u a l c o v e r i n a

s e c t i o n s a r e j o i n e d t o g e t h e r and to the s t r u c t u r e by P o l y - Z i p

s t r a p p i n g w h i c h f o r m s an a i r - t i g h t seal a n d h o l d s the c o v e r i n g

in p l a c e w h i l e p e r m i t t i n g a c o n t i n u o u s a i r p a s s a g e b e t w e e n the

c o v e r i n g s h e e t s . The a i r g a p b e t w e e n t h e i n n e r and o u t e r l a y e r s

- 7 1 -

i ;> m a i n t a i n e d b y l o w p r e s s u r e a i r f r o n a c::u i 1 b l o v . e r . :,

o f p o s s i b l e c o n d e n s a t i o n p r o b l e m s d u r i n g t h e w i n t e r , out.', i

i s u s e d t o p r e s s u r i z e t h e a i r g a p .

I n d i v i d u a l g r e e n h o u s e s a r e c o n n e c t e d ô-'otln-• •• ;-,

c o r r i d o r w h i c h i s a l s o c o n s t r u c t e d o f d o u b l e l,~>yor i>l.i'.'. i'

m e t a l t u b i n g f r a m e .

A . 2 . 2 . 1 A i r C i r c u l a t i o n , H e a t i n q a n d C o o l i n g

T h e a i r c i r c u l a t i o n a n d h e a t i n n s y s t e m r u n s ; - - . '

T w o s e p a r a t e h e a t i n g c o i l s , e<.ich h a v i n g o v c - r . i i !d i m e n s i o n s o f 2 . 8 m b y 2 . 8 in a n d e a c h r o>-s t ru< 'o f 1 7 0 m o f 1 9 m m O . D . f i n n e d t u b i n o ( 1 M i s i -e a c h 9 . 5 m m i n d i a m e t e r a n d 0 . 9 m m t h i c k ) c o n : . 't o 5 c m i n l e t a n d o u t l e t h e a d e r s

F o u r a i r c i r c u l a t i o n f a n s , e a c h \)ov:-?r^d !.-y i0 . 7 5 k W t w o - s p e e d m o t o r a n d c c m a b i o o f d e ! i v < v i7 m 3 / s ( 1 5 0 0 0 S C F M ) a t 31 P a ( 1 / 8 in o h o f ••.•.•'•»•p r e s s u r e d i f f e r e n t i a l

T h r e e m o t o r i z e d air l o u v e r s y s t t ) " 1 ; f n r <• • '.>" '•a i r m o v e m e n t t h r o u g h t h e h c i s e

A t e m p e r a t u r e a n d h u m i d i t y c o n t r o l ••. V S U . T :

A p o l y e t h y l e n e a i r d u c t l o c a t e d i n , a n d ' i c c n ' y 1

t h e a t t i c a r e a o f , t h e g r e e n h o u s e s u i j u o r t o d ,:ih o r i z o n t a l g r i d s t r u c t u r e .

T h e a i r c i r c u l a t i o n a n d h e a t i r n v s t C M i h a . t < <•

s p e c i f i c a l l y d e s i g n e d t o p e r m i t u s e o f t h e c i r c u l a t i o n f.

t h e d u a l c a p a c i t y a s o n c e - t h r o u g h v e n t i l a t i o n f a r r -iri'l •<

r e c i r c u l a t i o n f a n s f o r t h e h e a t i n g s y s t e m . I n t.n< ' K M I

a i r i s d r a w n t h r o u o h t h e g r o w i n g area a n d d i .. c f-<; r M '".' :'.

a t t i c r e t u r n d u c t . C o o l a i r f l o v / s d o w n tm.- r e * :.r-i l i u c t ,

t h r o u g h a n o p e n l o u v e r l o c a t e d a b o v e t h e f i n n •• - -; •..;'. >"

t h e f i n n e d c o i l s , r e t u r n i n g t o t h e q r o w i n g a r o d . ! h ' r •

a i r t e m p e r a t u r e f r o m t h e c o i l i s c o n t r o l l e d t w ••• <' :'>

w a t e r f l o w r a t e t o t h e c o i l t o a s s u r e t h a t i mire <i :•:'.'• l /'

- 7 2 -

p l a n t s a r e n o t s u b j e c t to e x c e s s i v e h e a t s t r e s s . All f a n s a r e

i n d i v i d u a l l y c o n t r o l l e d by t h e r m o s t a t s a n d c o n s e q u e n t l y m a y be

p r o g r a m m e d t o c i r c u l a t e a i r at u p to a m a x i m u m of 2 8 m / s . At

the m a x i m u m a i r c i r c u l a t i o n r a t e , t h e f i n n e d c o i l h a s b e e n

d e s i g n e d to t r a n s f e r 1 5 3 kW ( m a x i m u m a i r t e m p e r a t u r e i n c r e a s e

a c r o s s coil of 4 . 2 ' C ) to t h e g r e e n h o u s e a i r . D e s i g n d e t a i l s of

tho coil a r e g i v e n in T a b l e A - l .

H u m i d i t y c o n t r o l is o b t a i n e d by e n e r g i z i n g t h e i n l e t

and e x h a u s t m o t o r i z e d l o u v e r s l o c a t e d in t h e e n d w a l l s , r e s u l t i n g

in the s i m u l t a n e o u s e j e c t i o n of h u m i d a i r a n d t h e i n f l o w o f f r e s h

o u t s i d e a i r . O n c e - t h r o u g h v e n t i l a t i o n d u r i n g p e r i o d s o f e x c e s s i v e

g r e e n h o u s e a i r t e m p e r a t u r e s is a c h i e v e d by o p e n i n g t h e i n l e t a n d

e x h a u s t l o u v e r s and c l o s i n g t h e r e c i r c u l a t i o n a i r l o u v e r l o c a t e d

a b o v e tus f i n n e d c o i l . All l o u v e r o p e n i n g s m a y be m a n u a l l y

a d j u s t e d to n a t c h s e a s o n a l t e m p e r a t u r e v a r i a t i o n s , t h e r b y

a l l o w i n g a m o r e u n i f o r m m i x i n g o f f r e s h a n d r e - c i r c u l a t i n g a i r .

D u r i n g w a r m - w e a t h e r o p e r a t i o n , w h e n p e a k d a y t i m e t e m p e r a t u r e s

e x c e e d 1 5 ° C , s u p p l e m e n t a l c o o l i n g is r e q u i r e d if g r e e n h o u s e

t e m p e r a t u r e s stre to be m a i n t a i n e d at 2 1 ° C . T h i s c o o l i n g is

a c h i e v e d by d r a w i n g o u t s i d e a i r t h r o u g h a n e v a p o r a t i v e p a d l o c a t e d

a c r o s s the e n d of t h e g r e e n h o u s e . T h e c o m m e r c i a l l y a v a i l a b l e pad

(5 cm t h i c k n e s s ) is c o m p o s e d o f a s p e n f i b e r s , a n d at a d e s i g n a i r3 2

f l o w r a t e o f 1.0 m /s p e r m of f a c e a r e a c a n cool f r e s h a i r to

w i t h i n 2 . 8 ° C o f the a m b i e n t w e t b u l b t e m p e r a t u r e ( t y p i c a l l y 1 8 ° C

d u r i n g p e a k d a y t i m e p e r i o d s ) - A w a t e r f l o w o f a p p r o x i m a t e l y

0.12 k q / s p e r m e t e r o f p a d l e n g t h m u s t b e s u p p l i e d to t h e t o p of

the nad to m a i n t a i n a c o n t i n u o u s l e v e l o f m o i s t u r e in t h e a s p e n

r i b e r s . T h i s f l o w is s u p p l i e d m o s t c o n v e n i e n t l y by a r e c i r c u l a t i n g

p u m p w h i c h d r a w s w a t e r f r o m the pad c o l l e c t i o n s u m p a n d d e l i v e r s

to <i p e r f o r a t e d h e a d e r a b o v e t h e p a d .

- 73 -

TABLE A-1,

Design Parameters and Capital Cost Summary of WarmGreenhouse Heating and Ventilation Systems

Qil0lis 1 Heat Exchanger Design

Design Heat Load (kW)

Water Inlet Temperature (CC)

Water Outlet Temperature (°C)

Air Inlet Temperature (CC)

Air Outlet Temperature (°C)

Water Flow Rate (Mg/h)

Air Flow Rate (m 3/s)

Heat Transfer Coefficient(kW/m 2.K) (Based on InsideSurface Area)

Corrected LMTD (°C)

Heat Exchange Surface Area (m )

Length of Finned Tubing (m)

Capital Cost

(Includes Installation)

Heat Exchangers (IncludingFabrication)

Fans and Support Structure

Louvers

Instrumentation and Control

Capital Cost/Greenhouse

Capital Cost per GrowingArea ($/m 2)

I n d i v i d u a l_House

153

5 4 . 0

3 7 . 0

1 3 . 3

2 2 . 5

a. i

28

0 . 4

?4 .4

1 6 . 2

340

House

i J1^

• . • • ! . ' " '

3 7 . r:

I B . •-

6 . 0

' ' ! . ' • ' " •

! • ' •

. - ' '- . ' •

i o

32Q0

3000

2200

1000

94P0

25.30

?7U')

" 0 0 ; ;

If irr.i

/ • i j

-,;_ ,

- 74 -

.\. :\ 3 Des i gn of S i n g l e R o o f G r e e n h o u s e O p e r a t i n g Un_it

The s i n g l e r o o f g r e e n h o u s e u n i t c o n s i s t s o f 4 e s s e n t i a l !

i d e n t i c a l e n d - u n i t g r e e n h o u s e s a n d 8 e s s e n t i a l l y i d e n t i c a l c e n t r a l

g r e e n h o u s e u n i t s . Each of t h e s e u n i t s c o n s i s t s of a d o u b l e p l a s t i

layer s u p p o r t e d o v e r a s e r i e s (0.91 m s p a c i n q ) o f 2.5 cm

•IJI vtinized pipe a r c h e s . The e n d s of e a c h arch of the c e n t r a l u n i t

g r e e n h o u s e s are c o n n e c t e d to a t u b u l a r r i d g e p o l e , w h i c h , in turn

i> s u p p o r t e d by a s e r i e s of c o l u m n s a t t a c h e d to a l i g h t l y

r e i n f o r c e d qre.de b e a m . For l a t e r a l r i g i d i t y , the a r c h e s are

j o i n e d by 2 x 4 r a f t e r s . The s u p p o r t a r c h e s of t h e e n d - u n i t

g r e e n h o u s e s are a t t a c h e d to end p l a t e s on a l i g h t r e i n f o r c e d g r a d e

beam and to i m m e d i a t e l y a d j a c e n t r i d g e p o l e s .

The g r o w i n g s u r f a c e p r e p a r a t i o n , d o u b l e p l a s t i c c o v e r i n g

and a i r - g a p p r e s s u r i z i n g s y s t e m is i d e n t i c a l to t h a t of the s i n g l e

g r e e n h o u s e d e s i g n ( S e c t i o n A . 2 . 2 ) .

A . 2 . 3 .1 A i_r C i r c u l a t i o n , H e a t i n g and C o o l i n g S y s t e m

The air c i r c u l a t i o n and h e a t i n g s y s t e m for e a c h of the

h o u s e s in the s i n g l e r o o f g r e e n h o u s e is s i m i l a r to t h a t of the

i n d i v i d u a l g r e e n h o u s e ( S e c t i o n A . 2 . 2 . 1 ) . In the h e a t i n g m o d e , a i r

is d r a w n f r o m the g r o w i n g a r e a and d i s c h a r g e d i n t o an a t t i c

r e t u r n d u c t . This air f l o w s d o w n the r e t u r n d u c t , p a s s e s t h r o u g h

an o p e n l o u v e r l o c a t e d a b o v e the f i n n e d coil and o v e r the f i n n e d

c o i l s , r e t u r n i n g to the g r o w i n g a r e a . In the c o o l i n g m o d e , o u t -

side a i r is d r a w n t h r o u g h the g r e e n h o u s e by the c i r c u l a t i o n f a n s

and d i s c h a r g e d t h r o u g h the g r e e n h o u s e r o o f a b o v e t h e a c c e s s

c o r r i d o r .

B e c a u s e of r e d u c e d heat loss p e r u n i t g r o w i n g s u r f a c e ,

the end and central h o u s e s have l o w e r a i r c i r c u l a t i o n r a t e s and

h e a t i n g c o i l s u r f a c e a r e a s than the c o r r e s p o n d i n g s i n g l e q r e e n -

h o u s e s . K c u r c i r c u l a t i o n fans a r e e m p l o y e d in e a c h e n d h o u s e ,

- 7 5 -

b u t o n l y t h r e e f a n s i n e a c h o f t h e c e n t r a l h c . - . p • - i i ••

a r e a s a n d d e s i g n h e a t l o a d s f o r e n d a n d c e n t r a l h a u i n <u"o

i n T a b l e A -1 .

A . 2 . 4 C o m m e r c i a l Ci r e e n h o u s_e__F a c j 1 i_t_i e s

T o f a c i l i t a t e a n e c o n o m i c c o m p a r i s o n b e t w e e n " M > < _ ,

l a y o u t s , i t w a s a s s u m e d t h a t t h e m a x i m u m h e a t l o a d o f t .

r e s u l t i n g f a c i l i t i e s w a s t o b e h e l d c o n s t a n t r a t h e r t i c : l-.-.

f a c i l i t y g r o w i n g a r e a . T h e h e a t l o s s o f t h e s i n n l e r o o f <•••

u n i t is a p p r o x i m a t e l y 8 0 . " t h a t o f t h e i n d i v i d u a l h o u s e ;.»it

T h e r e f o r e , t h e f a c i l i t i e s c o n s i s t o f 1 ) 2 5 o p e r a t i n g ,.;.,r.

s i n g l e r o o f g r e e n h o u s e , a n d 2 ) 2 0 o p e r a t i n g u n i t s o f i t - i v i

g r e e n h o u s e s .

S c h e m a t i c d i a g r a m s o f t h e l a y o u t o f t h e r e s pi-,, r. i v

g r e e n h o u s e f a c i l i t i e s e r e s h o w n i n F i g u r e s A-.? a n d •'-<•.

A . 2 . 5 C a p i t a l C o s t E s t i m a t e

T h e i n s t a l l e d c o s t o f t h e c o m p o n e n t s o f t h e r e s :.•(.•<.!

g r e e n h o u s e h e a t i n g s y s t e m s i s s u m m a r i z e d i n T a b l e A - l . < , r

b e n o t e d , e v e n t h o u g h t h e h e a t l o s s p e r u n i t g r o w i n n s :J r f :<<•

l o w e r f o r t h e s i n g l e r o o f u n i t t h a n t h e i n d i v i d u a l d o s i " n , t.w2

c a p i t a l c o s t s p e r m o f g r o w i n g s u r f a c e are s i n i l a r .

T h e c a p i t a l c o s t o f t h e h e a t i n g a n d v e n t i 1 a 11 (•" *. v

f o r t h e 2 2 0 g r e e n h o u s e s i n t h e 8 h a f a c i l i t y coi:.vor. <".{- :*' s'i'ii

g r e e n h o u s e s i s a b o u t $ 2 , 0 0 0 , 0 0 0 . F o r t h e 1 0 h,* f o c i l i * / ••!•:

o f s i n g l e r o o f u n i t s , t h e e s t i m a t e d c o s t i s i?. , •. T') , fy)l] •

- 76 -

1

LIMI

TIO

NEX

CLUS

>

100 m

LEGEND

60 cm pipe

25 cm pipe

20 cm pipe

GREENHOUSE CONNECTIONSNOT SHOWN

F'lGURE A-.?. Layout of operating units and warm water distributionsystem, based on individual greenhouses.

- 77 -

MIT

t\

EXCL

USIO

I

111iIi11i

i

i

i

l

•

1

TOO m LEGEND

60 cm pipe

50 cm pipe

20 cm p ipe

5 cm p ipe

GREENHOUSE CONNECTIONS NOT SHOWN

Layout of operaling uniLb diid asystem based on single roof greenhouse.

- 78 -

DISTRIBUTION SYSTEM WITHIN THE GREENHOUSE FACILITY

A.3.1 System Description

The warm water distribution and return system withinthe two greenhouse facilities are schematically shown inFigures A-3 and A-4. As may be noted, the systems were constructedfrom various pipe sizes, and were sized to assure that t h e t o t a lsystem pressure drop did not exceed 200 kP*. A listing of thepipe diameters and lengths of supply-return line required isgiven in Table A-2.

All pipe employed was assumed to be carbon steel. Wherepossible, the most inexpensive pipe which would match the maximumpressure requirements (620 kPa) of the system was specified. Forexample, Schedule 10 pipe was specified for the 60 cm main rupply1i nes.

A.3.2 Capital Cost

A summary of the estimated capital cost of the distribu-tion systems for the two greenhouse facilities is given inTable A-2. Installed pipe costs include excavation costs (2 meterdepth), yard handling, welding and installation, pipe costs (at$1.40/kg of steel), sand cover and backfilling, but do not includeprovision for expansion loops or insulation. The most appropriateinsulation, if in fact insulation is necessary, has yet to bedetermined.

for the 60 cm line, the cost of pipe accounts forapproximately 70 percent of installed cost, indicating that,substantial savings could be made if a cheaper pipe material withcorresponding cheaper installation costs could be specified.

- 79 -

TABLE A - 2

Sys tems S p e c i f i c a t i o n s a n d C a p i t a l C o s t Summary fitG r e e n h o u s e Warm W a t e r D i s t r i b u t i o n S y s t e m ' /

Ind i v i dua 1_ 1°_4.1eJ

System Specifications

Maximum Flow at Design Conditions (kq/h) 1.8 x 10

Maximum System Pressure Droo (kPa) ~ 7 0

Maximum Design Pressure (kPa) 620

Capital Cost

P i p i n g

PipeDi a m e t e r

(cm)

60542520155

S u m m a r y

I n s t a ] l e dC o s t ( a )

( $ / « )

39536024518716482

(m)

460

9751460

550

Sub-total

Valves, Manholes, e tc.(at 252 of Installed Piping Cost)

TOTAL

Cosill180,

240,273,

45,

738,

185,

923,

t

000

000000

"00

ooo

, o o o

,000

(tint

• : . ; o' f. I ;.

(a) Per m e t e r of i n s t a l l e d return and supply line.

(b) Meters of i n s t a l l e d supply-«-eturn line.

- 80 -

A.4 MODERATOR HEAT EXCHANGE AND WARM WATER SUPPLY SYSTEMS

The warm water supply and moderator heat exchange systemswere designed to supply up to 1.8 x 10 kg/h of warm water at54°C to the respective greenhouse facilities. To supply this warmwater, two heat supply systems were assessed: 1) the moderatorneat exchange system of a single reactor was modified, and 2) themoderator heat exchange systems of two separate reactors weremodified. ,

A.4.1 System Design

The moderator heat exchange system of a G-2 CANDUreactor is designed to cool 0.94 m /s of heavy water from an inlettemperature of 71°C to a return temperature of 43°C. To achievethis cooling, two heat exchangers, each transferring 60 MW of heat,are connected in parallel flow circuits (Fig. A-5).

Modification of a moderator heat exchange system depends,in part, on the requirement for standby heating capability for thegreenhouse facility during a reactor shutdown. For a facilitylocated at a single reactor power station, standby capability wasassumed to be provided by an oil-fired hot water system (Fig. A-6).At a multi-unit station, it was assumed that standby capabilitycould be provided from a modified moderator circuit in anadjacent reactor (Fig. A-7). As discussed below, standby heatingcapability influenced the design of the modified heat exchangesystems.

The oil-fired standby system associated with a singlereactor installation was assumed to provide the standby designheat load of 26 MW and to be available as a supplementary heatsource during those periods when greenhouse load demand exceededthe normal requirement for 23 MW. Consequently, the moderator

- 81 -

CALANDRIA

71 °C

36°C

2 0 °C COOLING WATER

43°C

FIGURE A-5. Existing moderator heat exchange .••/. \ • ••:,. 'CANDU reactors: desi gn temper at •;; ;.•:_, \i. ,v;:..

- 82 -

43 °C CALANDRIA

71 °C

I

COOLING WATER

-J

49 °C

37 °C

STANDBYHEATING

PUMPHOUSE

i I

s;

FIGURE A-6. Modified moderator heat exchange system and warmwater supply system for single unit station.

- 83 -

UNIT ONE

CALANDRIA

COOLING MATER

54»C

37°C

T

PUMPHOUSE

i. _ _ _ _ _ _

UNIT TWO

.71 °C

.63 °C

I

i

CALANDRIA

FIGURE A - 7 . M o d i f i e d m o d e r a t o r h e a t e x c h a n g e an-', warm v . i ' 's u p p l y s y s t e m f o r m u l t i - u n i t power' s t a t i o n .

- 84 -

heat exchangers for a single unit station were designed torecover only 23 MW of heat* resulting in a reduced capital costin the moderator heat exchange system. During periods of peakdemand (up to 35 MW) it was assumed that the necessary additionalheat (12 MW) was added to the light water flowing to the green-house facility at the pumphouse. Consequently, the designoutlet temperature of the light water stream from a single reactorstation is lower than the corresponding temperature from amulti-unit heat exchange system (Table A - 3 ) .

Wr.en a multi-unit station is modified, the exchangersin each of two reactors must be modified to provide 17.5 MW atpeak demand and 26 MW during shutdown of one of the reactors.Both requirements can be met by designing each exchanger to meetits peak demand of 17.5 MW. This is possible since the temperatureof the light water supplied to the greenhouse facility may bereduced from 54°C to 35°C and still maintain the greenhouses attheir standby temperature of 7°C, if the flow of light water ismaintained to the facility. Thus, by allowing the return watertemperature from the greenhouse facility to drop to 24°C, andby increasing the flow through the remaining on-line reactorheat exchange system from 0.9 to 1.35 x 10 kq/h, the heat recoverycapability of the on-line heat exchanger increases from 17.5 to26 MW. The c ^ i e t water from the exchanger (at 41°C) is mixedwith the remaining 0.45 x 10 kg/h of light water bypassed at thepumphouse to produce a return stream of 1.8 x 10 kg/h of lightwater at 35°C for the greenhouse facility.

The increased pressure drop resulting from an increasedflow through the exchanger of a single unit is compensated, inpart, by the reduced pressure drop associated with a reduced flowfrom the pumphouse to and from the moderator heat exchange system.

A summary of the design data for the two moderator heatexchange and water supply systems is given in Tables A-3 and A-4.

- 85 -

TABLE A-3

Design Parameters and Capital Cost Summaryof Moderator Heat Exchange Systems

Single-Unit Station Two-Unit Station

Exchanger Design Parameters

(Two Heat Exchangers/System)

Design Heat Load (MW)

[)2O Inlet Temperature (°C)

D2O Outlet Temperature (°C)

Light WaterInlet Temperature (°C)

Light WaterOutlet Temperature (°C)

D2O Flow Rate (kg/h)

Light WaterFlow Rate (kg/h)

Heat Transfer ?Coefficient (kW/m.K)

Corrected LMTO (°C)

Heat ExchangeSurface Area (mz)

Capital Cost Summary

StandbySystem

11.5

71 .0

65.6

37. 0

49.0

1.8 x 10 6

0.9 x 10 6

1 .71

23.0

290

PeakingSystem

8.6

71 .0

67.0

37.0

49 .0

1.8 x 106

0.7 x 106

1 .71

23.0

215

Dcsi

1 7.

71 .

63.

37 .

54

1 . 8 v

0 . 9 x

1

i *;

555

iLn.

5

0

r,

.i

1 L!C

i:-

.71

.4

V. ij r 1

Stan0>U'/a

[••'

r•y.>

41

l .;' >

1 .4 X

t .

^ ;

' " I'.) i • V

1 ;l

1 11

71

Modified System Cost ($) 640.000 475,000

- 86 -

TABLE A-4

Design Parameters and Capital Cost Summary of Main SupplyPiping, Pumphouse, and Standby Heating Systems

Main Supply Piping System

Design Data

Maximum Flow Rate (kg/h)Maximum System Pressure (kPa)Piping Network

Pipe Diameter (cm)Pipe Length (m)

System Pressure DropPiping (kPa)Moderator Heat Exchanger (kPa)

Capital Cost

Installed Cost ($'m)Total Cost (S)

Single-Unit Station

Standby Peaking

Two-UnitStation

1.8 x 106i>0

541220

34070

360440,000

1.4 x I620

451220

34050

330400,000

1 .8 x 10c

620

601220

165100

395480,000

Pumphouse

Capital Cost (S)

Pumps (4 x 75 kW)Piping, Electrical and ControlsBui 1di ng

TOTAL

405010

,000,000,000

405010

,000,000,000

405010

,000,000,000

100,000 100,000 100,000

Standby Heating System

Design Heat Load (MM)

Capital Cost ($)

Boilers, including sparesOil Storage TanksPlumbing and ElectricalInstal lationBuildingContingenci es

26

237,00060,00074,00030,00037,00092,000

26

237,00060,00074,00030,00037,00092,000

TOTAL 530,000 530,000

- 87 -

At m a x i m u m f l o w , the anticipated system

(greenhouse d i s t r i b u t i o n , m o d e r a t o r heat e x c h a n g e and supply

s y s t e m s ) is less than the m a x i m u m design pressure of 020 i.To.

This flow may be delivered by 4 pumps operated in p a r a l l e l , em-

p o w e r e d by a 75 kW m o t o r and c a p a b l e of a net d e l i v e r y presvj-

of 520 kPa. The pumps would be actuated a u t o m a t i c a l l y by

p r e s s u r e c o n t r o l , and are located in a pumphouse adjacent to

the q r e e n h o u s e f a c i l i t y .

A.4.2 Capital Cost of Heat Supply Systems

The capital cost of the heat supply systems include, 'r,

cost of modifying the moderator heat exchange s y s t e m , construction

of the supply l i n e s , pumps and pumphouse and of the stan'oy h"^ t.t ••'

s y s t e m . Individual costs of each item are p r e s e n t e d in Tab!.- • :

and A - 4 .

Costs of modifying the moderator heat exchange <ry.t(i

were based on data supplied by R e n s h a w (Appendix C ) . The2

e s t i m a t e d cost of $1100/m of exchanger surface includes fabrica-

tion and i n s t a l l a t i o n of the e x c h a n g e r , piping modification.-,.

c o n t r o l s and additional heavy w a t e r holdup in the exchanger.

A.S NATURAL GAS GREENHOUSE HEATING SYSTEM

To assess the relative economics of the proposed w> ,tt

heat recovery s y s t e m for g r e e n h o u s e s , it was necessary to ev^lud

the capital and o p e r a t i n g costs of a competitive fossil fired

h e a t i n g system. The fossil-fired system chosen for evaluation W

a natural gas heated system in a single roof g r e e n h o u s e facility

of 10 ha.

- 88 -

A. 5.1 Description

The natural gas heating system chosen is commerciallyavailable and referred to as the Fan Jet system. It consists ofan axial flow air circulation fan (0.75 kW motor) mounted near theroof at one end of a greenhouse unit. A perforated, one meterdiameter, polyethylene film air duct is attached to the dischargeside of the fan and extends the length of the greenhouse. Thetwo-speed fan operates continuously, inflating the tube andrecirculating air throughout the greenhouse.

Two natural gas furnaces are mounted adjacent to, andon either side of, the main air circulation fan. Each furnace isequipped with a fan (0.25 kW motor) which draws air from thegreenhouse and discharges heated air directly into the intakeside of the main circulation fan. The operation of the furnaceand furnace fans is controlled by thermostats.

When either the greenhouse temperature or humiditybecome too high, a motorized louver is energized at one end ofthe greenhouse. Simultaneously, two exhaust fans (each with a0.75 kW motor) at the opposite end of the greenhouse are energized,and fresh air is drawn through the greenhouse. The exhaust fansoperate against a gravity-controlled discharge louver.

Additional cooling may be obtained by installation ofan evaporative cooling pad adjacent to the inlet louver.

A.5.2 Capital Cost

The estimated capital cost of the components of the FanJet natural gar heating and ventilation system are listed inTable A-5. As may be noted, it was assumed that the capital costof the system for an end-unit and a central-unit greenhouse wereidentical .

- 89 -

TABLE A-5

Capital Cost Summary of Natural Gas Heatinoand Ventilation Systems

Heating System

Furnaces

Distribution Fans

($/Greenhouse)

800

(1 x 0.75 kW; 2 x

Ducting

Instrumentation

Installation

0.25

Sub-

kW)

total

700

100

250

500

2350 705,000

Ventilation and Air Circulation

Louvers (1 motorized; 1 gravity)

Exhaust fans (2 x 0.75 kW)

Control and Instrumentation

Installation

Sub-total

TOTAL (300 Greenhouses)

1200

100C

250

_300

2750 825,000

1 ,530,000

- 90 -

A. 6 MAINTENANCE AND OPERATING COST SUMMARY

The yearly maintenance costs of the heating systemcomponents were estimated as a percentage of Installed capitalcost. A listing of the capital cost percentages assumed forthe respective components, together with the resultinq estimatedyearly maintenance costs are given in Table A-6.

The yearly operating costs of the heatinq systemcomponents are listed in Table A-7. The only utility consumptionconsidered was electricity. To obtain electrical consumption(kWh/a), the estimated yearly load factor of the component wasmultiplied by its rated yearly consumption. Electricity wasassumed to cost 15 m$/kWh.

- 91 -

TABLE A-6

Maintenance Cost Summary

Moderator_Wa_st_e Heat_ Del i very System1;

l n - R p a c t o r Heat F.xcharuie SystemM.iin Supply Syr. teni Pi pi noPumphouse

PumpsPi pi ni) and e l e c t r i c a lC o n t r o l sBuildinq

S t a n d b y H e a t i n a

TOTAL

C a p i t a l

10

__Do

One U n i t

'. ta nd! yHe a t inn

19 ,

4 ,

i] ,

26_.

60

,200,80-'

,00060'!("• *\ C\

?oo,5 00

,300

l_1d_r_s_

_S_td_t

P e a k

14,

»1 %

1 Of")

i nq

.bO

or-;!'!! 'i

b'-

I i •

?00b i ^

b b:)

u<• t ,,t i

• ' •

4 .•;

t

! .''

b •'. . •'•

Greenhouse Heatina System

Do 1 U r s

Warm Water Heating SystemHeat Exchanger and PipingFans, LouversInstrumentation and ControlsFan Support StructureWater Distribution System

TOTAL

C a a i t a lL 0 S

255Ci

I ndi vH o u s e

14,53,11 ,

96,

idTs_U

060000onn

_b_00

b60 1 1 3 . -,'.y

Natural Gas Heating SystemHeatinq and VentilationGas Distribution

TOTAL

(a) 8 hectare growing surface(b) 10 hectare growing surface

; » . - . • : • )

7 7 .

- 92 -

TABLE A-7

U t i l i t y Operating Cost Summary

_*iJLe_Jif-AL I'e l i v e r y System

L i q h t Water Pumping(4 x 75 kU pumps)

3,3 Pumping

Assumed AnnualLoad Factor

0.52

ElectricalConsumption

kWh/a

1.35 x 10c

OperatingCost(j/a)

20.250

20,000

Greenhouse Heating and Ventilation

Harm Hater System

Individual Houses (8 ha)

Heating System Fans(880 x 0.75 kW)

Ventilation System Fans(880 x 0.75 kW)

Block Houses (10 ha)

Heating System Fans(1000 x 0.75 kW)

Ventilation System Fans(1000 x 0.75 kW)

0.50

0.18

0.50

0.18

2.9 x 10s

1 .0 x 10v

3.28 x 10°

1.21 x 10c

43,500

15,000

49,200

18,150

..atural Gas Heating System (10 ha)

Heating System Fans(300 x 0.75 kW;600 x 0.25 kW)

Ventilation System Fans(1000 x 0.75 kU)

0 .

0.

50

18

1

1

.64

.21

X

X

1 0 '

10 6

24

18

,600

,150

- 9 3 -

A P P E N D I X B

S T R U C T U R E O F W A S T E H E A T G R E E N H O U S E I f i D U S T k Y

A g r e e n h o u s e i n d u s t r y b a s e d o n t h e u t i l i z a t i o n o f w a ^ t , .

h e a t w o u l d n e c e s s a r i l y i n v o l v e c o o p e r a t i o n b e t w e e n s e v e r a l ' e v e l

o f g o v e r n m e n t , a h y d r o - e l e c t r i c u t i l i t y , a n d t h e q r o w e r s . 1'. 's

n o t t h e o b j e c t i v e o f t h i s A p p e n d i x t o d e s c r i b e h o w lnn i n d u s . i ' '

w o u l d b e b u i l t a n d o p e r a t e d , b u t s i m p l y t o p o i n t o u t s o m e o f ttu

p r o b l e m s a n d t h e i r p o s s i b l e s o l u t i o n s a s a b a s i s f o r fwt'jre

di s c u s s i o n .

T r a d i t i o n a l l y t h e g r e e n h o j s e v e g e t a b l e i n d u s t r y in

C a n a d a h a s b e e n c o m p o s e d o f a l a r g e n u m b e r o f i n d i v i d u a l h o i o i ; <r-

v a r y i n g i n s i z e f r o m " p a r t - t i m e " o p e r a t i o n s o f a f e w h u n d r e d

s q u a r e m e t e r s u p t o a m a x i m u m o f p e r h a p s 4 h a , w i t h tl>e a v e r a a e

s i z e b e i n g a b o u t 0 . 4 h a . It h a s b e e n p o s s i b l e f o r a n i n d i v i ci - < i

t o e n t e r t h e g r e e n h o u s e b u s i n e s s , o r e x p a n d h i s g r e e n h o u s e area,

o n t h e b a s i s o f h i s p e r s o n a l d e c i s i o n . It ha<; a l s o b e e n ^ o s s i b ! "

f o r m a n y g r e e n h o u s e o p e r a t o r s t o b e e n q a q e d i n m i x e d f a r m i nq-.

w i t h o r c h a r d s , v i n e y a r d s o r f i e l d c r o p s o f v e q e t a h l e s in ai'.<.' i t i o n

t o g r e e n h o u s e s .

U t i l i z a t i o n o f w a s t e h e a t w i l l r e q u i r e a c h a n n e f r o n t h e

t r a d i t i o n a l o r g a n i z a t i o n d e s c r i b e d a b o v e . S o m e o f t h e f a c t o r ' ,

w h i c h w i l l i n f l u e n c e t h e n e w o r g a n i z a t i o n a r e :

1 . A d a p t a t i o n o f t h e n u c l e a r s t a t i o n t o a l l o w w a ^ t eh e a t t o b e u t i l i z e d w i l l b e r e c u i r e d w h ^ i i^n

n u c l e a r s t a t i o n is b u i l t .

2 . C a p i t a l i n v e s t m e n t i n t h e m o d i f i c a t i o n s to t h en u c l e a r s t a t i o n a n d d i s t r i b u t i o n s y s t e m w i l l l er e q u i r e d b e f o r e g r e e n h o u s e p r o d u c t i o n b e o i n s .

3 . T h e g r e e n h o u s e i n d u s t r y w i l l b e r e q u i r e d t o l o - a t en e a r t h e n u c l e a r s t a t i o n w h i c h m a y i n v o l v e p o o rs o i l s a n d h i g h l a n d v a l u e s o r t a x e s .

4. distribution costs will require that the green-houses be built close together (high density)y;iic^ may preclude mixed farming.

5. Since most of the capital costs will be incurredbefore any greenhouses can be heated, it will benecessary that most of the greenhouses beginoperation as soon as the distribution system iscompleted. When all available heat has beenutilized, further expansion by individuals willnot be possible.

Five possible structures for the waste heat greenhouseindustry are shown in Table B-1. Ownership and operation by ahydro-electric utility (hydro), is probably not a viable optionsince operation of agricultural enterprises would be consideredto be outside the mandate of most such utilities. Hydro asowner and leaser would also almost certainly be outside theutilities mandate. This organization would put the leasee in theposition of tenant rather than owner, a position which is notpalatable to most farmers.

Ownership and operation by a large corporation wouldhave the advantage that the corooration would have the financial,organizational and engineering capabilities required to carryout a large project. It is probable, however, that grantingexclusive rights to waste heat to a large corporation would be apolitically difficult decision. It would be opposed by theexisting greenhouse industry, since they would consider thecompetition to be unfair. Operation of 4 to 8 ha as a singleblock might also encounter "negative economics of scale" as havebeen noted in the greenhouse industry.

The final two possibilities are similar in that theyenvisage either hydro or a growers co-operative acting as autility. This utility would be responsible for acquiring, anddistributing the heat. It would recover its cost by charging a

TABLE B-l

Five Possible Organizations of an Industry Utilizirg WasteHeat for Greenhouse Vegetable Production

Ownership ofmodifications tonuclear station

Ownership ofdi stributionsystem

Operation ofdistributionsystem

Ownersrtip ofgreenhouses

Cost recovery ofheat -s J ppl y s v:. te:r

Ownedand operated

by hydro

hydro

hydro

hydro

h / d r o

;a ies ofv e g e t a b l er.roduce by

h y d r o

Owned Dy hydro ;leased tooperator

hydro

fiydro

hydro

leased l.yhydro tooneratcr

1 eL.se rharqeand month'1/

Owned andoperated by

large corporation

hydro orcorporation

corporati on

corpora ti on

corporati on

fixed anrHict 1fee or

k?at charge

Heat supply fromqrov.ers

co-operative asa uti1lty

hydro orqrowers C O - O D

qrowers C O - O D

arowers co-op

individualopera tors

hydro tyf i xed anr ua1fee or heat

c h a r o e ." r o w e r ; c c - ^ n

i t;.i t (. "ia r q e .

Heat supplyfrom hydro

as a utility

hydro

hydro

hvdro

i ndi v i dualoperators

hook-up feeand

n e 3 t c 'i a r o e

10en

- 96 -

hcok-up fee (dependent on distance from the distribution point andon capacity) and a heat-use charge. It would be advantageous fornydro to act as the utility since design, construction and opera-tion of the distribution system would be simple for them butwould be relatively more difficult and expensive for a growersco-operative. Thus, for the purposes of thi study, we haveassumed that hydro would act as the utility and the division ofresponsibility would be:

1. Hydro would be respon:-ible for traditionalutility responsibilities:a) in-reactor modifications to heat exchangerb) pump house, controls and supply pressure

in primary linesc) layout of distribution grid and primary

feeder linesd) metering heat suDplied to greenhouse unitse) electrical, domestic water, sewer and storm

sewer systems and also roads.

2. Greenhouse operator would be responsible for:a) heat exchange equipment within greenhouseb) return and leakage within greenhousec) operations withinthe property line.

The question of land costs and taxes is of particularimportance if the nuclear power station is near a major city.Since land prices, zoning or taxation policies could make wasteheat utilization in greenhouses economically impossible near agiven nuclear power station, the question might arise "is suchutilization desirable?". It will be necessary, therefore, thatdata to make rational decisions be available.

Although the organization of this greenhouse industrywill require creative problem solving, there are advantages thatshould accrue from use of the waste heat system:

- 97 -

1. A f t e r c o n s t r u c t i o n , the h e a t i n q c o s t s of the w a s t eheat s y s t e m will e s c a l a t e at r o u g h l y the same rateas the c o s t of e l e c t r i c i t y . S i n c e e l e c t r i c i t y c o s tm a y well e s c a l a t e at a l o w e r rate than fossil fuelc o s t , w a s t e heat s y s t e m s may gain a c o m p e t i t i v ea d v a n t a g e in the f u t u r e .

2. From the p o i n t of v i e w of the i n d i v i d u a l g r e e n h o u s eo p e r a t o r , the w a s t e h e a t system will be s i m p l e rs i n c e he will not h a v e to o p e r a t e and m a i n t a i nb o i l e r s . D i s c u s s i o n s w i t h g r o w e r s in the L e a m i n g t o narea i n d i c a t e that t h i s is a m a j o r a d v a n t a g e .

3. The high d e n s i t y of g r e e n h o u s e s in a g i v e n a r e a , amithe r e q u i r e d g r o w e r s o r g a n i z a t i o n s h o u l d m a k e p o s s i b l ec o - o p e r a t i v e b u y i n g , g r a d i n g , p a c k i n g and s h i p D i n g .I n c r e a s e d s p e c i a l i z a t i o n is also p o s s i b l e , as wellas » m o r e a g g r e s s i v e and forward l o o k i n g a t t i t u d eon the p a r t of the g r o w e r s .

4. The e x i s t e n c e of a p r i m a r y user of w a s t e heat (theg r e e n h o u s e s ) may a l l o w the d e v e l o p m e n t of s e c o n d a r yu s e r s . T h e s e m i g h t i n c l u d e use of g r e e n h o u s e e f f l u e n tas the s o u r c e for h e a t pumps in the o p e r a t o r s h o u s e s ,p a c k i n g s h e d s and g r o w i n g rooms or the use of r e t u r nw a t e r f o r soil h e a t i n g or in t e m p o r a r y crop s h e l t e r s .

5. I n t a n g i b l e s , such as the s u b s t i t u t i o n of a w a s t ep r o d u c t ( h e a t ) for a n o n - r e n e w a b l e r e s o u r c e ( p e t r o l e u m ) ,the d e v e l o p m e n t of g r e a t e r C a n a d i a n s e l f - s u f f i c i e n c yin food p r o d u c t i o n , and the d e m o n s t r a t i o n of am o d i f i c a t i o n to the C A N D U r e a c t o r s y s t e m which m a y beof i n t e r e s t to d e v e l o p i n g c o u n t r i e s , are a d d i t i o n a la d v a n t a g e s w h i c h m e r i t c o n s i d e r a t i o n .

- 98 -

APPENDIX C

HEAT EXCHANGER COSTS FOR THE MODIFIED MODERATOR CIRCUIT

Costs of modifying the moderator heat exchange system

were based on data supplied in a memorandum from R. H. Renshaw

(Division Manager of Process Engineering, Atomic Energy of Canada

Limited, Power Projects at Sheridan P a r k ) .

It should be noted that the nuclear station referred

to (Bruce A) is not a G-2 CANDU reactor station, and therefore,

heavy water flows and temperatures quoted are different than

in the G-2 moderator system. Further, since the heat exchangers

are designed for full flow continuous operation, operating costs

(essentially heavy water pumping costs) are significantly greater

than in the heat recovery system proposed in this report.

The pertinent sections of the memorandum follow:

g'ARM WATER FROM MOVSRATOR COOLING

We have '/put fieoaest ton data on mode-tatoi heat fiZCovzMj

at 140'f.

We do not have, fieady nu.mbe.fih. In Heiponse. to ijou.fi

\equzAt, %'e. have calculated a comparison between Bnuce A, not

uptatzd and pnoducina H2O at 9S°F, and Biuce A, not upKated and

\t-optimized to pioduce H2O at 140"F.

Thii ttiofik <t'a<j donz with a hzat zxchanqzK optimization

computtfi pxogfian dtblqnzd ^01 8iuce A.

A4 ijou anticipate., thtfie. anz design diîcaltizi,. We

have, uncovered iowe 0^ them in designing $on vziy watm salt

coofinn situations in which an intoxmediatz fifizsh wate.fi

- 99 -

(oup -ii iliquified. The i,oKt o^ optimization that c.'c have ifctshete molt oft lehi, ignofiei the&e, on aitumei than a-ie. ici'.ubUei.e.. that ultimate heat iink \equifiementi> axe net, thcttempefiatufte coeîcienti an.e tolenable OK negative, thatend-ikield deiign it, not aêcted, and AO (,01th.

A iub&tantiat aid if, in the viing.% in the ionm <•:' 'ii.evident and fowet holdup heat exchange*.*. ('e an.e picpativdetailed data at pn.ei>ent, but toe do not include it in thepieient iooik.

- 100 -

TABLE C-1

design Specifications and Calculated Costs forModerator Heat Exchanger

A s s

CosCosCosCosHea0?0D2OH?0H20

j in •.• t i

t oft oft oft oft re::itemotemptemptemp

ons

tubing ( I nco10 v)D2O oumpinqH2O "Dumpingoved. from calandria. to calandria. from lake. to lake

Reference

$125/kg$2.25/ft$420/kw$420/kw75MW(th)187.8°F105°F68°F98 °F

New

$125/kg$2.26/ft$420/kw$420/kw7 5MW(th)187.8°F127°F68°F140°F

Results Reference New

L.2O costH/X system pioinq costHeat Exch. costOther capital

504,06956,806

751 ,867

Total Capital: $1,312,742

Total Operating: $ 202,119

$ 906,27067,532

1,392,720

$2,366,522

j 195.732

D2O flowH2O flowHeat Tx surfaceLMTO (corrected)

3,120,914 lb /h8,530,500 1b /h

13,311 sq ft50.680

4,265,250 lb /h3,554,375 lb /h

26,210 sq ft30.670

The International Standard Serial Number

ISSN 0067-0367

has been assigned to this series of reports.

To identify individual documents in the series

we have assigned an AECL—number.

Please refer to the AECL—number when

requesting additional copies of this document

from

Scientific Document Distribution Office

Atomic Energy of Canada Limited

Chalk River, Ontario, Canada

KOJ I JO

Price S7.00 per copy

2650-76

Date post:	08-Dec-2020
Category:	Documents
Upload:	others
View:	4 times
Download:	0 times

ATOMIC ENERGY §?S& L'ENERGIE ATOMIQUE OF CANADA … · A Waste Heat Utilization forking Party was...

Documents