This design, properly engineered for a specific application, should be able to partially heat a home and/or supply domestic hot water and/or a steam powered electricity generator, in virtually any climate in the US! Common building materials and construction techniques are generally used in the construction of the various components. This can keep the cost of the system relatively reasonable. Considering the savings that can accrue from having very reduced heating bills FOREVER, even that cost would soon pay for itself! That effectively makes any of this Solar Heating Systems FREE! There would also be the benefit of never being dependent on foreign oil or other uncertain or expensive heating sources in the future.
Solar heating had a brief boom time in the 1980s. Government tax incentives and rebates created a huge demand for solar devices, and a large number of companies popped up to sell things. Unfortunately, many of those companies didn't really know what they were doing! Manufacturers made a lot of different kinds of products, and some even did some research to advance their craft. Installers appeared everywhere, and suddenly EVERYONE was an expert!
It was astounding to witness the insanity of the time. We also operate a company that makes very high efficiency fireplaces and woodstoves (JUCA). A customer buying one of our woodstoves (in about 1980) was bragging about the solar heating system that he had just had installed, for which he had paid $7,000. When I inquired about details, it turned out that he had received three 4 x 8 solar panels mounted on his garage's roof, that was meant to heat his domestic hot water. During succeeding months, he became disillusioned with the performance of it (and therefore loved the performance of our woodstove he bought even more!) Since he realized we were knowledgeable in the subject, he would occasionally call for possible suggestions from us. (He had given up on the installer and the manufacturer of the solar collectors.) After a number of such conversations, we eventually realized that the garage was not on the south side of his house and that the collectors were facing a little north of west! It's astounding that someone would install them pointing such a weird and useless direction, and then to charge him so much for it, too!
Many of the manufacturers were equally unprepared to sell large numbers of products. Most manufactured liquid (water) based systems, and seemed completely oblivious to the concept of electrolysis. This basic chemistry concept relates to ion transport between dissimilar metals in such a system. Aluminum and copper are particularly susceptible to corrosion due to electrolysis. Many of those companies (including nationally known companies) offered Five- or Seven- or Ten-year warranties on their products, only to find failure in half of their products within a year due to electrolysis!
Narrowing the field down to intelligently designed and intelligently installed solar systems, the better quality solar space-heating products that are still available on the market have always been (and are still) cost-ineffective. That is, they would not pay for themselves in fuel savings during their expected lifetimes.
The government also financed a few totally solar-heated, moderate-sized houses in the 1980s. In one, a $30,000 house had a solar heating system installed that cost about $700,000. It worked very well! But, it could never pay for itself.
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With this setup, the conventional heating fuel savings would be about $150-$200 per year (about $30 per month). Sounds impressive, huh? The system would actually have to operate perfectly for about 160 years to re-coup the initial cost, not counting repairs, maintenance and lost interest on money that could have been left in the bank! This argument is basically why solar heating has remained impractical for space heating of houses --- it requires a lot of Nature's cooperation, and even then is not cost effective.
Some attempts at partially supplying solar space heating have been made. In general, these same arguments apply. Installing a few collectors to reduce house space heating might seem like a good idea, but we are not aware of any existing system that could even pay for its own cost, much less accomplish actual heating bill savings.
UNTIL NOW!!!
Staying for a moment more with existing systems, A common "solar home" has three or four of those 4 x 8 collector panels. Better-planned installations have some heat storage provision, which might involve 20 tons of rock storage. Let's examine this. If the three collectors were perfectly efficient, they could collect, on a perfectly sunny day in January, at noon, about 300 x 4 x 8 x 3 or 28,800 Btu/hr. If the outdoor temperature was about 15 degrees F, then this COULD be enough to (momentarily) supply the entire (very well-insulated) house's heat needs. But that's ONLY just at noon, and there is no room for clouds, or temperatures below 15, or even the system inefficiencies that always exist. If any of those circumstances apply, then it cannot entirely do the heating job (even at noon!), and backup heat is therefore necessary. The 20 tons of rock storage could hold up to 200,000 Btu of heat, but even that would only assist the solar heating system for less than a day of cloudy weather. (Remember that 960,000 Btu/day house loss (for a more normally insulated house) mentioned above?) The result is that you would regularly need to use conventional fossil fuel heating to do the bulk of the heating. The approximately $10,000 that people spend to have such a system installed, will never pay for itself. BUMMER!
Due to these considerations, we feel that trough collectors are advantageous over full paraboloid collectors. The mirror surface is less complex, only curving in one dimension rather than two, making it less complex to build and therefore less expensive. Also, the drive system really only needs to follow along a single (tilted) axis, making for less complicated and expensive drive systems and less involved pointing logic.
Like that system, we plan for just one "receiver", mounted on a utility pole. To the north of that pole are an array of large, movable, curved mirror assemblies. Each of those separate mirror assemblies has a major shaft that is parallel with the Earth's rotational axis, so the shaft points to the North Star.
The full design of each mirror assembly has a number of additional features, but the overall concept is that of a four-foot by eight-foot panel, resembling a sheet of very thick plywood, attached to that shaft. Attached just in front of this panel, are two separate four-foot by four-foot standard single-strength mirrors. These are NOT plate glass mirrors, but thinner, with 1/8 inch thick glass.
It turns out that, by applying a "squeezing" pressure to the vertical edges of such a mirror, it will bend. If that pressure is not too great, the mirror bends without breaking! We have had many years experience with this, and have found that such 1/8 inch thick mirrors can be bent to amazing curvature in such a way! Our application, however, only requires the very slightest of curvature, and there is absolutely no danger of breaking the mirror.
It also turns out that the shape of the curve that the mirror takes is astoundingly close to being the desired parabolic shape!
Instead of dealing with a very complex, $2,000 parabolic trough collector, we are taking commonly available building materials and a $40 mirror, and creating just as good a system! Instead of each assembly costing several thousand dollars, you can see that these cost around $100. This great economy allows building MANY of the concentrating mirror assemblies, to collect massive amounts of solar heat in the pole-mounted receiver!
The reference earlier to two separate 4x4 mirrors was to reduce the difficulty of handling 4x8 thin mirrors, to lessen the future cost if you ever have a neighbor's kid break one, and so the two half-mirrors could be slightly tilted so the two of them could both better hit a small receiver tank on the utility pole.
You should be able to see that our approach is to use the general idea (proven over many years) of movable parabolic collectors, but to do it in a way that is far less expensive, and probably even DIY-able.
Now, each of these many separate mirror assemblies still has to move to reflect the sunlight up onto the receiver on the utility pole. It would be possible to use the traditional motor and gear train method, with a computer directing each of them (they all have to point in different directions so all the light hits the receiver). But that is still a very expensive approach, even though you now have economical mirror assemblies.
The one unique contribution of us to this system (other than squeezing the mirrors to become somewhat parabolic!) is the economical drive system that directs each mirror assembly. We do NOT manufacture such devices, but could provide you with the instructions to easily assemble them out of commonly available materials. If you choose to use our Version 3, you would just be paying us for (1) a number of details on these matters already mentioned, about the assembly of the mirror assemblies and the receiver assembly; (2) additional guidance on how to get and use the energy collected in that receiver; (3) and the information on making the tracking drive systems. For this, we currently charge $250.
Where other companies' solar products aim at collecting and supplying minimal amounts of energy, with VERY expensive products, our approach (with ALL of the Versions) is to collect and supply MASSIVE amounts of solar energy! If a specific application requires gathering a LOT of energy, then all that is needed is to build more separate concentrating reflector assemblies. Lesser energy needs would likely indicate fewer of the reflector assemblies were needed. There is a LOT of flexibility present, since you could always build a few more mirror assemblies at some later time.
If the application requires storage of that collected heat, a large hot water storage tank, such as those used with other water-based solar systems, might be required. Since our approach is always on a larger energy scale than competing solar systems consider, a pretty large capacity storage tank might be called for.
A substantial portion of the cost of a Version 3 System could be in actually using the energy collected. If energy storage is desired or necessary, that tank can be pretty expensive, as much as nearly everything else, if the person builds most of the assemblies. If generated steam is to be used in a turbine to generate electricity, that turbine and alternator may also cost as much as all the parts WE normally consider the solar Version 3 System, the array of movable concentrating collectors and the receiver. So, there is no obvious way that we can better guide you on total costs, but you should be able to do that on your own, knowing what your desires are.
As to limitations on the Version 3 System, there are relatively few. If you feel the need to generate 10,000 watts of electricity, well, that would not be a problem. Say you build 20 mirror assemblies, each of which is the 4x8 size. That's 640 square feet of sunlight that you would be intercepting. Each square foot (on a sunny day) is over 300 Btu/hr, so that would be a total of 192,000 Btu/hr. If ALL of that could be converted to electricity, that would be over 35,000 watts! A variety of unavoidable inefficiencies exist in the various parts of this system, and there are heat losses, too, but getting 10,000 watts of electricity would be easy!
By the way, NO competing solar supplier would even DREAM of supplying that much electricity from solar! Today, commonly, photovoltaics are used for generating electicity, and enough photovoltaics for even 1,000 watts generally costs around $7,000. So, 10,000 watts from photovoltaics would involve at least $70,000 in purchases! Our system would involve those 20 mirror assemblies (home-built for around $150 each) and the utility pole and receiver ($500) and a turbine and alternator ($???). Instead of $70,000, this probably amounts to around $5,000, only about 1/14 as much! Solar generated electricity can start to make sense!
We have sort of blue-collar attitudes toward such subjects. Super-rich people do not NEED to save on their heating bills! BUT, they are the ones who can afford to pay for those competitive extremely expensive systems that might not actually work like their promoters say they will. We're not like that. Our goal is to (1) save people money on their heating bills and (2) be kinder to the environment than society has been in the past.
The version we have been describing here is one of the group of three. It is the only of the four that uses water-antifreeze as the collecting medium. It's use and operation could be made automatic, with even and comfortable home heating or hot water supply, or substantial electricity generation. It is a system that can often be added to an existing house or building (with a big yard for the mirror assemblies).
This system is a sort of home-sized version of the large scale Solar Power Tower electric generation systems in the US Southwestern desert. Many independent moveable curved mirror assemblies are mounted on separate pedestals in a field. They each continuously move to reflect the sunlight to a steam boiler mounted on a separate tower / pedestal.
Version 3 REQUIRES a good amount of yard area to be committed exclusively for the various parts of this system. Most other parameters of this system have a lot of flexibility.
As mentioned above, we could supply plans and drawings for building the various component sub-assemblies, along with an assortment of useful information and suggestions, for $250.
Depending on MANY variables (installation options, climate, etc), the annual savings on heating (or electric) bills may be $1K. This means that this Solar heating system should completely pay for itself in just a few years. After that, further savings are just gravy! All this suggests that there are a couple additional values involved. First, the security of KNOWING that the house will be partially or fully heated regardless of political events in the Mid-East or decisions of executives or politicians that might affect fuel supplies or prices. Second, given these things, the property's VALUE would probably be increased more than the cost of the system, because MANY homebuyers would want such security.
This version is designed to be a liquid-based system. The design is generally NOT based on exotic glass or exotic materials or insulations in collector assemblies, so there is no major mumbo-jumbo arguments about using high-emissivity glass or other advanced subjects. Just generic mirrors are used, for example, and not special ones. With very large total solar collection area, we feel the logic of the system is obvious. If it isn't, please e-mail us, and we can discuss whatever subjects you would like. We have a Physicist available to field your questions, so, hopefully, we can respond to any technical subject you might bring up!
Please contact us so that we may discuss the possibilities for your needs.
E-mail to: cj@mb-soft.com
Performance and storage will be extremely great. The VERY large collector area and storage space make it certain that NO back-up heat will EVER be necessary for heating the house.
Performance and storage will be great, but the necessarily smaller collector area and storage space make it possible that back-up heat will sometimes be necessary for heating the house.
It has very good performance but has intrinsically less performance ability than any of them. It is a low-tech approach to solar heating.
We have no intention in trying to "cut in" to the market for such products! Each of the four Versions (especially Version 1) is intended and designed and engineered for SERIOUS solar space heating; situations where no competitive technology exists that can do the job!
SO, for the multitude of people who read about the Versions, and then ask us to supply them with something that might go on their roof, they're barking up the wrong tree! The only Version that could possibly be applied to an existing roof is Version 4, by far the least sophisticated and efficient of the four! And, even then, the Version 4 system involves far more than just nailing some panels to a roof. So, please realize that these Versions are NOT competitors to those available roof panel systems. We actually have no competition at all, because no one seems to know how to ENTIRELY and COMFORTABLY heat a home exclusively with solar energy. Except us!
Solar Heating