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Discussion Starter #1
Nice title eh?

Today while driving to my summer accounting class I thought of a way to drastically lower the intake manifold temperature using thermoelectric coolers, or TECs.

I'm sure everyone is aware that their car performs better with cooler air getting into the cylinders. If you have been to a drag strip you have probably seen people cooling their intake manifolds with bags of ice between runs.

What is a TEC?

A Thermoelectric module is a very small, very light and completely silent solid state device that can operate as a heat pump or as an electrical power generator with no moving parts. When used to generate electricity, the module is called a thermoelectric generator (TEG). When used as a heat pump, the module utilizes the Peltier effect to move heat and is called a thermoelectric cooler (TEC).

Basically it has two sides, when you run an electric current through it, one side gets cold and the other side gets hot. The cooler you keep the hot side, the colder the cold side will be. Most TEC's have a Delta T of 50-70 degrees Celsius, this means that the cold side will be 50-70 degees colder than the hot side. Using multiple TEC's together increases the cooling ability.

I drive a 6th gen. Accord V6. On my car the intake manifold sits directly on top and is exposed. If I were to design a coldplate that fit the precise contours of the manifold to effieciently transfer heat from the manifold to the coldplate and have a series of TEC's sandwiched between the manifold coldplate and a copper waterblock for removing heat from the TEC, I would be able to cool my manifold to temperatures nearing -40degrees Celsius.

Oh yeah, there are many varieties of TEC's that operate off of a 12v DC power source.

Opinions, questions, and comments are welcome. I only have a rough mental sketch of this device and no action will be made towards fabrication until I am 100% certain that something of this nature would be beneficial to the automotive industry.
 

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that sounds like an interesting concept. do they have to be custom built or can you buy one? if so, how much do they run for?
 

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Discussion Starter #3
haha, I have done a good bit of searching and to my knowledge cooling of this nature has never before been used on any part of the internal combustion engine. my purpose in this posting is to try to find flaws in my theory so that they may be rectified or altered. one foreseeable issue that has come to my mind is the possibility of frost forming on the inside walls of the manifold.
 

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lazy accord said:
one foreseeable issue that has come to my mind is the possibility of frost forming on the inside walls of the manifold.
Interesting concept. But condensation getting into the engine could be a big problem, especially if it's a really humid day.
 

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Discussion Starter #5 (Edited)
precisely, unless there was a way to dehumidify the air before it reaches the manifold, which in theory air with 0% humidity would make for an even more intense combustion and further increase efficiency. but removing humity completely from air is an intricate task and one that may not be possible at a rate high enough to feed an engine.

edit: As soon as i can get my hands on an accurate hygrometer with a low end range of 0% I'm going to start doing some testing. :)
 

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constantly in pursuit
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well, if you get the air below 0, its not going to have much water in it, right? just make sure to have some drainage on the TEC, and no water would get in, would it? as long as it sloped away from the intake within the piping?
 

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lazy accord said:
edit: As soon as i can get my hands on an accurate hygrometer with a low end range of 0% I'm going to start doing some testing. :)
Good luck! :)

hammer03 said:
well, if you get the air below 0, its not going to have much water in it, right?
It would take a large unit to rapidly cool that much air to a temperature below the freezing point of water before it gets into the engine. Otherwise you will have warm air hitting the somewhat cool piping where condensation will start to rapidly build up.
 

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good point. but condensation on the piping means less water in the air, right? if you channeled the underside of the intake piping to draw water away from the motor, and plumbed an exit somewhere, maybe it would help?
 

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Saiken
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I highly doubt it would work, unless it could be made so the heat sink is on the hood and shielded from the inside air, while the cooling plate was attached to the engine. All engines are dependent on one thing, a flow of energy from a higher state to a lower one. In this case, your electricity is supplying the power but, the cooling cycle is from hot to cold. I dont think it would be effective. If the engine bay temp reaches a high temperature, your delta T would be small and your cooling effects would diminish over time.

To combat humidity, you could insulate the cold plate from the air, but its probably not necessary. You won't be sitting still enough for water in air to condense. Excess water molecules will diffuse out of the engine bay into surroundings and air from outside will rush in as your moving.
 

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lazy accord said:
haha, I have done a good bit of searching and to my knowledge cooling of this nature has never before been used on any part of the internal combustion engine. my purpose in this posting is to try to find flaws in my theory so that they may be rectified or altered. one foreseeable issue that has come to my mind is the possibility of frost forming on the inside walls of the manifold.

about the only flaw i can think of...not really a flaw, but if you used it on the intake manifold I would also use the same technology further up the intake system at the same time. just becuase if you drop the temp of the charge in the intake, you will also drop the pressure (the whole PV=nRt thing) and a sudden drop in pressure inside the intake manifold might cause some bizzare problems. but other than that I think is sounds like a neat idea
 

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If it just made the intake manifold itself cooler by 59+ degrees, it would be a big help. As for condensation, I dont think that would be a problem unless you were cooling while the engine was off. The amount of air going in the engine would offset the condensation, if anything the small amount of water would help furthur to cool the engine as it evaporated through the manifold!!!
 

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I have looked into this and probably not feasible for several reasons. First, the amount a TEC can cool is low compared to the amount of cooling needed to cool your intake charge. Think about how much air your car is sucking in at WOT.

You must have a big heat gradient for a TEC to work. If the hot side stays hot, the TEC will not work very well. Thus underhood temps will prevent you from getting a good delta T. Even if you were to cut a hole in your hood, I don't think the TEC will generate enough of a temp gradient to make a difference.

Finally, TEC's require a lot of amps so having enough of them to make a difference would probably load your alt so much that it probably negates any benefit seen.

Sorry to be so negative, but as I said, I have thought about this somewhat and IMHO this idea really isn't very viable :(
 

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Saiken
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how about you turn your hood into a giant water based radiator, similiar scalbert's intercooler idea. The surface area from the hood and the constant fresh air moving over it could provide some good cooling effects if you punp water from an ic kit through it.

Making a hood that could do this would be very expensive probably.
 

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Discussion Starter #14 (Edited)
well, my plan was to have a slim waterblock attatched to the "hot" side of the TECs. the only way to get the "cold" side to freezing temps is to remove the heat from the hot side. the waterblock would be made of copper and would have water circulated through it at a high rate of speed and that water would be cooled at another location and then recirculated. the condensation i spoke about would not be an issue on the outside of the intake manifold, it would cause problems on the inside. I have been trying to come up with some way of dehumidifying the air before it reaches the manifold. Ive ordered a few TECs and will begin testing when i get some spare time.

this whole idea came to me while i was designing a cooler for my computer, haha

also on the issue of condensation. if we were in fact able to lower the manifold temp to well below freezing, that condensation would be in the form of frost which would reduce air flow.

A thought that came to my mind on the issue of air humidity is that air looses its ability to hold moisture under two conditions that i know of off hand. 1) very low temperatures and 2) when it is compressed.

also it may be possible to line the internal walls of the manifold with something that resists condensation... but it would have to be pretty damn thin lining.

I don't have much free time to devote to this idea which is why I posted it here to maybe get some input. I work 5 days a week and take 8hrs of class during the summer, however, I do plan to do some experimenting on this idea and possibly testing on a lawnmower engine or something :)
 

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lazy accord said:
this whole idea came to me while i was designing a cooler for my computer, haha
Computer nerd :up2: :D

lazy accord said:
I do plan to do some experimenting on this idea and possibly testing on a lawnmower engine or something :)
Good idea :) . You should never do R&D testing with something like this on the only car that you own.
 

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Hmmm, very interesting thread.

So basicly the two drawbacks are condensation on the intake piping (inside and outside), generating enough power to power the unit, and cooling off the heatsinks?
 

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Saiken
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If we knew what temperatures and pressures are present in the intake manifold we could determine the dew point(temperature where condensation occurs) by graphing an excel sheet of raoult's law and some other law.. I did it in class a few semesters ago.

I dont think that condensation inside of the manifold would be a bad thing. It would just be combusted in the cylinders and turned to steam upon ignition. The energy required to turn water into steam would also have some beneficial cooling effects imo.

In think, the energy and time required to go from engine compartment temperatures to freezing would be too great to worry about. If anything the temp will stabilize far above the freexing point(remember heat is being generated by the engine constantly). The lowest temperature you could reach, ideally would be the temperature of your heatsink or circulating water. You could look into compression and expansion of your liquid, similiar to your kitchen refrigerator, in addition to circulationg it for increased cooling effects.


I think there is potential behind your ideas. please post results when you can. Also, if you have access to measuring equipment, try to get measurements of temperatures and pressures. Ill do some research and post back on refrigeration cycles if youre interested on using that in addition to circulation of fluids.
 

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Discussion Starter #18 (Edited)
DrachenV6 said:
If we knew what temperatures and pressures are present in the intake manifold we could determine the dew point(temperature where condensation occurs) by graphing an excel sheet of raoult's law and some other law.. I did it in class a few semesters ago.

I dont think that condensation inside of the manifold would be a bad thing. It would just be combusted in the cylinders and turned to steam upon ignition. The energy required to turn water into steam would also have some beneficial cooling effects imo.

In think, the energy and time required to go from engine compartment temperatures to freezing would be too great to worry about. If anything the temp will stabilize far above the freexing point(remember heat is being generated by the engine constantly). The lowest temperature you could reach, ideally would be the temperature of your heatsink or circulating water. You could look into compression and expansion of your liquid, similiar to your kitchen refrigerator, in addition to circulationg it for increased cooling effects.


I think there is potential behind your ideas. please post results when you can. Also, if you have access to measuring equipment, try to get measurements of temperatures and pressures. Ill do some research and post back on refrigeration cycles if youre interested on using that in addition to circulation of fluids.

very nice. You are very right with what you say.

My thoughts on your idea of compression and expansion similar to the kitchen refrigerator are that this would be an expensive approach. granted, 12v condensor units that operate the same as kitchen refridgerators are available, they are costly. That is actually another way that people cool their computers. My ideas for removing heat from the tecs include yet another application of the TEC. However, I am going to try to effectively cool the liquid with a single tec mounted atop an aluminum cooling box. I have ordered two TEC's of different power use to begin testing.

I plan to begin my testing with the design of the liquid cooling box. since this is the last place to which the heat will be transferred and expelled into the air, i thought it a good place to start. I just made a simple diagram to allow u to picture my thoughts.

NOT TO SCALE for at this point I have no idea what the scale would be.



Oh I also plan to get a small digital thermometer that has long wired sensor for outdoor readings to start monitoring engine bay temp to see exactly what kind of heat we're dealing with.
 
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