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Where can I find a/an (ideally black) watertight fabric that could be used for a solar water heater? Answered

I'm in sunny New Orleans, and we are encountering a ridiculously cold snap.  I don't keep my house too warm, so I'm dying with electric heater cost.  Since I know my windows are one place where a lot of solar might be collected, and energy is lost, I am trying to find a way to collect passive solar energy.

The idea is to sew several tubes into watertight fabric in a design like a radiator, and then fill them full of water.  The idea is that this will absorb the heat from the sun and then, as night falls, act as insulation against the cold.  And I am hoping that I could hang them in the windows of my house and remove them when it warms up.

Does anyone have a suggestion for watertight fabric that I could use for such a project?
D. Adrian


You're looking at 2 different technologies at the same time -
Capture/storage - and insulation.  They have different features and requirements.

First - the energy coming in your windows as light is already being greenhouse effect-trapped into your house by the windows.  Putting black in the window will just localize where the light is converted to heat.  Using that heat near the window later to keep 'the area near the window' warm will work, but will be no more efficient than a clear window.  Opening the curtains while its sunny and closing them when its dark has the exact same effect.

As for passive - seal your windows!  Get rid of drafts.  Most homes have the equivalent of a hole about as big as your computer monitor in leaks.  Weather stripping, plastic for over the windows, Sealing unused chimneys, putting those foam insulators under your electrical outlet covers, and insulating the roof will have the biggest impact on your house heat bill.

If you really want to collect heat and use it later, you need an active system with storage tanks, collectors (preferably outside) and radiators/heat exchangers inside. 

There are lots of good instructables on making solar collectors - if you want to make your own sealed-bags of water I would recommend rolls of pvc, and gluing tracks with rubber cement.

 i don't know to much about soler power but it sounds to me like a black trash bag would do the trick 


8 years ago

Well, I know that waterproof Hypalon fabric is used to make rubber rafts, such as the Zodiac. I'm not sure, however, how the seams are waterproofed but I suppose the retailer could tell you that.

You should check out the website "builditsolar.com"  they have HUNDREDS  of ideas..  I think a better idea would be to fill beercans with sand. plug the ends with duct tape. stack them up in a glass coverd box. (paint the cans BLACK first).  the water idea might have problems of leaks and or freezing at night. 

Another idea that my father-in-law uses is he leaves his main furnace OFF, and he runs a couple little electric space heaters to just heat a small area of the house (near the TV) during the day. Then at NIGHT they turn the heaters OFF because when sleeping, the covers keep you warm.  This method works MOST MONTHS of winter and costs much less than heating the whole house.  They live 60 miles NORTH of st louis, so it gets pretty COLD up there.  If you are willing to withstand a house temperature of 60 degrees, you could just leave your furnace OFF during mild months of OCT, NOV, and half of DEC.  I have found that as long as OUTSIDE temps stay 35 degrees or higher, then my house doesn't go below 60.  sixty is only MILDLY uncomfortable. so we leave furnace OFF completely during those days/months.  Then when SEVERE COLD MONTHS hit us, we go ahead and crank up the furnace and just pay the bill.  This works out as mostly JANUARY and FEBRUARY is furnace ON... then march/april/may furnace OFF again. 

Use black trash bags.  They can be glued to hold water.