Nexus - 0402 - New Times Magazine-pages

Page Content (OCR)

— ATMOSPHERIC ENERGY — HARNESSING THE "POWERS' OF THE ATMOSPHERE der. The pressure of the atmosphere acting on the top half of the piston forced it down. By continually repeating this process, a powerful machine was put to work pump- ing water. In 1827, Robert Stirling took out his patent for a hot air engine which used the heat of the air. From the very start, the hot air engine offered an irresistible fascination for the inventor because even the crudest attempts with it always resulted in an effi- ciency far superior to that of the steam engine. This is readily explained as being due to the far greater temperature range possible working with air than is possible with steam. This is because the efficiency of an engine depends upon the limits of temperature to which the working fluid is subjected. It is practical to use a higher working temperature with air than with steam because there is no fixed relation between the pressure and temperature of air, such as exists in the case of steam. slow rate may accomplish a great deal of work, if it only keeps at it long enough, while a very high rate may be represented by a very small quantity of work, provided it be expended in a sufficiently short space of time. Thus, a windmill of only a few horsepower, compressing air by working steadily day and night for weeks and months, may compress millions of cubic feet of air and thereby perform a vast amount of work. The air which is compressed by the windmill is stored in suitably large pressure vessels or compressed air tanks. To give an idea of size, an LP gas tank similar to the ones used in service stations is ideal. These can be pumped up to a pressure of 200 to 300 psi. This represents a consider- able amount of energy stored in a pressure vessel in the form of compressed air. A convenient way to use this compressed air is to use the pressure of the air to move a piston in a cylinder, preferably in alter- nate directions. This reciprocating force moves a conductor through a magnetic field, thus generating electricity. If, for example, a piston had five square inches of surface area and a pressure of 100 psi were applied to it, we would obviously have a piston in a cylinder with 500 pounds of push. In such a case, the load from the conductor going through the magnetic field ideally should be about 400 pounds resis- tance. When the conditions are similar to this, the air has no choice but to give up the heat ince early times mankind has had a constant and reliable source of power in the form of the wind. Man was quick to find ingenious but simple applica- tions for this force of nature. Obvious examples are the sail and the windmill. What is not so obvious are the underlying principles, as defined in physics books; to be more specific, the principles of thermo- dynamics. Thermodynamics is connected with heat; that is to say, measurement of heat, and laws relating to the conversion of heat into mechanical work. Nature gives a wonder- ful example in the movement of the wind. The atmosphere basically moves because over the land, for example, the temperature can be higher than over the ocean, with the result that the hot air rises over the land and the cooler air flows in to take its place. In thermodynamics, the terms T: and T2 are frequently quoted. T: usually refers to a specific temperature and T> refers to a temperature which is less than Tu. Otherwise expressed, the bigger the tem- perature difference, the more energy there is available. Applying this to the move- ment of the wind, if the atmospheric tem- perature of the Earth were the same every- where, presumably there would be no winds. One of the earliest attempts to harness the power of the atmosphere, apart from using the windmill and the sail, was attempted successfully by Newcomen, a Dartmouth blacksmith, and patented in 1705. The device consisted of a vertical cylinder and a piston which was connected to a horizontal beam. The other end of the eam was connected to the piston of a ump. The weight of this side of the beam was sufficient to draw the piston to the top of the cylinder. Steam was admitted from a oiler through a valve to the cylinder. When the supply of steam was turned off and some water injected into the cylinder, the result was that the steam condensed, ‘orming a partial vacuum inside the cylin- PUTTING COMPRESSED AIR TO WORK Having reviewed at some length the vari- ous forms of machinery available, I decid- ed as a starting point that the windmill took a lot of beating as far as reliability and power were concerned. For example, it is quite easy to obtain six to 10 horsepower from the wind. It is obvious that power, or the rate at which work is done, has nothing to do with the quantity of work accomplished. A very A Dynamic Linear Mass Accelerator (DLMA Linear Engine) working prototype, producing 250 volts at 50 hertz. NEXUS - 47 by Anthony M. Hansen FEBRUARY - MARCH 1997