Sorry to be so late, WW - I forgot where this thread was. (Senility, you know) Anyhow, TEd explained the heat pumping cycle of a refrigerator quite well, but nobody's mentioned that in earlier times electricity was thought to "condense" on a plate in a capacitor, leading to the misnomer, electric condenser.

As for running the car's A/C with the windows open, I don't think I've ever seen a compressor ruined by doing so, but it would be possible. Some recent A/C systems run the compressor constantly, and control the temprature through the use of a suction throttling valve, while others use a fixed orifice. The older systems with both a compressor clutch and an expansion valve seemed a bit more prone to failure. I've been out of automobile service for ten years, so I'm not really up to date on this stuff anymore. Now, if you want to know about chain saws or lawnmowers...

This brings up yet another question: Why do we refer to the refrigeration system of an automobile as "air conditioning?" A heater also "conditions" the air, as do the emissions of a passenger who hasn't showered in some time, etc.