Can I use my car's air conditioning unit to cool a refrigerator in the car? I would remove the evaporator unit from the air conditioner, construct and fit an evaporator coil to the refrigerator box, add an appropriately calibrated switch and thermostat to the circuit to switch the compressor in and out but the rest of the unit would remain in place.


The vehicle is a bus, engine at rear, currently no aircon, I have a car air conditioner that I can run off the motor. Fridge would be a permanent install. Could fit a domestic freezer evaporator to the fridge onboard, then plumb it into the car compressor etc. use a thermostat to switch the compressor in and out. I agree may be easier to just fit a dometic RV fridge unit but less fun.


1 Answer 1


The principles that a car AC and a refrigerator are built on are the same, i.e. a heat exchanger, so I'm sure with enough engineering it can be done. However, it's going to be challenging and probably impractical to achieve. It would have to be a permanent setup and where will the fridge be, the trunk? If so, you'll have to run refrigerant lines from the front of the car to the back, which isn't going to be particularly efficient. Using your car's AC to cool a fridge will mean you can't use it to cool your car at the same time most likely. There's also issues with the type of refrigerant, if they both don't use the same type you may have a poorly running refrigerator.

You'd be better off using your car's power supply to run an unmodified refrigerator, it would be a lot less messing around, all you'd need to do is run power to wherever you want the fridge. If it's a big fridge you may want a beefier alternator, which is much simpler to install than what you are proposing.

  • This sounds like a much better idea. How on earth is the OP going to get refrigerant lines to the back of the car? Sounds really impractical. Nov 30, 2017 at 10:44
  • It depends on the car, I'd think under the chassis would make the most sense. Those lines are expensive too!
    – GdD
    Nov 30, 2017 at 10:53
  • OP never said back of the car... He could cut out the lower passenger side of the dash to install it for all we know.
    – JPhi1618
    Nov 30, 2017 at 15:44
  • It could be a SUV or a minivan, no idea, but he'll have to figure out the pipework anyhow.
    – GdD
    Nov 30, 2017 at 15:57

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