A/C compressor drag?

[MaineShark]

How much parasitic drag does a typical A/C compressor have? Just curious exactly how much it costs, in terms of power loss, to have the A/C installed and running.

Joe

 

[corvettecrazy]

I don't know exact numbers, but it is definately a noticable difference when driving,

 

[KANE]

I don't know exact numbers, but it is definately a noticable difference when driving,

Conservatively- I have heard 10-20HP.

 

[Bob Chadwick]

Depends on the generation. Their efficiencies have improved dramatically since becoming routinely available on cars in the 60's and 70's.

Another thing to consider is wind drag. With the newer, more efficient compressors it is likely more efficient to run the a/c at highway speed rather than open a window.

 

[MaineShark]

I'm not much interested in cooling the cockpit - that's a secondary concern. I'm more curious about using the A/C system to cool a water tank, for an air-to-water intercooler. Packaging another radiator in a C3 is pretty hard (I already have the engine radiator, the A/C condensor, an oil cooler, a transmission cooler, and a hydraulic fluid (P/S and hydraulic brake booster) cooler. I just don't have room for another radiator.

I've heard of other people doing it, and it makes sense to me - the engine is only running on forced induction a small fraction of the time, so the water tank would have time to cool down sufficiently between bursts of compressor usage. While the engine is making boost, an air-pressure switch could kill the A/C clutch, to eliminate the parasitic drag.

Sounds a lot better than filling the tank with icewater, and being out-of-luck once the ice melts...

Joe

 

[KANE]

I'm not much interested in cooling the cockpit - that's a secondary concern. I'm more curious about using the A/C system to cool a water tank, for an air-to-water intercooler. Packaging another radiator in a C3 is pretty hard (I already have the engine radiator, the A/C condensor, an oil cooler, a transmission cooler, and a hydraulic fluid (P/S and hydraulic brake booster) cooler. I just don't have room for another radiator.

I've heard of other people doing it, and it makes sense to me - the engine is only running on forced induction a small fraction of the time, so the water tank would have time to cool down sufficiently between bursts of compressor usage. While the engine is making boost, an air-pressure switch could kill the A/C clutch, to eliminate the parasitic drag.

Sounds a lot better than filling the tank with icewater, and being out-of-luck once the ice melts...

Joe

Have you thought about electric? I would think with an inverter, you could get something from JC Whitney to work.

 

[MaineShark]

Have you thought about electric? I would think with an inverter, you could get something from JC Whitney to work.

I presume you mean running a small cube fridge off of the car's electrical system? I thought of that, but it would be less efficient than the direct-drive A/C system that's already there.

I also thought of using a solid-state cooler, but it doesn't have the same BTU capacity as the car's A/C system, and packaging is a concern (the heat sink is immediately opposite the cold sink, unlike the A/C which allows the evaporator and condensor to be mounted far from each other). I need to do more research on these, though, as it might still be a possibility.

Joe