VOA慢速英语 Making a Solar Water Heater

　　The black metal plate is called a collector. There are several kinds of metal sheets that can be used for the collector. Metal sheets that have raised sections will work very well. These corrugated sheets often are used to make the roofs of houses.

　　Once the water is heated, it is kept hot with material called insulation. This allows the water to stay warm for a long time.

　　The second part of the solar water heater holds the water for the system. This storage tank can be a container that holds about one hundred liters. Two rubber pipes are attached to the water storage tank. One pipe lets water flow into the system. The other lets water flow out.

　　When the water heater is working correctly, water will flow from the storage tank to the collector and back again. You can use the hot water at the top of the tank for washing and cleaning. You can change the flow of water so that the temperature is hot or warm as desired.

　　This solar water heater is easy to build and operate. It will last about two years before the rubber pipes need to be replaced.

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