Building and installing passive solar heating panels

I posted a few photos over on news:alt.binaries.pictures.woodworking but am aware that not everyone has access to the alt.binaries hierarchy. For those who don't, and for anyone who'd like to see a bit more of the project, I've put the whole collection of photos (and a bit of text) on a web page at the link below.

Making these things is my "day job", so there aren't any plans or how-to but there's enough visible to provide a few ideas for anyone who might like to build their own.

Warning: I've shrunk all photos to 640x480, but the page may still take a while to load.

-- Morris Dovey DeSoto Solar DeSoto, Iowa USA

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Morris Dovey
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It seems as though he could have put a lot more solar heaters on that wall.

Just how much heat is he going to get out of this installation?

Reply to
Lee Michaels

installation. It looks like an excellent piece of work and I'm sure your customer will be a beneficiary of future lower utility bills. Its one small step on the path to make our country less dependent on imported fossil fuel. Joe G

Reply to
GROVER

There was room for one more (where the window is located), but he really wanted to be able to look out on the pond and livestock.

| Just how much heat is he going to get out of this installation?

He's going to be getting a _lot_ of heat - probably enough that he'll be intentionally trading heat for fresh air on clear midwinter days. On the not-so-clear days he should be comfortable during the daylight and early evening hours.

The construction crew was amazed by the force and temperature of the airflow, but the fact is that the potential drops off fairly rapidly around the time of the vernal equinox. I suggested they return for a look-see sometime around the winter solstice, when output will be at its maximum. They had a bit of difficulty accepting that the output might be almost doubled. :-)

The plan is to add a couple of slow-turning ceiling fans to push the warmest air down to warm the shop floor (which will serve as a sort of "thermal flywheel") to extend the warm hours during winter.

Because the panel is mounted vertically, output will be negligible close to the summer solstice.

-- Morris Dovey DeSoto Solar DeSoto, Iowa USA

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Reply to
Morris Dovey

| Thank you for posting such interesting pictures of your solar | installation. It looks like an excellent piece of work and I'm sure | your customer will be a beneficiary of future lower utility bills. | Its one small step on the path to make our country less dependent on | imported fossil fuel.

I'm fairly proud of this installation. Iowa farmers (like farmers everywhere, I suspect) are very careful about any move away from what they /know/ works. This customer installed a geothermal heating unit in his ~3K sqft home and claims that his highest monthly heating cost over the past two years was $29 (a year ago January) - and he was courageous enough to be the "guinea pig" for a new panel design. It knocked my socks off that he was willing to tell me that he was well-satisfied within a half-hour of a March installation.

Solar heating isn't free (a friendly nod to JClarke here), but the energy used /is/. I'm not much of an eco-freak, although it might seem otherwise - but I'm all for anything that harmlessly and inexpensively improves the quality of life for everyone.

It's not about "big steps" - it's all about small steps - and it's not so much about where petroleum comes from as the fact that there's only a finite supply of the stuff and the that supply is being consumed at a globally accelerating rate. The geopolitics is a result of the supply situation - not vice versa.

The performance of these two panels is the result of some 35 years of small steps - small steps like using highly reflective aluminum ribbon in the heat absorber and /using/ that reflectivity to trap energy, like bending and spacing that ribbon to trap _all_ wavelengths from RF to IR, and choosing ribbon dimensions that provide a "black body" behavior aimed at imparting the absorbed energy to air molecules in an optimized fashion...with all the limitations of a wood shop with low-precision tooling and low-cost materials. (I never claimed I don't enjoy challenges. )

Lower utility bills? Not a chance! What I've done is provide the warmth he wanted so he can walk in, turn on the lights, fire up the dust collection system, and run his multi-horsepower tools when it might otherwise be too uncomfortable to work in the shop. :-)

-- Morris Dovey DeSoto Solar DeSoto, Iowa USA

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Reply to
Morris Dovey

heating. Any electical usage for ww tools, lighting etc. would be independent of that amount. The total electrical energy measured at the meter should be somewhat less than it would have been if the user had electrical or gas fired comfort heat. The saving per billing cycle can be layed off against the capital investment of the solar equipment to determine a payout period. I am not an accountant but I believe there are some tax advantages for the purchaser of such equipment. Unfortunately it does matter where the petroleum comes from since we import so much foreign oil we must endure the vagaries of the countries of origen and the economic problems that come from the balance of payments. This sounds like a heavy load to put on the back of your solar devices. But as I originally said you have taken a small step in the right direction. You said you were proud of your work, as well you should be. From the photos it appears to be well made with a very professional look about it. Joe G

Reply to
GROVER

...snip

I think that pretty much reflects a practical approach. I fully support cost-competitive alternate approaches that work. Therein lies the rub with most alternatives thus far, either 1) they are not cost competitive (or only will be if no maintenance is required and they last 20 years) or 2) they don't perform as well as what they are replacing -- either they don't provide the same quantity or require significant intervention and work on the part of the user.

Looks like the panels you are putting in place are definitely addressing problem #2, and most likely pretty close to fixing problem #1.

+--------------------------------------------------------------------------------+ If you're gonna be dumb, you better be tough +--------------------------------------------------------------------------------+
Reply to
Mark & Juanita

| The portion of utility bills I refer to are dedicated only to comfort | heating. Any electical usage for ww tools, lighting etc. would be | independent of that amount. The total electrical energy measured at | the meter should be somewhat less than it would have been if the user | had electrical or gas fired comfort heat. The saving per billing | cycle can be layed off against the capital investment of the solar | equipment to determine a payout period. I am not an accountant but I | believe there are some tax advantages for the purchaser of such | equipment.

Ok.

| Unfortunately it does matter where the petroleum comes from since we | import so much foreign oil we must endure the vagaries of the | countries of origen and the economic problems that come from the | balance of payments.

Agreed - but notice that all of this is related closely to supply and demand dynamics. A reduced demand produces the same effects as an expanded supply which (I would expect) would produce the same effect as a "stronger" purchasing currency.

There's a geometric (perhaps even exponential) growth in demand globally, a diminishing global supply, and (in the case of the USA) a weakening currency. The first two factors are sufficient to establish that, in the absence of some major breakthrough, we can expect energy supply problems everywhere - and the third factor can be interpreted as an indicator that the USA, along with other nations lacking strong currencies, may experience those problems with an above average level of discomfort if we lack the self-discipline to put (and keep) our economic house in order.

The vagaries of oil-producing countries are significant only because of the supply/demand imbalance. As we've seen several times in the past, attempts by cartels to manipulate prices failed consistantly whenever even one major supplier declined to participate in artificially restricting the supply - but note that all of those scenarios played out in the context in which supply _could_ meet demand. If/when the restriction is not artificial, we'll all be in need of a fallback strategy.

Of course, if we conduct our foreign affairs in such a way that not even one supplier would break ranks, then we could find ourselves in a serious bind.

| This sounds like a heavy load to put on the back of your solar | devices. But as I originally said you have taken a small step in the | right direction. You said you were proud of your work, as well you | should be. From the photos it appears to be well made with a very | professional look about it.

Thanks - but even I recognize that it's not much of a step. I suspect that its primary value will be to impress upon a few folks that there are some viable alternative technologies. The panel /is/ well-made, but the professional look comes from a good installation job by the construction crew.

In the context of this group, I'd be really pleased know that if people weren't woodworking in the wintertime, it wasn't because their shop was too cold and/or the energy to heat it was too expensive.

-- Morris Dovey DeSoto Solar DeSoto, Iowa USA

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Reply to
Morris Dovey

| I think that pretty much reflects a practical approach. I fully support | cost-competitive alternate approaches that work. Therein lies the rub with | most alternatives thus far, either 1) they are not cost competitive (or | only will be if no maintenance is required and they last 20 years) or 2) | they don't perform as well as what they are replacing -- either they don't | provide the same quantity or require significant intervention and work on | the part of the user. | | Looks like the panels you are putting in place are definitely addressing | problem #2, and most likely pretty close to fixing problem #1.

Well, they aren't the "magic bullet" that most people seem to crave. They do a first rate job of producing heat during the daylight hours, but they won't produce heat between sundown and sunup. Still, that represents a significant portion of the heating requirement, especially for people who're comfortable sleeping in a cooler environment. I think it's possible to shrink purchased heating energy requirements by a significant amount (30-70%, depending on local climate and the particular residential structure.)

In combination with improved building technology - I've been hearing about R-60 SIP panels - it should be possible to achieve 100% of the heating requirement with solar in much of the USA.

A passive panel doesn't need much in the way of maintenance. Any exposed wood needs to be protected with paint (just as with any other wood component). There aren't any moving parts, motors, or controls to fail - so those can't present problems. I think any well-constructed panel that's kept protected against the weather should last as long as the structure in which it's installed.

Payback period depends mostly on factors which are likely to vary from site to site - latitude, weather, shading, etc., and the cost of conventional energy over the life of the panel. My take has been that anyone who eagerly spouts performance numbers either doesn't understand or is full of blarney (or both). I know I haven't done myself any favors with this, but I've refused from the beginning to attach a Btu output rating to my panels. What I've done instead has been to encourage people to install solar panels incrementally. They will probably start out with too little capability, but they'll certainly be able to recognize when they have enough - and they won't have been conned into spending for more capability than they need.

For anyone who finds that disturbing, I've created a web page with data maps from

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(National Renewable Energy Labs) for the USA showing their 30-year statistical analysis at
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- and there's a link at the bottom of the page for downloading a Win/DOS executable that makes it easy to play with their numbers (and get outputs in Btu).

I've also attempted to catagorize passive air-heating solar panels by configuration at

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- which might be a good starting point for anyone interested in designing their own panels.

-- Morris Dovey DeSoto Solar DeSoto, Iowa USA

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Reply to
Morris Dovey

... snip

Just out of curiosity, if you don't mind saying, how much would an installation such as you showed in the pictures cost?

+--------------------------------------------------------------------------------+ If you're gonna be dumb, you better be tough +--------------------------------------------------------------------------------+
Reply to
Mark & Juanita

| Just out of curiosity, if you don't mind saying, how much would an | installation such as you showed in the pictures cost?

I'd better not mind saying.

A pair of 8'x6' panels costs $3190 if picked up at the shop.

Discounts available for senior citizens, family farms, and military (current or hon disch).

-- Morris Dovey DeSoto Solar DeSoto, Iowa USA

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Reply to
Morris Dovey

Thanks

+--------------------------------------------------------------------------------+ If you're gonna be dumb, you better be tough +--------------------------------------------------------------------------------+
Reply to
Mark & Juanita

Thanks very much for sharing your experiences and info! I think it's a fantastic idea, and it's only a matter of time before non-petroleum based energy becomes a necessity. One question - if a potential customer doesn't happen to be located near Wisconsin, do you ship the panels, or sell detailed instructions, or have some other method of distributing your product more widely? I was also wondering... if you turn one of those panels upside down in the summer, will it blow cool air? Thanks again, Andy

Reply to
Andy

Andy wrote: || I've also attempted to catagorize passive air-heating solar panels || by configuration atwww.iedu.com/DeSoto/SC_Types.html- which might || be a good starting point for anyone interested in designing their || own panels. | | Thanks very much for sharing your experiences and info! I think | it's a fantastic idea, and it's only a matter of time before | non-petroleum based energy becomes a necessity. One question - if | a potential customer doesn't happen to be located near Wisconsin, | do you ship the panels, or sell detailed instructions, or have some | other method of distributing your product more widely?

Andy - check my sig. I'm in Iowa - and yes, I can put the panels on a truck for shipment (BTW, I can fit 180 of the 4'x6' panels in a 40' cargo container.)

I've also given serious thought to finding partners around the world who can produce for local markets. The most recent prospect is located in the Ukraine.

| I was also wondering... if you turn one of those panels upside down | in the summer, will it blow cool air?

Smartass. You didn't check my web site, did you? Follow the link below to see a teaser for a (maybe) solar-powered air conditioner.

-- Morris Dovey DeSoto Solar DeSoto, Iowa USA

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Reply to
Morris Dovey

Morris Dovey wrote: | Andy wrote: ||| I've also attempted to catagorize passive air-heating solar panels ||| by configuration atwww.iedu.com/DeSoto/SC_Types.html- which might ||| be a good starting point for anyone interested in designing their ||| own panels. || || Thanks very much for sharing your experiences and info! I think || it's a fantastic idea, and it's only a matter of time before || non-petroleum based energy becomes a necessity. One question - if || a potential customer doesn't happen to be located near Wisconsin, || do you ship the panels, or sell detailed instructions, or have some || other method of distributing your product more widely? | | Andy - check my sig. I'm in Iowa - and yes, I can put the panels on | a truck for shipment (BTW, I can fit 180 of the 4'x6' panels in a | 40' cargo container.) | | I've also given serious thought to finding partners around the world | who can produce for local markets. The most recent prospect is | located in the Ukraine. | || I was also wondering... if you turn one of those panels upside down || in the summer, will it blow cool air? | | Smartass. You didn't check my web site, did you? Follow the link | below to see a teaser for a (maybe) solar-powered air conditioner. |

< Morris scratches his head, then rubs his chin... >

Hmm. You did get me thinking, tho. Seems as if it should be possible to rig a solar panel used for heating in the winter so that it might also be used to run the double-Stirling air conditioner in the summer.

< ...and stumbles off into the darkness mumbling to himself >

-- Morris Dovey DeSoto Solar DeSoto, Iowa USA

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Morris Dovey

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