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Walk-in Commercial Refrigeration

How Much Will I Save?

Once you improve the efficiency of your walk-in refrigerator or freezer, you will enjoy energy savings year after year. Since there is a cost to implementing each measure, you should focus on the measures that save sufficient energy and money to repay the investment in a relative short time, such as three years or less.

Estimated savings over one year are presented in Table 2 and Table 3 for a number of energy-saving measures. Qualified refrigeration contractors can provide cost estimates for the energy efficiency improvements that may be appropriate for your system.

Table 2. Estimated Annual Energy Cost Savings From Reductions in Parasitic Refrigeration Loads

  Average Saving (%) Walk-In Refrigerator Walk-In Freezer Walk-In Refrigerator/
Freezer
Annual operating cost before upgrades (may vary)   $1,300 $1,700 $2,400
Measure Approximate Annual Savings
HE* compressor 7.5 $98 $128 $180
HE evaporator fan motor 7.5 $98 $128 $180
HE evaporator fan motor 4 $52 $68 $96
HE lighting 6 $78 $102 $144
Anti-sweat control 3 $39 $51 $72
Defrost control 3.5 $46 $60 $84
Total** 31.5 $411 $537 $756

*HE = High efficiency
**Savings are additive

Table 3. Estimated Annual Energy Cost Savings From Improvements in Operating Conditions

  Average Saving (%) Walk-In Refrigerator Walk-In Freezer Walk-In Refrigerator/
Freezer
Annual operating cost before upgrades (may vary)   $1,300 $1,700 $2,400
Measures* Approximate Annual Savings
Floating-head pressure control 6.5 $85 $111 $156
Natural liquid refrigerant sub-cooling 7 $91 $119 $168
Mechanical liquid refrigerant sub-cooling 12.5 $163 $213 $300
Liquid pressure amplifier 10 $130 $170 $240
Evaporative condenser 6 $78 $102 $144

*Savings are not necessarily additive because of interactions between measures.

Savings From Heat Recovery

Heat recovery savings for water heating can be significant, especially for once-through water-cooled systems. Actual savings depend on the size of the refrigeration compressor, the amount of cooling water normally consumed, the amount of hot water used in the facility and the pattern of hot water usage. The Homewood Health Centre in Guelph, Ontario, spent $9,400 to switch to heat recovery and realized annual energy savings of $4,090. The payback period was only 2.3 years.

Space heating savings from heat recovery can also be significant, depending on the quantity of heat that can be captured during the heating season for distribution to the building's heating system. A significant portion – from 25 to 40 percent – of rejected heat can be used to offset energy required for heating. However, during warm weather the heat must be exhausted to the outdoors to prevent increased air-conditioning loads.

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