Changes

For fridges, a general guideline is to provide 400-600 Btu of cooling per cubic foot of interior fridge space. For freezers, it is 900-1200 Btu per cubic foot. If you're buying a commercial unit, hopefully the manufacturer will have right-sized the interior volume, insulation and compressor efficiency.

When you have determined the cooling capacity and compressor size, the next step is to consider the energy requirements and source. A typical constant-cycling system, using a popular Danfoss compressor, will draw around 7 amps when running. If it cycles 30 minutes per hour, it will require 39 Amp Hours (AH) (7/2*24). A typical cold-plate system, drawing 35 Amps, and cycling for two straight hours per day, will require just 3 AH (35*2/24). Overall, a cold-plate system is far more energy efficient, but requires a heftier energy source (larger DC system or engine) when it is running.