Indeed, the volume supplied by the a/c is not sufficient. If you increase the air flow to the point where it could supply the engine, you would no longer be cooling it to a significant degree, because it would flow past the evaporator coil too quickly to get cooled-down.
What can be done, on forced-induction systems, is to use an air/water intercooler, and draw the cooling water from a reservoir instead of using a radiator to cool it. A pump circulates water from the reservoir, through the intercooler, and back to the reservoir. The water in the reservoir is often cooled by something simple like ice, but could be cooled by an evaporator coil submerged in the tank.
The water in the tank has a lot of thermal mass, so it maintains its temperature fairly well. Under normal circumstances, the air going into the engine is "cool," so the difference between the water temperature and the air temperature is small, and the transfer is inefficient; the a/c system can easily keep up with that small transfer, and maintain the water temperature at the desired point.
When the car is running on boost, however, the difference in temperature between the water and the air increases, which increases the efficiency of termal transfer - the percentage change in air temperature increases. This, of course, depletes the supply of cold water. But a forced-induction vehicle only runs under significant amounts of boost a small percentage of the time, so anything other than sustained high-boost driving will allow the system time to recover, between the sporadic uses of boost.
Since the a/c system does so little in comparison to the amount of heat added by forced induction, all it's really doing during that time is to create un-needed drag on the engine, so a pressure-activated switch is used to disable the a/c clutch whenever the manifold pressure goes positive. As soon as the car comes out of boost, the switch allows the compressor to resume its duties, re-cooling the water for the next time it will be needed.
If I go forced-induction on the Shark, that's what I'll be doing. It's not like there's room for a second radiator, anyway, so I might as well get creative.
Not quite what you were looking for, but still something interesting to think about.
Joe
