VIVA SERVELL! -----Original Message----- From: Gill Ediger [mailto:gi...@worldnet.att.net] Sent: Wednesday, December 10, 2008 4:29 PM To: texascavers@texascavers.com Subject: [Texascavers] Refrigeration over fire?
At 03:45 PM 12/10/2008, Matt Turner wrote: >I'm really curious on how this works. I keep thinking it's April 1st. You'd do well, Matt, to just keep on considering every day to be April Fools Day. There's a whole herd of folks out there who'd have you believe all sorts of hocus pocus. Natural science, however, will provide the answer and the solution to the problem. Gas refrigerators have been around for a long time. We had one that used natural gas in our rent house when I was a kid. I have one in my shed now; it came out of a travel trailer and used propane. The principle of refrigeration (except on days like today when you just leave the door open) is that when a gas under high pressure escapes through a nozzle to a lower pressure it cools down in the process. Your home refrigerator uses an electric compressor to mechanically compress the gas (used to be freon, now is something else). The gas refrigerator uses a small flame (about the size of a candle flame) to heat its gas (traditionally ammonia because it has a lower boiling point, but now could be some other high tech gas ???). In both systems the gas is expelled through a fine orifice into the cooling coils located within the freezer compartment. As the gas expands it cools down considerably--sufficient to freeze water. The thermos-sized thingy shown suspended over the camp fire is probably some variation on that same gas refrigeration theme. There is likely a gas filled cylinder in the bottom that is heated by the fire and that HP gas is forced through a nozzle into the LP coils surrounding the upper chamber--or a probe or something similar. A few years ago there were several (European?) beer companies that had cans which would cool a warm beer in a few seconds whenever the top was popped and the pressure released. They had a captive, pre-pressurized cylinder with a valve of some sort that was triggered when the initial pressure in the can was reduced. Or something along those lines. Ain't science grand? --Ediger --------------------------------------------------------------------- Visit our website: http://texascavers.com To unsubscribe, e-mail: texascavers-unsubscr...@texascavers.com For additional commands, e-mail: texascavers-h...@texascavers.com --------------------------------------------------------------------- Visit our website: http://texascavers.com To unsubscribe, e-mail: texascavers-unsubscr...@texascavers.com For additional commands, e-mail: texascavers-h...@texascavers.com
