Very Passive Solar Heating

It has been TOO long since I've paid attention to this blog! Many reasons, most of which involve taking care of my parents - so please forgive me.

However, that's not the topic of this post. I found a very cool site during the last year and will highlight it in a future post. Right now, I'm going to focus on the topic of passive solar heating.

We all know that if you sit in the sun, you'll get hot. If you sit on black top in the sun, you'll get burned.

Somewhere in between those two things is what I'm trying to work with.

Looking at other solar heater designs, I thought of an idea. Since so many use windows, and windows that are fastened to the wall of your house, why not use the windows that are incorporated into the wall of the house - namely, those you peer out of on a daily basis.

I have the perfect room for the initial experiment - it's a very small, unheated room. 8x12 with 2 large windows that are about 20% of the floor space and face ESE and S (roughly). They have full screens that sit on the inside of the frame. I took those screens and set them at an angle - not the perfect angle for my lattitude, but close enough without making fancy frames to hold them in place - right now it's the curtain rods doing the work.

On sunny days, this simple arrangement heated this room 5 degrees when the temperature outside was between 25* and 32*. Cloudy days had absolutely no change in temperature and colder days saw less temperature change.

This year, I bought good old black netting - similar to fish-net stockings, but smaller grid. I used double faced tape, cut the netting to size and fastened it to the window frames. Very close to the window on the bottom, as far out on the top as possible without making a special frame. I discovered you need 2 layers of tape since there is so little surface area holding the netting to the tape - sandwich the netting between the layers of tape. Works like a charm.

While there isn't as much surface area to the netting as with the window screens, it is far darker than the screen, and will allow for more air flow, which should create more or = heat exchange as the screens.

I've set them up in the dining room windows, of which there are 4 and in 1 living room window - using the last of the netting I purchased.

I will be keeping some unofficial statistics and will post them in a month or so. It's a $2 trial. That works for me. And if I got 5* for that $2 investment, that should add up to a 5-10% savings on heat - paying for the netting in roughly a week. I know - not every day will be sunny, most of all where I live. However, even if it turns into a mere 1% savings over the heating season, it'll still be at least a 1000% return on my money. I'll be having it!

Storm Window Solar Panel

9/28 - Well, there's no fixing it. A friend of mine and I tried to no avail. Crap. If you use a vinyl window, make sure to put screws in the vinyl to hold the window in place. Do NOT expect the locks and actual tracks to hold it in place. They won't. As you can see, the track failed after the locks - which if you look closely at the upper left corner - bent and allowed the window to release. Otherwise, the plans at the bottom of this post are rock solid. The vinyl fails between 200 and 300 degrees fahrenheit. So - it got that kind heat built up in it - it works!

8/31/08 - Yes, I know - talk about delayed projects. It's all assembled and was awaiting another strong body to help me place it by the shed.
You know what I found out? The vinyl the new windows are made with isn't capable of withstanding whatever the temp was inside the heater - even with air flowing through. I'm not pleased. I have to now figure out how to FIX it before I start working on installing it.

Well, I'm going to dabble in DIY solar.

My mom and I are building an outbuilding. Or, for those in the architectural know, a backyard cottage (cackle). Just heard about it this term last Sunday. Go figure. It's actually going to be a work shop for a very small money-making hobby. Another term I'd not heard of.
Anyway, heating it is a concern. We're going to have to keep it at a somewhat constant temp of at least 50 F. That means we need a heat source for winter - which is up to 5 months here in upstate NY.

I stumbled upon the following article from Mother Earth News

I know this won't be sufficient for a 24 hour period, particularly when there's no sun - we compete with Portland OR for fewest sunny days and most precipitation. However, every little bit helps and would surely help us save space by having a smaller heater - of whatever type. I'm really against oil since it leaves a film - regardless of how clean it burns or how sealed a unit. No woodstove - not tending 2 woodfires, thank you. Not piping gas and getting into that regulatory hassle. That leaves electric and pellet stove. We might do electric this year and see.

I have insulated it better than 90% of the homes in the US, along with GREAT windows, so heat loss will be minimal. I'm also in the process of insulating the actual house far better, so that will allow for extra electricity to be used out there without disrupting any aspect of the budget, in case the money making part of the hobby doesn't start making right away.

They used old sliding glass door glass. I have an extra window from the shed that I am going to use for the project. Here are my plans that I drew up


This church used soda cans - we have cat food cans! No cutting! (I'm virtually gleeful about this part).

I can't use steel - no gots. But, I have a ton of scrap lumber from numerous other projects. Plus a lot of radiant barrier insulation, fiberglass insulation, and styrofoam insulation. 10/24 - My cousin made the boxes for me - so he didn't go quite by instructions. Pissed me off no end, but I use what I have...


Flat black paint - I may go with a high heat type used for wood stoves just because I know it exists. 10/24 - went with an oil based for durability.

Piping - I'm seriously considering 2 sizes of PVC pipe. Smaller for actual air flow. Wrap with insulation and insert into larger pipe. Did this - worked great!

Wall Openings - Have 2 separate openings in the wall, rather than a single one as many window solar heaters have. One low for cold air return and one high for heat. It'll still syphon the way it's supposed to, but without the mixing of temperatures with a 2 chamber unit as so many have.

Can Arrangement - I was thinking a 'best fit' placement to begin with. Alternate the cans as if making a pyramid. But, with the radiant barriers I have, I'm wondering if purely adjacent to each other would work better, allowing some light behind, reflecting back up onto the sides of the cans for added heating. Comments? I did purely adjacent. We'll see!