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For folks living in the northern hemisphere, their collectors need to be tilted southward. The tilt angle is 15 degrees plus the latitude of the installation site. This is the ideal configuration that allows you to collect maximum sunlight all year round. For example, Arizona has latitude of 33 degrees. Adding 15 degrees to its latitude gives us 48 degrees -- this is the tilt angle your panel should be in order for it to harness maximum energy. But this is just theory... Most homeowners choose to mount the collectors at the same angle as their roof. They are concerned about the aesthetics of the installation. After all, who would love to see a gigantic piece of material sticking out like a sore thumb from their roof? Even though we will not arrive at an optimized configuration (from an engineer's point of view), such setup ultimately serves the user's needs and wants. Fortunately, solar heat collectors are more forgiving than their photovoltaic panel cousins. Tilt deviations that fall within 20 degrees (either direction) from the optimal angle will not cause serious loss to their efficiency. In fact, tilting them up to 15 degrees northward from its optimum angle can have its advantages. During summer, water will not overheat and during winter more hot water is produced. The opposite is true: tilting your heat collectors southward, away from optimum tilt angle, results in more overheating during summer and less hot water during winter. This may not be a bad thing after all -- some folks would prefer to have more hot water during summer to maintain their pool temperature. With this knowledge in mind, you can adjust the angle to suit your needs. Preferably, tilt angle is allowed to be changed according to seasons. But the hardware required to implement this setup often end up as an ugly structure of metal and joints. Not many homeowners are receptive to such mess. Moreover, there will be more moving parts to be maintained. When orientating your heat collectors, you should ideally point them to true south. Similar to tilt angle, heat collectors can tolerate a far wider deviation in orientation angle than solar panels. They can receive most of the solar energy even if you installing them 15 degrees off true south. Beyond this tolerance, the effectiveness of the heat collector decays rapidly. You may often be forced to make a choice between an east-biased or west-biased orientation away from true south. Perfect orientations tend to be impractical at times. If you're in this fix, choose the west so heat collectors can be exposed to more heat as a result of higher ambient temperatures in the afternoons. As you line up your compass to find true south, remember that it is pointing to magnetic south instead. Corrections must be made to locate the optimum orientation. To do this, you need to compensate for the magnetic declination of your site. As you are evaluating the installation site, remember that shadows cause your heat collectors to be drastically less efficient. Although solar water heaters are not as sensitive to shading, it is good to place them in an open, unobstructed location from 9am to 3pm so they can be exposed to the maximum amount of sunshine during this critical period. Using a standard shade analysis tool like a solar pathfinder, you can make it easier for yourself to evaluate the shading condition of your location. You can finally prepare to mount the collectors, having determined its orientation, tilt angle and location. Whether you buy the mounting rack or make it yourself, the choice of material is as important. In areas of low humidity, painted angle iron may be used. Otherwise, materials like aluminum or stainless steel is more suitable as they are more resistant to corrosion. Solar water heaters installed in rainy, tropical and coastal climates will benefit from these materials.
Article Source: http://www.bharatbhasha.net Article Url: http://www.bharatbhasha.net/family.php/240323 Article Added on Sunday, June 13, 2010
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