New Refrigeration Measures - FHP Status Report-

& -Request for Input-

September 21, 2010

Acknowledgements

We would like to thank the following for their support:• Avista Utilities• Bonneville Power Administration• Puget Sound Energy

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Agenda

• Objectives of RTF subcommittee meeting

• New measure update presentation– Floating/Reduced Head Pressure Control

for Stand Alone Refrigeration Compressors

• Next steps

Floating Head Pressure Control for Stand Alone Refrigeration

Compressors

Michele FriedrichBen Cartwright

Dustin Bailey

Technology Overview

• This measure requires using controls and/or expansion valve retrofits to change (lower) a fixed head pressure set point

• Allows condenser to operate at a lower temp. depending on ambient conditions and system demand

• Lower condenser temp. operation = less compressor work, more condenser fan energy

• Compressor efficiency increases due to discharge pressure decrease

Variable Assumptions for SensitivityBase Case Variables Remote condenser with multiple single compressors

Variable Units Min Max Typical

Refrigeration Load per compressor mbtu/h-compressor 10 100 60

Condenser sizing over ref load 1.3 2.1 1.7

Compressor sizing over refrigerant load 1.1 1.3 1.2

Number of condenser fans/ fan size Number / HP 4 / 1.5 6 / 0.5 5 / 1base case Cond head pressure min control setpoint (SCT) Degree F 85 95 90

Suction Temperature (medium and low) Degree F -30 40 15

Climate Zone Snohomish Boise Portland

Non-variable Assumptions Units Min Max Typical

EE Fan control for floating VFD with 10F TD OA drybulb T-stagedEE case Cond head pressure min control setpoint (SCT) Degree F 60 70 70

compressor motor size HP 5

number of compressors per condenser 5

Base case Fan control OA drybulb T-staged OA drybulb T-staged

Sensitivity for Condenser with Multiple Compressors

Remote Condenser Sensitivity Diagram

0 100 200 300 400 500 600 700 800 900

Condenser setpoint

Suction Temperature

Compressor Oversizing

Number of fans per cond

Cond sizing Factor

Climate Zone

Compressor Efficiency

EE Condenser setpoint

kWh Savings per Year/Compressor hp

85 °F

90 °F

95 °F

40 °F

15 °F

-30 °F

110 %

120 %

130%

4 Fans

5 Fans

6 Fans

210 %

170 %

130%

Snohomish

Portland

Boise

70 °F

60 °F

COP= 3.1

COP= 2.7

Assumptions for Condenser with Multiple Stand-alone Compressors

Variable Units LT MT Notes

Refrigeration Load per compressor mbtu/h-compressor found size to match comp HP

Condenser sizing over ref load 1.85 1.5 refrigerant schedules for single

comp/ remote cond

Compressor sizing over refrigerant load 1.17 1.13 refrigerant schedules for single

comp/ remote cond

Number of condenser fans/ fan size Number / HP 4/1 4/1 assume 1 HP fans for designbase case Cond head pressure min control setpoint (SCT) Degree F 94.3 94.3 Assume factory set for R22

Suction Temperature (medium and low) Degree F -20 20 GS search for evap temp

Climate Zone Portland Portland weight for climate zones

Non-variable Assumptions Units

EE Fan control for floating OA drybulb T-staged OA drybulb T-stagedCan not use ambient following

on multiple comp.EE case Cond head pressure min control setpoint (SCT) Degree F 70 70 assume balanced port valves

compressor motor size HP 9 7.5 refrigerant schedules for single

comp/ remote cond

number of compressors per condenser 5 5 refrigerant schedules for single

comp/ remote cond

Base case Fan control OA drybulb T-staged OA drybulb T-staged

Only control available for multiple stand alones to one

condenser

Action Items from Sept 13:Head Pressure Control Valve

• There is no visual indication of the setting on the valve. If it is a non-adjustable valve (the majority on stand alone compressors) then it is factory set at 180 psig +/- 5 psi. For adjustable valves the setting must be made with pressure gauges (no gauges or indicator on valve.) Factory setting is 180 psig +/- 3 psi.

Action Items from Sept 13:Head Pressure Control Valve

• Analysis assumed 404A refrigerant which has saturated condensing temperature of 82.3oF at 180 psig (194.7 psia) and accuracy is 80.6 to 84.1oF.

• If R22 refrigerant is assumed, it has saturated condensing temperature of 94.3oF at 180 psig (194.7 psia) and accuracy is 92.5 to 96.1oF.

Action Items from Sept 13:Compressor and Condenser Sizing

• Refrigeration Schedule Search for Stand Alone Compressors: 26 compressors, 6 stores

• Compressor oversize median is 1.15

• Condenser capacity over refrigeration load median is 1.6

Action Items from Sept 13:Number of fans, Size of fans

• Fan size is dependent on cost and noise, size range from ½ to 1-½ HP.

• 1-½ HP fans cost less than multiple 0.5 HP fans

• ½ HP fans are quieter than 1-½ fans

• Chose 1 HP fans as predominate fan size.

• Refrigration schedule review showed typical is 4 fans.

Action Items from Sept 13:Fan Control

• Base case fan control for multiple stand alone compressors can only be OA temp control as compressor systems are all separate so you can not control by pressure.

Action Items from Sept 13:Compressor Efficiency

• Compressor efficiency changes by size even for same type of compressor

• Remote Condenser with multiple compressors, assume 7.5 to 10 HP compressor efficiency (from refrigeration schedule search).

• Condensing Unit – size from ½ HP to 10 HP. Data for compressor HP from GS can weight by compressor size.

Condensing Units

Condensing Unit Variable Assumptions for Sensitivity

Base Case VariablesVariable Units Min Max Typical Min Max Typical

compressor COP / motor size None / HP 0.9 / 1/2 1.4 / 5 1.3 / 3 2.0 / 1/2 2.9 / 5 2.8 / 3

Compressor sizing over ref load Degree F 1.1 1.3 1.2 1.1 1.3 1.2

Condenser floodback control setpoint (SCT) Degree F 92 96 94 92 96 94

Climate Zone Snohomish Boise Portland Snohomish Boise Portland

Non-variable Assumptionsnumber of compressors per condenser 1 1

Base case Fan control on/off

w/compon/off

w/compNumber of condenser fans/ fan size #/ HP 1 / 1/2 1 / 1/2Refrigeration Load per compressor mbtu/h-compressor 10250 19083

Suction Temperature (medium and low) Degree F -20 20

Fan control for floatingon/off

w/compon/off

w/compFloating Condenser minimum setpoint (SCT) Degree F 70 70

Condensing unit MTCondensing unit LT

Condensing Unit- Low TempTornado Diagram

0 100 200 300 400 500 600 700 800 900 1000

Compressor Efficiency (COP)

Refrigeration compressor oversizing(% over Load)

Condenser set point (SCT)

Climate Zone

Energy savings per compressor HP

COP=1.40, 5 HP

COP=1.27, 3 HP

COP=0.94, 1/2 HP

92.5 °F

94.3 °F

96.1 °F

130%

120%

110%

Boise, ID

Portland, OR

Snohomish, WA

Condensing Unit- Medium TempTornado Diagram

0 100 200 300 400 500 600 700

Comp Eff

Condenser set point (SCT)

Refrigeration compressor oversizing

Climate Zone

Energy savings (kWh/yr-HP)

Boise, ID

Portland, OR

Snohomish, WA

COP=2.889, 5 HP

COP=2.751, 3 HP

COP=1.978, 1/2 HP

92.5 °F

94.3 °F

96.1 °F

130%

120%

110%

GS Stand-alone Compressor Size Distribution up to 10 HP

HP Frequency1 110 6%2 209 11%3 300 16%4 69 4%5 358 19%6 95 5%7 11 1%

7.5 339 18%8 14 1%9 28 1%10 176 9%

Remote Condenser 25 expansion valve/condenser Cost

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EquipmentEquipment

CostLabor Unit

Number of units

Total Notes Source

Adjustable Flood Valve

$ 166.60 $140.00 Per

Condenser1 $ 306.60

1 flood valve per condenser

Sporlan

Bypass valve $ 79.70 $140.00 Per

Condenser1 $ 219.70

1 bypass valve per condenser

Sporlan

Filter drier $ 41.75 $ 17.50 Per

Condenser1 $ 59.25

1 filter drier per condenser

Sporlan, HVAC/R Wholesaler

Balance Port TXV $ 129.64 $ 35.00 Per

evaporator25 $4,116.00

5 low temp cases per compressor. 5 compressors. 25 cases. One evaporator per case. One TXV per evaporator. 25 txvs.

Sporlan, Grainger

Total $4,701.55 per remote condenser

Condensing Unit 3 expansion valve/condenser Cost

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EquipmentEquipment

Cost Labor UnitNumber of units Total Notes Source

Adjustable Flood Valve $ 166.60 $140.00

Per Condenser 1 $ 306.60 1 flood valve per condenser Sporlan

Bypass valve $ 79.70 $140.00 Per

Condenser 1 $ 219.70 1 bypass valve per condenser Sporlan

Filter drier $ 41.75 $ 17.50 Per

Condenser 1 $ 59.25 1 filter drier per condenser

Sporlan, HVAC/R Wholesaler

Balance Port TXV $ 129.64 $ 35.00 Per

evaporator3 $ 493.92

3 low temp cases. One evaporator per case. One TXV per evaporator. 3 txvs.

Sporlan, Grainger

Total $1,079.47 per condensing unit

Condensing Unit 2 expansion valve/condenser Cost

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EquipmentEquipment

Cost Labor UnitNumber of units Total Notes Source

Adjustable Flood Valve $ 166.60 $ 140

Per Condenser 1 $ 306.60 1 flood valve per condenser Sporlan

Bypass valve $ 79.70 $ 140

Per Condenser 1 $ 219.70

1 bypass valve per condenser Sporlan

Filter drier $ 41.75 $ 17.50 Per

Condenser 1 $ 59.25 1 filter drier per condenser Sporlan, HVAC/R Wholesaler

Balance Port TXV

$ 129.64 $ 35Per

Evaporator2 $ 329.28

2 medium temp cases .One evaporator per case. One TXV per evaporator. 2 txvs.

Sporlan, Grainger

Total $ 914.83 per condensing unit

Next Steps

Next Steps

• Confirm and weight savings

• Finalize costs/hp of compressor

• Calculate BC ratio

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