Why isn't there an independent Air Conditioning system in a vehicle whereby fuel consumption is not affected?

Question

Though the cooling process may be slow, can we use the engine heat for expanding the gases and pass through a ventury as in some old refrigerators.?

Answer 1

Air conditioning is accomplished by moving heat energy away from the interior of the car to the condenser mounted in front of the radiator. To do that requires energy and a lot of it. That is why the power bill goes so high during the summer.
It is possible to have an AC pump that is not mounted to the engine so it does not affect your MPG. Actually you see them all the time mounted on the tops of campers and on the fronts of many big-rig trailers.
However, those AC units still require fuel to operate. Whether or not you fill the AC's fuel tank at the same time you fill the engine's tank, makes no difference in the end. For example, if you drive from DC to LA, you might put a total of 200 gallons of gas in the car's tank and 40 gallons in the AC's tank. You have still burned a total of 240 gallons. I
internal combustion engines are not 100% efficient and need to use energy just to run. By tapping off the car's engine and not having a second motor running, that 4 day trip would use 220 gallons. You would save 20 gallons.

Answer 2

A single phase air conditioner needs 1 HP per Ton (12,000 BTUs per hour). One Horse Power is 746 watts.
Most electric motors are 60 - 70% efficient.
So, 746 watts x 160% eff = 1230.9 watts needed to produce 1 HP of work
So, for the 4 Ton A/C unit , we need a 4 HP compressor motor
I believe most condenser fan motor are about 1/3 - 1/2 HP on a one ton. So I think a 4 ton would have about a 1 1/2 HP motor (I am guessing)

That would adequately cool a 6,000 sq foot building.

A car requires much less. The car compressor runs off the harmonic balancer so let's say it drains less than one HP from your engine's performance. Cold air is circulated by the same fan that powers your heating system....maybe 1/2 HP.
The overall effect of both is negligible when it comes to calculating effects on performance and economy.

An independent system would require an independent fuel source, independent fuel storage making the vehicle heavier. That would adversely affect fuel consumption itself.
Right now engine heat together with heat from the air expands the coolant in the condenser so your suggestion would result in the system not being 100% independent.

My point is, the overall efficiency would conceivably not improve by redesigning as right now the cost and effect on performance is small in relation to the operation of the vehicle.

Hope I wasn't too technical.

Answer 3

Interesting Idea, but you would still need a compressor, unless you use a miniature version of the vapour absorption method, which is really not proven even for larger installations.
One take on the existing system is to install a turbo which would drive the compressor, rather than taking it off the engine's power. But it would require higher rpm's to run and would not work if your car is already fitted with a turbo for the engine.
If the car is very small, maybe you could get a solar powered battery pack, and put a small compressor in the boot and get it to cool the insides. that way when you are parked in the sun, the car would actually be cooling.

Answer 4

You need an independent energy source to operate it , this will by itself rob the car of efficiency.

The cost of manufacturing will go up. The net result may be more overall energy used, and less fuel efficient car.

Fox waggon in their station waggon had separate gas heater, which used gas from same tank to keep passengers and the drivers warm, it had lots of problems, as the car got older.

Answer 5

what would run it,electrical power would have to be made and that takes power,you could power it of a drive shaft but that takes power you could use a swap cooler but they are inefficiant and would ned to be filled with water all the time,the system you are talkin about is an absorbtion unit,they stop working when the outside temp gets too high and would you really like a system full of ammonia in your car

Answer 6

GIT THE GIT