DEVELOPMENT REPORT – How to Make a Solar Water Heater（在线收听）

DEVELOPMENT REPORT – How to Make a Solar Water Heater
By Gary Garriott

Broadcast: Monday, November 29, 2004

I'm Gwen Outen with the VOA Special English Development Report.

Solar water heaters save on energy costs. They also save on oil and other forms of energy needed for electric or gas-powered water heaters.

The Taiwan News reported this month that the Ministry of Economic Affairs will increase its budget for a program to help pay for solar water heaters. The program was supposed to end this year. But officials have decided to continue it through next year. A ministry official said Taiwan is among the top users of solar water heaters in the world.

Solar water heating is used worldwide. The device we are about to describe was developed in Afghanistan more than thirty years ago. Since then, it has been used in many countries. It can heat seventy liters of water to sixty degrees Celsius. It can do this between sunrise and noon on a clear day with an average outside temperature of thirty-two degrees Celsius.

There are two parts to the solar water heater. One part is the solar collector. This is made of metal sheets painted black. The collector is placed in contact with the water.

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 insulation material. This helps the water stay warm for a long time.

The second part of the solar water heater is the storage tank. The tank can be a container that holds about one hundred liters. Two rubber pipes are attached to the 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. However, it will heat water only on sunny days.

You can get more details from the group Volunteers in Technical Assistance. VITA is on the Web at vita.org. And you can find more Development Reports at www.tingroom.com.

This VOA Special English Development Report was written by Gary Garriott. I'm Gwen Outen.