Sunday, May 03, 2015

Time to think about next winter

"What?  It's just now Spring!?!" (Northern Hemisphere only, your mileage may vary, see dealer for details.)

Yes, it's time to start considering how you're going to keep warm next winter.  Time to get firewood cut for the winter after this, split this winter's wood, so on and so forth.

"But my friend...have you ever considered...SOLAR?"

I'm not talking about the traditional solar hot water collectors of yesteryear.  Yes, they work, but jeeze, old technology.  Ick.  How about something more...innovative?

"How about...SOLARSHEATS!"

The concept is simplicity itself.  A black collector heats air, not water.  The heated air is them moved by a solar powered fan to the interior of the building you want heated.  It will even work on an overcast day, though at reduced efficiency.

The true joy of this is that you don't have to buy the over-priced Northern Tools version.  While I'm sure it's very nice, that price.  A handy person can build these on the cheap.  Allow me to tell you just how cheap.

A few years ago, I happened across this concept.  I had an outbuilding that I wanted to heat, but no good way to heat except with kerosene heaters.  At one time I had used a wood stove, but the homeowners insurance agent had had a litter of kittens over it, even though it was using a lined chimney, sitting on a concrete slab and the wall it backed up to was cider block.  Yeah, go figure.

I got tired of having to start the heater going 3-4 hours before I wanted to use the outbuilding.  I needed something that would keep it warm enough that it would warm up quickly when I fired up a heater.  But, cheap so-and-so that I am, I didn't want to spend money heating a space I wasn't using.

As I said, I happened across this concept.  So, a bit of thought later, I took a couple of large cardboard boxes, a can of black spray paint, some acetate sheet, duct tape and a razor knife and set to work.  I cut the boxes down so that two would sit in a large window that faced west.  Trimmed to 4" deep, I painted the inside of the boxes black.  I cut a 1" slot in the bottom of the box at the back to draw in cool air.  I taped the acetate sheet on and left a 1" gap at the top.  I used scrap cardboard to rig up some stabilizing feet.

I now had solar collectors that ran on convection only for the cost of a can of spray paint--everything else was salvaged.  Two of them filled a 4' x 4' west facing window.  I waited for sunny, cold day, which was a couple of  months out by the calendar.

The first day I put them in the window I came home, checked the building and was shocked.  It wasn't warm, it was noticeably warm, as in "I don't need the heater" warm.  These two crappy little collectors had raised a 21' x 21' x 8' (that's 3528 cubic feet of air) up to 65 degrees on a day that was in the low 40s for a high.  The building was, for all intents and purposes, uninsulated.

Obviously, these are not a solution for all your heating needs.  When the sun goes down, these things turn off, so you need something to get you through the night hours.  If it rains, they're pretty much useless, and while the do help on a cloudy day, you will probably still need some extra heat.  But if you can get the materials as salvage or for a minimal cost, a solar sheet (the spelling I prefer) is  a great low-cost way to supplement your other heating systems.  Being silent and not burning any fuel, they would also be a plus in any situation where you needed to maintain a low profile.

Just another tool in your tool chest in case you need it some day.


wheelgun said...

I don't have any connection to this build-it-solar site, but they have a bunch of plans for similar things.

And they even did testing on some competing designs to get the most bang for the buck.

B said...

What latitude are you? Doubt it'd do much here outside of Chicago....

Joel said...


The Freeholder said...

Wheelgun, I saw those links, but I didn't take time to explore them. Thanks for looking into them.

B, we're roughly 38.9 degrees north. You might be right about Chicago, but I don't really know. Solar isn't for everyone or everywhere. I do know that it actually is useful in more places than people think, but at the same time, it is not any sort of a be all/end all as many people think.

Joel, I wish I had taken pictures. That house is now 9 years behind us. I left them for the next owners. This house has a basement with tiny little south facing windows, all of which are to some degree obscured by bushes or overhung by the deck. The heat pump keeps the basement tolerably warm when it runs. When we're running the wood insert, the basement gets cold. We're looking into some sort of independent heat source for it now, but haven't found anything that we like.