Indian scientists develop next generation technology loop to generate clean energy

Indian scientists have developed a Supercritical Carbon Dioxide Brayton Test Loop Facility that will help generate clean energy from future power plants including solar thermal. The facility was inaugurated by Union Science & Technology Minister Harsh Vardhan at the IISc campus in Bengaluru on February 22, 2018. This technology is India’s first test loop fixed with solar heat source in the world.

Who all were involved in the development of test loop? The laboratory scale test loop was developed by a research group at the Interdisciplinary Centre for Energy Research, IISc, as part of the Indo-U.S. consortium called Solar Energy Research Institute for India and the United States. Pradip Dutta and Pramod Kumar of the Department of Chemical Engineering, IISc were the key scientists involved in this path-breaking innovation. The funding was provided by the Department of Science and Technology, Union Government.

Why was there a need of this Supercritical Carbon Dioxide Brayton Test Loop?
• Today’s thermal power plants use steam to carry heat away from the source and turn a turbine to generate power.
• However, it could generate more power if, instead of steam, Supercritical CO2 (SCO2) is used.
• The term “Supercritical” describes the state of carbon dioxide above its critical temperature of 31°C and critical pressure of 73 atmospheres making it twice as dense as steam.
• In order to make this technology a reality, a research group at Interdisciplinary Centre for Energy Research at Indian Institute of Science (ICER, IISc) has set up India’s first S-CO2 Brayton Cycle based solar thermal test loop at the laboratory scale.
• The group made tremendous progress and have developed optimized thermodynamic cycle designs, heat transfer and fluid flow codes for designing the test loop.
• Critical components such as compact heat exchangers and solar receivers and modern instrumentation along with loop control sequence algorithm were also developed.

Advantages of Supercritical Carbon Dioxide Brayton Test Loop?
• This early stage research could potentially be useful for meeting the energy needs of the country.
• The new generation high efficiency power plants with closed cycle CO2 as the working fluid have the potential to replace steam based nuclear and thermal power plants, thus reducing the carbon foot print significantly.
• It is designed to generate the necessary data for future development of scaled up power plants, which would require overcoming several technological challenges.
• This will give India an opportunity to become a world leader in this technology, and fulfil a major objective of the National Solar Mission which emphasizes indigenous manufacturing.
• The efficiency of energy conversion could also be significantly increased by as much as 50 per cent or more if S-CO2 is operated in a closed loop Brayton cycle.
• Smaller turbines and power blocks can make the power plant cheaper, while higher efficiency would significantly reduce CO2 emissions for fossil fuel based plants.
• Moreover, if the power plant used solar or nuclear heat source, it would mean higher capacity at lower operating costs.