Solar heating is a way of harnessing the Sun’s energy to provide heating for solar water systems, space heaters and pool heaters. It makes use of equipment that catches solar radiations and uses them for heating purposes. Using solar energy is a very efficient, fast and economical way of producing energy. The equipment consists of solar collectors. The collectors collect the sun’s energy for heating of water or air. The air or water can then be transferred directly to houses and buildings easily, thus cutting down on electricity costs dramatically. In the last decade or so, the efficiency of solar thermal systems has improved a lot, making them a very useful alternative for the future. By making use of solar energy for heating, we can reduce the consumption of fossil fuels and at the same time, electricity bills can be lowered as these systems do not run on electricity. It also provides clean energy, no pollution or by product is produced. Hence this form of energy is very environment friendly.
In order to harness solar energy to the maximum, the solar collectors should have appropriate dimensions and need to be oriented so that maximum sunlight falls on them during the day. Often a heat transfer fluid is used for heating purposes which is transported by making use of pumps. When these fluids reach their destination, the solar heat stored in them is transferred to the water through heat exchanger. This heated water is then transported to buildings or houses. In cold areas, antifreeze mixture is used to prevent the heating system from freezing damage. The heating fluid and portable water are not allowed to mix with each other by using separate circuits for them. That is why a heat exchanger is used to transfer heat. All kinds of solar heating systems require normal water heaters as a backup in case appropriate sunlight is not available. There are two kinds of solar systems, direct and indirect. Direct systems make use of open loop system where as indirect systems incorporate closed loop system. In the direct heating system, the water is circulated through all the collectors and hence it cannot be used in freezing climates. The indirect system is free from such limitations because the working fluid used in it is usually used together with an antifreeze solution. During the heat circulation, the heat is transported from the collector to the tank following the minimum distance path. The pipes can be made up of Copper and should be able to withstand high temperatures, corrosion and abrasion.
Solar heating systems have their limitations also. The amount of sunlight falling on the collectors is reduced greatly on cloudy days. And the collector requires extra protection during rain or hail as its surface can be damaged easily. Also, the direction of the sun changes constantly, so the collector cannot receive direct sunlight entire day. The maximum output is available when sun is directly above the collectors. But inspite of all these factors, solar energy is a strong contender as a substitute to conventional heating systems.
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