Clothes Dryer Heat Reclaimer
 

Hey all, just wondering if I could get some input from the smart people on this forum before i go to the trouble of prototyping this... I want to build a dryer vent heat reclaiming device. I've got some surplus 45gallon plastic drums, what I plan to do is pipe in the dryer vent but make the pipe extend under water in the barrel, and have another exit pipe above the water line, thus forcing the hot air to travel through the water in the barrel before exiting... transferring it's heat to the water in the barrel rather than heating the great out doors. The heated water can then be used in a number of ways, preheating water on it's way to the hot water tank, possible space heating applications if one plumbed in a heat transfer mechanism... etc.

Please have a look at my attached diagram (crude, I know - you can only do so much with MS Paint) and tell me where my thinking may be flawed? I know clothes dryer's are finicky if the vent pipes get plugged, but would this design really cause that much back pressure? I'm working strickly with an electric dryer, not gas... so no worries about that.

Thanks!!

Before you work too hard, think about this...
You likely only want to recover the heat when it is cold out. When it is cold out the humidity is usually low. Humidity helps the house feel warmer.
I use a commercially available flap. When its hot outside I close the flap and the dryer blows out side. When it cold outside, I open the flap and the dryer blows inside. The heat and humidity warms the house. There is an auxiliary screen to catch lint, that has to be wiped after each load.

This device seems to work well but I am disappointed with the quality. I have to tape the flap in position.

I was thinking of picking up one of those for my new house. The dryer will now be on the main floor but in a back corner...not sure how good that will work.

Yeah cdig, you may want to have some way to redirect it only when it's cold out. I wonder if there's a way to do that that wouldn't be too complicated.

The problem with those diverters is that you are now breathing in all your bounce sheets and laundry detergent residue that gets left behind on your clothes from the wash... smells nice, but that can't be healthy - who knows what chemicals they put in that stuff.

Beyond that, my washer and dryer are in the basement where the air is cooler, so I'm going to end up with condensation in the basement making it even more dank and smelly, not to mention the mold issues.

My plan is to possibly put a loop in the barrel that will preheat water on it's way to my hot water tank, so it really wouldn't matter what time of year I use it. Or possibly use the heated water for space heating in the winter by pumping it through a radiator in my furnace ducting. I would put it on straight pipe to the outside then in the summer months..

You could route the pipe to say... a furnace filter or something. Something washable would probably be nicer. A plastic mesh stretched over a frame perhaps? I would try to avoid the complexity of water, expecially sitting water which will end up growing bacteria and other non-nice stuff.

I think even a furnace filter isn't going to catch chemicals dispersed in the air tho... It would be nice if a guy could just pipe it straight into your furnace ducting and keep the fan running all winter, I'm just afraid of the chemicals... Call me paranoid!

How long would the dryer have to run to even get the water warm?
Also, I do not think there is enough air pressure from a dryer to push the air through that much water as in your pic.. I think there will be a lot of back pressure.

According to this page the back pressure cannot exceed 0.75" water column. That means your pipe cannot be deeper than 3/4 of an inch in the water, if the rest of your vent has zero pressure drop. I doubt that your dryer would even be able to function the way your system is drawn. If you had a coil of dryer vent in your bucket you might have reasonable success, but remember the moisture in the air is going to condense, so you will need a way to drain your heat exchanger, what ever method you develop.

Paranoid. :p

Those chemicals are on your clothes which touch your skin all day long. I wouldn't be bothered by the tiny amount you possibly might breathe in. I'd be more concerned with the particles of lint.

Awesome, that's exactly what I wanted to know! Thanks for the link.