A revolutionary technology announced by a company based in Haifa, Israel promises both large savings in primary energy consumption while producing copious amounts of fresh water from sea water in warm and hot climatic regions.
“Energy” technology is based on a series of ways to replace the use of 50-60% of the fuels by known technologies, including improved efficiency of use, the use of the fruits of the sun, such as: wind, bio-mass and hydroelectric power, and finally a method of using solar radiation for heat which by itself could save 30% of the fuel use.
A company called “Sharav Sluices” headed by Prof. Dan Zaslavsky describes a new method to use the fruits of the sun, this time hot and dry air. This source is supplied by the natural occurring Hadley Cell Circulation and is available over two arid and warm belts north and south of the equator.
The method is to build a tall and large diameter shaft and spray water from the top. The water cools the air which flows down and comes out through openings at the bottom. On the way it turns turbines that produce electricity.
An Energy Tower can be described as a device for producing wind on demand, 24 hours a day, 365 days a year. The tower itself is a vertical tube with characteristic optimum dimensions of 1000-1200 meters in height and 400-500 meters diameter. Water is pumped to the top of the tower and sprayed into the shaft. As the water falls, it partially evaporates and thus cools the air. This cooler air is denser and falls creating the downdraught.
The efficiency to produce mechanical work is proportional to the height of the shaft and the overall rate of production is increased in proportion to the cross-section area. The efficiency of producing electricity at a height of 1200 m is above 2%. Despite this seemingly low efficiency the global potential was mapped by 15-20 times the global use of electricity today.
An Energy Tower can be described as a device for producing wind on demand, 24 hours a day, 365 days a year. The tower itself is a vertical tube with characteristic optimum dimensions of 1000-1200 meters in height and 400-500 meters diameter. Water is pumped to the top of the tower and sprayed into the shaft. As the water falls, it partially evaporates and thus cools the air. This cooler air is denser and falls creating the downdraught. Thus, the chimney becomes a controlled vertical wind making machine and uses a well-known natural phenomenon referred to as “wind shear” in the enclosed shaft.
In the cylindrical shaft the air reaches velocities close to 80 km/h, representing kinetic energy equivalent to over 2.7% of the heat used.
The wind energy is converted to mechanical energy by turbines at the tower’s base which are connected to generators. Of the electricity thus produced just less than 1% is used for pumping and just over 0.5% consumed by friction. Thus, a little over 1.2% of the energy is turned to deliverable electricity. Even at night, the development estimates, there is still sufficient heat in the atmosphere to create airflow through the tower.
The development notes that the basic principles utilized by the Energy Tower have been reviewed a number of times by independent consultants and reviewing committees and have confirmed that the physical involved and the economic benefits are feasible. Moreover, Energy Towers can be built using available technologies, and while a tower of 1200 meters in height may seem improbable, civil engineers consulted have indicated that the concept lies within known, but as yet untried, engineering capabilities. Moreover, with its cylindrical structure, the tower is a relatively simple building compared to an 800-metre office building presently under construction.
In terms of the cost per unit of electricity produced, the Energy Tower outperforms hydro-, solar-, wave- and wind turbine-sourced electricity and, significantly, also in its availability to provide an uninterrupted power supply. An outstanding advantage of the “Energy Towers” is that it has 9-10 material tangible by-products, the value of which may be way above the electricity so far. For example, one is the capacity to produce huge volumes of desalinated sea water at half the cost of the best presently known technique. Having that much water at that low cost in a desert area will enable growing bio-fuels for transportation, to replace fossil fuels, not hurting in any way the conventional agricultural products, etc. But these are only two of the nine.