Homemade ERV and Energy Exchanged???

Ralph III

Occassionaly I get these brilliant ideas (worthy of patents btw, ) and wanted to share one with you folks in getting some input. Mostly, curiosity gets the best of me with Dad having been an Engineer...

Anyhow, what would happen if you ran an "uninsulated" fresh air flex duct within a homes existing ductboard or larger insulated flex duct? Would there be an appeciable amount of energy exchanged between the two over let's say 25 ft or so? Such as an ERV or HRV performs.

My sketch is just a general idea. The fresh air duct would terminate in the homes return plenum at some point, of course. I'm supposing the larger duct would have to exit the home as otherwise the energy exchanged would be meaningless? I'm not sure how condensation would be addressed or whether an issue given the exiting air would have been treated already?

This is just fun guys in sparking some possible input...

Thanks, Ralph

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M3 Pete

not sure how well it would work, but you would certainly need a flex duct that transmits heat well. I'm thinking aluminum flex would work pretty well, aluminum transfers heat well and the corrugations provide a lot of surface area. You would want to get the fresh air duct relatively centered in the larger duct to make sure you get as much heat transfer as possible.

I have thought about this too, to capture heat from a furnace chimney. But high efficiency furnaces already extract nearly all the heat, so it's unlikely to be cost effective to retrofit an older furnace. Plus you have issues if the intake duct develops a leak.

But your idea is just using conditioned air to transfer heat, so it "should" work.

Gary in WA

You can U-tube a pop can ERV pre-heater, or a underground (constant temp.) HVAC pre-heater or temper. Read about those every so often. A search on our own forum has someone pre-heating through the attic. Give it a try.

Gary

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Ralph III

The pop can heater is interesting but only good for heat, correct? We live in the deep south and such wouldn't be as useful for us. Maybe you can link to some videos?

I was thinking in terms of something that could exchange indoor air energy(cold or hot) with incoming fresh air. The duct within a duct seems to have a potential?

Ralph

Gary in WA

I was researching for heating only. In a few years I'll move (downsizing) to a small house which I want solar to supplement for heating. Pre-heat the air supply to ERV, crawlspace heat the floors from below during the day;http://www.n3fjp.com/solar/solarhotair.htm
And solar water/air heat 55gal. drums to carry through during cloudy days, with a convective loop-- to HW heater in the attic; http://www.ibiblio.org/london/renewa.../msg00018.html
I'd like to incorporate something like this also: http://solarwall.com/media/images-ma...rDuct-Spec.pdf

Just start researching the cooling side of it. Check with your local universities and local businesses for ideas specific to your climate. Research, research, online is easy but time-consuming... faster than books, though, LOL.

Gary

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