Abstract:

The heat exchanger area per unit power output (APR) is chosen as the objective function of the organic Rankine cycle system in present work, and several working fluids is used in investigation. The optimal system parameters are confirmed based on the analysis of the effect of pinch point temperature difference assignment on the system economic performance under the condition of heat source temperature, cold source flow rate and evaporation temperature. The results show that an optimal pinch point temperature difference assignment occurs, and optimal system economic performance can be obtained for the selected working fluid. The optimal pinch point temperature difference ratio is different for different working fluids. The optimal pinch point temperature difference ratio increases with the total pinch point temperature difference and heat source temperature increases. Instead, it decreases with evaporating temperature increases. However, the cold source flow rate has nearly no influence on the optimal pinch point temperature ratio. Pinch point temperature difference assignment has a greater impact on the choice of system parameters, and a suitable Pinch point temperature difference assignment can improve the ORC system performance effectively.

Key words: economic performance, ORC, pinch point temperature difference assignment