So, I'm learning about absorption refrigeration, mostly because I now have a fridge that uses it and I'm a nerd.

Engineering Quandry

The basic principles (that totally is amazing to me) is that you use heat to to boil ammonia and water that then cycles through an evaporator, mixing with with hydrogen to reduce its partial pressure then magic [Boyles law] happens and heat is drawn out of the medium where the evaporator is the Ammonia gas cools, and mixes with water and the hydrogen returns to the loop and it starts all over again. Its refrigeration without a compressor and only a heat source to drive the cycle. Its often used commercially to use waste heat and either chill fridges or power AC system.

After reading up on its use for AC systems I came across something interesting. The trouble with getting AC from Solar heat (blows my mind) is that you need 190 degree water or higher for the cycle to work. Then it occurred to me...what has an abundance of waste heat in the form of 190 degree water? a radiator for a car!

So here's my question: Aside from complexity and cost, why aren't we using that waste heat to drive our ac? granted the SOP is 1/4 of a compressor but the advantages are too cool (sorry) to not consider.

1. smaller radiator means less frontal area means more aerodynamic

2. FREE AC! its waste heat anyway, you would be putting that gas back to good use

3. No AC compressor sucking up my precious Horse Powers. Also, more MPG

4. If you used a air to liquid heat exchanger you could store cold air performance and send it BACK to the cooling cycle if needed OR cool other components like transmissions or differentials

5. its all driven by heat, nothing else, no electronics, no belts, nothing. (aside from blowing the cold air)

I Don't know the engineering behind the Cooling tonnage required for a car, but it seems that in a world of electrically decoupled accessories, this would be an area worth investigating.