# Hot water clothes dryer ?



## buddylee (Feb 20, 2012)

Haven't been able to find much info about these. Is there a commercially made one available ? I would prefer to buy one but not opposed to building one if possible. Any ideas ?


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## Jags (Feb 20, 2012)

Hmmm... interesting.  What kind of water temps is your Hardy set to?


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## jimbom (Feb 20, 2012)

You might look at district heating systems.  I recall we provided steam to laundries and I was told they used it for more than heating water for wash.  Steam delivered would definitely convert to sensible heat sufficient to dry laundry.  I really don't know the temperature inside a normal home dryer.  Me thinks the heat exchanger from hot water to air would be the clinker.

Our home circumstance, climate, and house configuration makes it easy for us.  We went to the dollar store and bought a clothes line for two dollars (?).  I know that is not your question and that you may not have the handy situation we enjoy.  But boy howdy, the pay back on that $2 has been darn good.  Build-It-Solar has a great collection of ideas for those able to dry clothes outside.


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## buddylee (Feb 21, 2012)

I can run it up to 180 but I don't see why it would have to be that hot in order to dry clothes. I've never worked on a dryer but I think I'm gonna get a non-working one just to take it apart and see how it's put together. Figured a little coil mounted with a blower behind it. No idea if this would work.


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## Jags (Feb 21, 2012)

smokingout said:
			
		

> Figured a little coil mounted with a blower behind it. No idea if this would work.



You will probably still need the tumbler to be operational and the blow (as you said).  Essentially, you would be replacing the heating element with pipes or a heat exchanger.

If you get an old one to tear apart, make sure it is an electric one.  The gassers are a different critter.  The older electrics just had the back wall covered in heating element (think toaster over).  I would think it would be fairly easy to replace the heating element with a copper coil or some such thing.


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## Retired Guy (Feb 22, 2012)

You will probably need about 16,500 btu to equal an electric dryer.


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## mikeyny (Feb 25, 2012)

built one many yrs ago. worked but not well enough. Dryers get up to 280 degrees to dry cloths quickly. Trying to supply constant 180 from a wood boiler takes a lot of wood, not really worth the hassle and takes too long to dry stuff. Cloths line in the boiler rm works great and keeps the humidity up.


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## guy01 (Feb 25, 2012)

here is a link from a much older thread 
http://www.hardyfurnaceparts.com/products.php?cat=18

you can just buy one if you want
Guy


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## benjamin (Feb 26, 2012)

The commercial companies make them for steam and they still have a massive heat exchanger (plus filter and recirculation IIRC?).  For a grand I'd take my chances with a few heater cores in an old gas dryer, or the holy grail, the condensing/dehumidifiying refrigeration clothes dryer.


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## peakbagger (Feb 26, 2012)

I notcied a reference in to "purchasing a hot water dryer" in an article about the Green Mountain Club's efforts to go renewable at their headquarters complex. One of ther employees posted about the installation of a wood boiler on this site a few years back. I think his name is Pete Ketchum, but dont know what the goes by on the site. If you are serious, if may be worth giving him a call at GMC.


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## dougstove (Feb 26, 2012)

When I lived in Sweden we had drying cabinets; the clothes either hung on hangers or sat on coated metal racks.  The hot air passed through with a small fan, as I recall.  They work fine, a tumbler is not necessary.


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## buddylee (Feb 28, 2012)

I spoke with an a small appliance repair man I know today and he said he would keep an eye out for a suitable used dryer. He said there was a brand that would suit me and should easily be modified.


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## markmudd (Mar 12, 2012)

Been thinking about this too for my wood boiler.   My electric dryer has a round duct that you could put a small copper coil or a small heating core type radiator into just before hot air goes into drum.  It might take longer to dry, but would spin the meter less.    Would need to install switch on the electric element so it would not turn on.    The drying closet sounds good if you had space.


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## MasterMech (Mar 13, 2012)

smokingout said:
			
		

> Figured a little coil mounted with a blower behind it. No idea if this would work.



Heater Cores from big SUV's (Like suburbans/excursions) or radiators from small cars?


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## nate379 (Mar 13, 2012)

https://www.google.com/search?q=Hyd...s=org.mozilla:en-US:official&client=firefox-a


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## rkusek (Mar 13, 2012)

I've thought about trying this as well.  One would think a heater core from a large automobile would work.  You would not even need to disable the heat element, just run it on air dry.  I think even my computerized dryer allow for a timed air dry setting.  If I wanted to utilize the humidistat, it looks like I would have to run a switch to a contactor to disable the heating element.  That would shut it down when clothes are dry.  One would have to get create an adapter out of sheet metal to form from the intake to the heater core but it certainly looks like it could be done.


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## GaryGary (Mar 14, 2012)

Hi
Here is another approach to drying -- not hot water, but an alternative to electric:
http://www.builditsolar.com/Experimental/AtticToDryer/AtticToDryer.htm

Gary


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## Tatnic Corners (Mar 16, 2012)

What about an air exchanger that saps the heat from the outgoing dryer air?


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## Dune (Mar 17, 2012)

Tatnic Corners said:


> What about an air exchanger that saps the heat from the outgoing dryer air?


 
It could certainly be done. The sticking point is the lint. I designed on which opens entirely to facilitate removing the lint.
Issues; Copper would work best, but is expensive.
Aluminum would work almost as well as copper. Copper can be readily soldered,  aluminum can be soldered or welded with difficulty and the exact proper materials.


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## GaryGary (Mar 17, 2012)

Hi,
I suppose a separate and easily cleaned lint filter could be placed up stream of the heat exchanger.

Another option might be to do a coaxial pipe counter flow heat exchanger.  That is,  make the dryer outlet duct somewhat longer, and enclose it inside a slightly larger duct.  Blow air through the larger duct with the flow in the opposite direction of the flow in the dryer duct.  I wonder how many feet of coaxial duct would be needed to pick up a worthwhile amount of heat?   Seems like a fun experiment to try.
Might have to make provisions for collecting condensation depending on how cool the dryer vent air gets.

We have vented our dryer inside off and on for several years.  In our very dry climate, it works well.  The moisture that would be a problem is some climates is actually a plus where we are.  We just use a couple of panty hose as to filter lint -- not the most elegant, but it works fine.

One thing that some people don't think about is that not only does a dryer heat up a bunch of air and exhaust it outside without using the heat, but that air exhausted outside has to be pulled into the house somewhere, so you not only lose the dryer heat, but you have to heat up a bunch of outside air to replace the vented air.  Has to be a better way.

Like the new forum software.

Gary


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## woodsmaster (Mar 18, 2012)

I've been considering making one. I'm affraid the clothes would take to long to dry to satisfy the wife. I may still make one for the fun of it and put it in the shop for a back up and mabey dry some heavy stuff that were not in a hury to dry. I have a dryer with a 4 or 5" tube that has a heating element in it. I was thinking of removing the element and replacing with a copper one like used in a domestic hot water tank. I have storage so suppling constant 185 degree water wouldn't be a problem.


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## gtjp (Mar 28, 2012)

Howdy:
Thermal Energy Transfer

USA COIL or THE COIL CO, PA
can work backwards from BtuH and tell you in a 2-row fintube (coil, as called, looks like a radiator you may know)
of say 17" x 20" in a (lint-filtering) box with some chosen entering 140-deg/  air leaving at 150-deg, having 160-deg fluid at say 10 gpm flowing in to the HX coil... (pick diff... or calculate: 
500(constant) x 10-deg diff[160-150fluid ] x10 GPM is 50,000 BtuH (5gpm, 25,000 btuh, or a 5-deg diff at 10 gpm: also 25,000 btuh)
Those coil cos can more closely discuss quickly how many btuh will be available...

our gas dryer runs on low at "164 degrees" booklet states in chamber-drum...
gas btuh on low is higher than a 5kw 16000 btuh... ? guessing 20,000, actual.

?
as a question of WORK DONE:
I have found in radiator heating from ~ 124 deg at 3gpm per 10,000 btuh, there is a need for about a 15 sq ft contact hx in coaxial fluid, or shell-tube hx's... for just a good 50,000 btuh///
(117 degrees returning to heater coil ~ x 15gpm, 1/6hp NRF- closed or B&G PL-36-open air or GFos up26-116F<iron> circulators   www.FlowCenterProducts.com )
And about 400 sq inches or 20x20 2-row air fin tube say in a furnace from the HW boiler at 160-deg; but the coil companies can derive a comparrison if you make up some objective examples and find btuh's desired.. ( gas dryer labels)-

About 60% MORE hx sq ft is needed in air for 140-150 deg fluids than 180-deg fluids, in some things used already for heating spaces... but there are charts about that on heat exchangers, and those with software ready to advise freely.

Hope you save a bundle !


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## Josh Carmack (Nov 18, 2015)

I'm new here, as a matter of fact this is my first post, but I will say the forum has helped me in various ways in the past. The lack of info surrounding hydronic dryers is why I joined.....

In February of 2015, my house caught fire on one of the coldest nights of our past winter. The clay and concrete wall collar failed, allowing the heat and fire from a very hot fisher woodstove to make contact with combustible materials in my wall. Insurance company wrote the damages at 29,000. I did all of the work myself, and repaired, and even improved on my house for a little less than 10,000.  I had around 17,000 left to do as I pleased with after the deductible and everything else was said and done. I bought an Earth Woodsman 405, and related materials to go with it. I then typically blew the rest on other things like tools, and newer diesel truck, and a really nice used 20' flatbed.

I have a wife, and 5 girls, 4 of which are ours jointly, and one exchange student, so you can imagine, that we wash and dry a lot of clothes, before I had even purchased my furnace, I was looking for ways to utilize it, anything and everything that furnace was capable of doing, I was going to do it. I Have a strong mechanical aptitude, and knowledge of how most things work in the world, I was sure there were kits and plenty of knowledge on how to make a hydronic dryer....I was wrong. I found ONE, that's right, a total of ONE kit to convert an electric dryer, and lots of forum comments stating it wouldn't work, or it would work poorly, and the original poster should just stop being so lazy, and install a clothes line.

Not to be deterred, when I purchased my furnace, I purchased two water to air heat exchangers, one sized to fit snugly inside my propane fired central unit, and the other was the smallest size they offered. I had already done the math on how many btu's an electric dryer uses, and came out with a figure hovering around 10,000 BTUs. The smallest exchanger they offered was a 12X20 rated at 60,000. I figured heck, might as well, if it doesn't work, I'll use it to heat my shop or basement using a scavenged squirrel cage. I had an old sears dryer sitting out in the back of the barn that we retired because it never was great at drying clothes, it had issues from the day it was brand new. Retrieving the old dryer, I set to work re-purposing it for use as a test bed. I set out to call this "new" dryer, my "Water Dryer"

I removed the back cover, and then the heater assembly and related duct. I then test fit the exchanger to see if it would fit inside the cavity, and it did, rather snugly. I then set about adapting it to actually reside there, and fit the air intake to the drum. I used a piece of 1/4" MDF that was slightly larger than the 12X20 exchanger. using a jigsaw I cut a hole for it to fit nicely over the back half of the heater duct. I then attached the MDF to the exchanger. The exchanger and mdf was then fit in the back of the dryer, and I was still able to use the mounting straps that held the original duct assembly into the dryer. The heater duct was a rectangular tube that was made from two pcs of stamped sheet metal that was riveted together. I simply drilled the rivets, and retained the back half of the duct as it was the simplest way to make a good seal for the drum flange, and the rivet holes made it rather easy to attach the mdf using very short sheet metal screws.

From there all I needed to do was convert the remaining electrics to allow the dryer to run. I have repaired, or helped repair a lot of dryers in my past, and I have never seen an electric dryer that doesn't use only one leg of it's incoming power to run the tumbler/blower. Meaning, every dryer I have ever seen, is powered by 240 volts, but the tumble/blower motor only run on 120, or one half of the power supply. That was also the case in this dryer, so I removed the original 30 amp wire, and replaced it with a salvaged cord from some power tool or etc that had failed long ago. With a little wire chasing I could see that one leg of the 240 went directly to the heater, and the remaining leg went to the heater, and everything else. Walla!, hook the common to the original common, and the hot, to the hot side that supplied everything else. Set the timer, and push start, and it runs.

Called upstairs to the wife and told her I was ready for my first test load. Thinking it was a failure from the get go, and hoping to make it a dismal failure, she brought the biggest load of wet clothes I have ever seen over and piled them in. It was a heaping basket full, the big baskets, about 2 feet long, 18 inches wide and deep. An hour later, the dryer was still running, so I checked them, and they were almost dry. BUT, the timer was still at the same setting. Gave them a few more minutes, and called my wife back down. She was pleased! That night we washed everything in sight, and then dried it using my "NEW" dryer. The drying time is about 20 to 50 percent longer than our unmolested dryer depending on the clothes, with towels being the hardest to dry in a reasonable amount of time. That was partly rectified by turning the spin speed up to high on the HE washer. Our last HE washer, a front loader failed catastrophically in the drum. It was a good washer, and it did a really good job at spinning the clothes, it would actually sound like an APU on a jet spooling up when it would spin the clothes out. Although, planned obsolescence, and a really fast spin speed caused the drum to explosively separate one day and killed the washer dead, since a replacement drum was 600, and the washer only cost new 750. We replaced it with a nicer top load HE, but it had a variable spin speed option, and to avoid what happened last time, we choose to set the spin speed on medium. We leave it there now, for everything except towels, and jeans.

Last night I decided to tackle the timer issue because for the last month we either had to check the clothes and manually stop the dryer, or use the unmolested electric dryer if we were not going to be able to check the water dryer for some period, IE we were sleeping, or out of the house. After some poking around with a DMM and tracing wires I determined the timer circuit was tied into various safety and dryness sensors in the dryer, one of which being the over temp sensor on the heater assembly I had removed. I simply re positioned the timer motor wires about the terminals on the back of the timer switch so that the timer motor drew it's power from the same terminal that sent power to the tumble/blower motor. Now, whenever the timer is in a position to send power to the motor, it runs itself as well, and since all settings on the timer send power to the motor it runs as expected with one exception being the auto dry function no longer works. Most dryer auto dry settings use a temperature sensor that only closes above a certain temperature. The way that works is as follows... A wet load of clothes will have a low exhaust temperature, lower than boiling, so in the auto dry setting, the timer cannot run, until the exhaust temperature sensor closes it's set limit. Once the sensor closes the timer will run, and shortly thereafter move to an off position. Unfortunately, that setting is Higher than the temperature the dryer is now capable of outputting and will not function.

Overall we are all pleased, it works moderately well only taking about 30% longer to dry, and after fixing the timer issue, if you set it on the longest run time, the clothes come out nice and dry. I have not measured the tumbler current draw, but I am guessing it is around 500 watts or less, so when compared to the original 4500 or so watts and slightly shorter run time, we are saving about 70% using it over the full electric.

How much wood does it burn?? I don't know exactly, but if I had to make a WAG I would say about 3 lbs or less per load. BTU content of wood is almost the same no matter the species, with that BTU content being around 8600. Cottonwood PER POUND has relatively the same amount of energy as does red oak moisture content not withstanding. I know that when the dryer is running, the furnace does not power the blower any more often than it does just sitting idle, Sitting idle the blower fires about every 30 minutes, mostly due to the 100 or so feet of uninsulated pex running around in the basement ceiling. Makes for a nice cozy warm trail leading all throughout the house. as well as the central unit blower not needing to come on as often as if it would if the underfloor pex was well insulated. Measuring temperature drops in and out of the dryer at my "Estimated" flow rate I come up with a figure of 10,000 BTU's, but it is probably lower, as I'm not calculating my flow rate for my pipe runs or number of joints, but simply using the pumps rated flow at 0 head.


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## Josh Carmack (Nov 18, 2015)

PS, yes I realized this was an older thread, but I revived it so it would perhaps come up in the next google search made by some guy like me looking for a little guidance like I was. 

I'd also like to add a little more information, I am running my water temperature at 185, by the time it makes it to the dryer, it is about 184, I have not measured my exhaust or drum temperatures, but if anyone is interested I will do so. I can say that the unmolested electric dryer with an empty drum after ten minutes measures 285 degrees at the drum inlet, and a palsy 200 at the inlet on low heat. Those measurements were taken with an infrared gun from outside the drum after 10 minutes or running empty. It is also important no note, I have never seen a dryer that uses positive draft to transfer the heat into the drum, for various safety reasons, they all pull air into the drum. The blower induces negative pressure on the drum, and the heater, be it gas or electric is ducted to the drum, with the heater being the first thing the air see, then the clothes, then the lint filter, and then the blower and out the exhaust. I did have pictures uploaded, to Face Book, but was embarrassed by how bad my basement laundry room wall looked and deleted them, I attempted to find them, and could not locate them on my hard drive, so I must have uploaded them to FB directly from my phone. IF anyone would like pictures, I would be happy to take new ones, or even upload a video to YouTube.


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## junkers (Dec 6, 2015)

the picture would be very desirable
thanks


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## Josh Carmack (Dec 8, 2015)

Pardon the appearance, the dryer sat in the semi open weather for 5 years.


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## semipro (Dec 9, 2015)

Josh Carmack said:


> it would actually sound like an APU on a jet spooling up when it would spin the clothes out.


Great description!


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## Josh Carmack (Dec 9, 2015)

semipro,, lol, funny you quote that. I pulled the drive motor out of the dead washer intending to use it on my home made fuel centrifuge. I could tell from the washers operation that it was what I THOUGHT to be a DC driven variable speed motor. Turns out it was a 3 phase 180V 480hz motor. The washer circuitry converts line voltage to DC, and then uses a logic unit to induce a varying frequency AC signal to drive the motor in oscillations, low high, etc. I assuming the sound was the invertor drive noise being induced into the motor windings. It is interesting to note, the motor is rated for a maximum of 480hz at 18,000 rpm. The last APU I worked on was self sustaining at 40,000, and was 100% at 120,000. Maybe the sound just made me miss working around aircraft lol.


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## junkers (Dec 10, 2015)

thank you very much


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## semipro (Dec 10, 2015)

Josh Carmack said:


> semipro,, lol, funny you quote that. I pulled the drive motor out of the dead washer intending to use it on my home made fuel centrifuge. I could tell from the washers operation that it was what I THOUGHT to be a DC driven variable speed motor. Turns out it was a 3 phase 180V 480hz motor. The washer circuitry converts line voltage to DC, and then uses a logic unit to induce a varying frequency AC signal to drive the motor in oscillations, low high, etc. I assuming the sound was the invertor drive noise being induced into the motor windings. It is interesting to note, the motor is rated for a maximum of 480hz at 18,000 rpm. The last APU I worked on was self sustaining at 40,000, and was 100% at 120,000. Maybe the sound just made me miss working around aircraft lol.



You should check out the motor drive on a Fisher and Paykel washing machine sometime.  I think it would interest you.


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