Adding another solar air heater

[precaud]

Yes Dave, your premonition was much closer than mine, no question. My mistake was about the impact of ground temps on the heating needs upstairs. It doesn't affect it as much as I thought it does. It does affect the basement; wood use down there was only a little less than last year. Piping some solar down there for next winter should reduce wood use down there significantly.

 

[PapaDave]

Do you have an idea how to do that yet (piping to the basement)?
I'm interested in your solution.

 

[precaud]

I know I'll have to make two large holes in the wall into the basement. It's a daylight basement so it will all be above ground. Beyond that, I'm just forming an overview of what will be needed.

A horizontally displaced heater does not benefit from natural convection, and has to be 100% fan-driven. So from a noise perspective, the larger the hole, the better (lower air velocity in the pipe and slower fan speed).

There are some interesting ideas for horizontal collectors that use aluminum downspouts as heat exchangers.

Since the basement has a longer season of heating needs than the upstairs (by 2-3 months), I will angle this heater upwards to increase it's solar collection, and cover it in the summer months.

My guess is, it will be easier to build than the previous two!

 

[precaud]

There is always an element of uncertainty going in to extreme weather, wondering if the system will perform well as it has in the past. The last 36 hours has been another real test, with a cold, sunless day of snow followed by temps plummeting, bottoming at -5F at 3am this morning, followed by a clear, cold day today (20F high). Yesterday it snowed all day and the woodstoves carried the heating duties; burned two loads upstairs in the AM, three downstairs during the day, and three more upstairs in the evening (none overnight). In the AM it was 64F, and seeing it would be sunny, I burned one small load upstairs to take the chill off, and by 8:30am the solar heaters were producing. (That's about a half hour later than usual, besides the extreme cold there was a light fog to burn off). By noon it was 70F upstairs, and 73F at 3pm. So once again I am relieved, the system really performed well, and showed that it is well-sized to the house.

 

[PapaDave]

Jeez precaud, if you keep this up, you'll find a way to stop using the stove too.
Is that what you REALLY want? :lol:
Nice to have options, eh, and to have created them yourself to boot!

 

[precaud]

Jeez precaud, if you keep this up, you'll find a way to stop using the stove too.
Is that what you REALLY want? :lol:

Help me find such a way, Dave, and I'll jump on it! Actually, nah, no self-respecting pyromaniac could ever give up their stove(s).

Nice to have options, eh, and to have created them yourself to boot!

Yes, that is satisfying, and it's great to have a success story to be able to share. And that is what I want to do now, to encourage others to go down this path. For if you look at where this house started 5 years ago (no insulation, $300+/month nat gas bills) and where it is now, you have to say; if it can be done to this place, then it can be done almost anywhere.

But very few people are thinking along these lines, even in locales where solar is a complete no-brainer. Example: there's a guy who redid the roofing on my garage/warehouse ten years ago. He lives a few blocks down the street and knows more about construction than I ever will. Last week I ran into him at the grocery store, he commented about seeing the heaters being built over the last few years and wondered how they were working. When I told him, he was floored. Most people view passive solar as something to play around with, and not as something that they can seriously use to carry the bulk of their heating needs.

 

[Redskins82]

Interesting!

It looks like you should have extended your roof a little farther out to shade the glazing during the summer when the sun angle is high.

I've got approximately 5' X 7' solar heater attached to to the south side of my trailer and it helps. It's paid for itself and I don't even live in a region that gets a lot of good sunlight during the winter. I might build another one that is not mounted on the side of the trailer. It would be a well insulated box shaped like a cold frame filled with black cinder blocks or rocks. I could draw air from the floor inside the trailer into the bottom of the box and flow air out of the back of of the box near the top back into the trailer. This type of design might work well for your basement. Some designs put the box inside the basement. Check out the part of this article about rock bin storage of heat. (broken link removed)

 

[precaud]

It looks like you should have extended your roof a little farther out to shade the glazing during the summer when the sun angle is high.

Yes, that was my one error in building this, covered it in post #10. But it hasn't been a problem.