project: solar-powered accessories for my car

background

the honda fit (mine is a second generation model, arguably the best gen) is a good, efficient car. it's about as simple in engineering as a car can be with modern standards, not putting too much stress on its little 1.5 liter engine. however, there's a flip side to this, which is that air conditioning and alternator load make a substantial dent in fuel economy.

this is made worse by my specific use conditions: i often have to work split shifts, meaning i have four hours in the middle of the day in sunny southern california during which i usually want to take a nap in the car. what i often end up doing is idling the engine in order to keep the air survivably cool, which is horribly wasteful and makes fuel economy even worse.

what if, instead of just heating the car, the radiant energy of the sun could help me cool the car?