Peltier A/C ???

[rvanengen]

I was just wondering, and maybe I am being too simple minded...

Couldn't one put a peltier (or an array) in the engine compartment of their car (near the exhaust) and run the power into the passenger compartment to another peltier (array?) that is setup for cooling?

Kinda like an solid state heatpump? :-) If it would work, people w/o AC could get it w/o any drag, and if you are not using the cooling, you could just divert the electricity to the battery. Heck, if you had enough heat, you could run the cars inside blower motor, and keep the car cool, even when the engine isn't running.

[Fourthbean]

If you are heating one side of the peltier, wouldn't that mean the other side would get cold? Or am I missing something. If the other side did get cold it would be more efficient to simply blow a fan across that side of the pelt into the cabin. Would require a bit more engineering to get right. Would love to put that in my car though!

[rvanengen]

Originally Posted by Fourthbean

If you are heating one side of the peltier, wouldn't that mean the other side would get cold? Or am I missing something. If the other side did get cold it would be more efficient to simply blow a fan across that side of the pelt into the cabin. Would require a bit more engineering to get right. Would love to put that in my car though!

No...I believe that is how they are supposed to work, but I think you get more power the hotter you can get it. Plus, you would need to get a LOT of heat near the A/C box to get the cooling so close...that's why I was thinking to let one set of peltier's generate "free" electricity from the engine's waste heat, and then you can have the more relatively isolated condensor box house the 2nd set and let it do it's best job cooling.

And if it would work, then you could also power the blower motor from engine compartment heat, and then if you are power-off at a traffic light, you are staying cool.

Also, if you are not using the cooler, then you could just let it divert to charge the battery for an overall lower load on the alternator.

[bbgobie]

This doesnt work.
Its like saying lets have a windmill generate electricity, that will power a fan whic will blow on another windmill to get more electricity.

The 2nd poster is closer, if you have the hot side of the peltier on the engine exhaust somewhere which makes it hot, good heatsinking and a fan blowing fresh air across, you would get electricity.

However if you want to cool your car, I think you would have to supply electricity in which case you wouldn't neseccarily have to put the hot side of the peltier against the engine.

In this case a peltier is not a very efficient a/c and your alternator would reduce your efficiency by more than your a/c pump would have to.

I think the better alternative is to just use the peltier as an electricity making device.

Originally Posted by rvanengen

I was just wondering, and maybe I am being too simple minded...

Couldn't one put a peltier (or an array) in the engine compartment of their car (near the exhaust) and run the power into the passenger compartment to another peltier (array?) that is setup for cooling?

Kinda like an solid state heatpump? :-) If it would work, people w/o AC could get it w/o any drag, and if you are not using the cooling, you could just divert the electricity to the battery. Heck, if you had enough heat, you could run the cars inside blower motor, and keep the car cool, even when the engine isn't running.

[rvanengen]

Originally Posted by bbgobie

This doesnt work.
Its like saying lets have a windmill generate electricity, that will power a fan whic will blow on another windmill to get more electricity.

The 2nd poster is closer, if you have the hot side of the peltier on the engine exhaust somewhere which makes it hot, good heatsinking and a fan blowing fresh air across, you would get electricity.

However if you want to cool your car, I think you would have to supply electricity in which case you wouldn't neseccarily have to put the hot side of the peltier against the engine.

In this case a peltier is not a very efficient a/c and your alternator would reduce your efficiency by more than your a/c pump would have to.

I think the better alternative is to just use the peltier as an electricity making device.

Certainly you can use an array of peltiers to make enough power to run a small A/C compressor and ultimately might be the easiest. Only need about 700 to 800 watts to accomplish that.

However, I hardly think it is in the realm of putting a windmill to drive a generator to drive a fan to drive another windmill...it is perhaps just a bit less efficient than an A/C compressor. Now, if I had suggested putting a windmill on the car to power an electric motor to make the car go faster...

This idea/thought/rambling is more for cars that do not already have an A/C system, but would like a small and relatively uncomplicated one. It works for small refrigerators in the car...so why not just scale it up a bit and you have some moderate A/C??

[bbgobie]

Originally Posted by rvanengen

Certainly you can use an array of peltiers to make enough power to run a small A/C compressor and ultimately might be the easiest. Only need about 700 to 800 watts to accomplish that.

However, I hardly think it is in the realm of putting a windmill to drive a generator to drive a fan to drive another windmill...it is perhaps just a bit less efficient than an A/C compressor. Now, if I had suggested putting a windmill on the car to power an electric motor to make the car go faster...

This idea/thought/rambling is more for cars that do not already have an A/C system, but would like a small and relatively uncomplicated one. It works for small refrigerators in the car...so why not just scale it up a bit and you have some moderate A/C??

Rereading it, yes it does work, just very inefficiently.
Peltiers are very unefficient so you would need a lot of peltiers + energy to cool a car. If the first set of peltiers generates electricity for a 2nd device which is for cooling, might as well make the 2nd device efficient. Otherwise it might come down to needing like 4 peltiers to power 1 for cooling.

[rvanengen]

Originally Posted by bbgobie

Rereading it, yes it does work, just very inefficiently.
Peltiers are very unefficient so you would need a lot of peltiers + energy to cool a car. If the first set of peltiers generates electricity for a 2nd device which is for cooling, might as well make the 2nd device efficient. Otherwise it might come down to needing like 4 peltiers to power 1 for cooling.

Point taken! Thanks...that's why I wanted to float this out there. I was thinking along the lines of a passive battery charger for the first try. Gotta LOT of underhood heat on my car, although I really should just do some exhaust wrap and put the peltier on the catalytic and run the wires back to the battery.

[rvanengen]

Originally Posted by bbgobie

Rereading it, yes it does work, just very inefficiently.
Peltiers are very unefficient so you would need a lot of peltiers + energy to cool a car. If the first set of peltiers generates electricity for a 2nd device which is for cooling, might as well make the 2nd device efficient. Otherwise it might come down to needing like 4 peltiers to power 1 for cooling.

On another thread I realized my error...I am looking at combining the Peltier and the Seebeck Effects! Thanks for the patience!

I think I will still look at trying a Seebeck effect battery charger...sounds kinda cool. (pun intended)