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Learning, Sharing, and Teaching => Do it Yourself Discussion! => Topic started by: prodarwin on November 21, 2013, 12:36:42 PM

Title: Waste heat recovery systems?
Post by: prodarwin on November 21, 2013, 12:36:42 PM
Anyone installed a waste-heat recovery system, either after their shower, or dryer?

http://energy.gov/energysaver/articles/drain-water-heat-recovery

http://hackaday.com/2011/10/06/reclaiming-waste-heat-from-appliances/


The water/water heat exchanger seems to have obvious benefits as when hot water is going out, there is always cool water coming in.  I don't have a way of installing one vertically though.  Not sure how well the horizontal system would work (supposedly much less efficient)

The dryer DIY method seems really easy, - it looks like its just an intercooler with a cpu fan stuck on it.  The potential for it to clog with lint scares me.
Title: Re: Waste heat recovery systems?
Post by: willn on November 22, 2013, 01:51:00 PM
The youtube vid was private so I couldn't see, but I don't think the lint is flowing differently--I was thinking that the radiator unit basically just wraps the existing exhaust duct, or replaces a section with its own enclosed tube.  If you weren't having a lint issue before this won't be any worse.

We had a crude diverter on our dryer exhaust that simply flipped down a door to point the air back into our basement.  Had a filter on it that sometimes worked to keep most lint at bay.  Now that we finished the basement we don't use it since it created a ton of dust.  But this idea looks very promising!
Title: Re: Waste heat recovery systems?
Post by: prodarwin on November 22, 2013, 02:14:55 PM
(https://s3.amazonaws.com/ksr/assets/001/023/968/dc7317678e3d182d6341166cfed7a6c9_large.jpg?1381406152)

I don't think its just a heat exchanger wrapped around a tube.  Looks like an intercooler to me.  Dryer air flows through the thick parts, and extraction air flows across through the zig-zag fins.


Title: Re: Waste heat recovery systems?
Post by: willn on November 22, 2013, 02:27:55 PM
Ok I see.  Yeah I think it would need a way to clean the airway, the other thing I wonder is the pressure created.  The dryer is designed for a particular exhaust pressure, I assume this would increase it?