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[report整理] SENEWS-2011-04-25

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This is the VOA Special English Technology report.

Solar water heaters are used around the world.And are not very difficult to build.This is then we are going to descibe is based on the design developed some years ago in an acdema Stanford .Since then, it has been built and used in many countries.It can heat 70 littlers of water to 60 degree celcies.It can do this between sunrise and noon on a clear day with an average air tempreture of 32 degrees celcies.There are two parts of the solar water heater.One part is made of a sheet of metal painted black.Black surfaces they can hotter in the sun than the surfaces painted in the other colors.This black metal plate is called a collecter.The collecter is placed in contact with the water,there are several kinds of metal sheets that can be used for the collecter.cooregated metal will worked very well.cooregated sheets are often used as rooves on housing.Once the water is heated, it is kept hot with insolation material.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 100 litters.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 collecter and back again.You can use the hot water at the top of the tank for washing and cleaning.You can change the the flow of water so that the tempreture 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.The results of someone else you will lead to make the solar water heater work,the sun,as you might imagine the heater will heat water only on sunny days.You can get more imformation about solar water heaters and other project form enterprize works viter.This group works internationaly to fight property.The website is enterprizeworks.war.Choose the link for news and resources then click on publications.

And that's the VOA special English technology report.

Tell us if you have ever built the solar water heater or have ideas for improvement,post your comment at VOAspecialenglish.com,where you can also find transcrips,MP3s and popcaps about our program.We also offer English teaching activities in the classroom section of our site.
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