What about Clothes Dryers?

[richhagen]

Tom, I would love to use a clothes line, but in the city where I live I would lose my clothes. :-)  

Maybe I can build one on the roof.  The neighbors would love that one.  I have a coin operated washer and dryer that I use along with my tenants in my building, I hate using gas to do something that doesn't require it, but it is slightly profitable and the tenants would just use machines somewhere else anyway.  If I were to make an impact I would have to figure out a way to power it without the grid or gas as well.  I would also have to keep it push button simple or the tenants wouldn't use it.  I have, however, been spending much more than I make from the machines on solar panels (hopefully they won't get stolen).  I've looked into the batteries and inverters required to power an electric laundry using conventional electric machines and it is too much to be practical at the moment, I would need a bigger roof and budget, or at least a sunnier location, and it with the life expectancy of the equipment, it would be a big economic loser at present.  Rich

[3rd Charm]

Hi all, Newbie here, and this is as good a place to put my first post as any.

I've been battling the electric dryer problem for decades. Fortunately we live way out in the sticks, so during the summer everything goes on the clothes line. There's nothing like sunshine dried country air fresh sheets to sleep on. Jeans and towels only need to be tumbled in the dryer a few mins to get rid of that natural starch nature and hard water provides , especially when the wind isn't there, which isn't very often.

Winters are another story however. We live in Manitoba (Canada), and winters are pretty cold, windy and nasty. Hanging clothes on the line? Forget it. They will dry in a few days, but mostly they just freeze instantly, turn into a para-sail and are blown away, never to be seen again.

A dryer is a must have item during the winter, but it eats electricity almost as bad as the furnace does. I've tried venting it through various home made filters, but they require constant cleaning, and even then there just seems to be more lint/dust in the house.

The humidity is a problem too, especially if your house is well sealed.

The first time I tried venting the dryer inside the house was a disaster. The laundry room become a steam bath, all the paint bubbled and peeled off the ceiling and walls, swelled the drywall, and even warped the hardwood floors.

That was an expensive lesson which took a long time to repair. If you want to try vent your dryer indoors, make sure you leave the door to the laundry room open, and dry at  a lower heat setting.

You can also build a multi-stage lint trap, and vent it into the cold air return of your forced air heating system, which should also filter that air one more time.

We burn  wood almost exclusively for heat during the winter, and have the furnace fan wired so that it can be turned on to circulate air without the elements lighting up.

This also takes care of the humidity problem when venting indoors, stops the static problem from burning wood, as well as eliminates somewhat that sweltering hot room effect the woodstove creates.

Most electric dryers are 220, the motor/fan assembly is a fairly small unit that runs on 120, the elements are what draws the juice. I haven't tried it (yet) but I think either replacing the element with some DC compatible stuff is possible, and of course a DC motor swap or rewire is doable. It may not heat the air as much with a DC element conversion, but that only means you will have to run it a little longer, which should be a problem if you get the juice for free, right?

When I get my first wind machine up and running, it's definatly on the list of things to do. If there is anything good about freezing cold arctic winters we have here, it is plenty of wind maybe too much for the machines you guys have been building.

I hope to have mine up soon, thanks to a lot of work and great ideas you's have all developed. Saved me a lot of disapointment to be sure, and taking down a wind machine when it's -40f in blizzard conditions, which is why I plan to fly at least 3 before next winter. My electric bill is about $6,000 a year. I'm determined to reduce it to the service fee for having a hook up.

[scottsAI]

Hello 3rd Charm,

Good first post.

Here is something that may help based on a dozen hours of research:

A simple improvement of the electric dryer you have is to put a Cross flow heat exchanger on the exhaust of the dryer. Do not make it more than 50% heat recovery, may cause the exhaust temperature to drop below the dew point causing condensation which will cause lint to stick causing the exhaust to get clogged. Test the exhaust temp before and after to determine percent of heat recovery.

Many dryers have lint filter on front with a blower on the front of the dryer (if lint filter is on top then blower is in back), with the exhaust pipe going front to back. A section should be straight, use this section as part of the heat exchanger. On the straight section surround it with a 6" dia vent tube, connect it to the intake of the fresh air, making sure it sucks the air from the back of the tube to front. This is a cross flow heat exchanger. The air as it enters the heater is now pre-heated.

Looks to be a low risk project. I hope to get an old dryer from the recycle center and try it out!

Have fun,

Scott.

[ghurd]

"cause the exhaust temperature to drop below the dew point causing condensation which will cause lint to stick causing the exhaust to get clogged"

I don't know about that.  Meaning any heat exchanger will probably drop the exhaust temp below the dew point?

My drier runs about 2' sideways in plastic curly pipe, then thin-wall PVC straight up about 5', then sideways again.

The curly pipe isn't so bad, but the verticle pipe clogs in (and for) the first (lowest) 2 feet. Soggy nasty mess.  10' farther away the pipe stays quite clean.

I just plan for the water to drip.  A heat exchanger would make it drip more, and I'd simply plan for that too.

G-

[scottsAI]

Hello ghurd,

"I don't know about that. Meaning any heat exchanger will probably drop the exhaust temp below the dew point?"

I was reporting from a study back in 1986 from Arther D. Little, Inc.

Their simulation suggested not to recover more than 50% heat in the exchanger or the air would be cooled below the dew point...

Sounds like your exhaust gets cooled in your pips already, and you understand the issue.

You thinking of trying it out? Going for more than 50% heat recovery?

I would love to know how it works. Couple friends with nice new dryers not willing to experiment but would consider doing it if good results were reported. Theory is only just so good.

Have fun,

Scott.

[ghurd]

"Theory is only just so good".

About 12 years now.

Cleaned the 'long' pipe once, but it was not worth the effort. About nothing but dust in there, and all at the lower part. Had it down, so I cleaned it, last year.

Maybe 99.9% of the 'crap' was stuck in the first 3 feet of verticle pipe or the 20~30 inches of 'twisty flex pipe'.

The lower part is cleaned every season, and for good reason.

The top horizontal run is really long, maybe 18'? Maybe a total run of 30'?

Not good I'm sure. There is a downward bend near the drier end.

The pipe is thin-wall PVC.

Water almost runs out of it, kind of fast too.  A steady drip-drip-drip, and in a couple places.

When vented indoors (not recommended) the heat from the dining room closet is VERY noticable. Long story, but still not recommended.

Meaning either my 6' of pipe is a good heat exchanger and should be well insulateded in warm times,

or my thin-wall PVC is a good heat exchanger as it is, and it simply can't be(?).

I would suggest they plan for a lot of condensation, and not worry about anything else.

(Expect and plan for it to drip)

Photos of the dungeon where my drier is kept upon request.  Not a pretty sight.

G-

[tecker]

My greenhouse doubles as a dryer I put a line down the walkways and turn on the exhaust fans It puts air down the center . I need a large door though to let nature in . I 've been keeping nature out lately.

[gale]

The "new" expensive clothes dryer in the US is based on a european design. The best part it is extremely efficient and your clothes come out wrinkle free.  It looks like a two level wardrobe.  A three foot deep case, four ft tall, by 3 foot wide, usually stacked on top of another unit.  The entire front opens as a door.  The interior is a series of rods place about 8 inches apart in multiple rows verticle and hortizontal.  The rods point out toward the door.  The clothes are hanged over the rods. The only moving part is a small fan which vents out of the top.  On the inlet is a small heater.

  A re invented clothesline, but it has several great advantages; 1) by heating the air only slightly, greatly decreases drying time, and helps holds the fabric color better.  2) the moving air-  generally eliminates wrinkles 3) The lack of tumbleing extends clothing life.  The retail unit costs about $1500.00

[coldspot]

"http://www.laundrysystems.electrolux.com/Files/pdf/Heat%20recovery%20pipes.pdf"

[GaryGary]

Hi,

Here is a nice simple scheme for heat from the attic:

http://www.builditsolar.com/Projects/SpaceHeating/BlackRoof/BlackRoofCol.htm

Gary

[GaryGary]

Hi,

There is a plus side to letting the water in the dryer exhaust condense.  You recover the heat that went into vaporizing the water.  This is about 1000 BTU per lb of water -- so it appreciable.  It seems like this is probably enough extra heat to be worth working out a way to solve the water/lint problem?

Gary

[scottsAI]

Hello ghurd,

A friend just bought a new dryer, wants to relocate with a long vent run.

Thanks for the heads up!!

The vent will be cooled just like the heat exchanger with the same problems, condensation and lint build up! I must give him a call. Thanks!

Have fun,

Scott.

[scottsAI]

Hello GaryGary,

Black roof cooling: Florida Solar Energy Center

http://www.fsec.ucf.edu/en/publications/pdf/FSEC-CR-1692-07.pdf

First started testing in 2005. Implementation leaves much to be desired. Shows it works.

I like your web, over the last couple months I have spent many days reading almost everything including your many links. Thank you.

Have fun,

Scott.

[scottsAI]

Hello GaryGary,

I agree.

I intend to look into lint solutions, go for the Max heat recovery I can devise.

Any ideas?

I have couple, keeps flunking the KISS test.

Have fun,

Scott.

[scottsAI]

Hello coldspot,

Interesting read, Yes, like what I have in mind.

The efficiency improvements are only 10% at 24'c?

Report I read with 50% heat recovery claimed 20% efficiency improvement.

So this is doing much less?

I hope to do more than 50% heat recovery! Heck with the lint!

There must be a solution. Any ideas?

Have fun,

Scott.

[alancorey]

Clothesline on a porch, that's the ticket, been doing it 8 or 9 years.  Don't have to worry about rain.  Wash your work clothes Friday night and if you don't have something dry by Sunday night bring it indoors for overnight.  Even if they're frozen clothes will dry in 3 or 4 days.  Plan ahead.  Driers are for emergencies.

  Alan

[Bruce S]

Scott;

  Here's a thought, I re-read some of my old Mother Earth News magz, and back when they were trying to design a better stove pipe for pot-belly types and such. They came up with the idea of using a venturi type catch.

Basically this turned out to be an opening in the first "J" not compeltely on the bottom but at a 45 degree , this allowed the seuit<-sp? to collect. I have a gas dryer and too need to come up with a much better way of recovering the waste air.

I have a little bit of room in our laundry area and am thinking of using some solid piping to make a turn out of the back, use a "J" connector cut an opening and use a gal pickle jar to allow the condensation to collect there.

With natrul gas, care must be taken to "bubble" the waste air first to due possible unburned gases, but by using the waste air back into the unit, this may work as the bubbler.

I am sure that lint would collect there as well due to gravity , which is why I am either going to use a glass jug or make use of a clear plastic gal jug.

I the Alky making biz this is simliar to refluxing:-)

Thoughts?

Bruce S

 

[scottsAI]

Hello Bruce S,

Sounds like your ready to give this a try.

Cool or should I say HOT!

I recently looked at a dust collector for woodworking.

Uses a large clear venturi...

http://billpentz.com/woodworking/cyclone/Measurement.cfm

Link is top right, other good stuff there.

Good enough for wood dust, may be just the thing for lint!

Thanks for the idea!

Have fun,

Scott.

[GaryGary]

Hi Scott,

Glad to hear that my site is keeping someone besides me up late

I like the FSEC scheme -- nice and simple.

Gary

[GaryGary]

Hi Scott,

Maybe a good lint filter upstream of the condensation area?

The link thats further down this thread has some pictures of a commercial unit that might provide some ideas?

Gary

[scottsAI]

Hello GaryGary,

You mean the electrolux?

Unit does what my goals are, recovery is less than goals.

Bruce in post 49 suggested a venturi, I saw one for woodworking post 50.

I like this idea! Don't know if it will work, looks good.

To go a little further by combining the venturi and heat exchanger into one unit.

Doing some quick math, looks like 400whr to heat, 200whr to run the motor.

600whr vs 3,000whr for electric dryer! Wanted 300whr, can't see it happening.

Have fun,

Scott.

[3rd Charm]

Condesation is a problem even when venting into the cold air return (well filtered through a home made lint trap first). a layer of fine dust builds up over time (sticks like glue too) making frequent cleaning of the cold air return duct for the fist 20 feet or so from where the dryer vent comes in neccessary.

I was thinking a heat exchanger would have the same problem, and eventually plug up both on the exaust and intake sides, especially in the winter, when you are drawing in fresh air.  I think the cold air return duct is the best way, at least for my set up, because buring wood takes care of the excess humidity. If you don't burn wood, humidity will be still a problem, especially if you have one of those fancy furances that regulates humidity to begin with. That would probably made that type of heating system go biserk, and vent all your air outside to get rid of the moisture.

When I get my wind machines built and flying, my main prioity is to heat a lot of water, and install hydronic radiant floor heating throughout the house and my workshop.

I'm getting old, and sick and tired of cutting and splitting 7 cords of wood a year, which now that the snow is gone, I should be getting started doing now. I'm going to gamble this summer and say the heck with the wood, I'll use my free time to build some windmills. Except for wire and magnets, I have everything I need. (except I'm already deviating a little from how things are done here. I'll be using dodge hubs and axles for my rotors).

If I can get the water hot enough, I should be able to use a few heater cores ripped out of some wrecks, (I have a large graveyard of auto's) and rig up a closed air system for the dryer so it doesn't suck any air out of the house, and I can keep the laundry room door closed. It might take a little longer for clothes to dry with that type of heat,(hot water radiant) but if all goes well, the power for the dryer motor will be free as well.

I do see one potential mistake that others may be making without realizing it when putting the magnets on the rotors, especially rectagular ones.  I see that great care is taken to make sure that the poles are stagered N-S-N-S, but how do you really know if the first magnet put down has the north pole facing up, or the south pole?  Worse, what about the polarity along the inner diameter and outer diameters? If those poles are facing every which way, that could cause a lot of stray currents to fly around , making uneeded heat. A Gausemeter should be used to make sure the poles on all sides of the magnets are properly aliegned, and perhaps put to better use cleaning up stray currents produced by other components.

Just a thought.

[scottsAI]

Hello 3rd Charm,

Not your typical newbie! Great.

Check my post 50, link to a (Hydro)cyclone Separator. Link is for wood dust, works with moisture and dust. I intend to integrate the cyclone + heat exchanger into one unit. I called it a venturi earlier, messed up the name. Just like when I called the heat exchanger a cross flow heat exchanger when it's a counter flow heat exchanger! I expect the cyclone will work Much better than the lint trap. Condensation will form in the cyclone/exchanger, expecting the water to wash the lint out. Collects in the bottom. Fine filter at the drain to get rid of the water keeping the lint. Depending on size may not have to empty every load. Wait a while after using dryer to empty the lint, time to dry out, no mess. Skipping the dryers own lint filter, here just gets in the way.

Using a counter flow heat exchanger I'm expecting to only use 300whr of heat or 1,023BTU, very small water to air heat exchanger needed for this amount of heat. If your going to mess with the inside of the Dryer, try recirculation all the air until the load is heated will reduce the heat needed by 20-30%. Which is how I got 300whr. I assumed full recirculation until temperature is up 80% and the heat exchanger is 85% efficient. Just heating the water in the clothes; 100'F * 1.5lb water / 3.4BTU/w = 100watts. Another 150whr for the tumbler and blower. At 450whr per load, almost not worth finding another heat source, but of course we will!

Heating

You seem focused on wind for heating. I take it not much solar during the winter?

Even with DIY wind gen I can build a 100KBTU solar heater for MUCH less. Check my post #30, I make a suggestion to build a nice but cheap solar heat collector.

Long term I would be more comfortable with solar than a wind gen due to maintenance. Send me email if you have questions.

For the large wind generators going with induction motor as a generator is lower cost.

One 24 foot wind gen is 5-10kw, which is only 34kBTU, need more than this to heat most homes.

Induction can be grid-tied if you have it and have net metering. Pitch control is required with grid-tie, which turns off most people, except me. I have a fundamental design.

I have a friend with 2000' ranch/basement, two face cords of wood for the winter in MI. He has one inch insulating shutters outside he closes at night. Most windows have 1 inch insulation tightly installed in the lower half. For backup he uses about $25/yr in gas, the monthly min is much more. He is thinking of removing gas, switching to propane, but would have to change all of his equipment...

N-S of magnets is found with a compass.

Or use the magnets themselves. (be careful) the actual order if N-S-N, or S-N-S does not mater. Same pole repulse, opposite attract! I have a Gausemeter:-)

Have fun,

Scott.

[BT Humble]

   Right on Tom, Memories of handing Mom

the clothespins....the mad dash to help bring in

the clothes when it started to rain...This poor

generation that will never know memories like this,

I actually feel sorry for them.

I've only ever owned a mechanical clothes dryer for a few years (my first wife insisted) and I hated it.

If it's sunny, my clothes go on the outside line.

If it's not, they go on a clothes horse inside.  They dry in a couple of days.

BTH

[helowrench]

Would you be better off (all things considered IE: lint accumulation, condensation, etc) by just plumbing the intake side of the dryer to draw air from a heat exchanger in your attic?

I have an available straight run of 30 ft horizontal and then a 30 ft drop into the dryer. Makes me think that I could run an uninsulated 6" steel duct  (to lower the airspeed and promote the heat transfer) through 40ft of attic space with the air intake screened and open to the outside air.

This would eliminate the heating of replacement air, while greatly increasing the dryer intake air temp (Dallas TX).

Rob

[Bruce S]

Scott;

 hadn't kept up with the replies here, sorry for that.

That link is quite intersting and very informative!!

I think you're right, if it'll pickup those pesky little dusties from working with MDF it'll certainly work with lint.

Thanks

Bruce S

 

[Bruce S]

Rob;

   That's an interesting idea. If you have fairly easy access to an internal wall that goes straight up to the attic; then a pipe using the incoming attic air during the winter time would allow for reuse of the heated air that migrates up to it.

Only thnig that would have to be careful about: those super tight attics that have almost no migrating heat.

If do this during the summer , then even that pre-heated air could help to cause an air draw down and possibly stir the attic heated air up.

I would put the draw tube up as high as possible, this would obtain the hottest point of air, most attics have hot and more importantly, dry air, this too would help in removing the moist air from the clothes.

On a side note about all the lint being captured, that stuff is great for starting fires:-!! in wood stoves , wood fireplaces etc. , better that just putting it in the dump.

OR if you have problems with deer eating the bark on your tender young fruit trees just put some of this stuff around, they'll steer clear of it.

Bruce S

[helowrench]

i do have direct access to the attic from my laundry room, and was thinking to put the intake tube on a run along the peak. Straight and level for about 30 ft then a simple 90 to turn it down, then a straight pipe 10 ft down through the ceiling into the laundry room.

As far as a "super tight" attic, mine is far from it, built in '78 upgraded to ridge venting in '03, I am also looking at additional insulation and solar powered attic exhaust fans to remove some of the excess heat in the summer (100 F very common in the 6 months of summer) but that is all for another thread. {I have to get some good temp logging equipment before I start that}

Rob

[scottsAI]

Hello Bruce S,

Your venturi comment, I translated it into vortex... But kept calling it venturi.

Rather funny, not the same thing. Did get me on to the right idea. (I hope).

GE has a 1998 patent using a vortex lint filter, goes in the dryer door.

Rather strange looking thing, can't find it in any of their units.

Not a full cyclone filter as the link above.

Wrapping the heat exchanger around the cyclone filter servers 2 functions.

1. lint filter.
   
2. Condensing heat exchanger
   
   

Electrical 400whr energy cost to dry a load!

Solar heat should drop it to 120whr/load for tumbler and blower motor.

The make up air can have a cost exceeding the dryer air heating cost. Air conditioned air is a good example. The math suggests it's better to get the dryer air from outside. Up north in the winter, the heat and moisture is generally welcome in the home.

Final step is Looking at using desiccants, no air in or out. May dry faster, need to finish my research.

Have fun,

Scott.

[ghurd]

I think if the exhaust is run into a 6' long tin 3.5 x 14.5" (?) duct pipe, on it's edge, the air would slow, the extra surface area would cool the air better, and the lint would settle to the low (3.5") side.  I don't think much would be on the top or sides.

Pop off the ends twice a year to pull out the gunk.

At about 12' total distance from the output, in my 4" PVC pipes, there was VERY little crap in there and all at the bottom. Looked about like someone slowly poured blue paint into the horizontal pipe.

I had a plan for a half dozen 4', 4" duct pipes "connected in parallel". A few dents here and there to add some turbulence to help with exchanging heat and seperating the lint?

Never did it.  Those Ts are expensive, and it takes a lot of Ts! LOL

Plan for a lot of condensation.

G-

[scottsAI]

Hello ghurd,

If the pipe cools, then the heat goes into the house? Michigan in the winter that would be good, not in the summer.

In your dryer it has a lint filter, so what your seeing in the pipes got passed it?

"Plan for a lot of condensation."

Ever measure it? Looks like 1.5 gal of water in the clothes. Wonder how much will condense out?

My first step is to get an electric dryer, GE's has couple models with a straight round 4" exhaust pipe, will put over it a 6" pipe for the intake air preheater. Found recirculation of the air until clothes are up to temperature reduces the heat needed by 20% or so.

Need to find out how large (long) of a heat exchanger is needed?

Counter flow has the shortest length.

Have fun,

Scott.

[ghurd]

Lint gets past it, yes. Much more than I expected.

How much condenses? I don't know. No way a gallon.  The outside exhaust looks like any other.

It drips out in about 6 places because I didn't cement it together. Have a 44 oz Taco Bell cup under the main drip, dump it every 3rd(?) load.

Lost cause in this basement, too damp/wet in summer to see much difference, nearly dries on impact in winter.

How big for a homebrew heat exchanger? Probably like wire, the bigger the better. LOL

G-

[GaryGary]

Hi Rob,

That does seem like a good idea.

I wonder if you really need the heat exchanger part at all?

Is there a problem with just drawing air from around the attic peak?

It seems like any air the new dryer inlet pipe draws from the attic will just be made up by a little more airflow into the attic vents?  

A dryer only uses about 170 cfm when running -- my wholehouse fan pulls about 4000cfm through the (somewhat enlarged) attic venting and into the house.

How do you get the dryer to use only the air that comes down from the attic inlet pipe?

Maybe, seal up the laundry room?  Or, some type of inlet manifold? Or?

In the winter, the attic scheme might be limited to sunny afternoons -- depending on the climate.

Gary