Thermodynamic evaluation of leak phenomenon in liquid receiver of ORC systems

Organic Rankine cycle (ORC) is a promising heat recovery technology for low grade energy. The liquid receiver is an important equipment in ORC system for it stores the organic fluids. This paper established a leakage model of zeotropic mixture in liquid receiver. The main impacts of the parameters, including the mass fraction of fluid, vapor mole fraction, and leak rate, on the thermodynamic performance of ORC system were conducted with environmental-friendly mixtures of R152a/R600 and R290/R245fa. The results revealed that the leak of zeotropic mixtures had a great influence on the mass fraction of fluid. It would further impact on the thermodynamic performance of system. The effect of liquid leak in liquid receiver on the net power output of system is less than that of vapor leak. The maximum increasing rate of net power output through vapor and liquid leakage were 0.19% and 0.04% of R152a/R600 at different initial mass fraction, and the maximum decreasing rate were 20.81% and 0.25%, respectively. The sensitive analysis showed that the net power output of system monotonously decreases as leakage rate increases.