Thermal performance analysis of an organic Rankine cycle considering flow pressure drop
For the organic Rankine cycle(ORC)system,a mathematical model of flow pressure drop and system performance was established,and the change characteristics of the thermal efficiency change coefficient of the ORC system under different evaporation pressures,superheat and pinch point temperature differences were calculated with R134a,R245fa,R123,R600a,R236ea and R141b as the system cycle working fluids,and the variation characteristics of the thermal efficiency change coefficient of the ORC system under the action of flow pressure drop were explored.The results show that the evaporator pressure drop is the primary source of flow pressure drop in the ORC system.The decisive operating parameters affecting the flow pressure drop of the ORC system are the evaporation pressure,followed by the temperature difference and superheat at the pinch point.If the evaporation pressure is less than 0.8 MPa,the decrease in the thermal performance of the system will increase.Except for R134a,the influence of the temperature difference and superheat on the flow pressure drop of the other working fluids is small,and the corresponding system performance change coefficients are less than 10%.The system uses R141b and R123 to achieve the lowest flow pressure drop,where the flow pressure drop has the lowest impact on thermal efficiency.