Why no electrical intercooler cooling?

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avriette
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Why no electrical intercooler cooling?

Post by avriette »

There are stupid questions below. You may need to get a beer first.

We just got a new fridge today. Let me back up. I'm a whisky man. And I like it single malt -- single barrel if I can find it, and I generally take it with a single or sometimes (for the 59.6% stuff) double distilled water ice cube. So this new fridge has one of those stupid "makes ice cubes that spill all over your freezer" things, which I proceeded to rip out when I got home today.

In the process of ripping it out (I was literally a-gouging with a phillips at one end and yanking with my right hand on the other end), I perceived what was my first 120vac shock in many years (I hadn't done this since back when I was soldering boards as a kid. However, I have gotten many a 20,000+ vdc shock when fussing around with ignition). This is a sensation you don't really forget, as it's rather unique. However, it appears I was wrong. I was not shocked, I was burned. And in fact, I think the proper terminology would be "I burned the shit out of my right hand" (maybe I should head to the Arlington Pediatric Center).

Now, now, what has this got to do with cars? Well, as you know, in order to make something very cold, you must make something else very hot. I think we all understand this. So this ice cube making thingie has a coil on the bottom of it which dissipates heat, and a corresponding coil on the top which freezes the (tap) water into their cute little buckets.

Now, said ice cream widget is about the size of my TMIC, and I could probably further disembowel it to get both the hot and cold parts out of it. And since it lives on 120vac, it's easy enough to get an inverter for 12vdc. This would mean, in theory, that I could keep my intercooler at a frosty 32F, whilst somewhere else in my car, something would get hot enough to burn the shit out of my hand. Again.

I have some curiosity about this, though, so here's where the stupid questions start.

If you are using power to drive the cooling element to cool the intercooler, you are creating additional draw on your alternator, which will result in lost power. The net effect might be negative power, even with a colder intercooler. Especially at tame boost levels.

Consider also the "electric supercharger." These have the same problem. They're able to generate 5-6psi and a fairly good CFM rate, but because they're such a horrendous draw on the alternator, the power you make with the additional air is lost generating the wattage for the supercharger.

Furthermore, I suspect I am not smarter than the guy who designed the placement and configuration of the STI TMIC. In fact, I bet he's a lot smarter. And I'll bet, if he thought he could electrically cool it, while venting heat to the atmosphere (say by a muffin fan or something), he woulda done it.

So what am I missing here?
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sirwilliam
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Post by sirwilliam »

I need a beer? Work sucks. :(

Why were you working on something electrical w/o unplugging it?
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zaxrex
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Post by zaxrex »

The first stage of the compressor coils are hot with heat, and I think that is where he burned his hand. These coils would stay hot after unplugging the power.

If it was a burn from electrical resistance heating something up while you were plugged in, shame on you.

Ok, on to the real question/answer.

You are right in that it would take more power from the engine to crank the alt to push the inverter to make heat while phase changing and voltage step up to power an electric motor to compress the coolant to heat it up to let it expand to coll the coils to cool some of the air around it.

You would loose a lot less if you powered the pump mechanically from a pulley or something rather than converting mech - DCV - ACV - mech - thermal. But by then you are running what is in effect a supercharger for a closed fluid system.

If you want to get real freaky with the cheese-whiz, this is what you do.

Implement your ice making system in your car. The twist is to convert your air-air intercooler to an air-water/methanol intercooler. Use the ice maker to chill a large volume of water/meth while cruising or at low power. When you need to stomp on it, cut the compressor and just run circulation pumps to let that super cold water/meth cool your intake charge to below ambient temps.

This will only work for a time proportional to your water volume. then you would have to cut the compressor back on and wait a long time to re-cool the water.

That would be a lot of work for short term advantage over a normal air-water IC setup, but how long can you really stay on the gas?
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Post by avriette »

sirwilliam wrote: Why were you working on something electrical w/o unplugging it?
100% pure stupid courage, man. :twisted:
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Post by avriette »

zaxrex wrote: If you want to get real freaky with the cheese-whiz, this is what you do.

Implement your ice making system in your car. The twist is to convert your air-air intercooler to an air-water/methanol intercooler. Use the ice maker to chill a large volume of water/meth while cruising or at low power. When you need to stomp on it, cut the compressor and just run circulation pumps to let that super cold water/meth cool your intake charge to below ambient temps.

This will only work for a time proportional to your water volume. then you would have to cut the compressor back on and wait a long time to re-cool the water.

That would be a lot of work for short term advantage over a normal air-water IC setup, but how long can you really stay on the gas?
This to me doesn't to be really all that complicated. If you want to distill it down to its fundamental elements, it's almost a swamp cooler. No need to convert the air-air to air-meth, just have an element that had meth in it and was cooled by a circulating pump, like you said.

This is starting to sound really close to just "re-route the air conditioner into the throttle body." :lol:

As far as how long I can stay on the gas, I dunno if you've ever topped out the STI, but it takes a good minute or so from 75mph to get up to 155mph. Full boost the whole way. You'd really like to have the cooling under those conditions, I think. Tracking the car, you're on the pedal constantly. Having a way to keep the intercooler, you know, cool, is a good thing. Anyways, like I said, I was just wondering, having ripped pieces out of my refrigerator.
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zaxrex
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Post by zaxrex »

The meth is there to keep your water from freezing.

Your STi already has a sqamp cooler function. It is the IC sprayer. But don't use meth instead of water, talk about getting burned...

If you had a 7L resevoir at 28F, you could run a SZ-49 setup at 20 psi and get ~15% more air onto your engine over a 60 sec time period. That is like running your SZ-55, with the response of the 49!


Switch up to an insulated 15 L JDM STi tank and you can go 4 minutes at a time.
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Post by Sabre »

First thing I thought of when I was reading the first post was a pelter. Too bad pelters require so much wattage :( I ran one on my CPU here at home for quite awhile :twisted:

Here's an idea: replace the water/meth with nitrous. Reason being that you can recompress the nitrous while you are not on boost and then have it run through the intercooler while you are on. Seems more efficient than cooling the water/meth solution, but I could be wrong ;) Basically this is turning it into another A/C system though, so I guess freon (or whatever they are using now'a'days) would be a better thing to use.
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zaxrex
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Post by zaxrex »

The reasons why I keep going back to water are specific heat, volume, and time.

You cannot extract enough heat from a gas to use it only when cooling the intake. If you did, you would find yourself taking more power away from the motor than you would benifit from having a denser charge.

You have to have a coolant resevior to act as a temporary heat sink. Freon has 1/4 the specific heat capacity per mass as compared to water and is only 1/3 as dense. You would need 12x more freon than water to cool the IC. It would take as much if not more power to compress all that gas to get it to chill stuff again as compared to a very small amount being compressed over a long period of time and evaporated to chill the water.

Plus refrigerant is about $80/lb now. (7kg water)x12=84kg=185lbs. You would need to buy $1400 of freon :shock: .
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Post by Sabre »

lol, ok, point taken haha.

A place that I use to work at when I was in college use to make slush every night and then melt it during the day for cooling. Basically generating the ice at night saved them a bundle on cooling bills.
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