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Task 38

Solar Air-Conditioning

and Refrigeration

RESTMAC

Solar Air-Conditioning and Refrigeration -Introduction

Hans-Martin HenningFraunhofer-Institut für Solare Energiesysteme ISE, Freiburg/Germany

Workshop “Solar Air-Conditioning and Refrigeration”April 25, 2007Aix-les-Bains, FRANCE

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Task 38

Solar Air-Conditioning

and Refrigeration

RESTMAC

Overview

� Introduction

� Technologies

� Status, Examples

� Outlook

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Task 38

Solar Air-Conditioning

and Refrigeration

RESTMAC

Introduction

� Introduction

� Technologies

� Status, Examples

� Outlook

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Task 38

Solar Air-Conditioning

and Refrigeration

RESTMAC

World market for air-conditioning

0.000

10.000

20.000

30.000

40.000

50.000

1998 1999 2000 2001 2002 2003 2004 2005 2006

RA

C u

nit s

ales

(in

Mio

. uni

ts)

Japan

Asia (excl.Japan)

Middle East

Europe

North America

Central & SouthAmerica

Africa

Oceania

3

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Task 38

Solar Air-Conditioning

and Refrigeration

RESTMAC

Resulting increase in electric capacity

0

100

200

300

400

500

1998 1999 2000 2001 2002 2003 2004 2005 2006

tota

l ins

talle

d el

ectr

ic c

apac

ity in

GW

Japan

Asia (excl.Japan)

Middle East

Europe

North America

Central & SouthAmerica

Africa

Oceania

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Task 38

Solar Air-Conditioning

and Refrigeration

RESTMAC

Why solar heat for cooling / air-conditioning?

� Coincidence of solar gains and cooling loads

� Reduce electric peakloads created by air-conditioning

� High use of solar gainsduring the entire year

� Reduce summer surplussolar gains in solar systems designed forheating application (solar combi-systems)

1 2 3 4 5 6 7 8 9 10 11 12

Heating Cooling

DHW Solar

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Task 38

Solar Air-Conditioning

and Refrigeration

RESTMAC

Why solar heat for cooling / air-conditioning?

� Coincidence of solar gains and cooling loads

� Reduce electric peakloads created by air-conditioning

� High use of solar gainsduring the entire year

� Reduce summersurplus solar gains in solar systems designedfor heating application(solar combi-systems)

7.0heatdriving

coolingusefulCOP ========

1 2 3 4 5 6 7 8 9 10 11 12

Heating CoolingDHW TotalSolar

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Task 38

Solar Air-Conditioning

and Refrigeration

RESTMAC

Basic system scheme

Thermal driven cooling process

heat

chilled water

conditioned air

Thermallydriven coolingprocess

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Task 38

Solar Air-Conditioning

and Refrigeration

RESTMAC

� Introduction

� Technologies

� Status, Examples

� Outlook

Technologies

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Task 38

Solar Air-Conditioning

and Refrigeration

RESTMAC

heat storage cold production

sola

r co

llect

or fi

eld

air handling unit

hot w

ater

cold distr. building, loadheat cold storage

chill

ed w

ater

cond

. air

othe

r he

at s

ourc

es

heat distr.

chilledceiling

fancoils

heating

heat drivenchiller

desiccant air handling unit

solar collector

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Task 38

Solar Air-Conditioning

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RESTMAC

Small thermally driven water chillers – new productsentering the market

SK SonnenKlima GmbHSK SonnenKlima GmbHSK SonnenKlima GmbHSK SonnenKlima GmbHEAW

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Task 38

Solar Air-Conditioning

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RESTMAC

Desiccant systems

� Air handling units using heat driven air dehumidification

System using desiccant wheel System using liquid desiccant

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Task 38

Solar Air-Conditioning

and Refrigeration

RESTMAC

humidifier coolingloads

supply

backupheater

return

desiccant rotor heat recovery

am-bient

ex-haust

Desiccant system schematic

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Task 38

Solar Air-Conditioning

and Refrigeration

RESTMAC

Temperature needs

� Desiccant systems: 50 – 80°C

� Solar air collectors, flat plate collectors

� Adsorption: 65 – 85°C

� Flat plate collectors, evacuated tubes

� Single-effect absorption (comfort air-conditioning): 70 – 100°C

� Flat plate collectors, evacuated tubes, optical concentration without tracking

� Double-effect absorption: 130-160°C

� High efficient evacuated tubes, opticalconcentration with tracking

Glasabdeckung

Isolierung KollektorrahmenAbsorber mit Luftkanälen

Glasabdeckung

Isolierung Kollektorrahmen

Absorber mit Fluidkanälen

IsolierungKollektorrahmen

Glasabdeckung

Absorber mit Fluidkanal

Reflektor

Folie

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Task 38

Solar Air-Conditioning

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RESTMAC

� Introduction

� Technologies

� Status, Examples

� Outlook

Status, Examples

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Solar Air-Conditioning

and Refrigeration

RESTMAC

Status in Europe

� Approx. 120 installations

� Approx. 20 MW coldinstalled

� Specific collectorarea

� 3 m2/kWcold forchilled waterproduction

� 10 m2 per 1000 m3/h for sorptiveair handling units

39.1%

8.7%

27.5%

4.3%

4.3%2.9%5.8%

2.9%1.4%1.4%

1.4%

Germany

Greece

Spain

Portugal

Italy

Austria

France

Netherlands

Israel

Turkey

Serbia (Kosovo)

(2004-values)

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Task 38

Solar Air-Conditioning

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RESTMAC

Air-conditioning of a factory

� flat plat collector field: 2700 m2

� 2 adsorptions chillers with 350 kW cooling capacity each

� 3 compression chillers with 350 kW each

� air conditioning of the production facilities of a cosmetics factory

� site: Inofita Viotias (appr. 50 km north-east of Athens)

� largest system today

� interesting system concept: electricity saving by solar cooling

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Task 38

Solar Air-Conditioning

and Refrigeration

RESTMAC

Wine store cooling

� evacuated tube collector field: 130 m2

� single-effect absorption chiller with 52 kW cooling capacity

� no back-up system

� cooling of a wine store (about 3 million bottles) with 3 air handling units (25.000 m 3/h air flow)

� site: Banyuls (south France)

� one of the oldest systems; operates more than 12 years without problems

� solar autonomous and not buffer storage ==> storage on load side

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Task 38

Solar Air-Conditioning

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RESTMAC

Air-conditioning of a seminar room� solar air collector as only heat source: 100 m2

� desiccant cooling system (10.200 m3 per hour) with silica gel rotor

� no back-up system

� air-conditioning of the seminar room and the cafeteria in the building of the chamber for trade & commerce in Freiburg/ Germany

� simple solar system with simple integration into the air-conditioning plant

� no back-up, no storage

� promising concept for buildings with a high similarity of cooling loads and solar gains

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Task 38

Solar Air-Conditioning

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RESTMAC

Hotel air-conditioning

� parabolic trough collector produces heat at 180°C: 180 m2 aperture area

� double effect absorption chiller (cooling capacity 116 kW, 4 bar saturated steam; COP > 1.2)

� air-conditioning of a hotel and steam supply for th e hotel laundry

� LPG-fired back-up steam boiler

� site: Dalaman (mediterranean coast Turkey)

� first system with double effect chiller

� high overall conversion efficiency

� interesting concept for sites with high direct radiation

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Solar Air-Conditioning

and Refrigeration

RESTMAC

� Introduction

� Technologies

� Status, Examples

� Outlook

Outlook

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Solar Air-Conditioning

and Refrigeration

RESTMAC

Status

� Energy saving

� Primary energy saving for properly designed chilled water systems 40 – 60 %

� Primary energy saving for properly designed open cycles 20 – 50 %

� First cost

� 2 – 2.5 times higher compared to conventional reference systems

� Overall annual cost

� 1.2 – 1.5 times higher compared to conventional reference systems

� Close to break-even with funds in the range of 100 € per m2 of collector

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Task 38

Solar Air-Conditioning

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RESTMAC

Outlook

� Large potential, in particular in mediterranean count ries

� Potential for cost reduction

� Higher standardization

� Less effort in planning and design

� Lower component cost

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Task 38

Solar Air-Conditioning

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RESTMAC

… thank you for

your attention!

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Task 38

Solar Air-Conditioning

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RESTMAC

single-effect absorption

double-effect absorption

adsorption

steam jet cycle

many products for cooling power > 100 kW;

few products <100 kW; refrigerant/sorption pair either

water/LiBr or ammonia/water

several manufacturers; often direct fired systems; no

products <100 kW; refrigerant/ sorption pair in most

cases water/LiBr

a few commercially available systems (Asia);

refrigerant/sorption pair water/silica gel

tailor-made sytems for large capacities; refrigerant

water

water chillers produce chilled water which can supply any type of air-conditioning

equipment (e.g. air handling units, fan-coils, chilled ceilings,....)

Water chillers - market available systems

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Task 38

Solar Air-Conditioning

and Refrigeration

RESTMAC

Desiccant systems - market available equipment

� desiccant systems are used for direct air treatment

� they consist of a combination of sorptiveair dehumidification and evaporative cooling

� two major technologies exist

� systems with desiccant rotors– desiccant rotors available in a broad range

of sizes from several manufacturers– sorption material either silica gel or

lithium-chloride– cycle adjustable to different climatic

conditions

� systems using liquid desiccants– few systems in pilot plant operation– LiCl as desiccant material