Solar Thermal Power Plant

 

Solar Thermal Power Plant

A solar power plant converts solar energy into electrical energy.

 They can be divided into following categories:

1. Low temperature solar power plant using flat plate collectors

2. Medium temperature solar power plant using concentrated solar collectors

3. High temperature solar power plant using tower system

1. Low Temperature Solar Power System:

1.The low temperature solar power plants use the working fluid temperatures in the range of 60°C to 100°C which can be obtained using flat plate collectors. 

2.The systems need to use a working fluid having low boiling temperature like butane gas. The cold water is circulated into the collector with the help of a circulating pump. 

3.The heated water is circulated in a heat exchanger called butane boiler, where it generates the butane gas at high pressure. 

4.This butane gas supplied to a butane turbine to produce mechanical power due to expansion of butane gas.

5. The vapour coming out of the turbine is condensed in a condenser and sent back for recirculation with the help of feed pump. 

6.The mechanical power output of turbine is converted into electricpower by generator.

2. Medium temperature Solar Power Plant:

1.These systems employ parabolic array through concentrating collectors spread over a large area.

2.The general range of working temperature is between 250°C to 400°C. 

3.The working fluid, usually water, is heated as it circulates through the receivers. 

4.This heat is transferred to storage tank and fed to water where the steam is generated in the steam generator. This steam is utilized to run a turbine coupled to an electric generator, which converts it into electrical energy by electro-mechanical energy conversion. 

5.The exhaust of steam turbine is condensed in the condenser with the help of cold water circulated in the condenser.

6. A 30 MW plant have been installed in Rajasthan under the department of non-conventional energy sources.

3. High Temperature Solar Thermal Power Plants:

1.Such plants use heliostats and have high thermal efficiency, can build in the capacity of 50

MW to 200 MW. 

2.The solar dish collectors receive solar radiations which are collected at a common focusing point. 

3.Small volumes of the fluid are heated at this point high temperature.

4.In central tower receiver an array of plane mirrors called heliostats which are individually

controlled and tracked to reflect the solar radiations on a receiver kept on the tower of about

500 m height. 

5.The feed water in the absorber-receiver called boiler is converted into high steam

of about 600°C - 700°C.

6. This steam is supplied in a conventional steam power plant coupled to an electric generator to generate electrical power.