Working Principal of Solar Water Heater with Glass Evacuated Rods
The principles of solar heat have been known for thousands of years. A black surface gets |
hot in the sun, while a lighter colored surface remains cooler, with white being the coolest. This principle is used by solar water collector’s area which is comprised of Glass rods and is one of the best known applications for the direct use of the sun’s energy.
Solar Collector is made up of rows of parallel, glass evacuated rods. These rods are made up of Strong Borosilicate Glass, and two glass rods are fused together at one end. The inner tube is coated with a selective
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| surface that absorbs solar energy well but inhibits radiative heat loss. The air is withdrawn (“evacuated”) from the space between the two glass tubes to form a vacuum, which eliminates conductive and convective heat loss. Solar Water Heater works on natural convection phenomenon call Thermosyphon which is natures own characteristic that hot water rises up, get stored in tanks upper part and cold water flows down the tubes. These tubes perform very well in overcast conditions as well as low temperatures. Because the tube is 100% glass, the problem with loss of vacuum due to a broken seal is greatly minimized. Efficiency of solar heating systems and collectors has improved from the early 1970s. Among countries in Europe, Greece has become the leader in production of solar systems and exports 40% of all collectors produced and comprises 30% of the market in Germany. The industry‘s goal for the year 2005 represents 1,3 million systems and 5 million m2 of collectors. The Greek market installs 70,000 solar systems a year, reducing CO2 emissions by 1,5 million tones. China is again heading the list for use of Solar Energy |
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