Roger Priddle wrote:
I'm not sure I understand your point about "31°F is a lot warmer than -20°F" - are they the temps at which ammonia and butane change from vapour to liquid? The lower vapour/liquid temp. ("boiling point"?) makes sense to me to make circulation easier.
BTW, if I use propane/butane, what kind of pressures will there be in the system? Would it be different for ammonia? (This question is based on the notion that a system under less pressure would be more stable over longer periods - but I don't know if it's true or not...)
Pam Hatfield wrote:Here is a page about the Icy Ball which seems to be a fairly simple project although it still does use ammonia. These used to be manufactured in both Canada and the US.
http://crosleyautoclub.com/IcyBall/crosley_icyball.html There are some links on it to plans for making one, but all the links everywhere emphasize how dangerous this can be.
Another site has instructions to make one but also has some serious warnings about the hazards involved.
Any idea whether this would work using something other than ammonia?