+ All Categories
Home > Documents > LABORATORY TESTING OF AN ENERGY EFFICIENT...

LABORATORY TESTING OF AN ENERGY EFFICIENT...

Date post: 06-Jun-2020
Category:
Upload: others
View: 1 times
Download: 0 times
Share this document with a friend
3
30-65% Forecasted energy savings compared to a traditional dehumidification system. ENERGY savings WESTERN COOLING EFFICIENCY CENTER-UC DAVIS : CASE STUDY WESTERN COOLING EFFICIENCY CENTER » wcec.ucdavis.edu LABORATORY TESTING OF AN ENERGY EFFICIENT DEHUMIDIFIER FOR INDOOR FARMS Laboratory test at the Western Cooling Efficiency Center-UC Davis 100% Amount of water removed from the air that can be re-used to water plants. Water re-use WESTERN COOLING EFFICIENCY CENTER PROBLEM In order to remove moisture and heat generated by plant transpiration and lighting, indoor farming operations require dehumidification and sensible cool- ing. However, the ratio of dehumidification to sensible cooling needed exceeds typical requirements for residential or commercial buildings. Energy intensive dehumidification systems are often necessary to maintain the indoor condi- tions required for indoor farming. SOLUTION Traditional dehumidification systems provide dehumidification and increase the air temperature, as opposed to the desired dehumidification and reduction of air temperature. An alternative is MSP Technology’s dehumidification system that uses a plate air-to-air heat exchanger and a cooling coil that is part of a split compressor-based refrigeration system. This process results in a ratio of sensible to latent cooling that is well suited for indoor farming applications. Experimental laboratory testing and numeri- cal modeling were performed to estimate the annual projected energy savings from using MSP Technology’s dehumidification system over a traditional dehu- midification system. The results of this project forecast that implementation of MSP Technology’s system has potential to save 30% or more of the energy used for dehumidification and cooling in indoor farming applications. Assistant Engineer Derrick Ross instrumenting the MSP Dehumidifier in WCEC’s environmental chamber.
Transcript
Page 1: LABORATORY TESTING OF AN ENERGY EFFICIENT …wcec.ucdavis.edu/wp-content/uploads/2016/11/MSP_XCEL-Case-Stu… · WESTERN COOLING EFFICIENCY CENTER-UC DAVIS : CASE STUDY WESTERN COOLING

30-65%Forecasted energy savings compared to a traditional dehumidification system.

ENERGY savings

WESTERN COOLING EFFICIENCY CENTER-UC DAVIS : CASE STUDY

WESTERN COOLING EFFICIENCY CENTER » wcec.ucdavis.edu

LABORATORY TESTING OF AN ENERGY EFFICIENT DEHUMIDIFIER FOR INDOOR FARMS

Laboratory test at the Western Cooling Efficiency Center-UC Davis

100%Amount of water removed from the air that can be re-used to water plants.

Water re-use

WESTERN COOLING EFFICIENCY CENTER

PROBLEMIn order to remove moisture and heat generated by plant transpiration and

lighting, indoor farming operations require dehumidification and sensible cool-

ing. However, the ratio of dehumidification to sensible cooling needed exceeds

typical requirements for residential or commercial buildings. Energy intensive

dehumidification systems are often necessary to maintain the indoor condi-

tions required for indoor farming.

SOLUTIONTraditional dehumidification systems provide dehumidification and increase the

air temperature, as opposed to the desired dehumidification and reduction of

air temperature. An alternative is MSP Technology’s dehumidification system

that uses a plate air-to-air heat exchanger and a cooling coil that is part of a split

compressor-based refrigeration system.

This process results in a ratio of sensible to latent cooling that is well suited

for indoor farming applications. Experimental laboratory testing and numeri-

cal modeling were performed to estimate the annual projected energy savings

from using MSP Technology’s dehumidification system over a traditional dehu-

midification system. The results of this project forecast that implementation of

MSP Technology’s system has potential to save 30% or more of the energy used

for dehumidification and cooling in indoor farming applications.

Assistant Engineer Derrick Ross instrumenting the MSP Dehumidifier in WCEC’s environmental chamber.

Page 2: LABORATORY TESTING OF AN ENERGY EFFICIENT …wcec.ucdavis.edu/wp-content/uploads/2016/11/MSP_XCEL-Case-Stu… · WESTERN COOLING EFFICIENCY CENTER-UC DAVIS : CASE STUDY WESTERN COOLING

2 | WCEC | CASE STUDY DEHUMIDIFICATION TECHNOLOGY PERFORMANCE TESTING

A. STANDARD DEHUMIDIFIER B. AIR CONDITIONER

ADD WATERADD WATER ADD HEATADD HEAT

AA BB REMOVE HEATREMOVE HEAT

C. MSP DEHUMIDIFIER B. AIR CONDITIONER

ADD MOISTUREADD MOISTURE ADD HEATADD HEAT

CC BBADD HEATADD HEAT REMOVE HEATREMOVE HEATREMOVE HEATREMOVE HEAT

RECYCLE WATER

(IF PLUMBED)RECYCLE WATER

RECYCLE WATER

(IF PLUMBED)

RECYCLE WATER

A. STANDARD DEHUMIDIFIER B. AIR CONDITIONER

ADD WATERADD WATER ADD HEATADD HEAT

AA BB REMOVE HEATREMOVE HEAT

C. MSP DEHUMIDIFIER B. AIR CONDITIONER

ADD MOISTUREADD MOISTURE ADD HEATADD HEAT

CC BBADD HEATADD HEAT REMOVE HEATREMOVE HEATREMOVE HEATREMOVE HEAT

RECYCLE WATER

(IF PLUMBED)RECYCLE WATER

RECYCLE WATER

(IF PLUMBED)

RECYCLE WATER

MOIST RETURN AIR

DRY SUPPLY AIR

EVAPORATOR

PLATE HEAT EXCHANGER

1

2

3

4

MSP DIAGRAM

ABOUT THE TECHNOLOGY TEST METHODOLOGY

15.6 21.1 26.7 32.2 37.8 43.3 48.9 54.4Ambient Temperature (°C)

15.6 21.1 26.7 32.2 37.8 43.3 48.9 54.4Ambient Temperature (°C)

1

2

3

4

5

6

7

10,000

20,000

30,000

40,000

50,000

60,000

70,000

Tota

l Pow

er (k

W)

Capa

city

(BTU

/hr)

Capacity DR-55

Capacity R-410A Total Power R-410A

Total Power DR-55

60 70 80 90 100 110 120 130Ambient Temperature (°F)

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

5.5

6.060 70 80 90 100 110 120 130

15.6 21.1 26.7 32.2 37.8 43.3 48.9 54.4

COP

DR-55 R-410A

Ambient Temperature (°F)

Ambient Temperature (°C)

0%

20%

40%

60%

80%

100%

120%

0

1

2

3

4

5

6

7

60 70 80 90 100 110 120 130Ambient Temperature (°F)

COP

Ratio

DR-

55 /

R-4

10A

COP

R-410A COPDR-55 COP COP Ratio

Traditional dehumidifiers (Figure 1) remove moisture by

cooling the air below the dewpoint using an evaporator coil,

resulting in cold, dry air. The cold, dry air is then re-heated as

it passes over the condenser coil, supplying warm, dry air to

the space. The net result is an addition of heat into the condi-

tioned space. This requires another air conditioning unit to be

installed to remove both the heat from the lights and the heat

from the dehumidifier.

The MSP dehumidifier (Figure 2) combines a plate heat

exchanger, evaporator coil and a small, outdoor condensing

unit. This technology (Figure 3) brings in (1) moist return air

through a (2) plate heat exchanger to initially cool the return

air. This allows the (3) evaporator coil to focus most of its

energy on dehumidification, instead of both cooling and de-

humidification like a traditional dehumidifier. The cool dry air

then passes back through the plate heat exchanger to reduce

the temperature of the incoming moist return air and pick up

some of the heat as it is then (4) reintroduced into the condi-

tioned space. The heat absorbed by the evaporator coil and

from the compressor is rejected outside. The net result is dry

air delivered to the space with a small reduction in tempera-

ture, which counteracts the heat from the lights. A building

conditioning system for heating and cooling is then used to

make minor adjustments to space temperature as needed.

Characterizing MSP’s Performance

The unit was instrumented and tested in WCEC’s environmental

chambers to determine system power, capacity, and efficiency for

each of 29 steady-state tests conducted at controlled outdoor air

temperatures, indoor conditions, and indoor airflows.

Comparison to Traditional Dehumidification Systems

In order to estimate the difference in energy expenditures of MSP

Technology’s dehumidification system compared to a traditional de-

humidification system as applied to an indoor farm, WCEC created

two numerical models based on:

• Indoor building loads from plant transpiration and lighting

• Hourly weather forecast data

• Equipment performance data

The models calculated the annual energy expenditures of each

dehumidification system required to meet the humidity set point for

the greenhouse, as well as any additional energy expenditures nec-

essary to recondition the air to the desired indoor air temperature

after dehumidification loads were met. The difference in the energy

expenditures per square foot as well as the percent difference in

energy expenditure per square foot were calculated.

Figure 1: Traditional Dehumidification and Conditioning Strategy/Loads Figure 2: MSP Dehumidification and Condtioing Strategy/Loads Figure 3: MSP Diagram of Operation

Page 3: LABORATORY TESTING OF AN ENERGY EFFICIENT …wcec.ucdavis.edu/wp-content/uploads/2016/11/MSP_XCEL-Case-Stu… · WESTERN COOLING EFFICIENCY CENTER-UC DAVIS : CASE STUDY WESTERN COOLING

WESTERN COOLING EFFICIENCY CENTER » wcec.ucdavis.edu

The Western Cooling Efficiency Center was established

along side the UC Davis Energy Efficiency Center

in 2007 through a grant from the California Clean

Energy Fund and in partnership with California Energy

Commission Public Interest Energy Research Program.

The Center partners with industry stakeholders to

advance cooling-technology innovation by applying

technologies and programs that reduce energy, water

consumption and peak electricity demand associated

with cooling in the Western United States.

ABOUT WCEC

Theresa PistochiniEngineering Manager

Robert McMurryAssistant Engineer

Derrick RossAssistant Engineer

Paul FortunatoOutreach Manager

Western Cooling Efficiency Center

University of California, Davis

215 Sage Street #100

Davis, CA 95616

0

200

400

600

800

1000

1200

0 0.25 0.5 0.75 1 1.25 1.5 1.75 2 2.25

Ener

gy E

xpen

ded,

Tot

al (k

Wh/

ft2 )

Ener

gy E

xpen

ded,

Tot

al (k

Wh/

ft2 )

Latent Cooling Load, Watering and Transpiration (gal/ft2/day)Traditional Dehumidification System MSP Technology's Dehumidification System Traditional Dehumidification System MSP Technology's Dehumidification System

0

20

40

60

80

100

120

140

160

180

200

1.7 1.9 2.1 2.3 2.5 2.7 2.9

Energy Factor of Traditional Dehumidification System (L/kWh)

Climate: DenverTraditional dehumidification system e�ciency: 2.3 L/kWh

Climate: DenverLatent cooling load: 0.25 gal/ft2/day

RESULTS

Figure 4: Latent load from watering and transpiration versus annual energy expended for dehumidification and reconditioning of air

The results for the city of Denver, Colorado have been summa-

rized and presented to demonstrate the relationships studied.

• Energy expended per square foot as a function of latent

cooling load, which is affected by plant type, spacing, water-

ing and lighting schedules (Figure 4). Increasing latent load

increased the total energy expended for both systems and

decreased the percent energy savings attainable from MSP

Technology’s Dehumidification system, although in all cases

the projected energy savings was greater than 30%.

• Energy expended per square foot as a function of the energy

factor of the traditional dehumidification system. The expect-

ed savings from MSP Technology’s Dehumidification System

decreased as the efficiency of the traditional dehumidifica-

tion system efficiency increased, however, the savings in all

three scenarios was more than 50%.

RECOMMENDATIONSWCEC recommends conducting field testing of the technolo-

gy to further assess and quantify the energy savings that can

be achieved with the new MSP Technology’s dehumidification

system. Due to the recent legalization of recreational cannabis in

California, there is a pressing need to address energy efficiency in

indoor farming operations.

Figure 5: Traditional dehumidification system energy factor versus annual energy expended for dehumidification and reconditioning

of air

PREPARED BY


Recommended