ANNAPOLIS, MD--(Marketwired - Mar 22, 2017) - Solar Wind Energy Tower, Inc. (OTC PINK: SWET) (the "Company"), the innovator and creator behind the Solar Wind Downdraft Tower structures capable of producing abundant, inexpensive electricity to meet the world's increasing demand, announced today that it has released a report explaining "How the Evaporatively Driven Downdraft Power Production System Works."
Ron Pickett, CEO of Solar Wind Energy Tower, Inc. commented: "While fulfilling a request during a due diligence process, the Company commissioned this report. Management felt our shareholders and interested parties would appreciate the opportunity to review and perhaps gain a better understanding of how our solution works from a technical viewpoint, so we decided to release the report today to the general public."
How the Evaporatively Driven Downdraft Power Production System Works
The earth's atmosphere harbors an abundance of energy in many forms. Much of the energy is in the wind. Although the prevalence of wind farms has exploded in the last two decades, humans have been extracting energy from the wind for over 1000 years. Vast quantities of clean, renewable, and nearly endless energy also can be extracted from the atmosphere owing to the ability of water to transform from liquid to vapor and back again. The energy associated with phase changes of water in the atmosphere drive many major weather systems on earth, including large rain and snow storms, hurricanes, and thunderstorms.
One of the atmosphere's more dynamic systems is the severe downdraft (sometimes called a microburst or downburst) of a thunderstorm, in which rapidly sinking air (kinetic energy) is produced by the evaporation of the rain produced by the storm. The evaporating rain cools the air in precisely the same way that your skin is cooled by the evaporation of sweat (or how you cool-off after exiting a swimming pool); evaporation extracts energy from the air via the latent heat of vaporization. For every gram of liquid water evaporated within a sample of air having a mass of one kilogram (a kilogram of air has a volume of roughly a cubic meter in the lower atmosphere), the sample of air is cooled by approximately 2.5°C. Within a thunderstorm's rain shaft, air commonly is cooled to temperatures ranging from 5-20°C colder than the ambient temperature. The amount of cooling depends on the amount of available rain and the relative humidity (the cooling increases as the rainfall rate increases and relative humidity decreases). In storms with hail, the melting of hail produces additional cooling via the latent heat of fusion. The cool air is denser than its surroundings, and the dense air sinks to the ground owing to this negative buoyancy. Moreover, because liquid water is roughly 1000 times denser than the air in the lower atmosphere, the "substitution" of rain for air within the rain shaft effectively contributes an additional source of negative buoyancy.
The downdraft air accelerates downward as long as it remains heavier than the ambient air; thus, large downward speeds can be realized if the air remains cold (negatively buoyant) relative to its surroundings over a long downward trajectory length. In a severe thunderstorm downburst, cold air can experience a downward acceleration over a depth of several kilometers, easily attaining downward speeds of 50 mph or more. When this downward jet of air hits the surface, the air necessarily turns toward the horizontal and flows along the surface. The deflection can result in even faster horizontal wind speeds -- occasionally over 100 mph -- which can result in extensive damage, even exceeding the damage produced by a weak tornado.
The "Evaporatively Driven Downdraft Power Production System" works in precisely the same way as the thunderstorm downdraft. A continuous spray of small water droplets is introduced at the top of the tower. The cooling due to the evaporation of the water droplets, combined with the weight of whatever liquid water droplets remain unevaporated and fall through the tower, causes the air to become much heavier than the air that was previously in its place in the tower. The heavier, denser air sinks through the depth of the tower, is forced to turn horizontally at the base of the tower, and ultimately passes through the turbines as it exits the tower (though at speeds far less violent than in the most severe downbursts observed in nature!).
As air flows out of the base of the tower through the tunnels, air is continuously drawn into the top of the tower owing to the principle of mass conservation, and the spraying of liquid water droplets into the air entering the top of the tower maintains the evaporative cooling. Just as is the case for a thunderstorm downdraft, the cooling potential -- and therefore downdraft potential -- is dictated by the amount of water evaporated, which depends on the ambient relative humidity and available water.
There is a limit to how much evaporational cooling can occur, and ultimately how much power can be generated, because the air cannot be cooled indefinitely by injecting more and more water droplets. As water evaporates and the air cools, the relative humidity within the tower increases. Evaporational cooling ceases once the relative humidity reaches 100%. The temperature reached at this so-called "saturation point" -- that is, the minimum temperature achievable through evaporational cooling, and the temperature that determines the magnitude of the negative buoyancy, downdraft speed, and ultimately the power output -- is known as the wet-bulb temperature. Very roughly, this temperature lies midway between the ambient air temperature and ambient dewpoint (the dewpoint is temperature at which air would become saturated if cooled while maintaining a constant water vapor concentration, that is, not spraying water droplets into the air). As an example, if the ambient temperature is 40°C and the ambient dewpoint is 0°C (typical desert conditions in summer), the wet-bulb temperature is 17°C. The corresponding ambient relative humidity is 8%. If this air is brought into the tower and cooled to saturation (i.e., cooled until the relative humidity reaches 100%) by evaporating water droplets into it, the resulting temperature will be 17°C, which is a whopping 23°C cooler than the ambient air temperature (a temperature "perturbation" of -23°C). An air sample this negatively buoyant would experience a downward acceleration equal to the gravitational acceleration (9.8 m s-2) times [-23 / (273.15 + 40)], that is, -0.72 m s-2, where the factor multiplied by the gravitational acceleration is the temperature perturbation normalized by the ambient temperature, in Kelvins. To give a sense of how significant this downward acceleration is, if there was no horizontal deflection of the sinking air near the ground, this downward acceleration would result in a downdraft speed of 61 mph after the air descended just 500 m.
Assuming that sufficient water is available to be sprayed into the air in order to saturate the air, the amount of cooling, downdraft speeds, outflow speeds at the tower base, and power output increase with decreasing relative humidity. For this reason, a desert region is the most suitable site for a downdraft tower. Moreover, power output would be maximized in the late afternoon (when ambient relative humidity tends to be a minimum) and minimized near dawn (when ambient relative humidity tends to be a maximum).
About Solar Wind Energy Tower, Inc.
Founded in 2010, Solar Wind Energy Tower, Inc., and its wholly owned commercializing subsidiary, Solar Wind Energy, Inc., is the inventor of the patented Solar Wind Downdraft Tower, which uses state of the art technologies and construction systems to produce abundant, inexpensive electricity, 24 hours a day, 7 days a week.
The Company's core objective and focus is to become a leading enabler of clean, efficient renewable energy to world communities, at a reasonable cost, without the destructive residuals of fossil fuels, while continuing to generate innovative technological solutions to meet tomorrow's electrical power needs.
For more information, please visit:
http://www.solarwindenergytower.com, and https://www.facebook.com/solarwindenergytower and https://twitter.com/SWETower and http://www.arizonagreenpower.com
Cautionary Note Regarding Forward-Looking Statements
Statements included in this release may constitute "forward-looking statements". Actual results may differ materially from those projected in forward-looking statements. Such statements involve a number of risks and uncertainties such as competitive factors, technological development, market demand and the Company's ability to obtain new contracts and accurately estimate revenues, if any, due to variability in size, scope and duration of projects, and internal issues in the sponsoring client. Further information on potential factors that could affect the Company's financial results, can be found in the Company's various filings with the Securities and Exchange Commission (SEC).