# Harnessing waste heat from clothes dryer



## Heem (Nov 19, 2009)

Any thoughts on how to harness the waste heat given off by a clothes dryer? Obviously it's not safe to just vent it inside due to the extreme high humidity levels, but does anything safe exist to somehow take the heat given off and duct it elsewhere?


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## smokinj (Nov 19, 2009)

they sell kits for them at all the hardware stores


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## billb3 (Nov 19, 2009)

We don't use the drier much (twice a week tops in cold and bad weather), and it's electric, so during the Winter the exhaust dumps into a water bucket to catch the lint. It's so dry in the house the damp from 1 load is welcome.
We have and use an outdoor clothesline which  works well except for the dampest of humid weather in the Summer.

There are heat exchanger thingies, too, but I think you have to be doing a lot of loads of laundry to be worthwhile.
We had one in another house with a gas dryer and even  with two kids and relatives I never  thought it extracted  all that much heat.


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## Gooserider (Nov 19, 2009)

There are heat exchanger type items but they are often problematic - even with lint filters on the dryer, there are still enough particles in the dryer exhaust stream to clog up a heat exchanger very rapidly...

They make venting units, but as you said, the high humidity, not to mention the lint makes those problematic on electric dryers and they should NEVER be used on a gas dryer due to the CO hazards...

There really isn't a good way to recover that heat, and a good bit of it isn't really usable as most of the heat went into evaporating the water out of the clothing, and just like w/ wood, heat that goes into evaporating water isn't available for heating.

Gooserider


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## Delta-T (Nov 19, 2009)

sounds like this could be a job for.......the magic heat thingy!


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## Highbeam (Nov 19, 2009)

If you condense the steam into water then you can recapture the energy required to evaporate it. So there is more energy to be captured than is available from temperature differential alone. Know that any heat exchanger device that you use for this will produce tons of condensate. The condensate is a great place for airborn lint to stick so you will have a bunch of funky wet lint coating your heat exchanger reducing the efficiency. The wet lint will likely grow some nasty mold too.

No need to worry about CO from an electric dryer. I never liked the idea of gas dryers.


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## Jags (Nov 19, 2009)

Delta-T said:
			
		

> sounds like this could be a job for.......the magic heat thingy!



OMG - you post about the Magic Heat and then the very next post is...is...well, you know.


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## kenny chaos (Nov 19, 2009)

Jags said:
			
		

> Delta-T said:
> 
> 
> 
> ...





Yes, the next post was ripe.


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## Highbeam (Nov 19, 2009)

Somebody stepped in something


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## robert@plamondon.com (Nov 20, 2009)

I have one of the air diverter boxes, but, frankly, I think that five feet of aluminum ducting between the dryer and the vent gives you a good fraction of the available heat with no hassles at all. The diverter boxes put a lot of dusty lint into the room, in spite of the screen, and often too much moisture, too. 

So what worked for us was to move the vent to the outside to a point about five feet off the floor. The five feet or so of exposed ducting radiates pretty well.


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## woodgeek (Nov 23, 2009)

In Japan they sell closed loop dryers that basically use a blower/dehumidifier system that puts the water/condensate down the drain and has basically no waste heat.  Find a friend in Japan and do the cost/bene.


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## Hogwildz (Nov 23, 2009)

I split the difference. I have a rigid duct run to the outside through the basement. I out a "T" on it and put a heat reclaimer box on the other end of some rigid connected to the opposite side of the T.
So some dumps outside, the rest through the filter screen into the basement. It is dry here in the winter,so humidity not a problemo.
And the heat helps keep the basement a tad warmer. Of course dryer is only run a day or two a week, so no major gain.


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## Nessuno (Dec 4, 2009)

Winter days and burning with a stove makes inside the house superdry.  I welcome the moisture on the days when the dryer is being used.  It's also electric so pretty much all the heat stays inside.  
Using just a normal screen to filter but was wondering if anyone had tried something like pantyhose or something.  You'd probably have to increase the surface area of the filter, but something that I had wondered about.


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## festerw (Dec 14, 2009)

Home Depot has some 5-gallon bucket strainers, I've used one of them over the end of the pipe for a few years and it works well.


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