Better cooling of cars

One of the best ways to keep a car cool on a hot day is to park under some shade. Well, why not carry some shade around with you?

My idea here is to provide a double layer of steel on the roof, with the space between open to the air. When the car is parked, this space would heat up first and, with appropriate vents in the top, allow some of the heat to flow out with rising air, rather than go into the car interior.

Of course, this involves additional material, so there is a trade off between saving in reduced load on air conditioning etc vs. extra energy in mnufacturing the extra steel. Safety may be an issue, given that some people seem to still leave children or small animals unattended in closed vehicles (see my post "Better operation of car airconditioning").

I consider it may also be possible to use the heat transfer via compression/expansion that I posted about in "No refrigerant cooling" in the spaces between the two roof layers. I'll aim to get some sketches on this developed over the next few months and posted.