Outdoor Wood Furnace Info
All-Purpose OWF Discussions => General Outdoor Furnace Discussion => Topic started by: RSI on April 16, 2011, 08:54:02 PM
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I have been thinking about putting together a kit for clothes dryers. The problem is that to order the small size heat exchangers it costs 3-4 times as much for one as it does per unit if I order larger quantities.
If anyone here is interested in doing it let me know and if we can get enough people together for a batch it would be a lot cheaper for everyone.
I have not decided exactly what size heat exchanger would be best but I am thinking around 6x6" or 8x8" should be sufficient.
I know it works with 180 degree water but not sure how good it will for people that run at the lower temperatures. (ie: 140 degrees)
I have had one setup for a couple years but I just used a single row 12x12 heat exchanger with 1/2" pex feeding it. Using the custom size heat exchanger should work out a lot better because dryers suck air in and I don't think it is going through the entire 12x12 area and the extra thickness of the 3 row coil should heat the air a lot better.
Also, I used a second dryer instead of putting it on the main dryer. Mostly for safety since I didn't want to interfere with the heater on the dryer. Also, this allows to dry two loads of laundry if you get behind. ;D The dryer I put it on I removed the heat source.
You could probably use your main dryer but it would be up to you to make sure it is safe. (I would highly recommend removing the kit and going over the dryer to make sure it is ok after switching it back for the summer if you do this)
I used to have an indoor wood furnace so there was a spot about the right size for the second dryer where it had been.
It looks like heat exchangers would be around $100 each if we can get to the price break quantity. If we can get more together it would drop it more. Also, if doing it the way I will be recommending, you will need a pump also. I can supply that or you could get it on your own. Other parts would probably depend on the specific dryer but a universal kit may be possible.
If there is interest, I would like to see some pictures of the bottom inside and back of different dryers that you have so we could get the best size heat exchanger. If it could be mounted inside it would be a much cleaner looking install.
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Would a heater core from an old car work? About the right size and cheep from a auto salvage yard
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I could easily be talked into joining the HX core group. I am on electric everything and it's killing me. I do not have a dryer to start as of yet, but garage sale season is starting and there is always CL. Lost power for 19 hours yesterday for no reason, really want to stick it to the electric company. I'M IN!
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RSI- You come up with some great ideas! If this was 10 years ago when we had three kids living here I would of been in!
Since it's just the wife and I, our electric use has significantly reduced :) In fact during discussion of adding the DHW HTX, she could not see adding $800 (Parts and Labor) to something we have on a timer. (Only on 10 hours a day-Morning and evening). Little does she know, If I can find a kit before next winter, to install it myself, I will!
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Would a heater core from an old car work? About the right size and cheep from a auto salvage yard
They might possibly work but I am not sure I would trust a used one. Also, not sure if they are thick enough to put out enough BTUs. Probably the only option would be to use radiator hose on most of them.
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I could easily be talked into joining the HX core group. I am on electric everything and it's killing me. I do not have a dryer to start as of yet, but garage sale season is starting and there is always CL. Lost power for 19 hours yesterday for no reason, really want to stick it to the electric company. I'M IN!
If you watch craigslist, a free one usually turns up. I think I got tired of waiting and paid $50 for the one I used.
I have a Whirlpool (some Kenmores are the same) and it was pretty easy to do. I took the back panel off and mounted the heat exchanger there.
Other brands may be easier or harder. If you can get a gas version it will not require much anything for rewiring but the electric version has a better duct in the back for connecting to. (I ended up using the tube out of an electric on a gas model)
One very important thing is to have good drum seals. Since the dryer pulls air in, if the seals are bad it won't heat up. My first attempt didn't work at all for this reason.
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RSI- You come up with some great ideas! If this was 10 years ago when we had three kids living here I would of been in!
Since it's just the wife and I, our electric use has significantly reduced :) In fact during discussion of adding the DHW HTX, she could not see adding $800 (Parts and Labor) to something we have on a timer. (Only on 10 hours a day-Morning and evening). Little does she know, If I can find a kit before next winter, to install it myself, I will!
$800 to heat your domestic hot water? :P
Do you have a tankless water heater?
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Yep, thats what the dealer wanted. $400 for parts, $400 for labor. Our HWH is a 50 gallon electric model. AO Smith.
Here's a pic of it: http://outdoorwoodfurnaceinfo.com/forum/index.php?action=media;sa=media;in=35;preview (http://outdoorwoodfurnaceinfo.com/forum/index.php?action=media;sa=media;in=35;preview)
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RSI- You come up with some great ideas! If this was 10 years ago when we had three kids living here I would of been in!
Since it's just the wife and I, our electric use has significantly reduced :) In fact during discussion of adding the DHW HTX, she could not see adding $800 (Parts and Labor) to something we have on a timer. (Only on 10 hours a day-Morning and evening). Little does she know, If I can find a kit before next winter, to install it myself, I will!
That price is insane......if you have just a "basic" knowledge of plumbing, you can easily install a plate exhanger in your water line "after" your water tank. In 6/09 I paid $169 for a 20 plate (for my polebarn radiant floor heat) couple fittings and done.
BTW, I think the heater core idea is a "winner"
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Any of you guys got a source in general for good quality plate exchangers for DHW and this dryer experiment? I really want to stick it the power company more so than the propane guy. 19 hours without power this weekend, the gennie does everything but bake water and dry the clothes. Hence, I am on the hunt to cure these problems forthwith.
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I just came up with an idea that might make a dryer kit more universal.
What do you think of putting everything in a box and just running a hose into the dryer? It could be mounted a few feet away. There might be a little temperature drop doing it this way but might be ok. Then a 12x12 heat exchanger would work ok.
This way might even be able to use the main dryer and just wire in a switch to disable the heater.
If anyone wants to try it, I will put one together for the price of the parts. Send me a PM if interested.
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RSI- Ever think about using a heater core for a car? They are only about $25.
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They were mentioned in earlier replies.
Do you have any idea what model car would have a good one? Most of the pictures of them I can find online are constructed like car radiators which I don't like. (end tanks with pipe soldered in, probably with lead or the whole thing is aluminum)
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Here's the one I saw that reminded me of your project: (maybe not what your looking for?)
http://www.summitracing.com/parts/PLI-398247/ (http://www.summitracing.com/parts/PLI-398247/)
They have plenty to choose from: (maybe one of these will work?)
http://www.summitracing.com/search/Part-Type/Heater-Cores/?keyword=Heater+core&kr=Heater+core (http://www.summitracing.com/search/Part-Type/Heater-Cores/?keyword=Heater+core&kr=Heater+core)
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It looks like all of them are made the same way.
This is why I don't like the looks of them. How It's Made - Car Radiators (http://www.youtube.com/watch?v=ayQWXlRDW_c#)
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Ok, looking for opinions. Even if you have no interest in doing this.
Would you rather:
A: try mounting the parts inside the dryer and possibly have to remove permanently the back panel
or
B: have a separate box that would just need an air hose going to the dryer? The box would probably be 12x12x18". Probably smaller with custom made heat exchangers.
I would guess the separate box could be up to about 6 feet away (maybe more) but close is better.
The box would require a lot less modifications to the dryer also and may allow for switching back to gas / electric heat in a few minutes (or few seconds if you don't mind making it suck the air through the box all the time but there is a chance of the extra restriction causing overheating).
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Funny- During Easter dinner we disccused your dryer idea. Wife was all for it. We discussed adding a "winter" dryer. One that would use the OWB during the winter months. Of course we would have to find a second dryer.
If we ended up buying a new one, would a Gas or electric dryer be better for your installation? (Which one would be easier to modify?)
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The wiring is a lot simpler on a gas dryer because they run on 120v.
Electric will work but since it is 220 you would need to re-wire it for 120v.
If you have a very good number of people using craigslist in your area there is a good chance a free dryer will get posted with the heat not working. I think I ended up paying $50 for the one I used.
If you get a used one, make sure the drum seal is good. Otherwise it won't work. If the heater is still working but it won't dry very good then the seal is most likely bad.
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My wife reminded me my son had a Dryer that was not in use. But's it's electric. If I move forward on this I'll look for a gas unit for the simplicity of the install. (just have to add receptacle).
If I move forward on this, which is being encouraged by the wife, it won't be until the start of the next season. I have too many projects in the works now. Should of had the boat de-winterized and ready for a trip by now.
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It might be worth taking a look at the dryer.
Most electric dryers only use the 220 for the heater and run the motor off on 120 off one leg. It may be fairly simple to just put a 120v cord on it.
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Yeah, but is it easier to add the HX to a Electric or Gas dryer?
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That probably depends on the brand.
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Hey, I like the pink warning that I am dragging up an old thread.
Now that I've got my boiler running I'm thinking about this too. I'm recall reading somewhere that you can use one leg of the 220v going to the electric coil in the dryer to run a circ pump, then it's controlled by the tsat in the dryer.
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Are you going to keep the heating element connected? If not I would rewire the dryer for 120v. Most have 120v motors and controls and just run them on one leg of the 220 and use the other just for the element.
If you need help finding any parts, let me know. I now have a source for 8x8 heat exchangers and would like to find out how good they would work out for this.
My dryer has a 12x12 single row and works good enough but I think a smaller 3 row would work better.
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Here is my air to air clothes dryer heat exchanger--HE 26. It is made from an oil drum. It cost me under $50 and is lint and moisture free.
Clothes Dryer Heat Exchanger HE 26 Part I (http://www.youtube.com/watch?v=FUfaf8sPJHU#)
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RSI, buddy have you messed with these ideas anymore????
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No, there didn't seem to be that much interest.
Mine is still running good though. Probably 6 or 7 years since I put it together. I didn't put a filter on the heat exchanger so it could probably use a cleaning. It sometimes needs to be run twice to dry a big load of jeans.
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No, there didn't seem to be that much interest.
Mine is still running good though. Probably 6 or 7 years since I put it together. I didn't put a filter on the heat exchanger so it could probably use a cleaning. It sometimes needs to be run twice to dry a big load of jeans.
That still sounds great.... I'm gonna do it.
How do you feel about this idea, get a used dryer, install like a 12x12 on it and install a zone valve that would open to allow water into the coil when the dryer came on? You may have far better ideas since you've done this before
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I would use a pump instead of a zone valve. Just use 2 close spaced tees. Just hook the pump power to the heater wires in the dryer. I am not sure how much current they can put out so you might want to use a relay. If it is an electric dryer it would be able to handle it but probably best to just use a relay with a 240v coil.
This way the dryer controls the heat and can do a cool down cycle if you want to use it.
I think a 6x6 or 8x8 coil would be big enough and be easier to deal with. I have a 12x12 on mine but it is only 1-1/2" thick. I think being thicker would be much better.
Another nice thing about it is it makes using the clothes line not worth the bother since it costs almost nothing to use the dryer.
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I would use a pump instead of a zone valve. Just use 2 close spaced tees. Just hook the pump power to the heater wires in the dryer. I am not sure how much current they can put out so you might want to use a relay. If it is an electric dryer it would be able to handle it but probably best to just use a relay with a 240v coil.
This way the dryer controls the heat and can do a cool down cycle if you want to use it.
I think a 6x6 or 8x8 coil would be big enough and be easier to deal with. I have a 12x12 on mine but it is only 1-1/2" thick. I think being thicker would be much better.
Another nice thing about it is it makes using the clothes line not worth the bother since it costs almost nothing to use the dryer.
Ok.... My wheels are turning... I see what your saying about the pump...
Just gotta figure out where to mount the coil and duct, I don't have any 6x8's or 8x8's tho
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Scott , I had a customer who put a 12 x 12 heat exchanger on his dryer . He claimed that he was only getting 100deg air temps coming out of the coil and in comparison to the original electric dryer it took him twice as long to dry a load of wash , but he didn't mind , because this was free !
Anyhow , I have an extra dryer that I thought about converting , ( I have no idea when I'll find time ) . I'll be looking forward to hear how this works out for you .
Good Luck !
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I think I can get it hotter than that
RSI has been using one for 7 years, he said jeans take longer but no biggie
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Yeah, I get hotter air than that and I only have 1/2" pex lines going to it.
The air coming out at first is a lot colder because the clothes soak up most of the heat at first.
It doesn't get as hot as the electric dryer but that is much better for the clothes anyway. If the extra time (if needed) does cause a backup, the other dryer just gets used.
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Yeah, I get hotter air than that and I only have 1/2" pex lines going to it.
The air coming out at first is a lot colder because the clothes soak up most of the heat at first.
It doesn't get as hot as the electric dryer but that is much better for the clothes anyway. If the extra time (if needed) does cause a backup, the other dryer just gets used.
What kind of temps do you think I could get with an 8x8 ? Does those 8x8's have 1" lines? Just estimate?
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I have never actually checked the temperature on it but I am sure the 8x8 can make it hotter than my thin 12x12. I will stick a probe in the exhaust tube on it to see what it is running at.
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I have never actually checked the temperature on it but I am sure the 8x8 can make it hotter than my thin 12x12. I will stick a probe in the exhaust tube on it to see what it is running at.
10-4, I'm planning on sending it 180 degree water. My flow is good
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Even with the 1/2" lines the return is still hot. A dryer running over 200 degrees only uses 17K btu so it will be as good as you can get with that heat exchanger.
Adding a fan might help a little but not real sure. If the drum seal is leaking then it would but otherwise probably won't help any.
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Yep, we'll see how it does
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i have 12x12 externally with hose on old gas dryer and usually get about 105 temp out of vent it struggles with towels always run them twice replace drum seals when hooked up though it is on top of 220 dryer with 3 qtr plwood between them kinda like a double decker dryer exchanger sits on shelf on wall behind it been using 2 years happy with it
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I checked the temperature and it is not quite what I was expecting. I think the drum seal might be going bad or it has another air leak. I need to run it empty and see if it gets close to the same inlet and outlet temps. If not, it means air is getting in somewhere other than the heat exchanger. The air going in seems to be about 20 degrees less than the water temp. Green line is the vent and the purple line is the air entering the dryer.
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RSI, I can't see those numbers on my phone, what was the actual temps
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go to www.my-thermometer.com (http://www.my-thermometer.com)
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129, that's not bad.
What were you expecting?
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That was with it restarted the second time.
I guess the clothes do absorb a lot of heat when wet.
It did used to dry a little quicker so I think it is leaking air past the hx somewhere. Also, I think the 1/2" pex is what is keeping the inlet 20 degrees lower. Going with larger should get it hotter.
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RSI,
What are you using to track and trend this data ? Its pretty sweet.
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http://www.rsiboilers.com/parts/tempmon.htm (http://www.rsiboilers.com/parts/tempmon.htm)
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thank you
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RSI,
Thank you for that link.
I would really like to do this at some point with the monitoring. A wireless setup would be the best though I think for alot of these applications unless I oculd manage to get a wire out there for Modbus.