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ENERGY EFFICIENT INVESTMENTS INC.
ECM 10- Walk In Coolers
EEI recommends refngeration controllers on walk-in coolers and freezers and installing electronically
commutated (EC) motors on evaporator fans. A controller can start/stop the evaporator fans when operation
is unnecessary. The EC motors are 30% more efficient than the standard two-pole motors. Energy savings
will be realized by reducing the runtime of the compressors and evaporator fans as well as the reduction in
power load of the new fans. Each walk-in cooler or freezer will have a new EC fan motor and blade installed
as well as a dedicated controller. In addition, controllers will be installed on the freezer to optimize the
operation of the electric defroster and door heater. The controller unit senses when refngerant has ceased
flowing through the evaporator coil and controls the fan motors. Door and frame heaters are controlled based
on dew point, reducing their run time by 95% in coolers and 60% in freezers. The controllers will reduce
compressor and evaporator runtime by up to 10%.
Calculations
Energy savings will result from both reducing the fan power and the efficient control of the evaporator fans
and door heaters. In general, EEI uses the following approach to determine savings for this specific measure:
Existing kW Cost per kWh
Cost of Existing Equipment
Cost of Proposed Equipment Energy Savings
Listed Equipment Amperage x Voltage of Equipment Average Site Data Package $/kWh
= Existing kW x Cost per kWh x Effective Full Load Hours
= Existing kW x Cost per kWh x Full Load Hours Using Control
= Existing Equipment Costs- Proposed Equipment Costs
IPMVP Option B, Retrofit Isolation with All Parameter Measurement, has been chosen for this ECM. This
option has been chosen because the only parameters changing in the implementation of this ECM are the
evaporator fan power and run time hours, the condensing unit run time hours, and the door heater run time
hours. EEI will use current transducers to measure each parameter over a one month period to obtain a
representative loading profile.
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