Energy saving potential at partial load for vertical glass door refrigerated display cabinets.

An experimental study was performed on a vertical glass door refrigerated display cabinet in order to determine the energy saving potential at partial load operation, i.e. at less demanding climatic conditions and door opening frequencies than the design requirements. The cabinet was tested with full loading in a climate room according to ISO 23953. The baseline test was conducted at the design conditions of 25 degrees Celsius (25°C) and 60 percent relative humidity, with the tests simulating partial load conditions at 19°C and 50 percent relative humidity. Two different series of tests were performed: stable night conditions (closed doors, lights off) during a 24 hour span, and an ISO 23953 door opening test. The procedure was to minimize the total energy consumption and comply the specified M-package temperature class of M0 (-1 to +4°C), while adjusting the cabinet settings separately. The tests demonstrate that, compared to standard settings, the total energy consumption at partial load can be decreased by as much as 28 percent and 22 percent during stable night conditions and standard door opening test, respectively.