I was thinking, I am not to much on phase change cooling, or DIY for that matter. But I thought I would suggest this idea, which, not sure would even work. Would it be possible to take an old but working compressor/evaporator/condenser out of an small automobile and power it with a small 12 or 120 volt motor? Thus, powering the compressor? Like I said I don't know if it would work, but just an idea.