Supercritical carbon dioxide Brayton cycle for concentrated solar power

Garg, Pardeep and Kumar, Pramod and Srinivasan, Kandadai (2013) Supercritical carbon dioxide Brayton cycle for concentrated solar power. In: Journal of Supercritical Fluids, 76 . pp. 54-60.

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Abstract

Supercritical carbon dioxide based Brayton cycle for possible concentrated solar power applications is investigated and compared with trans- and sub-critical operations of the same fluid. Thermal efficiency, specific work output and magnitude of irreversibility generation are used as some of the performance indicators. While the thermal efficiency increases almost linearly with low side pressure in the sub- and trans-critical cycles, it attains a maximum in the supercritical regime at 85 bar after which there are diminishing returns on increasing the low side pressure. It is also found that supercritical cycle is capable of producing power with a thermal efficiency of >30% even at a lower source temperature (820K) and accounting for foreseeable non-idealities albeit with a higher turbine inlet pressure (similar to 300 bar) which is not matched by a conventional sub-critical cycle even with a high source temperature of 978K. The reasons for lower efficiency than in an ideal cycle are extracted from an irreversibility analysis of components, namely, compressor, regenerator, turbine and gas cooler. Low sensitivity to the source temperature and extremely small volumetric flow rates in the supercritical cycle could offset the drawback of high pressures through a compact system.

Item Type:	Journal Article
Publication:	Journal of Supercritical Fluids
Publisher:	Elsevier Science
Additional Information:	Copyright of this article belongs to Elsevier Science.
Keywords:	Supercritical CO2; Brayton Cycle; Solar Energy; Irreversibility
Department/Centre:	Division of Mechanical Sciences > Mechanical Engineering
Date Deposited:	28 May 2013 06:52
Last Modified:	28 May 2013 06:52
URI:	http://eprints.iisc.ac.in/id/eprint/46578

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