UPSC Prelims 2020 Question:

With reference to solar water pumps

consider the following statements: 

1. Solar power can be used for running surface pumps and not for submersible pumps. 
2. Solar power can be used for running centrifugal pumps and not the ones with piston.
   
   

Which of the statements given above is/are correct?

Explanation:

• Solar water pumping system operates on power generated using solar photovoltaic system. The photovoltaic array converts the solar energy into electricity, which is used for running the motor pump set. The pumping system draws water from the open well, bore well, stream, pond, canal etc. The system requires a shadow-free area for installation of the Solar panel.
  
  
• A surface pump is one that is installed on the ground. Surface pumps work well when the suction distance is less than 10 or 20 feet. A submersible pump is one that can be submerged in water. Submersible pumps are used in the majority of deep wells. Both are also compatible with photovoltaic arrays (for solar power). So, statement 1 is not correct.
  
  
• Solar pumping systems can be classified into two types – positive displacement pumps and rotating pumps. 
  
  

• Positive displacement (volumetric) mechanisms seal water in cavities and force it upward in low volume pumps. Pumps with diaphragms, vanes, and pistons are examples of these mechanisms. So, statement 2 is not correct.
  
  
• Centrifugal pumps are a type of rotating pumps. The output of a centrifugal pump is proportional to the speed of rotation. 
  
  

Therefore, option (4) is the correct answer.

Subject: Environment | Renewable and Energy Resources