Calculated Energy Savings for Disabling Anti-Sweat Door Heat on Glass Display Case Doors

A grocery store customer within PG&E territory installed Anti-fog film on the inside glass of a five-door frozen food display case and the door anti-sweat heat was disabled on the doors of the display case. PECI analyzed actual energy consumption for three weeks before and three weeks after the door heat was turned off to determine the avoided energy use from reduced load on the compressor and reduced door heater energy use during the post retrofit period. Energy data was metered at the doors and at the condensing unit serving the case to capture savings directly from the reduction in door heat power and to capture the reduction in load on the condensing unit. The pre and post metered data was also used to calculate estimated annual energy savings. As a result of this study, PECI supports that there are savings at both the door and the compressor for turning off the door heater on a frozen food case. However, PECI feels that additional testing needs to be pursued to verify the Anti-fog product’s performance at different conditions in the absence of door heat.