Energy Analysis of the S-CO2 Brayton Cycle with Improved Heat Regeneration

Abstract

Supercritical carbon dioxide (S-CO2) Brayton cycles (BC) are promising alternatives for power generation. Many variants of S-CO2 BC have already been studied to make this technology economically more viable and efficient. In comparison to other BC and Rankine cycles, S-CO2 BC is less complex and more compact, which may reduce the overall plant size, maintenance, and the cost of operation and installation. In this paper, we consider one of the configurations of S-CO2 BC called the recompression Brayton cycle with partial cooling (RBC-PC) to which some modifications are suggested with an aim to improve the overall cycle’s thermal efficiency. The type of heat source is not considered in this study; thus, any heat source may be considered that is capable of supplying temperature to the S-CO2 in the range from 500 °C to 850 °C, like solar heaters, or nuclear and gas turbine waste heat. The commercial software Aspen HYSYS V9 (Aspen Technology, Inc., Bedford, MA, USA) is used for simulations. RBC-PC serves as a base cycle in this study; thus, the simulation results for RBC-PC are compared with the already published data in the literature. Energy analysis is done for both layouts and an efficiency comparison is made for a range of turbine operating temperatures (from 500 °C to 850 °C). The heat exchanger effectiveness and its influence on both layouts are also discussed.