We Americans have a thing for “the coldest beer in town”. Just go to England for a long draught of a pub’s typical fare to see what I mean. I can still manage to get that seemingly only-cooled-in-the-shade British ale down when I’m there, but it’s not what I’m used to back here in the old colonies. Truth be told, it’s not the way I like my beer, either. Six-packs are meant to be ice-cold. Kegs, too. Refrigeration of beer has always seemed like a good way to spend a few kilowatt-hours of electricity. But, as always is the case, the fewer the kWh used, the better.
Refrigeration performed by a compressor-based system is better at cooling than electric resistance is at heating. One kilowatt-hour of electrical energy input into a space introduces exactly one kWh of heat (3412 BTUs) into it. At least with mechanical refrigeration you usually get more than one BTU of cooling of a space from every BTU of electrical energy input into the system. The actual amount of cooling achieved depends on the relative temperatures of the cooled space and the air around the condensing unit. Unfortunately, the warm weather that makes a cold beer so refreshing is also responsible for so much energy being needed to cool it down.
Refrigeration in the middle of July is an inherently energy-intensive process. Lots of energy is needed to run the compressor and the condensing fans, and more and more of it is needed as the weather gets hotter and hotter. Evaporator fans need electrical energy to operate to transfer the cooling to the space (and the beer) and also need it for periodic defrost cycles to keep the evaporator coils free from ice and frost. The glass doors of cold walk-in coolers require electric heaters to warm the doors and keep moisture in the air from condensing on the glass and door frames, which otherwise creates fog that obscures the view of the beer on the shelves and makes the door frames drip water. The colder the walk-in, the more door heat that is needed. All that electricity used inside a walk-in cooler turns into heat, which just makes the refrigeration equipment run that much harder and use even more electricity.
However, there are a number of ways that Freeaire can save energy to cool beer the American way, like with ECM evaporator fans, intelligent defrost, evaporator fan control, door heater control, and even by harnessing good old American winter weather with a Polar Power® package. Other blogs will deal with each of these in depth.