Influence of the compression pressure ratio on the energetic and exergetic efficiency of a solar driven regenerative closed Brayton cycle with helium as working fluid

Abstract

One of the causes of the lack of competitiveness of solar thermal energy is its low energy and exergetic performance Therefore, it is necessary to investigate the possibility of using more efficient cycles. Closed Brayton cycles are an attractive alternative because of their good performance achieved in other applications on the same range of temperatures. In this work the energy and exergy efficiency of a closed Brayton regenerative cycle have been calculated. The working fluid of the power block is helium. Also, the influence of the compressor pressure ratio on the energetic and exergetic efficiency has been analyzed. For this, a model of the plant in Engineering Equation Solver (EES) has been made. The maximum energy efficiency is 22.44% while the maximum exergetic efficiency is 24.09%. Both are obtained for a compressor pressure ratio of 1.634.