Instructables

Solar Hot Water Heater Batch Pre-heater

This is a Solar hot water Batch Type pre-heater that pre-heats the water for my hot water tank inside the house. Cost $45.00 to build. I made it out of garage sale and Goodwill items and scrap wood I had laying around. It has been heating water up to 140 degrees and circulates thru the tank by natural flow no pump needed as it is lower than the main tank.
 
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Step 1:

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This is what it looked like when I finished. I added extra insulation and foamed all the cracks.

Step 2: Parts and pieces

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This is a fresh water tank from an old camper trailer that was given to me. This project can be scaled up or down to suit your needs.

Step 3:

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A piece of old peg board, A sheet of masonite would have worked better but this is what I had.

Step 4:

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Cut frames and sides from scrap plywood. This is not the true curve but it is what I had for material.

Step 5:

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3 pieces of .50 cent glass. Foil backed styrofoam board ends scrap from a garage remodel.

Step 6:

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Tank painted .96 cent Wall Mart black. 99 cent space blanket glued to the peg board.

Step 7:

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Box with glass added. Not attached yet, time to start plumbing.

Step 9:

Built a box around the fittings, with an access hole to reach shut-offs. I'm making a small garden box under pipes. The Bird bath is two gum ball machine stands, one upside down and inserted in the up right one. I have been doing a little art lately, You can check it out at my link. http://etsy.com/shop.php?user_id=6226255

Step 10:

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Added another 1/2 inch of foil backed insulation and painted to match skirting. Sealed all the cracks with silacone sealant.
ddpkd5 years ago
What a great idea! I am considering trying a solar heater for my pool(30 ft,round, 52" deep, approx 10,000 gals) I am only looking to pick up about 10 degrees to 75-85 F. Do you think this is feasible? would a batch style be the most effective? Would an old water heater tank be large enough? I have unobstructed sun all day. All comments or suggestions would be greatly appreciated.
gn0stik ddpkd11 months ago
This combined with perhaps fresnel lenses, or parabolic mirrored dishes, etc, could theoretically give you near boiling hot water on demand as long as you tracked the sun with it. However the addition of a tank would allow for hot water at night, and would help make sun tracking far less critical. See Kingofawesome's Fresnel lens projects.
aleutianwind (author)  ddpkd5 years ago
Hi I think your idea sounds OK. I would try for a least 30 gallons and a larger box, about the size of an old sliding glass door. I see them in garage sales all the time. Getting the correct curve would make it heat better also.I just used what size I had available. Insulate as good as possible and double glass if you can find it. I am very happy with the output of this one, on nice days I don't turn on the electricty to my main tank. Good Luck with your project.
Thanks for the input. I'm finalizing plans now and will hopefully install and test late April/early May and will post results.
dlchlh ddpkd5 years ago
I have a 28,000 gallon pool in NJ with all day sun (when it's shining). I was about to buy a $150 solar collector panel (black poly with many individual channles..made for pools)to test functionality and was poking around for DIY ideas instead. Did you have any luck building this? I'm curious how the constant flow you'd have with a running filter impacts the ability to heat the water...ie is the flow too fast for the collector to warm it up?
phredrik dlchlh4 years ago
Hey I've thought of this too, was wondering if it would be better to make something with more surface area, using black hose, since the water is flowing constantly. I've seen models that go on a roof with small black hoses. My idea was to use a hose run back and forth inside a box like this,
THere is another way to want to warm your pool. Cover the pool so you decrease the evaporation. The change of state of water consumes many more calories then radiant heat loss. I have even heard of nets holding foam blocks that just decrease the surface area which loses heat by evaporation.
knektek4 years ago
you want a layer of foil on every household roof. With the foil reflecting the light into the center of the street, warming your thing in a cylindular form.
Very nice design for the pre-heater. I'd like to build one to pre-heat the water that goes into my automatic dishwasher, to save the electricity that the washer uses for pre-heating. It would need to heat 4-5 gallons to 140-150 degrees F. I think the most difficult part would be the plumbing.
RENATO.ROSS4 years ago
excelente idéia. temos muito sol aqui no brasil e irá funcionar muito bem!!!
jlabaume4 years ago
Jalloy5 years ago
(removed by author or community request)
aleutianwind (author)  Jalloy5 years ago
Hi Yes you can add it, I hope it helps someone get started. It has been working great now that we got our sunshine back.
roughly5 years ago
i love this site -- i love you guys -- i.........I'm getting carried away here -- good job !
Davetech5 years ago
The nice thing is it costs little to build, less to maintain, and nothing to operate. Even if you build a system that just suppliments your present system, every bit of energy you harvest is money saved. It amounts to turning sunlight into money! Thanks for sharing your expertise with us.
Matt4_165 years ago
Great Idea!
TheDogofWar5 years ago
Looking forward to more info on the floor project, any progress?
aleutianwind (author)  TheDogofWar5 years ago
Hi Not much progress on this project. It was working great for a few months but I had to drain it in this freezing weather. I have some small leaks so I won't put the RV antifreeze in till I get new hoses. I added a remote wireless temp. unit so I can monitor the water temperature from the living room. I will take more pics and start a new instructable when the weather clears up.
Very cool... er, hot! I would like to have seen how you hooked it into the plumbing with a diagram and some pics.
renzo244415 years ago
I will surely be waiting for that instructable! Theres nothing like a warm floor on a morning shower! Thank you!
renzo244415 years ago
I would love to see if this could be applied to a "home made radiant heat system" for a crawlspace.. use the tank to heat the antifreeze and have it circulate through the radiant heat piping.. would it be a direct connection? i am seriously wanting to do this to add heat to my kitchen and bathroom floors, or make the crawlspace air less cold....
aleutianwind (author)  renzo244415 years ago
Hi I just added a pic in view 12 that shows my new panel that I got for free on freecycle dot com, just had to solder a few leaks. It heats a tank under the floor. You could use a batch type heater also and get the same results maybe better as there is more storage.
Scurge5 years ago
Great i'ble, simple, cheap and very green! Well written too.
shooby5 years ago
Yeah, this is awesome. Imagine one of these in every home, the savings would be incredible.
LinuxH4x0r5 years ago
Great job, 5/5