Solar Hot air

Discussion in 'Solar and Geothermal Water Heating Forum' started by Semon, Dec 29, 2011.

  1. Semon

    Semon New Member

    Messages:
    36
    Location:
    Tn.
    I have mt solar panel just about ready to go on the roof.
    Is there a way to keep it from steeling cool air from my shop in the summer and to keep it cool?
    Block off the in and out air flow I would think it would get extremely hot.
  2. Dana

    Dana In the trades

    Messages:
    2,839
    Location:
    01609
    Thermal air panels almost always work better on walls, not roofs. Mounted on an angled south facing roof the summertime stagnation temps could easily exceed 200F, maybe even 300F. Mounted on a wall there is better convective cooling, and a large fraction of the mid-day solar radiation is reflected due to the high angle of the sun.

    Any solar air panel should have both a backflow preventer flap or valve and a louver or register for shutting off the output for stopping convection currents when heat isn't wanted. With an active blower version a standard closeable hot-air furnace or AC register well enough for blocking the unwanted hot air flow.
  3. aaronsteven

    aaronsteven Guest

    I think Dana is correct and it is the perfect solution for you!

    Can you please give a bit more information about "Thermal air panels" Dana ?
  4. Dana

    Dana In the trades

    Messages:
    2,839
    Location:
    01609
    There is copious amounts of web-info on thermal air panels, including a reasonable selection either linked to or residing in Gary Reysa's BuildItSolar website.

    For most North American locations a vertical (wall) orientation works pretty well, and without provisions for heat-dumping putting it on a roof pitched lower than about 20:12 (no, that isn't a typo) in TN doesn't work out very well. With heat dumping and due-south orientation a 12:12 roof can work nearly optimally for heating-season output, but would still overheat in fall. Without heat dumping provisions the stagnation temps inside the panel can get ridiculously high- high enough to damage or degrade many materials that might otherwise be used to build the thing. Mounted vertically within 30 degrees of due south the hit in heating season performance can be reduced by as much as 15%, but managing the unwanted solar gains the rest of the year is much easier.
  5. solarhotairpanels

    solarhotairpanels New Member

    Messages:
    1
    Location:
    Warwick, Rhode Island
    portable solar hot air panels

    In ref to the question above.. I too would mount them where you can get to them easily.
    I mounted the 3 I built on legs.

    2 are mounted vertically
    1 is mounted horizontally..

    1 on my back deck..
    2 on the ground but on 2x4 legs about 3 ft off the ground to account for snow build up.

    They all work perfectly mounted vertically and even the one I mounted horizontally turns on and off automatically like weeee the people.

    19 degree temps?
    no problem

    They all kick on when the sun hits them and produce over 90 degree temps into the house.
    Most of the time the temps are in the 100's

    no soda cans
    no lexan

    just flat plate (aluminum flashing) collectors with ripple clear roofing material for glazing..(plexiglass) purchased from Lowe's

    If anyone needs my build info just email me thru this website ok?
    2x8panel.jpg 4x8panel-FRONT.jpg 4x8panel-REAR.jpg
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