Heating a house

inbyte
inbyte Registered Users Posts: 1 ✭
in Solar Beginners Corner #1
Hello guys,
I whis/think to heat a house (200 m2) like this: 2-3 presurized water panels, 3-6 kw power panels and 4-6 kw wind turbine. All this directly heating (without a battery bank) a water tank of 1500-2000 liters. I'm new in this kind of stuff so if some of you can help out if its duable and what is needed in the arrray to work (DC water heater or AC - more efficient to transform to ac or to leave it to dc, etc.)
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  • Photowhit
    Photowhit Solar Expert Posts: 6,006 ✭✭✭✭✭
    #2
    DC at higher voltages become problematic in that it will arc easily. It would be more efficient though.

    An integral part of my solar system is my wood stove!

    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.
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  • Estragon
    Estragon Registered Users Posts: 4,496 ✭✭✭✭✭
    #3
    As a start, I'd work out the design heating load.  This will be a function of local climate, and house construction details (eg. type, size, and orientation of windows, insulation, etc).  In a very mild climate and/or very well insulated structure, solar/wind powered primary heat might be viable (with something like Photwhit woodstove as backup). 

    Solar is marginal though, as heat tends to be most needed in winter, when the sun is low and days short.  In my location (Canada), winter (Dec) sun only provides ~2kw/sq.m/day on average, so it would take a very large array and huge storage tanks to handle the heating load.

    Small scale wind is also marginal in most locations, unlikely to be viable unless average wind speeds are > ~30-40km/hr and terrain is free of obstructions (trees, houses, etc.).
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,639 admin
    #4
    Guessing,
    http://www.solarelectricityhandbook.com/solar-irradiance.html

    Brescia
    Average Solar Insolation figures

    Measured in kWh/m2/day onto a solar panel set at a 44° angle:
    (For best year-round performance)

    JanFebMarAprMayJun
    2.61
         		3.70
         		4.63
         		4.59
         		4.97
         		5.30
     
    JulAugSepOctNovDec
    5.52
         		5.32
         		4.48
         		3.28
         		2.49
         		2.08
     

    https://www.timeanddate.com/weather/italy/brescia/climate

    Looks like a Mini-Split heat pump system might be interesting--Electrical energy wise, people have pretty good results with down to near freezing with them. And you get A/C and humidity reduction in summer, if needed.

    If you have the land and a sunny spot, there are folks that have built fairly big collectors and water storage for their winter heating:

    https://www.builditsolar.com/Projects/SpaceHeating/SolarShed/solarshed.htm

    If I guessed your location correctly, you don't have a lot of solar (northern Italy, mountain region?).

    In times past, people were really looking at ground sourced heat pumps (drill wells for water, bury piping, etc.)--But Air Sourced heat pumps (typically mini-split systems) have done a very good job of both cooling and heating.

    Very roughly, heat pumps can harvest more energy down to near freezing, than a simple electric resistance heater.

    Solar Thermal (water) systems--You run the risk of becoming a plumber (keeping pumps running, water leaks, freeze damage).

    -Bill

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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