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Wood Fired Thermosyphon Heater


awoodman
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Has any one atempted to build one? I have been searching the net for months and found verry few that don't require the use of a pump. I built one that ran through the pump on low speed and heated the water up from 80deg.-110deg. but it took about 4-5hrs. uses a lot of elect.

I found this Chofu heater on the net (cost about $800.)

chofu10.jpg

Also this type of heater using stainless steel coils. (Dutch tub)

Asbak.jpg

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Nope, never tried. I'm a bit of an off the grid type myself and I thought of all that "hippie" stuff before I got my tub, but after actually owning ne a while I can tell you I'd never consider it again. Who wants to have to stoke a fire 6-8 hours just to enjoy a soak?

Your boat is mad cool. You got bigger pix somewhere?

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We sell a few of the Chofu heaters every month. People seem to be very happy with them, but I think it's more of a "life style" thing. A lot of these people are living off-grid, and for them, it's just a way of life, that they've chosen.

ofuro_chofu.jpg

chofu9.jpg

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A friend, who lives off the grid, has a galvanized steel horse watering trough. He set it on some concrete blocks and builds a fire under it when he wants a soak. When it is up to temperature, he puts the fire out. Both he and his wife fit in it.

One problem though, his old tub was getting rusty, so he went to the feed store to get a new one. the first time he set a fire under it, it leaked! It turns out that the trough manufacturer no longer solders the seams, they use an adhesive like gutter sealer and that just burned away!

Dave

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That's hilarious. It's like the boiler on a locomotive!

My uncle and aunt were sharecoppers. Back in the 40s they lived ina sharecropper shack and had no bathroom, people would bathe in a tub in the yard. My uncle decided he had enough carrying hot water a pot at a time so he put the tub up on bricks in the yard and built a fire under it. When he got in the tub lost its footing and he ended up rolling down the hill naked with the tub, water, and some of the fire...

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Dr. Spa I'd like to see pics. of the inside of the Chofu firebox. I understand their is a bafel inside that is water-filled also along with the 1'' water-jacket surrounding the stove fire box.

Be nice to see how it is built. Could you send pics????????

No bones about it the electricity these things use realy adds up.

My FREE tub came with a working pump but the electronics were gone.

And poptones that is used to heat an inground pool. Cheaper than a tankles water heater but I wonder which would use less propane.......

http://www.redneckpoolheater.com/

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My plan which didn't come this year but will by next (It's dependent upon a bathroom update which is behind) is to use solar on the roof. I have planned a shower on the deck near the spa where the french doors open and so there will be hot running water with an outlet into the spa, overhead on the shower, and this will tie into the house hot water as the bathroom shares the wall with the outdoor shower area. I have to get the bathroom finished inside, the pergola done and the outside wall finished before it can be completed, but I am wondering how best to integrate the solar heat source. In the summer the spa is actually hot during the day just from the sun, it's at night and in the winter when extra heat is needed. A heat sink is needed to store the heat, but the best heat sink by far is water, and the biggest container of water happens to be the hot tub itself, so....

One option I'm seriously considering is a solar closet. A room 3'x6' with 6" of insulation all around would give me space to store 400 gallons of water and still have reasonable access. Problem with that is having to reinforce the flooring in the back part of the house - what was formerly a porch and so is the weakest part to begin with. Why not build a small shed near the tub with a south facing glass wall and let the sun do most of the work for you? A 6x6 foot shed with 6" of well taped styrene insulation all around will keep the heat through some pretty severe cold. 48 sq ft of solar glass collector, two small baffles to allow air to circulate and the best part is you can increase efficiency if needed easily by simply adding a reflective wall nearby to throw more light on that surface. Start saving milk jugs to stack in it - fill it with 300 or 400 one gallon plastic jugs and you won't need fires, just a small pump to circulate the water through a heat exchanger (ie 30 feet or so of floor radiator).

Do you know of Nick Pine and his research into this? I didnt have a garden this year because of the move but I had a 4x10 foot greenhouse literally made from sticks and a 15 dollar roll of plastic that kept me in fresh tomatos all the way through thanksgiving! A few well placed jugs of water can help the sun do miraculous things. http://www.ece.vill.edu/~nick/solar/solar.html

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  • 5 months later...

I have sat in an off grid farm yard tough with copper pipe running through a 55 barrel drum (fire in the drum). And yea know it was worth the wait. There is something special about waiting for the water.

Has any one atempted to build one? I have been searching the net for months and found verry few that don't require the use of a pump. I built one that ran through the pump on low speed and heated the water up from 80deg.-110deg. but it took about 4-5hrs. uses a lot of elect.

I found this Chofu heater on the net (cost about $800.)

chofu10.jpg

Also this type of heater using stainless steel coils. (Dutch tub)

Asbak.jpg

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  • 1 month later...

Well it is another season and new Ideas I am converting a wood fired stainless canner I have had for a few years.

I still have to drill holes in the tub and install the 11/2'' thru-hull fittings, like the ones I installed in the steel tank.

PIC_0852.jpg

Here is a pic. of the hot tub I got for free last year.

600x450PIC_0727.jpg

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more pics.

I also have an idea to shrink the amount of water in the tank so it would heat up faster. The outside dia. of a plastic 55gal drum is about 2'' smaller, so if I cut it to fit inside with 4'' of space off the bottom that should do the trick. Just bolting it around the top lip to keep it in-place. I also have a stainless lid that came with this but it just lays on top. It would be nice to have a sealed lid for it.

PIC_0855.jpg

PIC_0861.jpg

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I got it fired up this evening the water temp is 60 and after about 45min. the outlet temp coming into the tub is 90. I used 3/4 ply laid on top of the stainless lid for rigid support and ratchet straps for now.

PIC_0885.jpg

A pic. with the stove door open.

PIC_0884.jpg

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