Peltier Devices

[BeenzMeenzWind]

I've seen these things quite a lot, as they're used in some airborne equipment. Just wondered if anyone knows how efficient they are? I Googled it and the figures from different sources are quite varied. Would have thought the simple construction would have made them all pretty similar.

Just out of casual interest. Never seen any cheap enough to bother with in UK. Well, not so far.

[JeroenH]

For heating: >100% efficient, as they are heat pumps. You get the heat of the electrical power AND the heat that is taken in by the cold plate.

For cooling: very low efficiency. Don't know any numbers, but I do know that my 12V 50W peltier cooler box keeps my beers barely cool while my fridge at home (about the same power consumption, compressor) has no trouble keeping a large amount of food and drinks cool.

[BeenzMeenzWind]

About what I thought. Seems like most of the variation in quoted performance is on the cooling side. Manufacturers trying to make their stuff sound like it does a better job than it really does?

A friend of mine has a factory fit 'beverage cooler' behind the armrest of the back seat on his 'rep-mobile'. It does a good job of warming up the trunk but ain't great at keeping 'beverages' cool. Although, if you put cold ones in there, they do stay fairly cool for a while.

[pyrocasto]

Maybe you have to find the right one? My cooler will freeze water if I leave it closed too long, and I dont remember too much heat(though there had to be some).

I was looking into them as a dumpload to help cool my house in the summer.

[stevesteve]

I can't quite handle the >100% efficiency bit. If energy is being used to do work then some must be lost.?

I guess what this means is that the heat out of the hot side is greater than the heat taken in through the cold side... OK I can deal with that... worked out what you meant while typing. Energy still lost from the system.

[BeenzMeenzWind]

Hmm? Maybe Dave's is just a crappy one. I remember playing about with one during training. That would get pretty cold, come to think of it. Not sure if it was freezing? I was Googling them the other night and apparently some don't really radiate much heat from the back and others can. Like you say, must be different sorts of 'em?

[Bruce S]

Hello All;

    If they're not keeping stuff cold look at the fan. I have a rather large one and when the fan got stuck on the cover the cooling ability went down the drain. On the other side of the coin, these can (with enough heat) be used in reverse to generate elec. Not a lot mind you but .....

Bruce S