The Solar Heating System has all this collector area as a large glass, fairly conventional wall. This wall is sloped back at a specific angle depending on the latitude of the house.
The Demonstration house was designed with one very large glass wall, such that a huge Great Room (40 feet by 20 feet by over 20 feet high) would be the focus of the house. This one large area is not actually necessary. With the Demonstration House, our intent was to prove a point, that a rather large house (over 3,600 square feet of living area) in one of the cloudiest, snowiest, coldest, nastiest climates (near South Bend, Indiana) could be entirely heated by solar heating. In that direction, we thought it would emphasize the point by having a Great Room that was so large that a two-bedroom ranch-style home could nearly fit inside that one room! In a more practical home, that area might be broken up into two or three rooms. The glass wall surfaces would still need to exist, but they could be set back (a la condo style construction) to break up that large exterior surface.
(The remainder of this text is normally only used related to the Computer Simulation results printouts).
Solar Energy Collection
This column shows the amount of heat collected on a particular day, in thousands of Btus. You have probably noticed that there are many days where the Solar Gain is ZERO! (Not a misprint!) If the STORAGE is entirely FULL, the Solar System's automatic overheat-avoidance systems automatically take over, to eliminate gaining too much heat (see above explanations).
Rather than overheating the storage or the house, the System just chooses not to collect the heat in the first place!
If the day is a mild day, where little or no heat is needed, the same heat avoidance systems go into effect. If no heat is needed, none is collected. If a limited amount of heat is needed, just that amount is collected!
Of course, there is one other possibility for why there might be a zero in the GAIN column. If the sky were completely overcast, no solar heat would be available for collection.
You might have noticed that the system is capable of collecting around 2 Million Btu of heat in a single day! It is extremely rare that that would ever actually be necessary. It would involve many consecutive cloudy days (that partially deplete the storage) followed by a completely clear one. It's much more common for the System to collect the necessary amount early in the day and then for it to automatically invoke its anti-overheating systems, to maintain a constant house temperature.
House Heat Loss Load
Our calculations of the heat load (in thousands of Btu) for the day, are based on the standard 'R' factor analysis for fairly standard construction materials. During the hours of daylight, our computer simulations have assumed that the outdoor temperature was constant at the HIGH temperature value from the Weather Bureau records. During the hours of darkness, we have assumed that the temperature was constant at the LOW temperature value from those records. Since Winter days have more hours of darkness than daylight, this causes the simulated heating load to be generally slightly more that was probably actually the case on those days. This implies that the solar heating systems should work even slightly better than these simulations suggest.
On mild days, where the High temperature was above 70°F, it would have been possible to let the house heat up from that, to reduce the necessary heat for the following night. The simulations do not include such a choice. We felt it more desirable to maintain a constant 70°F inside the house day-and-night and so our simulations reflect that our system intentionally chooses to NOT collect that extra heat.
Most of the house is constructed with fairly standard materials and construction. The exterior wall opposite the glass wall is an eight-inch thick wall, with fairly common double two-by-four construction, for best 'R' value. The roof and sidewalls are built to modern standards, but no exotic insulations are necessary.
The large glass wall is a separate matter. While it is collecting solar energy, it acts as an insulated window, with two layers of glass separated by an air space. The air space is much larger than the fraction of an inch of a normal insulated double-pane window. The two panes of glass are several inches apart!
During any circumstances when solar energy is not being collected (at night, when the storage is full, or when there is no Sun), an automatic system blows Styrofoam peanuts into that space. This tremendously increases the 'R' factor of the window wall, from about the 2 of a double-pane insulated window up to above 15! Whenever the Sun rises, or comes out from behind clouds, or if the storage needs extra heat, the peanuts are automatically blown back into their storage reservoir. There are actually several sub-systems involved in that whole mechanism.
By the way, this system also represents one of the three systems that defend against over-heating the house. If a logic circuit would sense that the storage was full, the house thermostat was satisfied and there was bright sun beaming down, this heat-defense mechanism would automatically fill (insulate) the window wall to reduce the heat gain.
While we're on that subject, a second over-heating defense involves a set of automatic roller shades just inside the window wall. We think that optimally, the outward facing surface of those roller shades should be black, but research will be necessary on that. The PRIMARY reason for the existence of the roller shades is for the situation when the house wall thermostat is satisfied but the storage is calling for extra heat to be collected. The roller shades would automatically roll down during that circumstance. Heat to the Great Room would be blocked (to keep from overheating it), but heat would still be collected by the system and sent directly to the storage. Since this mechanism would be present for this contingency, it is also present for additional defense against excessive heat when none is needed by the house or storage. (Hence the current uncertainty about the color of the outer surface of the roller shade!)
The Solar Heating System also includes an even more effective defense against over-heating. Between these three primary heat-defense systems, and a variety of secondary systems, the System is easily able to maintain whatever house temperature the resident chooses!
Heat Storage Provision
A very extensive and unique heat storage provision is installed beneath the (standard) concrete basement floor. In the Demonstration house, it was designed to generally hold about 7.5 million Btu of heat, FAR more than any normal solar heating system. It does NOT involve any exotic or expensive storage media, and only involves common, inexpensive materials. Again, the heat storage method is unique in solar heating approaches.
That amount of storage is enough to entirely heat the whole house for more than two weeks in zero outdoor temperatures, with no sun at all! We have even planned ahead and designed the storage to only be able to give up its heat at a rate a few times more than necessary for heating the house. Even if an exterior door is left open for an entire day during the dead of winter, the storage will not completely deplete itself.
There are no chemicals to ever become depleted and no exotic pumps or mechanisms that could some day break down. The storage, as well as the entire Solar Heating system is incredibly environmentally friendly! The design of the storage also follows the general line of the rest of the logic of the Solar Heating System in being as simple as possible. Sometimes, simplicity can be very elegant.
The way the storage is designed, the possibility of zoning the house is possible. Separate wall thermostats in various rooms of the house could maintain different temperatures in those rooms.
By the way, our design criteria included the very conservative approach of not allowing the storage to ever get above 120°F. The 7.5 million Btu of heat storage is at that temperature! All of the structures and materials of our system and storage could withstand MUCH higher temperatures, and so the ACTUAL storage capacity could be MUCH higher! We limited it to a 120°F temperature for a variety of reasons. Again, our primary intent and goal was a CONSTANT, COMFORTABLE and RELIABLE heat, and we have attempted to consider all things that might affect that. If some truly unforeseen change in our climate should occur, where the house's heating needs become 20% higher (like if the entire Earth should drop in temperature by 20°F!), it would be simple, quick and easy to change the storage temperature to be allowed to go up to 130°F. Just that small change would increase the heat storage by around 20%! Planning ahead!
Backup Heat Necessary
With the Solar Heating System, this subject is rather meaningless. The System is intended and designed to entirely and always, reliably heat the whole house, with immense extra collection and storage capabilities for unexpected contingencies. We are convinced that a backup heating system is not necessary. As you can see from the simulations, the Demonstration house we designed for South Bend, Indiana, NEVER ONCE needed backup heat during the 40 years of simulations.
Better than that, the STORAGE was rarely below half-filled during those 40 entire winters! It still could have gone many more sunless days in January or February! And this is for a huge house with around 3,600 square feet of living space! And this is in a climate that is one of the four cloudiest in the United States, and which has truly nasty cold winters with enormous snows. (By the way, snow on the ground actually IMPROVES the performance of our system by as much as 6%. The white snow reflects some extra solar energy to our collector areas!)
As a result of REALLY thorough engineering and countless computer simulations, we are TOTALLY certain that a (Version I) Solar Heated house, ANYWHERE in the USA, would not even need a conventional furnace!
In a sense, this represents a wry irony! Our sister company, JUCA Super-Fireplaces, manufactures wood-burning fireplaces and stoves that similarly heat entire houses. For over 28 years, tens of thousands of homes have been entirely heated with JUCA woodburners. Obviously, if the Solar Heating System ever needed a "backup", a JUCA would have been the perfect choice! (Hundreds of people who spent small fortunes on [competitive] solar heating systems wound up buying a JUCA, and then bragging to their friends that they were "independent". We think they seldom mentioned that their solar contribution was minimal and the JUCA virtually was alone in heating their house! And yet, with the Solar Heating System, a JUCA is unnecessary!
Even more, consider when you go south on a winter vacation. You know how you turn the heat down, to minimize your heating bills? And then you come home to a cold house? Think about the system. Why not just leave it as normal? No heating oil or gas would be consumed. I guess that's not that important a difference, and no one really complains about coming home to a cold house, but it actually would not be necessary with the Version 1 System!
Solar Heating Simulations - NorthWarm Solar Version 1
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