Optimization of Brayton cycles for low-to-moderate grade thermal energy sources

Proposal and study of a balanced hybrid Rankine–Brayton cycle for low-to-moderate temperature solar power plants

“…In this paper, the fluids established as reference are water, CO 2 , R125 and acetone, to take into account the effect of the critical temperature and the c p /R parameter described in Refs. [1,13].…”

“…In Refs. [1,13], authors remark that the main irreversibilities of the cycle are found in the compression process (Brayton cycles) and in the regenerator (both in Rankine and Brayton cycles), and that both losses may be reduced thanks to the very variable properties of the fluid around this region. In these works it is also commented the importance of adjusting the heat capacity of the working fluid during the heating processes to that of the heat carrier that comes from the finite heat source (e.g.…”

“…They might introduce additional advantages for unattended operation, like simplicity and robustness and thus they may lead to cheap designs, but the disadvantages seem to have a high impact in the selection of the cycle [13]. Brayton cycles have been proposed with moderate-to-high turbine inlet temperatures, i.e.…”

Extremum-seeking control of a supercritical carbon-dioxide closed Brayton cycle in a direct-heated solar thermal power plant

“…The simplicity and potential ability of real-gas closed Brayton cycles such as one with supercritical-CO 2 to be integrated with existing inexpensive solar collectors is also an attractive feature [5]. The supercritical-CO 2 CBC is also being considered for power generation from other medium-grade heat-sources including waste heat [6] and for integration with post-combustion CO 2 capture for efficiency improvements in coal-fired power stations [7].…”

Comparative study of alternative ORC-based combined power systems to exploit high temperature waste heat

“…Further researches [18,19] indicate that DORC has great potential for waste heat recovery. Unlike ORC, Brayton cycle (BC) regards gas as working medium which suits high temperature operation well and it has some interesting advantages over Rankine cycle, such as simplicity and reliability, because it does not involve phase change during the whole process and can work at low pressure ratios [20]. Previous studies [21,22] have explored its application in waste heat recovery, and air is considered as working fluid.…”