I recently visited my brother in New Zealand. Kiwis are inveterate DIYers, and the previous owner of his boat had installed a home-made engine-driven refrigeration system around an automobile air conditionning compressor and a holding plate. That was one powerful little freezer! Cooled our beer right down with just a few minutes of running the engine. He says it takes very little operation to keep food absolutely frozen.I've not heard of using a car ac compressor before. My brother says it's common practice in NZ - is it done here?