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Active Solar Energy
Active solar heating systems are perhaps the most familiar methods of harnessing solar energy. These use solar panels to collect heat from the sun. Sunshine heats water flowing through flat collecting panels, which work like radiators in reverse - they absorb radiation to heat water. Such a system can provide hot water directly or for use in a central heating system. Solar panels provide clean, CO² free heat, which, can be used to provide domestic hot water, to heat swimming pools and to provide service hot water for commercial buildings such as hotels and hospitals. In Ireland, a correctly sized unit can provide 60 percent of a household's hot water needs over a year. The panels are usually placed on the roof of the house and angled to catch as much direct sunshine as possible. Ideally solar collectors should face south however, an orientation up to 45° east or west of due south will not significantly decrease performance. It is estimated that current solar collector installations represent just 0.2% of the estimated practical solar heating resource available.