Pinch-Point Temperature Difference Analysis of Dual-Loop Organic Rankine Cycle
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Taking the dual-loop organic Rankine cycle of waste heat recovery from diesel engine exhaust as the research object, benzene and cyclohexane were selected as the working fluids of high-temperature cycle, and R134a was selected as the working fluid of low-temperature cycle. Taking the net power output per unit heat transfer area, the mass flow of the working fluids and the net output power of the cycle as the objective function, the influence of the pinch-point temperature difference (PPTD) of the high-temperature evaporator and the low-temperature condenser on the system performance are discussed. The research shows that when the pinch-point temperature difference of the high-temperature evaporator increases, the total net work of the cycle output, the mass flow rate of the working fluid, and the required heat transfer area are reduced, and the net work output per unit heat transfer area is increased. There is a best match between the pinch-point temperature difference of the high-temperature evaporator and the low-temperature condenser. When the sum of the pinch-point temperature differences of the high-temperature evaporator and the low-temperature condenser is 30 °C and 40 °C, respectively, for all selected working fluids, there is an optimal pinch-point temperature difference of the high-temperature evaporator.
KeywordsOrganic rankine cycle Diesel exhaust Thermodynamic analysis Enthapy
The authors wish to acknowledge the financial support of the Natural Science Foundation of Tianjin (No. 16JCZDJC31400).
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