My house has a full basement except under the kitchen where there's a crawl space. It's colder'n you know what under there, pipes freeze, ugly.
The back of the house faces dead south and there is a roof over the porch at about 30 degrees, 60 sq. ft. I was thinking of building a box on the roof filled with water filled tubing, the tubes would heat from the sun, then travel down to a baseboard type heater in the crawl space. This space is about 15 X 12.
a.) Would the heated water travel via convection, pumping itself through the system?
b.) When not in use in the off season, would a simple on-off valve stop the action and be safe over the summer?
c.) The tubes would be filled with glycol or equivalent.
I have a picture somewhere and will post it when I find it.
Any thoughts or experience is appreciated.
Dan
I think that for the water to syphon by itself, the collector (yours is proposed on the roof) would need to be BELOW the output. Hot water rises, cold water sinks. So I'm guessing your arrangement will need a pump.
My thoughts have always been to put a simple pump in the system that was powered by a solar panel and a temp switch. If the temp in the collector is warm enough and the sun is shining enough to spin the pump...you're good to go.
Please update us as and if these plans progress!
Clem
Sustainable power junkie
Speaking of which...
Anyone experiment with DIY photovoltaic cells? I've seen some references to making them with titanium dioxide (white paint pigment) and berry juice. Anyone ever make a big one? Got any links? I got all this roof space....
I recently finished building a 3 season sunroom out of what was once a deck for a customer. when the frame was up and enclosed, I went under the structure and filled the bays with paper backed insulation. I then sheeted the entire underneath with 2" foam board insulation, taking my time to get it nice and tight. Kind of a pia to layout because in many places you cant see the joists anymore. I then taped all seams. Then I covered the whole thing with 1/2" plywood. I know this doesn't answer your question, but I'll tell you what, it works.
Many moons ago, after a trip to the science museum in Toronto, we incorporated a system that may work for you. We mounted a bunch of old(but good) car radiators on the roof of the race shop. They were all piped together, framed then covered with lexan. We had run old copper pipe and fin tube lengthwise in the floor joists and created a 'grassroots' radiant heating system. We used a low voltage circ pump to keep it running. Worked like a charm for very little money. We learned(the hard way) to fill the system with glycol. I'm currently running a similar set up in my house to heat the floor in my kitchen and foyer, but utilize the returns from my boiler.
gamby
SuperDork
2/16/09 8:36 p.m.
The hot new setup is radiant heating via solar panels.
Tubing runs along the floor--either underneath the hardwoods or embedded in the slab--and the panels heat it. I dunno if a pump is involved, though I'd like to say it's completely passive via convection, but don't quote me on that...
<--still waiting for them to get to the $5k mark for an array...
Here's the roof in question. The panel would sit on the slanted roof right behind the umbrella, it faces south and gets sun all day. I'm looking for a box full of tubing that runs down to something like baseboard heat that would be in the crawl space under the kitchen.
Dan
You'll want to insulate the crawlspace too. Something to help retain that heat through the night when the sun's not warming it up. Extruded, rigid foam insulation board around the inside of the foundation is what I'm thinking. Sealing up gaps and eliminating drafts will make a huge difference.
Clem
