Energy Analysis of Various Supermarket Refrigeration Systems

Modeling and analysis work was done on various supermarket refrigeration systems for their energy efficiency, TEWI (Total Equivalent Warming Impact), and annual operating cost. The systems which were modeled in detail include parallel racks, distributed, self-contained, glycol secondary loop, and CO2 secondary loop (medium temperature) and cascade (low temperature). Based on R404A modeling results, distributed systems with scroll compressors have energy usage 6 to 9% lower than the baseline parallel rack system. On the other hand, selfcontained units with horizontal scroll compressors and water-cooled condensers have energy consumption 11% higher than parallel racks, and glycol fluid secondary loop systems have energy consumption 15% higher than parallel racks. CO2 secondary loop/cascade systems with propane as primary refrigerant have energy consumption comparable to parallel racks. The CO2 systems also have low TEWI.