Sliding Pressure Inventory Control of a Supercritical CO2 Cycle for Concentrated Solar Power-Analysis and Implications

Seshadri, L and Kumar, P (2024) Sliding Pressure Inventory Control of a Supercritical CO2 Cycle for Concentrated Solar Power-Analysis and Implications. In: Journal of Solar Energy Engineering, Transactions of the ASME, 146 (1). pp. 1-25.

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Abstract

This paper presents the use of sliding pressure inventory control (SPIC) of a 10 MW super-critical carbon dioxide Brayton cycle for concentrated solar power, incorporating printed circuit heat exchangers. Load regulation using SPIC for three representative ambient conditions 45 °C, 30 °C, and 15 °C are considered. While a wide operating range from 10 MW to less than 1 MW part load is obtained, a notable cycle efficiency decline at part load is also seen. Irreversibility analysis reveals that deterioration in recuperator and turboma-chinery performance are primarily responsible for cycle performance degradation at part load. Nevertheless, useful inferences are obtained from the 10 MW SPIC irreversibility study. With a slightly increased value of heat exchanger length, a non-condensing 1 MW subcritical CO2 cycle operating between 35 bar/53 bar is found to be as efficient as a 1 MW supercritical CO2 cycle operating between 88 bar/210 bar. The major benefit of choosing the subcritical CO2 cycle for 1 MW scale applications is the significantly reduced turbomachinery speed (�26,000 rpm) in comparison with supercritical CO2 turbo-machinery (�67,000 rpm) for the same power scale. These advantages are found to be true for air-based ideal gas cycles operating between 35 bar/53 bar too, with the latter requiring nominally smaller heat exchangers than the subcritical CO2 cycle. The final choice of working fluid, however, for these low-pressure cycles would depend on practical considerations, such as material compatibilities at high temperatures, corrosion considerations, and cost. © 2023 by ASME

Item Type:	Journal Article
Publication:	Journal of Solar Energy Engineering, Transactions of the ASME
Publisher:	American Society of Mechanical Engineers (ASME)
Additional Information:	The copyright for this article belongs to the American Society of Mechanical Engineers.
Keywords:	Brayton cycle; Carbon dioxide; Concentrated solar power; Corrosion; Deterioration; Heat exchangers; Inventory control; Solar energy, Clean energy; Concentrated solar power; Load regulations; Part load; Power analysis; Printed circuit heat exchangers; Sliding pressure; Supercritical CO 2; Supercritical CO2; Thermal power, Heat transfer
Department/Centre:	Division of Interdisciplinary Sciences > Interdisciplinary Centre for Energy Research Division of Mechanical Sciences > Mechanical Engineering
Date Deposited:	18 Jan 2024 11:22
Last Modified:	18 Jan 2024 11:22
URI:	https://eprints.iisc.ac.in/id/eprint/83606

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