From September to November 2013, a study was conducted on the walk-in freezer at the Union, Mo., Taco Bell restaurant. The study’s purpose was to compare energy consumption and temperature control of the freezer using two scenarios. In the first, the system operated with standard mechanical controls, including a thermostat, defrost timer and defrost termination device. In the second, the system was controlled using a KE2 Evaporator Efficiency (KE2 Evap) controller, developed by KE2 Therm Solutions, Washington, Mo.,in place of the mechanical controls. 

At the start of the test, the KE2 Evap controller was installed to monitor the room and evaporator coil temperatures, while the mechanical controls were still providing the actual system control. The target temperature for the walk-in freezer was 0°F. The controller monitored the freezer and gathered data on the energy consumption of the compressor, evaporator fans and defrost heaters.

Afterwards, the system switched to the KE2 Evap controller, monitoring the same data points. Then, operators analyzed the pre- and post-retrofit results to develop a comparison of the energy consumption.

In addition to documented energy savings of 51%, this location also realized the benefits of troubleshooting via the communications capabilities of the KE2 Evap controller. Shortly after installation, review of operation on the Home page and Graphs page identified an anomaly where the freezer temp was increasing slightly while in refrigeration mode. This observation was quickly diagnosed as an intermittent issue resulting from the improper functioning of the door closer. This was quickly rectified. Undetected, this issue would have led to increased run time of the refrigeration equipment, and possibly resulted in a freeze-up of the evaporator coil.

The KE2 Evap also eliminatedice buildup on the freezer on walls and ceiling.