Un-insulated water heater tank by woodstove!

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As you may know, an electric water heater can be 30% of your electric bill...
Well I got to thinking... I have this nice woodstove which puts out a lot of heat and it is always 80 to 100 degrees (F) next to the woodstove.
Is there some way I can use this heat to "pre-heat" the water going into my hot water heater????
Well I came up with an idea and tried it out. It works!
I got a used 50 gallon water heater at a recycling center. Then removed the sheet metal cover and removed the insulation. So now I had just a bare metal 50 gallon tank. I painted it black as in theory black absorbs heat better.
Then I placed this tank next to my woodstove. Then disconnected the cold water going to my hot water heater and ran that to the bottom (drain) connection on the tank by the woodstove. Then ran a pipe going out the top of the tank by the woodstove to the cold water inlet of my electric hot water heater. (Cold into the bottom, warm out the top.)
Note: My electric water heater is located on the other side of the wall next to my woodstove.
After just a few hours, the water coming out of the top of the tank by the wood stove was about 70 degrees. (The water from the city going into the tank is 40 degrees F.) At this point the bottom of the tank felt cold and the top was not cold.
The next morning, the entire tank was slightly warm.
Anyway I am now "pre-heating" the water going to my hot water heater. So instead of my water heater having to heat up 40 degree water, it will only need to heat up water which will be from 70-80 degrees. Perhaps warmer if I have the woodstove going full blast and have not used any hot water for a while. So should save some $$ on my electric bill.
Building code note: Now that I see this idea works, I'm going to install the tank next to my woodstove to "code"* like a water heater tank would be. That is drip pan, T&P valve, and strapped to wall for earthquakes. *I don't suppose code covers anything like this? I also installed a valve and pipe to outside for draining the tank.
Temperature and "steam" note: The temperature next to my woodstove never gets above 115 degrees F. and water boils at 212 degrees. So no possibility of steam being created.
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that sound like its working and and I see no question here. One application that I have seen is to use a wood boiler to heat all of your hot water with a heat exchanger. It can also be used to heat the entire house in several different ways.
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Just curious: why is it that you want to heat hot water?
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wrote:

Because water that doesn't contain heat is ice.
Besides, he said: "Anyway I am now "pre-heating" the water going to my hot water heater."
If it is pre-heated, then the water heater IS a hot water heater, smartass.
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On 3/28/2008 10:38 AM snipped-for-privacy@hotmail.com spake thus:

Well, maybe a *warm* water heater. The linguistic redundancy ("hot water heater") has always amused me, too.
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Kind of like PIN number and
NIC card
and
VIN number and
CDL license. and and and.... the list is endless.
lots of dumasses, I've even seen "PIN number" on official bank documents and such.
s

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On Fri, 28 Mar 2008 16:24:43 -0500, "S. Barker"

It is the way the language develops. If you want to pedantic, how many times have you seen 72 point type advertising-
BABY SALE!
... or such obvious idiotic hyperbole from major metropolitan newspapers as-
"All the news that is fit to print"
or spaceships splitting infinitives -
"to boldy go where no man has gone before"
There is a reason for the usenet rule of not commenting on spelling and grammar. It wastes time and drains energy from the actual topic being discussed. We've all done it, but at about one or two thousand posts into using the medium, most of us realize that it is non-productive and more annoying than the original gaff.
The tempering tank idea is an old one. In my Pop Mechanics encyclopedia, one is shown being hung from joists in a cellar, near an old coal burning furnace. Sometimes tanks like this sweat, and can be a problem in the living space.
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Very observant. How does that relate to my question? Nothing was said about heating ice water, just heating hot water.
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because by default, all water that isn't ice water contains heat, and could be considered some form of hot? one person's warm is another person's hot. :)
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But not all ice is absent of heat. Unless the ice is at absolute zero.
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pot? kettle? :)
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on 3/28/2008 11:16 AM Lee K said the following:

You know what he meant. Have nothing else to contribute?
--

Bill
In Hamptonburgh, NY
  Click to see the full signature.
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i figured he was being funny.
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:)
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Get gas if you can, my electric water heater was 50% of my electric bill or 35$ a month, my gas tankless costs me now 6$ a month. I kept the tank to preheat water also.
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Sounds like a great idea to me. That tank of warm water (I think such a thing is also called a "tempering tank") also radiates heat back into your space when the stove fire goes down and so the room should hold a more even temperature. It's also an emergency water supply -- assuming you can get the water in the tank out with no watter pressure if, for some reason the main water supply fails.
Living on a farm many years ago, we had a similar arrangement. The uninsulated hot water tank was placed next to the coal furnance to soak up radiant heat and a loop of steel pipe went from the tank through the fire box in the furnace to speed up the process. There was an auxiliary kerosene heater also connected to the tank for heating water in the summertime.
TKM
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If you have the time get another tank, put it outside with bypass valves, when nightime temps are above incomming water temp let the tank fill, the sun will heat it fast
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And in the winter it'll bust wide open.
s
If you have the time get another tank, put it outside with bypass valves, when nightime temps are above incomming water temp let the tank fill, the sun will heat it fast
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"ransley" wrote in message

Actually for the summer, I am thinking about running a bunch of plastic pipes in my attic which gets to be very hot. Plastic because I will need to drain it each fall to prevent the pipes from freezing.
Also with this idea, I am thinking of installing another insulated water tank and using a solar powered pump to circulate water slowly from the insulated tank through the attic pipes and back to the insulated tank.
My city water is very cold year round. In the summer I would run it through the tank by the woodstove first and this would help to cool the living room (when using hot water) and bring the water up to room temperature. Then on to the attic/insulated tank, then on to the electric water heater.
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You'd probably be dollars ahead to simply get that heat out of your attic and reduce the load on your AC.

Why would you waste money on an under-powered and over-priced solar pump that quits working when the sun goes behind a cloud when a conventional pump works so well and draws so little power?
Solar water heat from the roof works well but generally, the tubing itself needs to be exposed to the solar radiation. Radiative energy transfer is much more effective than convective in this situation.
I did a similar system on my restaurant's flat tar roof. I simply laid several hundred feet of direct burial black PVC pipe directly onto the tar. I tried industrial black garden hose before that but it wasn't sufficiently UV-resistant to last very long.
On bright sunny days, the water would almost boil. In all cases when the sun was shining, this system made all the hot water the restaurant needed. There was a NG-fired tankless heater for other times, of course. This system used no tank and no fancy plumbing. City water went in one end of the tubing and hot water came out the other. A three-way valve let me quickly switch the solar heater in and out as needed. All manual control which was good enough.
John -- John De Armond See my website for my current email address http://www.neon-john.com http://www.johndearmond.com <-- best little blog on the net! Tellico Plains, Occupied TN I don't speak Stupid so do speak slowly.
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