Case Study: Heat Recovery with an

Ammonia Heat Pump

Kraft Foods

Don Stroud

Vilter Manufacturing LLC Emerson Climate Technologies

Sam Gladis

Kraft Foods - Oscar Mayer

Processing Facility

Davenport, Iowa

OVERVIEW • Project Definition

• Design Parameters

• System Description

• Actual Results

• Operation / Maintenance

• Recommendations and Conclusions

Project Definition

• Meat Processing Facility

• Refrigeration

• Conventional Industrial Ammonia

• Screw & Reciprocating Compressors

• Evaporative Condensers

• Heating

• Steam Boilers

• Stack Condensing Economizer

• Pre-heat Economizer

• Direct Contact Hot Water Heaters

Design Parameters

OBJECTIVE: Use an ammonia heat

pump to replace the use of a direct

contact water heater.

Design Parameters

OBJECTIVE: Use an ammonia heat

pump to replace the use of a direct

contact water heater.

Direct Contact Water Heater • Capacity = 7.013 MMBtu

• Average Flow Rate = 170 gpm

• Average Inlet Temperature = 62.5°F

• Outlet Temperature = 145°F

• Fuel: Natural Gas

• Efficiency: 97%

• Hourly Operating Cost = $50.61

Ammonia Heat Pump

Summer Capacity = 8.200 MMBtu

Flow Rate = 205 gpm

In/Out Temperatures = 65°F/145°F

Suction: 160 psig

Winter Capacity = 5.738 MMBtu

Flow Rate = 135 gpm

In/Out Temperatures = 60°F/145°F

Suction: 105 psig

Design Parameters

Ammonia Heat Pump

• Isolate the ammonia heat

exchangers from the potable water

• Monitor the performance with a

SCADA system, 29 points of data

Design Parameters

Ammonia Heat Pump

Summer 205 GPM, 65F to 145F 8,200 MBH/3.41 = 2,405kW

Suction = 160 psig, Condensing = 510 psig

Power = 594 HP/1.34 = 443kW

COP = 2,405/443 = 5.43

Winter 135 GPM, 60F to 145F

5,738 MBH/3.41 = 1,682kW

Suction = 105 psig, Condensing = 510 psig

Power = 562 HP/1.34 = 419kW

COP = 1,682/419 = 4.01

Average COP = 4.77 Average Hourly Operating Cost = $19.40

Design Parameters

System Description

• Refrigeration System

with Ammonia Heat Pump

• Hot Water System

with Ammonia Heat Pump

• Detailed Description

Ammonia Heat Pump

Compressors Condensers

Receiver

REFRIGERATION

Heat Pump

Hot Water Storage Tank

WATER HEATING

Direct Contact Hot Water Heater

(PRIMARY)

62°F

145°F

Hot Water Storage Tank

WATER HEATING

Direct Contact Hot Water Heater

(BACKUP)

62°F

145°F

Heat Pump

62°F

145°F

155°F

145°F

65°F

Heat Exchanger Inlet Temp

Outlet Temp

Heat (MBH)

%

Subcooler 75°F 85°F 1,025 12.5%

Desuperheater 85°F 89°F 410 5.0%

Oil Cooler 89°F 94°F 512 6.2%

Condenser 94°F 155°F 6,253 76.3%

TOTAL 75°F 155°F 8,200 100%

8,200 MBH TOTAL HEAT

Of REJECTION

Desuperheater

Oil Cooler

Subcooler

Condenser

155°F

94°F

Actual Results

Summer: 209.9 GPM , 68.4F to 145.4F

8,080.6 MBH/3.41 = 2,369.5 kW

Suction = 170.5 psig, Cond’g = 478.1 psig

Power = 364.0 kW

COP = 2,369.5/364.0 = 6.51

Winter: 125.7 GPM, 67.8F to 145.1F

4,857.6 MBH/3.41 = 1,423.6 kW

Suction = 110.4 psig, Cond’g = 462.7 psig

Power = 336.9 kW

COP = 1,423.6/336.9 = 4.23

Actual Results

4,857.6 MBH/3.41 = 1,423.6 kW

Power = 336.9 kW

COP = 1,423.6/336.9 = 4.23

Summer: Winter:

170.5 psig

478.1 psig

110.4 psig

462.7 psig

8,080.6 MBH/3.41 = 2,369.5 kW

Power = 364.0 kW

COP = 2,369.5/364.0 = 6.51

0

250

500

750

1,000

1,250

1,500

1,750

2,000

2,250

2,500

2,750En

erg

y (k

W)

160 PSIG Host System Condensing Pressure

(Heat Pump Suction Pressure)

Heating Energy

Heat Pump Water Heater

Use

ful

Use

ful

Pu

rch

ase

d

Pu

rch

ase

d

2,112 2,049 2,049

361

$0.00

$10.00

$20.00

$30.00

$40.00

$50.00

$60.00

160 PSIG Host System Condensing Pressure

(Heat Pump Suction Pressure)

Hourly Operating Costs and Savings

Energy costs based on $7.00 per MMBtu natural gas and $0.045 per kWh electricity

Heat Pump

Direct Contact Water Heater Savings

$16.26

$52.03

$35.77

Other Savings

• To the existing ammonia system

the heat pump performs as an

additional condenser

• With heat pump operating,

condensing pressure drops 3-5 psi

• 105 HP (78.3 kW) power reduction

• ≈ $15,000 savings (half year)

Other Savings

• To the existing ammonia system

the heat pump performs as an

additional condenser

• When condensing pressure is at

minimum 105 psig, the heat pump

offsets condenser fan & pump power

• 105 HP (78.3 kW) power reduction

• ≈ $15,000 savings (half year)

Other Savings

• To the existing ammonia system

the heat pump performs as an

additional condenser

• 7,000 MBH Condensing Capacity

• 4.8 GPM Water Savings per 100 tons

• 14 million gallons water saved/yr

• 2.4 GPM Water to Drain per 100 tons

• 7 million gallons sewage savings/yr

• Comparable water treatment savings

Operation & Maintenance

• Operation

• PHA Performed prior to install

• Risks evaluated and recommendations

applied to design

• Fully automated operation

• Minimal operator input required

• Maintenance

• No different than existing

refrigeration equipment

Recommendations and Conclusions

• Consider all hot water loads/uses

• Perform energy assessment

• Hot Water Load Profile

• Refrigeration Operating Conditions

and Load Profile

• Daily and Seasonal Weather Data

• Utility Costs

• Electric, energy & demand

• Fossil Fuel

• Water / Sewage

• Water Treatment & Softening Chemicals

• Heater/Boiler & Condenser Maintenance

Case Study: Heat Recovery with an

Ammonia Heat Pump

Thank You