iDRY Vacuum Kilns

Sponsors:

heating hot water with a wood stove.

Started by muddstopper, January 23, 2013, 06:46:59 PM

Previous topic - Next topic

0 Members and 1 Guest are viewing this topic.

Ford_man

Years ago in my grandparents home they had a small stove in the kitchen that had a steel pipe loop inside it the water would inter the lower pipe and come out the upper pipe into a tank that was behind it . the tank was not insulated. It made the kitchen real warm , winter and summer, no AC. splitwood_smiley
.

lowpolyjoe

Quote from: muddstopper on January 26, 2013, 07:41:32 PM
http://www.michigan-horse.org/preheater/

Looks like a great setup.  I never would have guessed Plaster of Paris would stand up to that sort of heat.  Although i've never used the stuff myself

brendonv

Looks nice Bill G.

I'd be interested to find out how this is plumbing into your hot water system. 
"Trees live a secret life only revealed to those that climb them"

www.VorioTree.com

https://www.facebook.com/pages/Vorio-Tree-Experts-LLC/598083593556636

Bill_G

I have a 120 gallon tank in the basement , because the tank is lower then the heat source I have to run a circulator pump . This means when the power goes off I have to close 2 valves and open the system to prevent steam buildup . So I have a cold water line feeding the tank and a hot water line off the tank plumbed into my house hot water , so the cold water comes into the tank as the hot water is used . If I had my tank higher then the stove I wouldn't need a pump or have to worry if the power goes out .

Bill_G

So basically the same setup as any hot water tank would be .

r.man

It might move the water with just convection but I don't know that it will. If you were to try it would be an easy way for me to find out.
Life is too short or my list is too long, not sure which. Dec 2014

r.man

Bill how is your heat exchanger piped into your hot water tank.
Life is too short or my list is too long, not sure which. Dec 2014

muddstopper

I have an old 60gal water heater that was just replaced with a newer unit. As soon as I get the copper pipe, I will be building something similar to the one here, http://www.michigan-horse.org/preheater/.

Power failure and recirculation is something I am worried about. I know that even with a small fire, the sides of my heater get around 400*F. Certainly hot enought to cause steam and high pressure. Not sure how I would put the water heater/storage tank high enough for convection. The water inlets on the tank are located at the top, but that would only be a foot or two above my heater height. Only other option would be to hang it from the floor joists someway.

Would the use of a check valve on the intake side of the heater coil cause the heated water to automaticly move towards the storage tank. I would think that would work in a closed system, but what would happen as soon as someone turned on a facuet? Would the 60 gal tank be big enough that it wouldnt overheat? My regular water heater is also 60Gal, but I dont think I really want to recirculate the stove heated water into it, Only let hot water in whenever I turn on a hotwater facuet.

Bill_G

It would move by convection if the tank was above the heat source , but my tank is below the heat source . My cold water from the house goes in the cold water line on the tank  , the hot water is plumbed from the hot water tap on the tank to the hot water line for the house . I pump the cold water from the tank drain to the woodstove and back to the tank where the blowoff is . Here is a link to some basic setups .

http://ir.library.oregonstate.edu/xmlui/bitstream/handle/1957/24750/ECNO1164.pdf?sequence=1

John Vander

Quote from: Bill_G on February 05, 2013, 10:01:03 PM
This is my setup with 120 gal tank and pump . I put a relief valve on the high point in the system and one on the tank . Been working great for two years .

  

 
This is exellent stuff! Great idea!
Tree and saw accidents nullify years of forestry experience.

Bill_G

Old technology , This is how we heated our water when I was growing up  , but still works great . If you are heating with wood anyway , may as well get free hot water .

Bill_G

This spring we will be mounting 5 solar panels on the roof to heat with in the warm months .

muddstopper

I think i have it figured out so i will post my ideal and let everybody critique it before I start building.

My stove is in the basment, and so is my water heater. The flue for the stove is located in the center of the basment and goes up thru the house and out the roof. The flue is 12in flue lined block. What I think I can do is stack 2 or 3, or ever how many, more 12 inch blocks beside the flue and set my storage tank on it.  That would put the inlets to the tank 4 or 5 ft higher than my stove and above my current water heater. Then build my coils for the stove and plumb into the storage tank. This should put my storage tank high enough for convection to take place. I will then plumb the storage tank into my conventional water heater so that as the hot water is used it will be replaced with hot water from the storage tank. I am also thinking that if one was to wire a recirculation pump to the water heater thermostat, that anytime the electric element came on, it would also recirculate water from the storage tank into the conventional water heater. This should keep the water heater full of hot water without it being super heated and with minimal use of electricity.

What do you think?

muddstopper

Quote from: Bill_G on February 06, 2013, 06:38:21 PM
This spring we will be mounting 5 solar panels on the roof to heat with in the warm months .

Bill, My buddy built 4- 2x2 solar collectors for his house, roof mounted. He used a 60 gal water heater tank for a heat exchanger, and a solar powerd recirculation pump.  We cut the bottom out of the tank and installed copper pipe, then welded the bottom back in. The copper pipe carried the potable water for use, the solar collectors just heated the water in the storage tank. He has one of those tankless gas water heaters. His biggest problem wasnt getting hot water, the problem was the water got to hot. He has small children and there was a real fear of scalding. He unhooked 2 of the collectors and got the water temps back down to a more manageable level. You might want to start with just 2 or 3 collectors and see how it goes before installing more than you really need. Over heating might not be an issue since you will be using a much larger storage tank, but with 5 collectors, you never know.

WH_Conley

Muddstopper, you have the same setup I do as far as the stove. To get natural convection circulation I am not sure it would work with both lines going in the top of the tank. I would think the cold would need to come out of the bottom of the tank and return in the top. That way the hot water would be rising and the cold would be flowing down. The same way my OWB works, only in reverse.
Bill

r.man

Most sidearms are piped into the drain tap hole at the bottom of the tank and the hole for the pressure relief which is either high on the side or on the top of the tank. Tee both of these so you can still have a pressure relief and a drain tap. If you have an older tank that doesn't have the separate pressure relief hole then you can tee into the hot water pipe which is always on the top.
Life is too short or my list is too long, not sure which. Dec 2014

muddstopper

Quote from: WH_Conley on February 06, 2013, 07:09:35 PM
Muddstopper, you have the same setup I do as far as the stove. To get natural convection circulation I am not sure it would work with both lines going in the top of the tank. I would think the cold would need to come out of the bottom of the tank and return in the top. That way the hot water would be rising and the cold would be flowing down. The same way my OWB works, only in reverse.

I am thinking, but not sure, but doesnt one line in the top of a hotwater heater tank have a tube that goes to the bottom of the tank. Would it work if it does? Either way, I would think I could remove the drain valve at the bottom of the tank and use that for a return. Hot water from heated coil into the top and colder water out the bottom to the heater coils. Now that I think about it, using the drain for a return would probably work best and leave me the other line on top to connect to my conventional water heater. I need to get out the paper napkin and a pencil and start schetching this up.

Edited to add
Then I scroll down and see thats exactly what r.man said.

WH_Conley

Sounds like r.man has it pegged. I didn't think about taking the T&P valve out.
Bill

muddstopper

I think I have this thing figured out. The usable front to back area or my stove measures 34in long by 18in high. I plan on cramming in as much 1/2 soft copper pipe as I can in this area. I will enclose the pipe inside of a steel/sheet metal housing just to protect it from a careless piece of wood or other from bumping into it.  The pipe will have inlets and outlet at the top and bottom facing back toward the chimney. The top line will go to the relieve valve side of the water heater tank, the bottom line to drain valve of the water heater. I will use tees to keep the relief and drain valves functionable. I will connect the top in/out of the water heater as it would normally be installed, fresh water in, hot water out. The hot water coming out of the tank I will connect to my regular hot water heater. This way, any hot water that is used from my electrically connected water heater should be replaced with hot water from my wood heated hot water heater. Hot water used from the wood heated tank will be replaced from my fresh water supply.  I will probably also add a check valve to prevent the hot water from the wood heated tank from creeping into my cold water system. I Will have to elevate my wood heated tank a few inches off the ground just to get the drain line to the same height as the bottom inlet of my preheater. The relief valve connection will be a couple of feet higher than the top of the preheater. I think this should allow enough height for natural convection to occur.

If this works out, I will probably install some sort of recirculation pump between the two water heater tanks. Since i wouldnt want to recirculate the water in the summer time I would need to install a cutoff switch or unhook the pump in the summer time. That is until I get my solar water heater collectors installed. I plan on a solar system large enough to heat the whole house which would lower my wood use and make my wood heated water heater obsolete

thecfarm

Could you put a few other shut offs and deviate it to the solar panels?
Model 6020-20hp Manual Thomas bandsaw,TC40A 4wd 40 hp New Holland tractor, 450 Norse Winch, Heatmor 400 OWB,YCC 1978-79

muddstopper

 I have thought about hooking the solar collectors to the water heater, but it will mean running a long distance of pipeing to get it hooked together. Since my solar panel collectors, once I get them built, will be roof mounted and pretty long way from my water heater, I havent figured out exactly how I will connect it to my water heater. I added on to the house a few years back. When adding on, I also added on to the basement area, ( junk room). This new basement is seperated from my old basement by concrete block. My plans for the solar heating system is to install a large water tank in the new basement and circulate the water from the tank to the collectors, which will be mounted on top of the  roof of the addition. I will install a copper heat exchanger inside the large water tank to keep potable water seperate from the solar collector water. It will be thru this heat exchanger that I plan on attaching to a radiant floor heating system. My water storage tank wont be pressurized, most likely just a rubber lined, insulated, wooden box with a lid. All water pressure will be inside the copper pipe of the heat exchanger and the tubing for the radiant heat system. A square box with large lid will make installing the heat exchanger tubing a lot easier than trying to coil it inside of a metal or plastic tank. Anyways, it a work in progress and although I have a picture in my head of how it will work, I havent really worked out all the details. I can certainly see the benefit of connecting the solar collectors to the hot water heater and can also see that if done right, my wood heater can supplement the solar heater when the sun aint shining.

muddstopper

Started building my preheater to go on my stove. If this works, the first pic is of the heat exchanger. I built this out of 1/2" copper pipe and used 90deg els to to make the bends. The elbows makes sure I didnt kink the pipe. Dimensions are 18" x 32". 30ft pipe total plus the elbows. I bend a piece of 26ga glavanized sheet metal to have a 1 1/2" lip all the way around. I took some 1"x3/4" alum channel and clamped it together and drilled 5/8" holes thru where the channel came together. This resulted in a hlaf of a 5/8" hole in each half of the channel. These half holes where used as saddles for the copper pipe to set in. I then capped with a strip of galvanized metal to hold the pipe in the saddles. I used machine screws to hold the sheet metal, saddle and strip together.


 

The second pic is of the preheater just propped up against the stove. I have to fab a couple of mounting brackets to attach to heater, but for now its just propped up with a couple of sticks of wood for a pic. Next wkend, I will attach to the waterheater tank i will be using to store the hot water.


 

Since I had to buy everything new, I will have about $200 in this when it is finished. This includes all the copper pipe, sheet metal, and then the expensive stuff, the fittings to connect to the storage tank and then into my electric water heater. I figured the cooper pipe would be a bank buster, but it turns out, its the fittings that will put you in the poorhouse. If this cuts the hotwater part of my electric bill in half, it should just about pay for itself by the end of this winter. Since all of my heat is supplied by the wood stove, it wont take but the next power bill to see if it was
worth it.




muddstopper

Hole cutter I used to cut the 5/8 holes in the alum channel.

 

These cutters are made to use in a drill press and use a spring plunger to push the cut metal out of the bit. I have found that replacing the plunger with a drill bit allows for cutting thin metal with a hand drill possible. Bit sizes are 1/2 thru 7/8 in this set.

r.man

Mudstopper, galvanized metal touching the copper will cause corrosion, this is why copper pipe straps are plastic, copper or other metal covered in plastic or paint. This might be one of the reasons that heating coils are copper and aluminum. For a bit more money you can buy copper all band.
Life is too short or my list is too long, not sure which. Dec 2014

muddstopper

r.man, I had never heard of that happening. Thanks for the tip. What is it that causes the corrosion, the zinc? What I will probably do is just split a piece of the leftover copper pipe, flatten it out and use it for the band. Or i could just take another piece of the 1x3/4 alum channel and drill it to make a cap.

Thank You Sponsors!