Dynamic Response of a 50 kW Organic Rankine Cycle System in Association with Evaporators

Abstract

Abstract:The influences of various evaporators on the system responses of a 50 kW ORC system using R-245fa are investigated in this study. First the effect of the supplied hot water flowrate into the evaporator is examined and the exit superheat on the system performance between plate and shell-and-tube evaporator is also reported. Test results show that the effect of hot water flowrate on the evaporator imposes a negligible effect on the transient response of the ORC system. These results prevail even for a 3.5-fold increase of the hot water flowrate and the system shows barely any change subject to this drastic hot water flowrate change. The effect of exit superheat on the ORC system depends on the type of the evaporator. For the plate evaporator, an exit superheat less than 10 °C may cause ORC system instability due to considerable liquid entrainment. To maintain a stable operation, the corresponding Jakob number of the plate heat evaporator must be above 0.07. On the other hand, by employing a shell and tube heat evaporator connected to the ORC system, no unstable oscillation of the ORC system is observed for exit superheats ranging from 0 to 17 °C.

Design and preliminary results of a 20-kW transcritical organic Rankine cycle with a screw expander for low-grade waste heat recovery

“…Evidence suggests that the thermal efficiency of an ORC system in a subcritical state is typically lower than 10% [7][8][9][10][11]. However, the transcritical ORC is more attractive for low-grade heat recovery because of the low exergy loss [12].…”

Condensation heat transfer of R245fa in tubes with and without lyophilic porous-membrane-tube insert

“…The copper tube had an inner diameter of 14.81 mm and an outer diameter of 18.97 mm. Such tube can be used in condensers of ORCs [20].…”

Study on Mixed Working Fluids with Different Compositions in Organic Rankine Cycle (ORC) Systems for Vehicle Diesel Engines

“…This technology has been widely studied and applied in numerous domains [5][6][7][8]. Wang et al [9] established an ORC system driven by solar energy.…”