VOA慢速英语 Development Report - Making a Solar Water Heater
时间：2019-01-11 作者：英语课 分类：VOA慢速英语2009年（四）月
This is the VOA Special English Development Report.
Solar water heaters are devices 1 that use energy from the sun to heat water. Solar water heating 2 is used around the world.
An example of a rooftop solar water heater being built in South Africa
The solar water heater described here is based on a design developed some years ago in Afghanistan. Since then, it has been built and used in many countries. It can heat seventy liters 3 of water to sixty degrees Celsius 4. 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 made of a sheet of metal painted black. This metal surface, placed in contact with the water, will heat the water. Black-painted surfaces that receive the sun's heat become hotter than surfaces of any other color.
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 5 sheets often are used to make the roofs of houses.
Once the water is heated, it is kept hot with material called insulation 6. 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.
There is also something else you will need to make the solar water heater work -- the sun. As you might expect, the heater will heat water only on sunny days.
You can get more information about projects like solar water heaters from EnterpriseWorks/VITA. This nonprofit group works 7 to fights poverty in many countries. The Web site is enterpriseworks.org. Choose the link for News & Resources, then Publications 8.
Transcripts 9, MP3s and podcasts of our reports are at voaspecialenglish.com.
And that's the VOA Special English Development Report. I'm Steve Ember.
- electrical labour-saving devices around the home 节省劳力的各种家用电器
- modern labour-saving devices such as washing machines and dishwashers 诸如洗衣机和洗碗机之类的现代化省力设备
- They will install a heating and lighting system in our house.他们将在我们家装上供热供电系统。
- If the pressure is too low,the heating system will act up.如果压力太低，供暖系统就会出毛病。
- In the metric system, measurements are made in metres and liters. 在公制中，用米和升作计量单位。 来自《简明英汉词典》
- This can holds five liters of water. 这个容器可装五升水。 来自《简明英汉词典》
- The temperature tonight will fall to seven degrees Celsius.今晚气温将下降到七摄氏度。
- The maximum temperature in July may be 36 degrees Celsius.七月份最高温度可能达到36摄氏度。
- a corrugated iron roof 波纹铁屋顶
- His brow corrugated with the effort of thinking. 他皱着眉头用心地思考。 来自《简明英汉词典》
- Please examine the insulation of the electric wires in my house.请检查一下我屋子里电线的绝缘情况。
- It is always difficult to assure good insulation between the electric leads.要保证两个电触头之间有良好的绝缘总是很困难的。
- We expect writers to produce more and better works.我们期望作家们写出更多更好的作品。
- The novel is regarded as one of the classic works.这篇小说被公认为是最优秀的作品之一。
- The related publications are far too numerous to list individually. 相关出版物太多，没法一一列举。 来自《简明英汉词典》
- A detailed list of our publications is available on request. 我们的出版物有一份详细的目录备索。 来自《简明英汉词典》
- Like mRNA, both tRNA and rRNA are transcripts of chromosomal DNA. tRNA及rRNA同mRNA一样，都是染色体DNA的转录产物。 来自辞典例句
- You can't take the transfer students'exam without your transcripts. 没有成绩证明书，你就不能参加转学考试。 来自辞典例句