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Discussion Starter #1
Ok, you experts tell me why this wouldn't work.

I was looking at my window mounted ac unit and started to wonder what if. The compresor in a cars ac runs off the cars engine, thus robbing alot of hp. what if we set up a small heat exchanger in front of the turbo, like an air/water intercooler, but instead of water, its a sealed AC system with parts made up of a window AC unit that runs off the battery(ie no power loss). We could mount the ac condensor(small) where the stock intercoolr goes(if you have a FMIC). I would imagine it would have an efficiancy exceeding 120%...

remember, an 11degree drop is 1% hp gain........my window unit right now reduces temps by 45deg......on a bpu thats 16rwhp!.....on Saads car thats 36rwhp!!


ok guys.......tell me y this won't work?
 

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Not a bad "brainstorm":D

The type of system you described is exactly how an A/C system would operate on a commercial aircraft. They too have an air cycle machine (actually looks like a huge turbocharger), heat exchangers and H2o seperators.
There would be a couple of issues you'd run into:
#1 The equipment you would use from a home A/C system operate under different conditions than your car. Typically they don't deal with extremely high, compressed air moving at a high rate. I don't think the system would be able to keep up.

#2 Like I mentioned before, commercial aircraft Pack (a/c) systems operate more closely to the system you are describing. They have the ability to mechanically reduce compressed air temps to below 39degrees, but the system is large and complex.
Hot bleed air is taken from the APU (auxillary power unit) and flowed to the turbine side on an ACM (air cycle machine). This is just like the exhaust gasses from your engine flowing to the turbine side of your turbo.
The compressed air is then cooled using primary and secodary heat exchangers and then sent through a water seperator and on it goes.
The Problem:
The amount of pressure you would lose in this process, even on a small scale like your car, would be tremendous. You would almost have to by a huge turbo that could support 40 psi just so you could have a sufficient cooled, compressed intake charge. Also remember to be effective, the system has to operate continuously, unlike the conditions in your car.

As was once told to me:
"Keep the thought processes...please don't let me playing 'devils advocate' limit your creativity. HKS is not the only bunch of guys that can come up with good technology for making our cars go faster."
 

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SupraForums Member
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Those packs are huge!

If you where able to install oneof those on your car, you would not only overboost the engine,but you will overboost your whole car along with you in it! lol


ATL, I dont think ill ever touch another one of those 27 pack systems. No more 27 down here at MIA. :)
 

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BLK-SP64 said:
what if we set up a small heat exchanger in front of the turbo, like an air/water intercooler, but instead of water, its a sealed AC system with parts made up of a window AC unit that runs off the battery(ie no power loss).
No power loss? There is no free lunch :) The alternator saps power from the engine just like everything else. Which is more effecient, belt -> A/C, or belt -> Alternator -> electricity -> A/C ?

Turbos take advantage of the ICE's ineffeciency. To get it for "free", you'd have to scavenge some other-wise wasted energy.
 

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Getrag Gearhead
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A/C works by the change of states of matter. The cycle starts at the compressor. Here the refrigerant is compressed. The temp and pressure is increased. The output is high pressure and high temp gas. From there it passes thru the condenser. This unit is the intercooler for the A/C. This unit will take the temp and lower it but the pressure will remain approx. the same. The compressed gas will begin to liquidize. The next Item it passes thru is the recieved/ drier. This unit has a inlet at the top and an outlet at the bottom. Its designed to discharge only liquid and also to lower harmful water/air from the system. It does this by utilizing a descant (you know the small packs of stuff that says don't eat when you buy a camera). The old refrigerant R-12 (CFC) used to utilize a descant called silica (sand) but the new refrigerant (used in the MK4) is R-134a (HFC) and is a synthetic refrigerant. The oil used in the system isn't mineral oil like the older systems and uses Poly Alkalene Glycol (PAG) and descant is Zeolite.

Once the refrigerant passes thru the reciever/drier it enters the cooler unit inside the dash. This unit is called the evaporator. Here the liquid refrigerant is metered thru a small valve called the Expansion valve right before it enters the evaporator. This valve modulates the amount of refrigerant to discharge from the valve into the evaporator. The evaporator's output is connected to the inlet of the compressor and this long process replicates. In the evaporator the refrigerant once again changes states. From high pressure normal temp liquid to low pressure very low temp gas.

In order for utilizing the A/C system for an intercooler would be very difficult for anyone who is trying to use it in place of an intercooler. The unit will not work for a drag car or a top speed run. It will work for a car that is piddling around traffic for only a marginal amount of time. Since the engine is powering the compressor and is a mechinical device there is efficiency loss. Also in the area where the refrigerant changes states there is efficiency loss. The only possibility for a drag car would be to have a very large reciever/drier (the size of a NOS bottle) and use it as a reserve. The unit will also require a weight scale and proir ro having the drag pass made the compressor is shut off. The vehicle makes the pass and if the reserve tank (drier) runs out the temp for the intercooler will rise. This can set off detonation and the system will need additional electronics or a programmable ecu (AEM EMS) to take away a set amount of timing to compensate for the rising temps (power loss). The low side of the system will begin to collect moisture from the atmosphere and have water dropping all over the track unless it were to have a catch tank for all the low side connections including the cooler unit.

Don't get me wrong it can be done. But now you get to see what all is involved here.

Joe.
 

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Shawn Davis
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I don't recall if its ford or chevy but they just showed this kind of system (or something similar) on a prototype truck. Check the off-topic forum for a post or two on it. I believe their system was more of a one shot deal. In other words they cooled a chamber of fluid (water?) using the AC system. Then when you flipped a switch the cold water would flow over your IC to cool it and then return to the reservoir. Then it would be cooled again over time by the AC for your next "shot".
 

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Live your dreams
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On a similar track...

Has anybody ever attemted to run the alternator off the wasted ex heat & kinetic air energy?
It seems that decoupling the alt will both, reduce the rotating mass (for faster accel) and overall reduce the robbed HP.

I realize that the cost, size and relative complexity of such a solution may not be worth it...
Nevertheless, I wonder...

Grant said:


... To get it for "free", you'd have to scavenge some other-wise wasted energy.
 

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Super Moderator, Piss me off. I dare you.
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Nitrous is my heat exchanger. :gotnx:
 
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