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Here Comes The Sun

INVENTION U.S.Patent 5308187.

It is a method of preheating air to a natural gas burner, like a hot water heater. But more importantly it can preheat air to a coal burning power plant, or any typical fossil fuel burner, such as a propane, or oil stove. Preheating of air is actually a very common practice in industry. For example, often air is preheated by molten metal from a blast furnace. The preheated air is then blown into the firebox and mixed with fuel. The net result is less fuel is burned. It is kind of like preheating air to a wood stove. The net result is not as much firewood is burned, thus you don't have to chop as much wood. The only difference is that solar energy is utilized by this patented process to preheat air, thus replacing the need to burn as much fuel.

It is huge. It is a little known fact, but the amount of energy falling from the sun unto parking lot paving alone will power the entire United States. Parking lot surfaces do get hot, especially in places like Phoenix. This energy can be usefully used to reduce natural gas consumption for perhaps hot water heaters or absorption cycle air conditioning. OIL AND GAS JOURNAL estimates state that within the next two decades close to 30 TRILLION DOLLARS (U.S.) will be spent world wide on energy development. The vast majority of it will be spent on development of energy from combustion of fuels such as oil or gas or coal, and a little wood. This patented invention is a hybrid system, a combination of both fossil fuel and solar produced air. Thus, is less expensive than entirely solar operation, or coal-only, or oil/gas only operation. Many places in the world such as North Africa, Mexico, Australia, and the American West have extensive solar energy. Even in the Pacific Northwest, there are sunny periods. In fact, Wind Energy and HydroPower as from rainfall, can be integrated with Solar Combustion Air. Thus, when the sun is cloudy, wind and hydropower can also manufacture hot air. It is a little known fact, but often the amount of sunlight falling upon a coal strip mine will power the entire coal burning power plant. Thus the idea is to construct these "solar parking lot pavements" on top of coal strip mines using recycled materials and local labor. This would be done as part of the land reclamation process. In short, it is estimated that the total cash flow over the lifetime of the patent would be over 10 trillion dollars worldwide, with adequate investment and R&D. Unlike other technologies like cold fusion, almost anyone with basic physics and economics can understand how it works.

Simple to understand. Solar collectors concentrate sunlight to a tiny spot which is very hot (often above 750 degrees F, but can be several thousand). The concentrated sunlight then manufactures hot air, which is (important) then compressed by photovoltaics or any type of blower or fan. The now compressed and heated hot air is then blown beneath a special pavement, not unlike a typical parking lot. Underneath the parking lot is a network of pipes (made of recycled materials). These pipes then transport the hot and compressed air to the firebox of a residential hot water heater, or better yet to the firebox of a coal burning power plant. The air is very hot in the range of 300 to several thousand degrees depending on application. The air is also compressed, and can be up to that of a typical water pipe (typically up to 50 PSI or three atmospheres). The air also travels very fast, up to the speed of sound (50 to 500 miles per hour). It is important to note that the friction of the air on the pipe also translates to heat. Because the pipes are below ground and insulated they trap the heat. Thus the pipes can preheat air at night or even in the middle of winter. Thus Solar Combustion Air can be used by the power plant 24 hours out of the day, year round. In effect, heat is stored underground like a battery, and then used when it is cold or at night. There are two designs. One design is for urban parking lots, where cars park around solar collectors. The second design is for rural application like coal stripmines in New Mexico or Arizona, which do not have cars parking on them. Because air is utilized instead of more expensive heat transfer fluids, the cost of heat transfer is minimal. If for example, a leak was to result from a heat transfer piping system, it would result in a loss of million of dollars of heat transfer oil. Furthermore, hot air requires less expensive piping than for heat transfer fluids. Steam piping would be prohibitively expensive, but if hot air should leak....who cares!

This is the only invention that cuts emissions of pollution and Carbon Dioxide (Greenhouse Gases) in half. For a coal burning power plant this means that air pollution equipment does not have to be so big, or work so hard. Furthermore, it means that fuel bills are cut in half. This is easier on the environment in that not as much coal strip mining is necessary, or as much drilling for oil/gas required. It also means that the power plant can operate longer since there is less maintenance. Solar Combustion Air is very clean and less corrosive. To power a large power plant, like the size of Four Corners in Fruitland, New Mexico, it will require about 24 square miles of land area, and an extensive network of pipes. However, it recycled materials are used, combined with modern manufacturing engineering techniques, it is predicted that solar combustion air should be directly competitive with oil or gas or coal, on a cost per BTU basis. To date the best study on Solar Repowering of Power Plants has been done by Charles Bensinger of Santa Fe New Mexico. His study, which did not include Solar Combustion Air, reviewed related solar repowering technologies. His conclusion, is that hybrid solar-coal, solar-oil, solar-gas operation is 15 to 33% more expensive than oil-only, gas-only or coal-only operation. However, the technologies reviewed are more expensive than Solar Combustion Air. The conclusion drawn here is that with cost reduction of solar technology, it would be a marketable alternative. Eventually fossil fuels can be replaced with solar produced hydrogen, creating a solar-hydrogen conversion. The plan is to gradually build up the system. For example, the first year only a few square miles (for a large power plant) would be built, thus only handling 10% of the heat load. The next year, 20% of the heat load would be handled by solar, and so on. Thus, the system is phased in. Of note, is as the system is added, the new additions become immediately revenue producing. Thus, lending to easier financing.

Integration of solar technology really is in the interest of utilities. For example, by installing Solar Combustion Air on residential homes, it will help conserve natural gas. While conventional wisdom would say the gas utilities are opposed to solar, in reality solar integration helps "load level management". In effect, in the winter when natural gas pressure is low, it helps to replace some natural gas with solar. Thus, the line pressure remains high. The problem is not so much a "geologic" shortage of natural gas, as it is more of a lack of "pipe diameter" of pipe. You can only pipe so much gas through a pipeline at once. By integrating solar collectors, and other conserving technology, it helps natural gas utilities to maintain line pressure in even the coldest of winters. It also allows new land developments to build a gas utility for lower cost, since not as large of pipe diameter is required.

Additional information about solar energy can be obtained by reviewing the web pages of:


Power Plant

The above power plant is located in Centralia Washington. One of the rainest placest in the United States. A preliminary review for installing Solar Combustion Air was done by staff at Seattle City Light and at the power plant. Seattle City Light is a 8% owner. The conclusion: solar only operation would be difficult but if wind energy and hydropower was also integrated to make Solar Combustion Air it may be economically feasible.


The above computer 3-D simulation illustrates a possible view of what a converted Solar Combustion Air power plant would look like. Shown here are "dish type" solar collectors. However, other type of hot air solar collectors are available, such as Trough Type, which are square and long, and concentrating flatplates. Hot air is manufactured by the solar collectors and then compressed and blown underground. The underground pipe network feeds the power plant. Waste heat from the power plant can be used to power for example a "freon-turbine" which in turn drives a big fan, literally sucking the hot air from the solar collector field. Electric power from the power plant can also be used to help blow the air.

Patent Drawing

Illustrated above is the drawings used by U.S.Patent 5308187. Patented by Inventor Martin Nix of Seattle Wa.

Solar Cooker

Shown above is a special solar collector being engineering specifically for solar combustion air. The key is to simplify and design to economics. Many solar collectors are expensive, requiring large and expensive tracking systems. This particular design is a simple system, designed to be easily and quickly mass produced. A field of these can power a home or a large power plant.

Write to: Martin Nix PO Box 95173 Seattle WA 98145-2173 or email to SOLARSH@ESKIMO.COM