My car gets really hot in the summer. I've measured 15°F above ambient on a sunny day with the windows down. I've also suffered heat-related illness after 8 hours in the car at 100°F, though that was in May when I was still conditioned for winter.
I want to load ice into a large cooler in my trunk. A pump will draw liquid water from the bottom of the cooler and move the cold water near the driver's skin, then a return hose will send the hot water back to the cooler. It might be a very efficient system since it cools only the driver. I figure you'd burn through about a kilogram or two of ice an hour, so a large 40Qt Igloo cooler holding 25kg of ice could potentially last all day.
I was going to use a washer fluid pump, since it's 12V and I already have two spares lying around. Hoses: vinyl and/or neoprene, should come in under $10.
The only part I haven't figured out yet is the driver-to-water heat exchanger. Has anyone else built one? I'd need a tubing with small bend radius and good thermal conductivity, which has me thinking about copper. But vinyl might be more comfortable, and less likely to kink if you rest your weight on it. Thoughts?
There are liquid cooling vests available, such as the
(probably a thousand dollars) and
CoolShirt ($140).