Solar Heater question: Best glazing product?

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nateritter
Posts: 3
Joined: Tue Jan 05, 2016 7:38 pm

Solar Heater question: Best glazing product?

Post by nateritter » Wed Jan 06, 2016 7:45 pm

Hi all. Glad to have found this great resource and board!

I built a little screen-style solar heater that I can put into my office window. It's my first alt. energy type of DIY project I've ever done, and it works (kinda)! Now that I've proven to myself (a) I can do it and (b) it actually functions, I am going to work on optimizing it a bit. I put some of it together on the cheap.

There are a few things I think I can do better, but the first on my list is to replace the glazing on the front with something better. I literally just used some Warp's plastic wrap because it was less than $10 for the size I needed. Stapled it on the front and tested.

Obviously that's not great because (a) it probably won't hold up to the possible heat in the box and (b) it has tons of heat loss being as it's thin, not a solid sheet, and simply stapled to the edges of the box.

I started looking at what to replace it with. There are a ton of options, so I need some help getting down to what is best balancing cost with longevity, performance, and ease of installation in a 1x4 pine frame (I ended up putting two 1x4 frames together to make it a bit deeper, which seems like it would help heat more air). The height/width dimensions of the frame are about 45" x 45".

So, what have you found to be the best balance between cost, longevity, performance, and ease of installation?

Here's what I've found so far:

* Glass seems hard to find at the right dimensions and expensive to get if you go custom ($200+)
* Clear Polycarb roofing seems to be able to withstand potential high temps ($30-40 for corrugated + ??? cost of closure strips, ??? for flat)
* Clear PVC roofing seems to be a risk because of it's inability to handle high (200deg F) temps that might be possible

If you know of others and their approximate cost and/or other attributes, I would love to hear from anyone with experience with these.

Thanks!

techman
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Joined: Thu Dec 22, 2011 11:49 am

Re: Solar Heater question: Best glazing product?

Post by techman » Thu Jan 14, 2016 12:12 pm

What about looking for used glass windows that you can get for free and then either cut the glass to fit your project or rework the solar heater to fit the glass that you find?

I made a bunch of passive solar heaters a few years ago and had good heat output. The first year, before I was living in my camper full time, I kept it nice and cozy warm in there with just solar heaters. But I had the camper facing full south at that time to that helped a lot. And it was an exceptionally sunny and warmer winter that year.

In the following years I experimented with solar heating for the camper but with less success due to the windows facing the wrong way. Not optimal.

But if I was to make them all over again they would be with used windows.

nateritter
Posts: 3
Joined: Tue Jan 05, 2016 7:38 pm

Re: Solar Heater question: Best glazing product?

Post by nateritter » Thu Jan 14, 2016 5:17 pm

Good thought.

I'm not sure how to cut the glass. I've not done that before.

The goal with this one (and probably the next one) is to fit them into the window sills already in my home, so I've kinda got myself into a rock and a hard place with that one.

I have thought of putting them outside and somehow porting the hot air in, which would probably get more heat created. But, I'm stuck on that one too because the windows slide right to left to open, and opening those or partially blocking them with something flimsy would cool the room too much.

I hesitate to cut right into the house yet as this is still an experiment. I'm not interested in doing permanent changes to the home quite yet until I can get the right setup heating more often than it has been. So far there has been very little sun the past month, and the boxes don't seem to produce anything without direct sunlight, so although he boxes work under the right conditions, I'm not convinced we'll have the right conditions often enough to make permanent changes to the home (at least not yet, with these solar heaters). I need something that still produces heat even without direct sunlight, and I have no clue what that might be at this point.

If anyone has any suggestions for that scenario, then yes, I could build boxes to the dimensions of the glass I found.

techman
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Joined: Thu Dec 22, 2011 11:49 am

Re: Solar Heater question: Best glazing product?

Post by techman » Thu Jan 28, 2016 9:31 am

You would seal off one of your windows with foam insulation and putting two large holes in the foam. One at the top of the window and one at the bottom.

Use insulated duct tubing to run from the solar heater to your window.

The lower opening in the window is the cold air flow into the bottom of the solar heater. The top opening is the hot air flow back into your home.

This should work for now as you experiment.

nateritter
Posts: 3
Joined: Tue Jan 05, 2016 7:38 pm

Re: Solar Heater question: Best glazing product?

Post by nateritter » Thu Jan 28, 2016 12:04 pm

That's a good thought. That actually would solve another issue I'm confronting at the moment too - having zero visibility right now. It's not my top priority, but seeing outside is almost necessary when it comes to even a mid-term solution / experiment.

Thanks for the tip @techman.

techman
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Joined: Thu Dec 22, 2011 11:49 am

Re: Solar Heater question: Best glazing product?

Post by techman » Tue Feb 02, 2016 9:08 pm

No problem. Please keep us updated on your project and results.

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