Einstein's Refrigerator - Cooling Agent & Size Matter?? I'm looking at Einstein's patent #1,781,541 for a closed non-mechanical refrigeration unit approved Nov. 11, 1930, filed Dec. 16, 1927. http://www.fourmilab.ch/etexts/einstein/uspat1781541/www/" [Broken] I'd like to power it with the solar heat from 1 or 2 of my mirror covered mini satellite dish(s) commonly called a "Death Ray" on the youtube videos. The question I have is about the size and cooling agent refrigerants. First of all I don't want to build a big one, and I don't want it do be under 100's of PSI either, nor do I want to use dangerous Ammonia nor butane gas. Are there more modern possibly even better alternatives? Does size matter, can I scale it down as much as I want and it still make ice? I'd like to use a little Propane Gas instead of Butane, since we all have it readily available in gas form, and it isn't considered dangerous. I'd also like to replace the Ammonia with Methyl Alcohol (vehicle anti-freeze) since it is very cheap and easy to get at any auto store. Finally, I want to make it really small, I mean tiny, like 1 foot wide by 1 foot tall, using just a few ounces of fluid, out of ice maker tubing (or fish tank tubes) with fish tank aerators for distributor heads, copper tubing and aluminum cans (only where it needs to be heated), PVC hot/cold pipes for external tubes surrounding smaller tubes, using solar powered computer heat sinks and fans where heat condensers and/or heat ex-changers are needed. Will this be possible, or do I have to make it really big with all the dangerous uncommon ingredients to get it work? Thanks!