Q' about useing TECs for cooling car
 

How well would a system with two(or more) peltiers cool a car interior? The system would use two copper water blocks. 1 block, 12v pump, and 1 heatercore for each of the cold and hot sides. Would this at all be feasable? I am asking for a friend, I thought it might, but I'm not sure what the power drain on his car would be. What would be the most efficient way do do this, if it is at all possable?

Thanks
Steve

I have no idea why you would want to do this, but anyway...

You could connect it to the 12V line in the car with, say, a 20 amp breaker. You might need another alternator, so you may need to have a custom fitting set up so you can run 2 alternators to run the TEC's because they would draw alot of power.

would need to upgrade to police car alternator preferabbly(185 amp). Getting AC put in would be cheaper...

unless you got a low powered TEC and taped it to your forehead.

AC would still be better.

lol, and have water tubes running to ure forehead? would work, since the forehead is the best point in the human body for thermal exchange....

some time ago AGV made a TEC cooled motorcycle helmet. It worked (I tried one) but out here in the Texas sun it didn't seem worth the effort to plug it in or cost. Maybe....since 15 years have passed they could do a better job with it.
wj

have you ever heard people saying that a car consumes more fuel when the aircondition is on. that is what is going to happen to you if you add another alternator or exchange the alternator you already have with a bigger unit.

the tec's consume lots of power which would make the alternator more hard to turn and therefore consume more fuel.

Another problem would be that you will need to identify the ideal temperature for the car. running a car cooler than the ideal temperature will make no good and not even make it run hotter obviously enough.

i hope i made my point :rolleyes:

Basically my friend was cheap and wanted AC on a car that didn't have it, I told him it might work but I wasn't sure. I was figuring @14.4 volts 2 80watt pletiers would pull about 11 amps plus another 5-6 for the 2 12v water pumps. I just wasn't sure how cold the water would get, and if it would be enough to cool the inside down.

Thanks for the replies
Steve

A auto AC system is rated for about 10000 BTU or about 3000 watts. How well would even a few pelts cool 40 3.2G athlons? Not too well!

Don't even think about it.

murray- but think about some of the advantages- with a watercooled pelt taped to your forehead, the cop will probably completely forget why he pulled you over! :)

lol, u could also paint ureself green and pretend to speek only 1337....

TECs today are little different then the ones they had in the late 60s.

you're right about that, your math is a little off however.

2003 - 15 = 1988
wj

Thats the funniest thing ive heard all day LMAO...

]JR[

lol, why not just puour a bunch of liquid nitrogen into the car? i would be cold enough for you and wouldnt need a new alternater or anything

lol, u wouldnt be alive for long either!

yeh but you would be cold... thats whats important.

TECs are the least energy efficent menas of cooling something. Get AC installed it will be cheaper. Also in many cases running AC is actually more energy efficent than having the windows open. The increase in drag with the windows open actually consumes more energy than a good condition AC unit.

Okay, I'll bite on this one.
Show me proof (any proof...however ridiculous) that running the AC uses less energy. Maybe at 100mph but not at legal or semi legal speeds. This smacks of the Harley chant, 'loud pipes save lives'.
wj

My fluids professer mentioned it during a lecture on drag.

Think about when your going 65mph, the noise generated alone is a sign that there is plenty of energy being consumed. A new AC unit in good condition is very energy efficent. Also consider that the volume inside a car is rather small so we're not talking about a huge AC unit.

Hes right at highway speeds it better to have your air on... my father is an auto technician and at a class they said that.

I would hope that his students would realize that there are way too many different car designs floating around for that broad of a statement to be given much credence.
I would like for your prof to do a little more research into this and let people know his findings, after all he is there to educate not make biased blanket statements.
While I'm sure that statement is true of some vehicles it is not true of the majority of them.
Of the 25 cars I have owned through out my lifetime I have never lost gas mileage due to turning off the AC and opening the windows. These vehicles pretty much run the gambit from trucks to street racers.
wj

If you notice I did put the "in many cases" cluase in my original statement. I'd trust my prof when it has something to do with drag. Fluids is this guys entire life(to the point I feel sorry for him). Since we also have an auto guy backing him up it sounds pretty sure.

Keep in mind drag is realated to surface area. By opening up a window you greatly increase the surface area of the body. Your also generating alot of turbulence around the openings. So a car with its windows down generates much more drag than with the windows up. Most likely a truck wouldn't feel the gain much becuase its drag is already very high because of the flat end of the cab and the sides of the bed... A small car is pretty aerodynamic and would take a huge hit from the windows being open. A modern AC unit in good condition is pretty efficent. Also if you really got into the math the added mass of the AC unit would reduce the acceleration due to drag on the car.

Either way I'm sure the difference between open windows and AC is minimal. You'd probobly have to due some controlled tests in a lab in order to see the difference.

Maybe that is my problem, my experience with 'small' cars when not using ac is generally with a sunroof open and one rear window cracked to keep the turbulence to a minimum. with this new awareness I see that many of the newer breed pay little attention to air management with the windows down. So, I concede....your statement has far more validity than I initially thought. Thanks for educating me.
wj

I'm new here... mostly reading around and seeing that my ideas are not off base at all. Just wanted to make a few comments.

1) I own a 2002 Dodge Intrepid ES with real time fuel eco computer. Air-co on drops my mileage 2-3 miles per gallon. Windows open at any speed from 45mph to 117mph (where computer cuts out ignition) ...... no effect. Ok my hair gets messed up.

2) I seen lots of statements about watts this and watts that but until this tread when Murry13 said the magic word "BTU" I think many have been missing the point. In any cooling (or heating) system the total system BTU’s (British thermal unit) determines if the (in our case) cooling configuration will be able to remove the thermal energy quickly enough. I've been researching the use of aquarium water chillers. Rated in hp (usually 1/10hp to 1/2hp) these units are able to absorb 500-1000 BTU's of cooling goodness. Now... my thinking is why go to all the exotic trouble to insulate, water block, Multistage TEC, dual loop, inert ferro fluid cool (arh, arh, arh) your rig for a whopping 3-15% clock speed increase. Which translates to a barely noticeable performance increase at windows/game level. Why not just take a remotely located water chiller and chill a regular (if they are "regular" now) water cooling system and call it a day. Now, the afore mentioned aquarium water chillers start at $300 to $500 and go quickly to several thousand. But I liked the idea of a TEC chiller *IF* it can generate the BTU's without excessive thirst for power or other "exotic" measures. .... thoughts ??

p.s. If I’ve missed the “because we can” idea I’m sorry. I guess I’m just too practical.