Refridgeration
Hi Jim..You might consider a holding plate to be like a battery, in that it will store cold, like a battery stores energy. The difference in efficiency is more related to the type of compressor and cooling that is used. In the same box, with the same compressor system, each will use approximately the same amount of power to reach the same temperature. The main advantage of a holding plate is that the compressor is not cycling on and off every few minutes like an evaporator. I started with an evaporator and found the compressor to be on for 5 minutes, and off for 5 minutes, 24 hours a day. When I switched the same system to a holding plate, the compressor would run for 40-45 minutes and stay off for an hour and a half. The only thing I added was water cooling which helped freeze the plate much faster. Less switching on and off means less stress on the compressor, and longer service life. Holding plates are usually better, but also take up more space in your box.Hope this helps.