FAQ

  1. What is the difference between concentrating solar power (CSP) and other solar technologies?
  2. What is the diffuse sunlight?
  3. What is Stirling engine?
  4. Is CSP technology suitable for application in Hong Kong?
1) What is the difference between concentrating solar power (CSP) and other solar technologies?
Ans: CSP technologies concentrate the sun's energy using reflective devices such as troughs or mirror panels. The resulting concentrated heat energy is used to power a conventional turbine and produce electricity. On the other hand, most solar water- and space-heating technologies use sunlight directly to produce heat rather than using the sun's heat to produce steam that drives a generator to produce electricity, the way CSP does. Electricity can also be generated using solar cells that convert sunlight directly into electricity using the semiconductor materials.
   
2) What is the diffuse sunlight?
Ans: Solar radiation falling on surfaces comes from two sources: the parallel or direct rays from the sun and the diffuse radiation from the sky and the surroundings. The diffuse radiation from the sky is due to the sunlight that 'bounces' off particles and molecules in the atmosphere. The diffuse radiation from the surroundings is due to reflection from surfaces in the surrounding. For a relatively clear sky the diffuse component is small. As the sky becomes less clear, the percentage of diffuse radiation becomes greater.
   
3) What is Stirling engine?
Ans: Stirling engine is a heat engine which uses the potential energy difference between its hot and cold end to establish a cycle of a fixed amount of gas expanding and contracting within the engine, thus converting a temperature difference across the machine into mechanical power. The greater the temperature difference between the heat source and cold source, the easier it is for the Stirling Engine to operate.

The following website provides a very good introduction to the working principle of Stirling engine:
This web page has hyperlinks which may transfer you to third-party website.http://www.howstuffworks.com/stirling-engine.htm

   
4) Is CSP technology suitable for application in Hong Kong?
Ans: Since CSP technology uses mainly the direct beam component of the sunlight and in Hong Kong the annual proportion of the direct beam component is relative low (less than 50%), CSP technology is not likely to be applicable in Hong Kong's situation.
   
   
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