PV for supplment water heating

Buffalobilly
Buffalobilly Registered Users Posts: 1
in Solar Beginners Corner #1
:cool: I have a motor home with solar to keep the batteries charge, but this is about my home.
My home has 2 50g water heaters in series of which I only use the second 1 to heat the water at the present time. I have an old satellite internet antenna mount on the south side of the house(much sturdier than SAT TV mount) to use as a panel mount. The water temp going into the 1st WH is 47 Degrees F.
I picked up a new 230 watt PV panel for a very good price. I am thinking of converting the 1st WH form AC to DC using the panel I purchase as the power source to preheat the water. I did some calculating and figured a 3000w 120vac (4.64 Ohms) heating element would work. I would use the existing thermostat on the WH set a about 130 degrees F. I don't think I will ever get the water that hot.
There would be no battery or inverter, all out put would be to the heating element. The wire run is about 75ft
I figure to keep the price down I would use 12 gage romex for the wire run, all 3 wires in 1 cable for the + run and another 12 gage romex all 3 wires for the - run. Using bus bars in plastic junction boxes(4 of them) where I need to connect to the single wires out of the panel and single wires into the WH.
Now I would like some input on this.

Thanks Bill
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Comments

  • KozmoK
    KozmoK Solar Expert Posts: 42 ✭
    #2
    Re: PV for supplment water heating

    Buffalobilly,

    I am just learning - and in no shape to give out any advice but I did find this - http://www.cyboenergy.com/products/cimini1200h_overview.html Doesnt require any batterys - its a offgrid type microinverter. You will need a few more panels.
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  • bill von novak
    bill von novak Solar Expert Posts: 891 ✭✭✭✭
    #3
    Re: PV for supplment water heating
    Buffalobilly wrote: »
    I picked up a new 230 watt PV panel for a very good price. I am thinking of converting the 1st WH form AC to DC using the panel I purchase as the power source to preheat the water. I did some calculating and figured a 3000w 120vac (4.64 Ohms) heating element would work. I would use the existing thermostat on the WH set a about 230 degrees F. I don't think I will ever get the water that hot.

    Should work but isn't very cost-effective compared to:

    1) a standard solar DHW heater (batch heater, drainback isolated loop, direct loop, whatever makes the most sense in your area)
    2) a grid tied solar power system

    But if you have the hardware and the location - and you can't grid tie - it would work. Note that you may not be able to use the thermostat since it is designed for AC, not DC. At low currents/voltages you might get away with it.
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