My Intercooler Concept (A/C. Nuff Said?)

Hey guys! Some you may have already heard me talk about Air Conditioner-to-Air intercoolers (Freon-to-Air). Well here's my concept sketch. If you can find a junkyard with any in-window air conditioners, weld aluminum together, and find a switcher valve for A/C lines, you're all set! I'm gonna use an old unit my dad has. The blower motor is shot, but all A/C stuff is fine. Freon too! Which can't be made in the US. It has to be imported from Canada.

I'll buy some aluminum sheet metal, weld it to the radiator-like-unit in the old A/C unit, and... well, just look at the picture I made, based on my original sketch. See what you mad scientists think, if there are any flaewus or something (HEHE, flaws)

C:\WINDOWS\Desktop\AC Intercooler.jpg

I would expect the main HP increase to come from the turbo boost. There certainly would be an incremental HP gain by using an intercooler but I'm not sure the gain would be offset by the HP required to run the air conditioning unit. Using an intercooler would be a "free" HP gain as long as you don't have to expend HP to do it....

Thing is though, Air-to-Air intercoolers only get as cold as the outside air, and in the summer, which is the only time of the year I really use my Fiero alot, the air is kinda hot. So let's see, A/C coils produce what, 35 to 40 deg. F??? Less? Outside air is 90 in the summer, 80-100 by me in summer, so that's a bit of a temp difference. And if it makes the air that much denser, who knows, maybe it'll work.

I'll see if my cuz will let me use his civic as a test project when he turbocharges it at the end of summer (he's having too much fun with his Venom NOS right now). I'll try an air-to-air IC, and then link the A/C to my idea. He says he wants to take out his A/C anyway. After Nosin' the thing, he'll never be able to sell it, so it's kinda his learning, killing, destroying, tool.

How about liquid nitrogen? Works for the NYC phone lines underground. Plus Air Products Inc. is near my house, so NOS, Nitrogen, and other fine gaseous and liquid elements are 15 minutes away. (I'm kidding about the Nitrogen. It's illegal on cars, I think)

I do have one other idea. It will involve a 150Amp (or greater) alternator. Those ceramic peltier modules that run off 12V and draw about 3 Amps, get too cold to touch when you put a heat sink on the hot side. Get a radiator fan on those heat sinks, and I'll have something colder than A/C, without all the freon. Just more wires.

I'll make a drawing of that.

With a intercooler you gain power since the the density of air increase.

If you want to use a heatpump, like AC-compressors all the power that you got extra will be needed to drive the pump... basicly a bad idea.

It's better to use freon free R134 coolant... but it won't work anyway.

But there are ways that works, fore example the use of ice water. A water ic with a tank of icewater, but this is only suitable for dragracing since it only can be used once then you must get more ice and cold water.

The use of liquid nitrogen shoul also be possible, use the same way as with icewater, but when the nitrogen gets hot it will vaporise, so this is also a kind of "one time use only".

If we take a say 300 hp turboengine, the turbo will deliver about 0,3 kg of air per second, say that the temperature after the compressor is 120 degrees celsius and we want it to drop to 0 degrees, and for every 1 C and kg you will need to take 1kJ of energy from the air, in this case it means that the total energy per second will be 36kJ. This is practically a power of -50 hp, and that isn't easy to just cool away since the airtemp is higher than the temperature we want.

There's another important detail that I don't think anyone has mentioned yet - that the cooling systems will draw more power from the engine than they remove from the air. If you were taking 50hp out of the air, you might have to take 100hp off of the engine to accomplish this (more if you use the thermoelectric gadgets).

Originally posted by ivymike1031
There's another important detail that I don't think anyone has mentioned yet - that the cooling systems will draw more power from the engine than they remove from the air. If you were taking 50hp out of the air, you might have to take 100hp off of the engine to accomplish this (more if you use the thermoelectric gadgets).

I only mentioned that all extra power you got from by using a heatpump you will lose when you drive the pump, but it's correct that you will lose more.

By using a ait to air intercooler or a water to waterintercooler maybe you can get the temperture to drop to a little above ambient air temperature. In the example above that will be from 120+273 K to 30+273 K, this will mean a density increase/power increase (if we don't consider the losses from the ic) of around 1-((30+273)/(120+273))=0,229, 22,9%.

I have a sneaking suspicion that the AC condensor would not be able to handle the power requirements of this application... Then again, the power rejected by the condensor will be a multiple of the power accepted by the evaporator, and the evap may not be able to extract all that much heat from the intake charge. Tough to say off the top of my head...

AC compressors that are used in cars take around 10 hp... and their cooling effect won't even be near what's needed.
The air flow into the coupe of a car is small, even at full speed, and the temperature drop is a couple of degrees, probably never over 20 C.

it's actually a tough problem to consider in full enough detail. I've just spoken to a friend of mine who used to work in engine development at Ford, and he said that at one time such a scheme was proposed there, and made it a considerable way before being dropped.

Seems to me like a sensible approach might be to combine this AC cooler with a normal intercooler, as a second stage, to reduce the load on the AC system. It's tough for me to say whether or not such a system could pay off in the end. When I get a little time perhaps I'll do some calcs to see.

By using a ait to air intercooler or a water to waterintercooler

You mean water to air. If it was water to water, you'd have a water cooled intercooler with a turbocharger pumping water. Kinda funny actually :)

And R-12 is colder than R-134, maiking it better than R-134. Freon was stopped only cause the ozone layer was depleting from it. This A/C thing worked ina Jaguar back in the 80's, but may I remind you that it means having a switcher valve to switch between the intercooler and the climate control. Now another thing, I have to turn off the A/C within two minutes of it being at full blast because it's too cold. My A/C got top ratings from Consumer Reports back in 84'.

Anyone know the HP loss between a 95Amp Alternator to a 150Amp one? I'd need that for the peltier modules, plus a deep cycle battery wouldn't hurt. See I'd use Air-to-Air intercoolers, but the thing is, my engine is in back (mid-engine actually), and efficiency of air-to-air intercoolers isn't like the eclipse's and 300ZX's that are practically made for air-to-air intercoolers. And water cooling isn't really good unless you're dragracing (one time ice water) or unless it's for a boat. I could link a water-to-air intercooler to the engine coolant system, but it means getting the rather large quad core radiator, which might actually shift more weight to the front (I have a weight ratio of 44/56, F/R). I'll try stuff, see what works.

I got money to blow on this anyway. I want to enter a car into the USCC that's going to be unique, which isn't something Sport Compact Car magazine has had in that contest in its two years.

Here's a low estimate for engine power input to each of those alternators:
95A * 14V = 1330W (electric)
1330W / 0.85 = 1565W (engine)
1565W = 2.10 HP (engine)

150A -> 3.32HP (engine)



I think you'd better do a calculation or two in/re the peltier modules before you try to use them. If SaabJ's estimated power rejection (50HP) is correct, and if the Peltier modules removed 1J heat for every 1J electricity consumed (they're typically worse than that), you'd need nearly 500 of the 2" by 2" 75W Peltiers, and a 2700amp alternator to handle the load. (Keep in mind that a 2700amp alternator is going to require 55HP or more to keep it running @ full output.)

Originally posted by ivymike1031
Seems to me like a sensible approach might be to combine this AC cooler with a normal intercooler, as a second stage, to reduce the load on the AC system.

This makes a lot of sense. After all, the A/C's original purpose is to move heat from the air blowing into the cabin. The A/C is only designed to drop ambient air a few degrees, imagine how much more work it is to bring down the temperature of intake air after it goes through the turbo. If you use an air/air intercooler to bring the intake temp closer to ambient, the A/C is doing closer to its original job. Still, consider how much air it's trying to cool. Therodynamics just don't seem to favor this, since the contributor of drive power and the beneficiary are the same engine.

If I were you, I would simply use an air/air intercooler. I know it doesn't look like you have any place to put one, but hear me out. First off, realise that an air/air IC follows a similar principle to the turbocharger: it takes advantage of a biproduct of the car's operation and turns it into something useful. The turbo uses exhaust gas to pressurize intake air, and the intercooler uses the wind that the moving car "creates" to average ambient air temperature with that of the heated intake air. The power gains are always greater than the pressure loss (as long as the IC is a reasonable size). Now here's how you fit it on your Fiero...

Ever seen an MR2 with a big air scoop running down the back window? It looks weird, but it works. Remember, the car has a wing shape, forcing air above it to move faster than air below it so that they arrive at the rear of the car at the same time. Take advantage of that by placing an intercooler right in the path of the accelerated air. I would remove the spoilter altogether and put a fair-sized intercooler in its place, mounted at roughly the same angle. You can then mould some fiberglass around the edges (non-functional surfaces) and paint it to match the rest of the car. Put a heat dispersing coating on it or something to increase its effectiveness, and you easily have the unique IC system you wanted. Hey, if you have money to burn, I'm sure you could have a shop design a custom IC to look however you want and still be functional. I've seen tapered ICs for motorcycles that might emulate the spoiler shape better. In any case, it ought to work and would certainly be very trick. With some tweaking, you should be able to get it to generate roughly the same downforce as the old spoiler, unless you want more (or less).

As far I know freons are only allowed in some developing contries, otherwise it's banned.

A watercooled ic works fine for dragracing and street, since you usually don't use full throttle for such a long time. The tank used should be so big that the water only needs to go through the ic once under full throttle.
When the engine is under boost the air is hotter than the water but when there is no boost the water is hotter that the air so then the intake air will cool the water.
Since water transports heat better than air a smaller ic will do the job, this also means that you can chose a copper core element without adding to much weight. Copper transports heat better than aluminium and this allow a even smaller ic to do the same job.
The cooler for a waterbased ic can be a oilcooler, or have the same size as one, this is because that water transports heat better than air as I mentioned above but also since the time when under full load (and boost) is usually shorter than under partially load.

A water ic with the engines coolant is basicly a bad idea.

And remember that heat is a must to get fuel to vaporise, too cold intake air can give problems.

Canada isn't a developing country... and u can get freon in all garages...

Originally posted by BeEfCaKe
Canada isn't a developing country... and u can get freon in all garages...

I wonder if these aren't freon replacements.

I've been looking into a Peltier-assisted intercooler as well. The best I've seen for efficiency is Melcor's UltraTec, which looks about 80% efficient. So for 1 W of electricity in you can move 0.8W of heat. I also figured that the temperature rise for 10psi of boost adds about 11kW of heat to a 350CFM airflow. (about 27lb/min.) That's a ridiculously high amount of heat for a Peltier system to move.

However, if you already have an 80% efficient air-air intercooler, you might think about trying to squeeze a few more percent of cooling out on the cold end of the intercooler. Assuming 80% of the added heat has been removed, you only have 2.3kW left to deal with. That's still too much for an average alternator, but maybe your 150A oversized unit could do the trick.

I figured for my 2.5L engine, the difference between 80% and 100% intercooler efficiency is about 24degF with a result of 12hp additional power. (Assuming 77F ambient temp.) I guess, if it's only going to cost ~3hp for the alternator, then you've at least got a net gain. Is it worthwhile?

There may be other things to add to the picture, like this thermoelectric generator http://www.hi-z.com/websit07.htm If you could wrap something like this around your muffler/cat/tailpipes/whatever and produce on the order of 1kW of electricity, then you can get to 100% IC efficiency with less HP loss. You may also consider lining the upper surfaces of the car with solar panels, and using transparent solar panels on your window glass. I figure maybe around 70 square feet of horizontal surface area on a car. Of course, solar panels cost something like $3.50-$5.00 per watt, and the high-efficiency industrial panels are usually encased in aluminum frames with glass faces, and quite heavy. You could probably get about 700W of power with this approach. If you were an all-out money-is-no-object racer you might get some of these panels custom-fabbed onto auto body panels instead of their usual construction. (The Ovonic a-Si cells are formed on a stainless steel substrate to begin with, so forming them on sheetmetal body panels isn't out of the question.) I actually contacted Sanyo Solar 8 years ago to ask them about fabricating their transparent solar cells onto automotive window glass. The price was a bit beyond me and I never pursued it further, but they are fully capable of doing it. My motivation at the time was simply to provide free power to keep the cabin cool (with my black car in southern california...) and also provide some "tint" effect to reduce the amount of sunlight that actually entered the car.

Hope that all made sense.

Hey here's an idea, I've toyed with this idea myself. try this, get an air/water intercooler, and instead of water, use something like pure ammonia or something with a low evaporating temp like that. It should work just like frige than, beacuse as the gas passes the engine, it will turn back into a liquid, right?

Convection cooling... hum placing certain liquids under a vacume decreases the boiling point temperature, and with liquids more heat can be transported at a faster rate... but your still going to have to deal with the problem of surface area to allow the gas to condence back to a liquid.

ok, mabey I've had too much beer or something, but are you saying that beside's the surface area thing, you think it's a good idea?