Replacement of low-efficiency shaded pole and permanent split capacitor (PSC) evaporator fan drive motors in supermarket refrigerated cases, walk-in freezers and refrigerators, beverage merchandisers, and refrigerated vending machines with highly efficiency electronically commutated permanent magnet (ECPM) motors.
Commercial refrigeration equipment includes refrigerated display cases and walk in refrigerators, self-contained equipment such as upright and horizontal merchandisers, beverage merchandisers, deli cases, reach-in refrigerators and freezers, walk-in coolers, refrigerated vending machines and ice machines. Supermarkets account for almost 7% of commercial sector electrical energy consumption with half of their use associated with refrigeration systems. A major opportunity for energy savings in supermarket refrigeration resides in the use of more efficient evaporator fan motors. Most evaporator fan motors are inefficient single-phase shaded pole motors. Small shaded pole motors can have efficiencies below 25% while permanent split capacitor motors may reach 50% at full-load. In contrast, electronically commutated permanent magnet (ECPM) motors have a full load efficiency exceeding 70% (some are up to 85% efficient at full-load) and offer variable speed capability.
These evaporator fan motors are quite small, ranging from 1/20th hp to 1/15th hp in output. Yet savings can be significant. An evaporator fan retrofit study conducted at The PG&E (PG&E refers to the Pacific Gas and Electric Company) Food Service Technology Center (FSTC) examined the replacement of two 1/8th hp evaporator fan motors in a walk-in freezer. Average input power for each shaded-pole motor was 135.5 Watts. An ECPM motor placed into the same service resulted in a power draw of only 44 Watts---resulting in a 67% reduction in energy use. As these fans run constantly, annual operating cost reductions were $104/year per fan (at $0.13/kWh). An additional benefit of using the high efficiency motor is that less heat is lost into the refrigerated space. For every two kWh of evaporator fan energy savings, an additional kWh of condenser power reduction occurs. Return on investment is dependent upon the baseline motor efficiency, new motor cost, installation cost and local utility energy rates and incentives.
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Baseline Description: 1/8th hp shaded-pole evaporator fan motor Baseline Energy Use: 1182 kWh per year per motor
Evaporator fan motors are quite small, sometimes with a drive motor of only 1/20th hp to 1/15th hp in output. Yet savings can be significant. An evaporator fan retrofit study conducted at the PG&E Food Service Technology Center examined the replacement of two 1/8th hp evaporator fan motors in a walk-in freezer. Average input power for each shaded-pole motor was 135.5 Watts (Angelo, 2006). An ECPM motor placed into the same service resulted in a power draw of only 44 Watts---resulting in a 67% reduction in energy use. As these fans run constantly, the baseline fan energy consumption is equal to 0.135 kW x 8760 hours/year = 1,182 kWh/year.
"Typical" Savings: 67% Low and High Energy Savings: 20% to 70% Energy Savings Reliability: 6 - Approved Measure
An evaporator fan retrofit study conducted at the PG&E Food Service Technology Center examined the replacement of two 1/8th hp evaporator fan motors in a walk-in freezer. Average input power for each shaded-pole motor was 135.5 Watts. An ECPM motor placed into the same service resulted in a power draw of only 44 Watts---resulting in a 67% reduction in energy use (Angelo, 2006).
The Pennsylvania Public Service Commission "Technical Reference Manual" dated June 2014 estimates the typical energy savings given that a 1/20th hp (90 input Watt) baseline PSC motor is changed out with an ECM motor in cooler and freezer service. Savings are deemed at 380 and 454 kWh/year, respectively. Annual energy savings are greater when the existing evaporator fan motor is of the shaded-pole design. In this case, input power is estimated at 142 Watts and savings are deemed at and 958 and 1,146 kWh for the cooler and freezer service, respectively.
Note: This is a deemed measure under the October 1, 2014 BPA "Energy Efficiency Implementation Manual". The deemed amount is $35 per motor for walk-in coolers or refrigerated areas.
Energy Use of an Emerging Technology is based upon the following algorithm. Baseline Energy Use - (Baseline Energy Use * Best Estimate of Energy Savings (either Typical savings OR the high range of savings.))
Simple payback, new construction (years): N/A
Simple payback, retrofit (years): N/A
Cost Effectiveness is calculated using baseline energy use, best estimate of typical energy savings, and first cost. It does not account for factors such as impacts on O&M costs (which could be significant if product life is greatly extended) or savings of non-electric fuels such as natural gas. Actual overall cost effectiveness could be significantly different based on these other factors.
Karas Angelo, 07/01/2006. GE ECM Evaporator Fan Motor Energy Monitoring PG&E Food Service Technology Center
Aurthur Little, 12/01/1999. Opportunities for Energy Savings in the Residential and Commercial Sectors with High-Efficiency Electric Motors Arthur D. Little, Inc.
Technical Advisory Group: 2009 HVAC TAG (#2) TAG Ranking: Average TAG Rating: TAG Ranking Date: TAG Rating Commentary: