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Photo: Michael Ross, RER Renewable Energy Research
The tiny Aegean island of Bozcaada-- not too far from the ancient city of Troy-- is a showcase for renewable energy technologies. In the main settlement, solar thermal systems adorn nearly every rooftop, and at the far end of the island, megawatt-class Enercon turbines tower over a PV-powered lighthouse.
Flat roofs are typical in the main settlement, and most roofs have a one- or two-panel solar system for providing hot water to the house. Single glazed flat plate collectors, seen here, are universal. The lower tank stores hot water generated during the day so that it can be used at night, in the morning, and on cloudy days. The larger, upper tank is not actually a part of the solar system: it is a backup water reservoir so that the family will have some water in reserve if the settlement's water supply fails-- apparently a not uncommon occurrence on this island.
In Turkey, most solar thermal installations are thermosyphon system. The hot water tank is located above the solar collectors, and water circulates between the collectors and the tank due to the buoyancy of the warm water in the collectors. The tank should, therefore, be maximally stratified, with the hottest water at the top (where the water from the collector enters and the hot water to the house exits) and the coldest water at the bottom (where the cold, fresh water enters and the water exits for the collector). Thermosyphon systems require few, if any, controls and no pump. They are only suited, however, to climates where temperatures remain above freezing during the system's season of operation.
Created 2005/08/11 Updated 2005/08/31 ©2005 RER Renewable Energy Research