Heat recovery from clothes dryer

[hdrider_chgo]

Re: Heat recovery from clothes dryer

How many loads of laundry do you do per week? What is your climate? When you do your calculations remember that not all input heat goes out the vent much of it is introduced into the room. Capturing it will cause condensation. A condensing dryer may be a good idea. Are you trying to capture the waste heat from the hot water from the laundry also? Just a thought.

I'll take your and Martin's word for it, but I wish I was more clear on the math. If I knew how much gas (or electricity) was used to dry a load of laundry, I could probably take it from there, and prove to myself confidently that it's not worth it.

Laundry varies quite a bit, but about 4 loads/week. That could easily increase by quite a bit, given the flexibility of the living space I have here.

Climate is Chicago. Cold winters, varies from 40's in winter to below zero. Hot, humid Summers.

Is a condensing dryer the same as a ventless? I'm not big on that concept.

The laundry does not use much hot water. We mostly use cold for wash. I am looking at capturing the heat from the bathroom shower and tub water, since that space is part of this phase of remodel. That subject is planned for a future thread.

[Ray Moore]

Re: Heat recovery from clothes dryer

That's not what he was trying to do. He was trying to develop a heat exchanger. The thread got off course on the subject of venting the moisture into the house. All good subjects though.

On the issue of a heat exchanger, they require lots of surface area. In a dryer vent you want to minimize surface area and maximize velocity. That helps avoid lint buildup.

If you simply make a double walled pipe like is used in a vented sealed combustion fireplace, the surface area would be too small to gain very many btus. If you increase the surface area you will cause lint buildup.

If you chill the dryer vent pipe with the incoming air, you will cause condensation buildup that will collect lint and clog the line.

I couldn't even get the numbers to come close to working on simply supplying makeup air to prevent the loss of conditioned air and if I had it would have required a runtime sensor or manual control to open the motorized damper. In the end the complexity and maintainance issues made me glad that it wasn't justified from an energy standpoint. I tried really hard to figure it out though.

When thinking about any of these issues, remember this maxim. No drying occurs without heat and heat loss. As we try to reduce heat and energy demands, it is easy to create moisture issues from the reduced drying potential. Or as Joe L. and others say, "There's no such thing as a free thermodynamic lunch."

[greentree]

Re: Heat recovery from clothes dryer

I dont think he was trying to heat his house with his dryer, this thread seems to have gotten a little overcomplicated.

Try one of these, http://www.improvementscatalog.com/h...eat-saver.html , if the homes drywall starts to crumble and people start passing out because your house is too tight you can remove it.

As I said I hooked one up in my basement. My home is 102 years old and has a tiny bit of leakage here and there. I dont know if it works or not but it was $10.00 so I dont really care and I'm not too worried that my house is going to rot and collapse while I'm sleeping.

Travis