I asked in this question if there was a heat powered fan for residential steam rads, to increase air flow over them since natural flow is pretty weak.
Alas, looks like some wood stoves can use such a device, but in the $300 range and they are pretty bulky.
Looking at parts, I found some cheaper ($40 US) Seebeck effect generators (Reverse of Peltier effect) and I am wondering if I can build one myself that is worthwhile.
Found a Seebeck generator here that looks to be about the right size, attach to my rad right where the steam comes in, stick a computer style heat sink on the back (bum one from work), and then run the power into a small fan.
Now to find a small fan I can fit under the rad, and needs low DC power.
I am tempted to experiment, since for $40 this should be simple enough.
I know my rad is not hot enough at 100C max, but I wonder if I can get enough power out to run a small battery powered fan styled motor…
Am I going to fail? Or is there a chance this might succeed?
Best Answer
I have a feeling their data sheet is optimistic, but let's go with that.
I've got right here a computer fan, moving a stream of air which is miniscule compared to most home radiators I've ever seen. It is consuming 1.6W of power to accomplish this feat.
Let's say you're already actually doing a really good job of moving air away from this radiator, and so its immediate environment is 25C. You stick a giant whopping block of copper on the back side of this generator, and end up with just a 5C rise over ambient on the cool side of the generator. (After, of course, coming up with a very thermally conductive connection between your round pipe and this flat object.) The chart says you need your steam pipe to be about 150C to get 1.6W out.
As I understand it, steam in homes isn't that hot. So you're not going to get the power you want, even under the above generous assumptions. And I don't think the air circulation you'll get from 1.6W of fan would even be worth it.