Solar Water Heating

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schmidtye30
schmidtye30 Registered Users Posts: 7 ✭
in General Solar Power Topics #1
Hi,

I was wondering what the avg. cost of a solar water heater system is and what the difficulty of installing one yourself is if that is even feasible?

We have 3 in our family (one 18 month old baby) so our water usage isn't crazy.

thanks,
Ryan
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #2
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    Re: Solar Water Heating

    How feasible DIY solar hot water is depends mainly on your site and your level of talent. It's basically clever plumbing. If you want to see lots of ideas along this line check out Build-It Solar: http://www.builditsolar.com/

    On the whole it's not the most difficult thing in the world to do.
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  • Seven
    Seven Solar Expert Posts: 292 ✭✭
    #3
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    Re: Solar Water Heating

    The kits I have seen are in the $2500 range.
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  • solar_dave
    solar_dave Solar Expert Posts: 2,397 ✭✭✭✭
    #4
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    Re: Solar Water Heating

    I would think in North Carolina it should be pretty easy to DIY a setup and get 9-10 months a year of hot water out of it. The link Coot gave is an excellent DIY site for solar hot water.
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  • waynefromnscanada
    waynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    #5
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    Re: Solar Water Heating

    Built my own almost 10 years ago, to feed into a 60 gal CDN tank (65 gal American?) 265 litre. Had a sunny day, and working outside so didn't use much today, just checked the temp readouts, 157F at the top and 149F at the bottom of the tank. I don't wast hot water, but use what I NEED, and except for a couple of days when it was luke-warm, I haven't run out of hot water all Spring or Summer. The tank is a standard electric model, but not connected to electricity, and I've added an extra foot of fiberglass insulation around and over it, which makes a huge difference. No pumps, no heat exchanger, directly heats the water, which is most efficient, and circulates through natural convection. I just have to remember to drain the panel if there's going to be frost overnight, and in winter the water is heated off the wood stove, so the panel stays drained all winter.
    Am I happy with it? Ya wanna believe I am!!!
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  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    #6
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    Re: Solar Water Heating

    I have built a number of flat plat collectors, that simply consist of a 2x4 box, with 2" of thermax, covered with a 3/16 piece of scrap steel. On top of that is a continuos loop of 1/2" copper plumbing pipe with sweat 180 degree elbows, all covered with scrap 34x77" patio door glass. (You can get these used for nearly nothing)

    A differential controller turns a simple grunfos pump on when the outlet temp of the collector is higher than the cold side of the tank. This circulates into a 60 gallon discarded hot water heater, and acts a pre-heat for demand gas water heater.

    The last one I built in the grey Pacific NW provides 100% of the hot water for two people from ~April-Sept. In the winter the controller has an anti freeze setting that runs the pump to keep the collector from freezing. It works fine to ~ +10F. In the winter, it produces perhaps 25% of the hot water needs depending on cloud cover. The entire collector is 12'x 3'.

    Total cost for me was under $300, for the pump and controller. Everything else was scrap. To buy the copper and the steel might run another $300, the glass can be had, as I said free or nearly free. (when ever one breaks an insulated patio door, they replace both glass panes, and discard the unbroken one, since you can't effectively seal a new one, so most glass shops have these tempered (un cuttable) panes available quite often for free)

    I would posit in your climate you could build a system like this, with little fear of freeze damage for under $1000, to produce enough hot water for 4.

    Tony
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  • solar_dave
    solar_dave Solar Expert Posts: 2,397 ✭✭✭✭
    #7
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    Re: Solar Water Heating

    FYI I bought my system installed with a 80 gallon electric hot water heater (no electric hookup) as storage. It is configured as a pre-heater for a Sears high efficiency gas hot water heater which never comes on so far, gas bill shows 2 therms usage. It is a pump circulated system controlled with a differential thermostat controller. I have little worry here about freezing, but it has replaceable pop offs in the panel just in case.

    Installed before any rebates it was about $4K. Part of the $4k was the permitting and the installation of the Sears heater bought separately. This time of year it brings the temp back to 150F by 9-10 AM with our normal usage.

    Funny as the Gas company called and asked why the usage was near nothing and wondered if the house was empty. Gotta love that.

    PS I just can do the roof anymore or would have considered a DIY.
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  • rollandelliott
    rollandelliott Solar Expert Posts: 834 ✭✭
    #8
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    Re: Solar Water Heating

    I'm in the middle of making mine a 4x10' unit I figgure about $1000 by the time I am done.

    There are 3 companies in Charlotte, NC that make them around $5 to 10K installed, pretty expensive!

    If you live in Florida you can do a direct loop and it is cheaper.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,439 admin
    #9
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    Re: Solar Water Heating

    Solar Thermal can be a nice source for space heating and hot water... And usually is "cheaper" per kWhr/BTU vs Solar PV Electric. Also, Solar Thermal lends itself very well to do it yourself projects. Note, these are plumbing projects and have their own issues (leaks, pump failures, installation issues trapping air, anti-freeze, storage, heat exchangers, etc.):

    Solar Shed and other Solar Thermal Links

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    #10
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    Re: Solar Water Heating

    PEX tubing make do it your self plumbing projects a great deal easier. Also, consider Shark Bite fittings to connect to house plumbiing. Even a rank beginner can tee into the existing plumbing easily. They are too expensive to use for all things, but for repairs and teeing into a line,, they are pretty slick.

    Tony
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