Has anyone Tried to Recycle heat from Dryer vent?

[Shaarx]

wrote

How do they run plumbing and wiring and ductwork in such a structure?

[Be Happy]

I am suppose that heat can be captured or recycled back into inside air, not by actually blowing vent air inside house but by sending it throu a coil of pipes with heatsinks that would take heat from the hot air passing through it and radiate it back into room. I have seen a similar technique using for allowing air ventalation from inside to outside by exchanging the heat energy from from to exhaust by conduction through metal.

[Dave C.]

It wouldn't work. As I posted before, I have used a heat recycling device with an electric dryer (Do NOT attempt this with a GAS dryer!!!). Venting the hot exhaust from the dryer directly into the room (through a lint trap/water bucket thingie) will indeed raise the temperature of 1000SF about

2-4 degrees F, and bump up humidity levels to about 60%. The problem is, the change is only temporary and wears off after an hour or two. So you'd have to do about 70 loads of laundry a week or more to see any difference in your heat bill.

Your suggestion would be even less efficient than that, as thermal energy would be lost before it affected room temperature. So I guess you'd have to run the dryer constantly, which wouldn't be very frugal. :) -Dave

[nicksanspam]

It would, in principle, but the heat sinks have to be very large to be efficient. Better to run the dryer output through a container with some sealed containers of water inside, and let them condense water vapor and store heat and slowly release it later, or hang the damp clothes in a closet with a few light bulbs controlled by a humidistat.

Every little bit helps.

Not necessarily.

Nick

[Albert]

jitney wrote: <snip>

This may be the most expensive idea yet; But it is also the best idea yet.

[jitney]

A friend of mine in the northeast built a greenhouse on the southside of his house for winter veggies and helping warm the house. He does the dryer exhaust/nylon stocking thing into it, as well as running greywater into a metal holding tank until its heat is gone. It keeps his bill for warming it to a minimum, and wall condensation is not a problem since he built it with two layers of clear rigid plastic. I think the moisture ends up condensing to the ground or the plant leaves.-Jitney

[Arri London]

LOL With great difficulty. Having been bombed during WW2 helped a lot. During reconstruction, it was easier in the parts of the church that were damaged, but the walls were put back to their original thickenss.

[Mogie]

Excellant suggestion below hang your laundry in order to save money. The poster was correct they are tiny fibers that will float through the air and can cause problems.

[~^Johnny^~]

Friction. It fits inside the casing. On windows with flush panels, the foam stripping could be on the rear-facing surface of the frame, and I suppose it could be tacked up with brads or staples... but I never had to give it that much thought, since all my single-pane windows are recessed in the casing a few centimeters. I have some sliding aluminum windows in the wall facing between the houses, but they don't have that problem, as they, like many aluminum windows, are double-glazed.

[~^Johnny^~]

Ah, very good -- but I use a 40 pint room dehumidifier.

In a closed closet, or in a closet with the door only cracked open, the DH doesn't run very often! But I don't dry =clothes= with it!

[nicksanspam]

Me too. More expensive. More efficient. Heats the house in wintertime.

Then again, Elana's Irish Whirlpool awz 541 condensing dryer could be reasonably fast and efficient. She says it has something that looks like a dehumidifier in it, with no cold water I/O, as in other condensing dryers.

Nick

[R.White]

You should be using kerosene or a mixture of fuel oil and kerosene for an outside tank to prevent fuel gelling/waxing. We use straight fuel oil up until the beginning of January and then a mix of the fuel oil/kero until the end of Feb. Never had a problem that way.

[Mogie]

The extra humidity is a breeding ground for molds. Can prove to be a very unhealthy thing to do.

[donald girod]

I did this for years--no mold problems, but lots of dust as a result. It is just about impossible to catch all the dust with a filter (unless it reduces airflow unacceptably). On balance, I think it is probably not worth the effort. My dryer was in the basement and the heat didn't make it very far. Neither did the dust, of course.

[JazzMan]

The only way I see it being practical is to design some sort of heat exchanger to use the outgoing hot, humid air to heat the incoming cool, dry air.

JazzMan

[me63401]

I agree

And Im surprised something like this doesn't exist that one can buy!

Maybe its our million dollar idea? Yes?

John

[Chris Lewis]

According to [e-mail]:

Naw. Google searches find plenty of the ones that will _really_ work. Problem being they're not cheap. Ie: I saw a site for a company that specialized in installing "rotating disk" heat exchangers on institutional dryers. But those things are pretty pricy - I'd suspect $1K or more _each_.

Haven't found anybody (yet) making rotating disk heat exchanger units suitable in size for a consumer grade dryer. The units I saw had 24" disks...

"Normal" heat exchangers (eg: required for highly sealed R2000 homes etc) aren't suitable because they'd plug up - as it is, they're $250 or more. "Rotating disk" ones are real neat - self-cleaning.

[nicksanspam]

Might be useful in an airtight house. A 55 gallon drum with a dryer feed at the top and a removable lid and some cheesecloth under the lid and over 27

3'x4" capped vertical thinwall PVC water pipes with air and water outlets near the drum bottom might be more efficient for the rest of us.

Nick

[Mogie]

Something like that does exist. Check out Home Depot.

[Aquarijen]

Back in college I used to rubber band a stocking to the dryer exhaust. Mine was also in the basement. Never saw mold, but I was in college, so I may not have noticed.

-Jen