# Pre-heating water using solar?



## Murramarang (Dec 18, 2011)

Hi all...I have been researching how people use solar (air) heating as a way to heat their homes and buildings - and I really hope I can get something going on my new small farm up here in Maine.

So that got me wondering.....and here is my idea.

I want to see if I can use the same solar concept to heat water from my well BEFORE it goes to my furnace. So water would be diverted from the intake to the furnace to the outside and through a simple homemade solar panel made up of black pipes in a glazed insulated box then back into the furnace. In this way even if the water was raised just 1 C as it passed through the solar box it would save fuel costs (in my case propane).

I am sure loads of people have thought of and done this....and maybe there is even a thread of 10 in here on this idea....but if you know of places for me to see how others have done this...drop me a note (or even better...a link).

Gaz


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## Capt Quirk (Sep 24, 2011)

I can tell you what doesn't work... We are off grid, and have to run the well pump off the generator. We fill two 55 gallon plastic drums, and pump our water from these with 12v water pumps. Using several ideas for heating water, I wrapped one barrel with heavy black plastic. I then went a step further, and drilled a hole in the side near the top, and one near the bottom. I put threaded pipe fittings in these, and wrapped the barrel with black garden hose, thinking the hose would super heat the water, and create a thermal siphon. I also set the barrel on a sheet of tin, so that the sun would heat that as well.

The actual results were under whelming. In fact, I would say the plain barrel is a few degrees warmer, than the one I spent $60 modifying.


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## DanielY (Aug 25, 2011)

The idea is pretty simple and is called a solar water pre heater This is a link to get you started on possibilities.
http://www.bing.com/images/search?q...er&qpvt=solar+water+pre+heater&FORM=IGRE#x0y0

Some issues to consider.
If your supply line simply runs through the collector panel. Water will freeze on cold nights. The simple answer is to be able to turn it off and drain it if it is going to freeze. Drawback is obvious if you ever forget to drain it which is pretty much guaranteed to happen. also you do not get your pre heating benefit during the coldest weather. Cheap answer cheap benefit.

So the complicated more expensive but better answer is to have a tank of antifreeze that is being pumped through the collector. You water supply line passes through this tank and the hot anti freeze warms the water in the supply line. One design I saw had a 300 foot length of supply line coiled inside the tank. Basically this creates an on demand hot water supply. this can then go to a traditional hot water tank that will just keep the water topped off as it tries to cool. But you avoid all the heating the cold water expense. Drawback of this design are if your supply line inside the tank leaks anti freeze ends up in your water supply. Select what you use in the collector carefully so you don't end up poisoned. there are safe anti freeze materials. You also want it colored so if it ever does leak you know it. Leaks in the supply line are not very likely but everything happens to somebody sooner or later. You could also pump the fluid in the tank to radiators in your home and heat with it. You just have to add collector panels in order to meet the heat requirements. I am looking at doing this with our house this next year.


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## DanielY (Aug 25, 2011)

Hey capt. You are going to have to get a bit more serious with the solar energy gathering. A barrel setting in the sun will get warm or even hot eventually. But it will only get good and hot on the best of sunny days. Also those barrels are going to release that heat nearly as fast as they gain it in cold weather. You not only have to capture the energy you have to hold onto it. In your case set your barrels inside an insulated cabinet with only the side exposed to the sun clear glass or plexiglass. see if that does not get you some serious increase in captured energy. You can boost it even more with a collector panel designed to collect the heat and transfer it to the water in lines running through the collector. A hose from the bottom of the barrel to the top is never going to create enough of a current to matter. That stuff only works for McGyver. The truth is any energy that is added to your barrel is equalizing in that barrel at a fairly fast clip. There is not enough of a temperature difference to really get a flow going.

I think the biggest bang for your buck will be simply putting a cabinet of plywood and insulation around those barrels. make the inside surfaces of those cabinets reflect back onto the barrels is another good move for the money. Aliminum foil will work.


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## Capt Quirk (Sep 24, 2011)

Yeah... when we started at the Homestead, we had no water or power. We were filling 1 gallon jugs, and setting them in the sun for warm showers. We took that a step further, and put them under a black tarp. On sunny days, that water was in some cases, too hot. I tried to get fancy, and failed miserably.


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## DanielY (Aug 25, 2011)

Captain for you I would say a solar powered pump controlled by a thermostat. use your barrels as the storage tank but collect the heat in a panel. You know how to get more than you want so all you need to do is be able to shut it off at the desired temp. That makes me want to cry cause you can use the extra for other things. But that doesn't matter much when all you want is a warm shower. Heck you can set up your barrels to get more heat than you need and pump hot water to another tank that is kept at the temp you want. it will pump in just enough hot water to gt up to a pre set temp. If you have more heat than you want then set up another pump that sends it to a radiator to heat part of the house. Again solar powered pump and a thermostat. A radiator does not have to be fancy or expensive. Just a bare pipe running along the baseboard would give off some heat.


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## Capt Quirk (Sep 24, 2011)

A baseboard would imply there is a house. That is on my list of "to do's".


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## Ky-Jeeper (Sep 5, 2010)

http://www.builditsolar.com


Should be able to find a suitable way here to heat water.


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## woodsy (Oct 13, 2008)

Ky-Jeeper said:


> http://www.builditsolar.com
> 
> 
> Should be able to find a suitable way here to heat water.


Good place to start for DIYers.
This link will go directly to some inexpensive homebuilt hot water collectors and systems.
I built mine modeled after Gary's 1K system 3 years ago, love it, already paid for.

http://www.builditsolar.com/Projects/WaterHeating/water_heating.htm#1KSolarWater


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## AgrarianDr (Mar 25, 2011)

DanielY said:


> I think the biggest bang for your buck will be simply putting a cabinet of plywood and insulation around those barrels. make the inside surfaces of those cabinets reflect back onto the barrels is another good move for the money.


Bingo! Heating it is one thing, "keeping" it warm is key, and in truth is actually MORE important in the big scheme of things.

Full Disclosure; Sorry Capt for laughing at your post. But, I'm allowed - cuz I been there/done that - with similar results


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