Peltier Intake
06-01-2003, 06:20 PM
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Peltier Intake
So my friend has an RX-7 and he was thinking about making a cold air intake by channeling all incoming air through a heat sink cooled by a bunch of peltier devices. Thoughts on the practicality of this?
06-01-2003, 06:48 PM
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Re: Wont that be the same thing as putting a FMIC before the turbo?
He has no turbo, he has a Gen 2. convertible. They didn't send any turbo'd convertibles to the US. So, he's just working with NA right now. Interestingly, he's considering find a donor Turbo II and doing an engine/tranny/rear end swap, but he's not sure if it'll be worth it. He drove a Turbo II and found it to be very jumpy, so he was wondering if all turbo cars are like that. He drove my A4 and realized that the Turbo II RX-7 might not be for him.
06-01-2003, 08:27 PM
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It will likely be ineffective or racers would use them too . . .
on a N/A engine, the more obstructions you put in the air path the less hp you can make. To cool the air, with any type of device, you need to run it around or through cooling vanes; that's why forced induction cars can use intercoolers and still benefit. Try to use an intercooler or peltier device on a N/A engine and you create a huge bottle neck or an effective system.
Best bet: Ram-air device: while driving, use the velocity of the car to force fresh outside air into a hood, grill, or bumper mounted scoop that channels the air into the engine creating positive flow in the intake system to completely relieve the engine from the burden of sucking the air in when at speed. If you watch F1, they are extremely efficient, allowing the generation of over 700 hp from a N/A 3.0l engine--yeah, I know that they use v-10s that redline around 12,000 rpm or greater, but it's still a mere 3.0l normally aspirated engine.
Best bet: Ram-air device: while driving, use the velocity of the car to force fresh outside air into a hood, grill, or bumper mounted scoop that channels the air into the engine creating positive flow in the intake system to completely relieve the engine from the burden of sucking the air in when at speed. If you watch F1, they are extremely efficient, allowing the generation of over 700 hp from a N/A 3.0l engine--yeah, I know that they use v-10s that redline around 12,000 rpm or greater, but it's still a mere 3.0l normally aspirated engine.
06-01-2003, 09:01 PM
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I don't think so
he would need many to bring the air down to an appreciable temperature that would make the system worthwhile and if you compute the cooling wattage required for that flow of air its way beyond what a series of peltiers can do.
Here's some rough math
A 2 liter engine at 3000 rpm will pull about 95 cubic feet of air in one minute. or 8 lbs of air/minute or 120 lbs per hour. which equals about 28.5 BTU per degree F. So if you want to drop 90 degree air to 50 degree air... thats 40 degrees, you need a peltier thats rated for 1140 BTU or 335 watts.
The problem is that you need much much much more power than that, cause you have to bring the air temp down rapidly and you don't have anywhere near 100% efficiency. Peltiers are absymal and your going to have lots of loss in the intercooler process itself and the energy your alternator will be taking from the engine.
Once its all said and done, it will probably take away power, not add it.
Here's some rough math
A 2 liter engine at 3000 rpm will pull about 95 cubic feet of air in one minute. or 8 lbs of air/minute or 120 lbs per hour. which equals about 28.5 BTU per degree F. So if you want to drop 90 degree air to 50 degree air... thats 40 degrees, you need a peltier thats rated for 1140 BTU or 335 watts.
The problem is that you need much much much more power than that, cause you have to bring the air temp down rapidly and you don't have anywhere near 100% efficiency. Peltiers are absymal and your going to have lots of loss in the intercooler process itself and the energy your alternator will be taking from the engine.
Once its all said and done, it will probably take away power, not add it.
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06-02-2003, 09:30 AM
#8
Re: Peltiers were an "overclocker's" trick. It's been replaced by water cooling. Try misting the I
Not only that, but you'd have to have a BUNCH of those suckers on there. Going from memory, none of them were more than 1.5x1.5 that I ever saw...They also don't transfer that much heat. Thats why they sorta worked with IC type chips.
06-02-2003, 12:25 PM
#9
you can get industrial ones in larger sizes....peltiers "could" work.
because of the expense and cost, one would have to do a decent engineering analysis before making one. if poorly designed, it could use more energy than it "produces".
06-04-2003, 10:04 PM
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Doing the math the amount of current required would...
...melt the current alternator. Plus, you've got to get rid of all the heat generated on the other side. And forget how fragile the damn things were. No wonder water cooling won out even with computers (not like the old IBM mainframes and Crays weren't doing that 20+ years ago).