I haven't built this yet but I've had an idea for it: Take a high-volume 12v blower or computer fan and string nichrome wire across the exhaust for the fan (of course aimed at the window), and wire that assembly to a relay so you don't melt your wiring harness (I've already rigged my blower to a switch that's independent from the heater switch so that it's full blast even if the heater's off). Once I find an appropriate blower for cheap (my Mav's is toast) I will implement it. Nichrome only costs about $.20 a foot and it would only take about a foot for this to work in theory (hair dryers are the same concept: A powerful blower blowing past nichrome wire). I'm interested to see what people think of this idea.
sounds legit to me... Just have to build a good case so the wires don't melt the fan. and if it's cold out.. .which it usually is when using rear deffoger....you'd have to make sure the wires get hot enough... I wanna do something similiar with AC.. Put a cooling elment out of a mini fridge in the central air box. right in the center of the dash ya know.... But you have to know if it can sufficiently cool/heat the air you're blowing in the short time it passes the wires to do it's job effectivly.. Or jsut try it.
Nichrome wire will definitely get hot enough. The mini fridge idea is one I've also thought about doing but it's more work than really worth where I live at least.
Having owned several mini fridges, I can tell you right now it won't work for AC. They work like a heat sink, a fan blows air over the hot side, some have a fan to blow over the cool side, too. They have to be in a container sealed from the outside temp, or they won't work very good. And they will only cool an enclosed container 20* to 30* below the air temp. So on 90* day, you get 60* cooling in the container at best. And that is in a container about 12" x12"x 12". To use one to cool a car, it would have to be as big as the roof to be effective, and the hot side would have to be outside the car.........
