How it works
The Evaporator Fan Controllers are developed for use in walk-in coolers and freezers like the ones found in convenience stores, flower shops, schools, hospitals, cafeterias, etc.
The fans in the evaporator boxes run at normal speed at all times, even if the thermostat is not calling for a cooling cycle. To save money, the Evaporator Fan Controllers monitor the temperature on both the intake and exhaust of the evaporator fan unit.
- When the temperature of the exhaust is lower than that of the intake, the fans will run at normal speed.
- When the temperature of the exhaust is equal to the intake temperature however, the Evaporator Fan Controllers will reduce the speed of the fans to save energy, significantly reducing energy costs.
When the compressor turns back on to meet thermostat requirements, the Evaporator Fan Controllers will then once again return the fans to normal speed. This temperature monitoring and fan speed control allows for energy savings without an impact on the overall temperature of the cooler or freezer.
Evaporator Fan Controllers: Compressor Runtime Comparison
Evaporator Fan Controllers were installed in a walk-in cooler in the Midwestern United States. Recordings were gathered using temperature sensors over the course of six days. The graphs below show the temperature change over a six hour time span which indicate compressor cycles.
Before EFC4045T Installation
After EFC4045T Installation
As shown above:
Cooling cycle is greatly reduced when the EFC sets the evaporator fan unit into low. When fan speeds are reduced, warm air does not mix as quickly with cold air in the walk in cooler. This results in a slower gradual warming cycle. Energy savings can be realized two fold:
- Evaporator fan speed is reduced
- Cooling or compressor "runtime" is reduced
Note: EFC's were installed and are operational in a typical convenience store. Results were derived from actual data taken from a test study done in August of 2010 at:
3949 S. Dixon Rd.
Kokomo, In 46902
Example Calculation of Energy Savings
|Compressor Off Cycle: 75%||Compressor Off Time per Year: 6570 hours||Power Consumption @ Low Speed: 0.036 kW|
|Hours per Year: 8760 hours||Typical Cost of Power: $0.10/kWh **||Power Consumption @ Normal Speed: 0.209 kW|
Measured values for two shaded pole motors in one unit *
(Power Consumption @ Normal Speed - Power Consumption @ Low Speed) x (Compressor Off Time per Year) x (Typical Cost of Power) =
(0.209 kW - 0.036 kW) x (6570 hours/year) x ($0.10/kWh) = $113.66/year
* = Actual measurement from test site.
** = Average US price of electricity as reported by the US Energy Information Administration.
Money Savings Calculator
Want to see how much money you could save? Change the values to meet your specific application and see how much the EFC can save you!
|Compressor Off Cycle:||Savings =
|Compressor Off Time per Year:|
|Cost of Power (per kWh):|
|Typical Power Consumption per Motor:|
|Number of Motors per EFC:|
This calculator is just an estimation of savings. It is in no way a guarantee of cost savings, as each application involves variables that cannot be taken into account in this calculator.
EFC4045T Installation Instructions
Shaded Pole / PSC Motors
- De-energize circuit to evaporator fan box.
- Locate wiring compartment side of the evaporator fan box. (Figure A)
- Use enclosed template to ensure proper spacing.
- Insert screw to hang EFC4045T.
- Hang EFC4045T on installed screw.
- Remove EFC4045T wiring compartment lid and install 2 screws to hold unit in place. (Figure B)
- Install conduit or other alternative applicable wiring such as SJ cord, NM90 wire, etc. in accordance with national and local electrical codes. (Figure C)
- Make appropriate wiring connections per national and local electrical codes. Refer to wiring diagrams below.
- Install Thermistor A (black wires) in exhaust (colder) airflow of evaporator fan box, using provided nylon tie. (Figure C)
- Install Thermistor B (white wires) near intake (warmer) airflow of evaporator fan box, using provided nylon tie. (Figure C)
- Set switches to desired settings. [40 volts (lower airflow, higher energy savings) or 45 volts (higher airflow, lower energy savings)]
- Re-energize circuit to evaporator fan box.
- Test system for proper operation. May take several seconds to switch to normal speed once the compressor is activated.