Atmospheric Solar Energy

Present global energy consumption - currently driven by fossil fuels, is dwarfed by available solar energy. Traditional solar collectors tap an infinitesimal portion of the 89,000 terrawatts reaching the Earth's surface while the sun is in the sky. Windmills use a minuscule fraction of the total atmospheric air motion that is itself only about 3% of the 12,000 terrawatts in atmospheric convective energy.

Solar energy absorbed by the atmosphere is present as heat (air temperature) and represents approximately 19% (33,000 terrawatts) of the total energy from the sun. The quantity of solar energy absorbed by the atmosphere adds to that reaching the Earth's surface, together amounting to 122,000 terrawatts.

A reservoir of atmospheric solar energy exists after the sun has set because solar heat remains stored in the air and is replenished each day by the sun. Wind energy is also available after dark. But atmospheric energy, unlike wind, is available everywhere 24 hours a day, 7 days a week, 365 days a year. Whereas traditional solar energy collection is eliminated at sunset or reduced by clouds, atmospheric heat is essentially present all the time.

Various components of the sun's energy are continuously interacting with one another, transferring energy back and forth. Depending on conditions, wind may arise from the action of storms. The storms themselves form in response to heating of the atmosphere and latent heat from evaporated water, all driven by the sun. These interactions may alter the energy balance locally, but the energy is more or less continuously available anywhere on earth.

ENGINE NO. 4832, H.K. Porter Company Pittsburgh, PA USA

Modern engine designers treat the atmosphere exclusively as a place to dump waste heat. But engines using heat from the surrounding atmosphere were manufactured and operated over a hundred years ago.

In 1890, the H. K. Porter Company built air locomotives which were quickly adopted by the mining industry. By 1900 Porter had 90% of the market for these machines. Over 400 compressed air locomotives were built before the company went bankrupt in 1939 after a long decline during the depression.

Few realize the extent to which atmospheric energy increased the output of Porter's locomotives. As much as 60% of the power produced by these engines came from atmospheric heat. And the machines were incredibly powerful. Many developed as much motive power as steam engines and hauled large tonnages of mined ore along steep inclines for long periods between recharging.

One such engine is shown in the image above. An atmospheric heat absorber (reheater) is visible running the length of the air tank near the top. Air is drawn in the front of the absorber and pulled through the heat exchanger by an exhaust air ejector at the back. Air powering the pistons is heated part way through the expansion by this absorber and atmospheric energy is converted to mechanical power before the air is exhausted through the ejector.

Modern versions of this old technology have increased the amount of energy extracted from ambient air and replaced compressed air with liquid nitrogen. Compressed air locomotives are long gone but experimental automobiles equipped with this technology have taken their place. All these machines extract solar energy from atmospheric air and the engineering requirements for doing so are now well known.

These examples show that the technology for processing atmospheric heat has been around for a long time. But the key to unlocking this source of power is a viable means of releasing solar energy from the atmosphere directly rather than simply restoring heat previously removed by compressors and gas liquifiers.

Repeating mistakes of the past, many critics incorrectly cite the Carnot theorem for closed cycles as "proof" that atmospheric heat energy from the sun can't be converted into useful work. Though frequently made, such assertions are not valid because they proceed from the wrong initial assumptions and fail to account for ubiquitous evidence to the contrary.

Natural heat engines would not exist if energy could not be released from ambient heat. The ability of these systems to convert such heat into mechanical energy and electricity has been amply demonstrated over and over again, at times spectacularly. Close attention to the mechanisms responsible for this phenomenon shows quite clearly what is required to duplicate the process by artificial means.

Specifications presently exist for manufacturable devices that overcome the twin problems of low temperature levels and heat rejection. Beyond that, applications have been identified where such technology makes commercial sense.

Aerosolar technology is not any sort of "silver bullet" but merely another one of the many options available for solving a variety of energy production problems with a range of solutions geared to specific situations.

The illustration above shows the condenser side of a split-system air conditioner application of the aerosolar concept. The unit looks very much like a conventional air conditioning unit except for certain additional components. The evaporator is not shown but is similar to those in conventional machines, except for the extra parts.

The capacity of these units falls into the same ranges as conventional vapor compression air conditioning units and is similarly scalable. Electric power consumption is about one-fifth that of a conventional unit, however. Over 80% of the power for operation comes from atmospheric solar energy.

Computations and preliminary experiments show that such performance is achievable in a well designed system. Theoretical models of the aerosolar process use NIST Standard Reference Databases for working fluids. Analytical methods are typical of those required for evaluating machines using polytropic cycle processes.

This is only one of the many applications for the concept. Efforts are underway to locate additional capital for a scalable manufacturing prototype. Additional adaptations of the aerosolar process can be used for generating electricity as well, although different machinery is required.