Options:

No Air-Conditioning:

Dual Shaft Motor: this option is the most similar to AC in a normal car is to run the AC compressor off the rear shaft of a dual shaft motor. The advantages are simplicity and similarity to standard cars but the AC will only work when the motor is spinning. This Saab is an example of using this approach.


Accessory Motor: Another option is to run a small 12V accessory motor which is attached to the compressor. This approach allows AC to be used when the car is stationary and means that there is no direct drain on the power to the drive motor but adds weight and complexity. This Honda is an example of using this approach.


Ice: Rather than storing electricity and using it to lower the temperature of the car it may be easier and cheaper to store a direct source of cooling; ice. Blowing air through an ice water mix is a rather effective form of cooling and might be sufficient for your cooling requirements. A DIY example can be seen here, or you may prefer Mr Sharkey's no nonsense approach here.


Compressor with integral motor: A more recent option is a compressor with a motor built in like your home AC unit. Some of the newer hybrids use this technology such as the Prius or this conversion which utilizes a variable speed control to maximize efficiency. With this option you also have more freedom as to where to locate the unit and you don't have a lot of mounting hardware to fabricate.

http://www.evdrive.com/BMW_project/AirConditioning.html Extension of the above is DC powered complete unit. Expensive , but compact. DC-Breeze is an example. ~$2,500 for 5,000 BTU / hr cooling all in a ~50 pound package... just plan for the ~580 Watt load to run it. Another integral motor option in 2011 is Cool Blue Air Conditioning Compressor/Condenser Unit, using your original evaporator.


Seat Heater-Cooler: Like some new vehicle seats cool the drivers backside. Thermoelectric cooling ( TEC ) technology. [Peltier] (From an advertizement) Inside the seat pad there is 6 polyethylene tube flask in the fire proof material. 1/3 of the tube can be felt when human body touches the surface. And immediately you can feel cool or warm. The car seat cushion’s power consumption is 30W. Working continually 33 hours will consume 1 watt–hour electricity. The thermoelectric ( TEC) car seat cushion works in low safe 12V voltage both it's cool and warm function. The tube, which carries antifreeze, can bear 150Kg pressure. And there is a pump inside the power box that transfers cool or warm to the pad surface. The power system is separated from the seat itself. In low voltage condition it is very safe to use in normal. All the materials are fire resistant to ensure safety. The circulatory system is airproof and no probability of leakage. Huimao China