Solar air collector - covering window?

MarquisMarquis Registered Users Posts: 7 ✭✭

I built a collector that I am putting inside my very large window facing south-west. The room naturally warms up when it is sunny, so I wanted to capture that sun exposure and produce pure heat. I'm not heating the house during the day, so the temperature goes down to 15 degrees Celsius. The air coming out of my collector is about 24-25 degrees Celsius. It seems effective. However, I just stumbled across this site: https://rimstar.org/renewnrg/window_...er_furnace.htm and basically, according to the author, there would be a net zero benefit to capturing the sun's energy through a window.

 I imagine that the benefits are much smaller because the double-pane glass prevents some of the sun rays from reaching inside the house. However, I would assume that the difference in temperature with the collector does somewhat prove it is effective. What do you guys think?

Thanks for the help!

Comments

  • BB.BB. Super Moderators Posts: 26,872 admin
    And many modern double pane windows also have have Low E glass (reflects IR radiation). Would usually make a very poor solar heat collector as most of the heat never gets through the window glass.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • Dave AngeliniDave Angelini Solar Expert Posts: 3,329 ✭✭✭✭
    I would (and do) place the collector outside of the window on the wall ;)
    "we go where power lines don't" Sierra Mountains near Mariposa/Yosemite CA
     http://members.sti.net/offgridsolar/
    E-mail offgridsolar@sti.net

  • EstragonEstragon Registered Users Posts: 1,616 ✭✭✭✭
    I'm going the outside route on a bunkie / outhouse I'm building next year. Likely just dark metal siding with an airspace between the siding and insulated wall with collector and ducting at the top of the two story, south facing wall. Hopefully enough to take the chill off the biffy.

    Have also seen air source heat pumps with exterior black evaporator panels used for hot water heating.
    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
  • MarquisMarquis Registered Users Posts: 7 ✭✭
    Thanks for all the answers!
  • Dave AngeliniDave Angelini Solar Expert Posts: 3,329 ✭✭✭✭
    Estragon said:
    I'm going the outside route on a bunkie / outhouse I'm building next year. Likely just dark metal siding with an airspace between the siding and insulated wall with collector and ducting at the top of the two story, south facing wall. Hopefully enough to take the chill off the biffy.

    Have also seen air source heat pumps with exterior black evaporator panels used for hot water heating.
    Or even the most basic of all back to our grandfathers, a hot water heat collector. Simple to drainback and  often no need for too much exposure or the problems of overheating the water.
    "we go where power lines don't" Sierra Mountains near Mariposa/Yosemite CA
     http://members.sti.net/offgridsolar/
    E-mail offgridsolar@sti.net

  • EstragonEstragon Registered Users Posts: 1,616 ✭✭✭✭
    The plan includes that too. I have a coil of poly water line left over, and an old propane tank type water heater which I plan to use for an outdoor shower. The pipe will go on a shed roof over SxS parking, and the tank on 2nd floor of bunkie. I'm hoping it will work with convection alone, but could add a small circ pump if needed.
    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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