Solar Water Heating

Toby
Toby Solar Expert Posts: 56 ✭✭✭✭
in Solar Beginners Corner #1
Not sure if this topic is suitable here but I'll ask.

What would you recommend as a good (best) quality and supported solar hot water heating system?

Thanks.
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  • solar_dave
    solar_dave Solar Expert Posts: 2,397 ✭✭✭✭
    #2
    Re: Solar Water Heating

    Lots depends on your location. I live in a non freeze zone so an flat plate no antifreeze system is acceptable.
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  • drew4justice
    drew4justice Solar Expert Posts: 36 ✭
    #3
    Re: Solar Water Heating

    Hi Toby. If you're handy, you might consider building something yourself.
    There's a couple different types, one requires antifreeze type glycol which is then sent to a heat exchanger to warn the water. This generally is more expensive and requires maintenance.

    I'm looking at starting to collect parts for a "drainback" system. This system would use 100% water and when the sun goes down, the water basically drains back down into a holding tank so the water doesnt freeze in the system exposed to the elements. In particular, this is what I'm considering:

    http://www.builditsolar.com/Projects/SpaceHeating/DHWplusSpace/Main.htm

    The heat exchange in this system is probably less efficient than a comercially based system, but it's probably a tenth of the cost.
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  • Toby
    Toby Solar Expert Posts: 56 ✭✭✭✭
    #4
    Re: Solar Water Heating

    I'm in N.C. and we do get freezing temps so it's either a glycol or drain-back. I can do DYI but not on a water project.

    Ideally I'd like the name brand of the best two or three systems available.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,642 admin
    #5
    Re: Solar Water Heating

    Solar Guppy has used these folks and found they were very supportive of DIY installers.

    http://solarroofs.com/

    The other question--It is getting almost to the point that heat pump style water heaters (either stand a lone or attached to a home A/C system) is getting hard to ignore for on-grid homes (even those with natural gas available).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • LucMan
    LucMan Solar Expert Posts: 223 ✭✭✭
    #6
    Re: Solar Water Heating

    AET solar (Eagle Sun) they have been around a long time & make an excellent product.
    Sunmaxx solar (slicon solar) new company but good products
    Sunearth another company that's been around a long time, I have not used them but they are equivalent to the AET's


    Many other brands are rebranded AET or Sunearth panels

    Stick with a drain back system, simpler,and mostly maintenance free.
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  • Toby
    Toby Solar Expert Posts: 56 ✭✭✭✭
    #7
    Re: Solar Water Heating

    Thanks for the links.

    Tank size appears to be a factor that will prevent me from going solar. Either 60, 80, 120 gallon tanks?

    From what I read, the systems have either gas or electric backup. What's the reasoning for such large tanks.

    Right now I have a 40 gallon electric in a bathroom storage closet.
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  • waynefromnscanada
    waynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    #8
    Re: Solar Water Heating
    Toby wrote: »
    What's the reasoning for such large tanks.

    Why the large tanks? Storage of hot water - - - enough to last you till it can be re-heated the next sunny day, or series of sunny days.
    I have an extremely well insulated 60 (Cdn) gal tank and if I'm very careful not to waste hot water, I very seldom run out. I think it got luke warm a couple of times this past year, other than that, plenty for me year round with no back up. But it requires the elimination of wasting hot water, and that's something most people not only cannot do, but don't understand or recognize such waste if they fell over it..
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  • Ralph Day
    Ralph Day Solar Expert Posts: 1,023 ✭✭✭✭
    #9
    Re: Solar Water Heating

    Wow Wayne! You must be doing a lot of things right to have SDHW year round. I have a 1 panel Enerworks sytem and even in the summer if we have 2 cloudy days and do laundry the propane Takagi has to supplement the hot water needs.

    How big a system do you have installed (number of panels etc)?. My panel is about 2x8 feet at 45deg angle. Maybe I should have got for the original 2 panel configuration, but I cheaped out 8 yhears ago. Today the install company is coming to service the glycol (remove and replace) for the first time. Maybe that was too long a wait.

    Ral;ph
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  • solar_dave
    solar_dave Solar Expert Posts: 2,397 ✭✭✭✭
    #10
    Re: Solar Water Heating
    Ralph Day wrote: »
    Wow Wayne! You must be doing a lot of things right to have SDHW year round. I have a 1 panel Enerworks sytem and even in the summer if we have 2 cloudy days and do laundry the propane Takagi has to supplement the hot water needs.

    How big a system do you have installed (number of panels etc)?. My panel is about 2x8 feet at 45deg angle. Maybe I should have got for the original 2 panel configuration, but I cheaped out 8 yhears ago. Today the install company is coming to service the glycol (remove and replace) for the first time. Maybe that was too long a wait.

    Ral;ph

    Maybe it is a prime time to ask about a panel add. Here in AZ a single 4x10 gets about 11 months worth of hot water. I would have done dual panels if I was in a colder climate or perhaps the newer technology vacumn heat pipes which seem to gather the radiation better.
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  • LucMan
    LucMan Solar Expert Posts: 223 ✭✭✭
    #11
    Re: Solar Water Heating

    When purchasing a storage tank look for one with a low standby loss (1/4 degree to 1/2 degree per hr). Some tanks are rated in BTU loss per day so some calculations will have to be made. 8- 12 degrees per day loss for a well insulated tank, 36- 48 degrees loss for an average water heater.
    It makes a huge difference if your water is 120 degrees after 2 days of no sun or if it is 90 degrees.
    Superstor & Vaughn are 2 of the most efficient solar water tanks available. Match the tanks to the amount of panels you use.
    Select the number of panels by the amount of hot water you consume and your climate zone.
    Here in NY I have 72 sq ft of east facing panels on a 80 gal. tank, 6 months of the year my oil burner is turned off.
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