Optimization on pinch point temperature difference of ORC system based on AHP-Entropy method

In present work, some organic working fluids are chosen to evaluate the matching relationship between the evaporation PPTD (pinch point temperature difference) and the condensation PPTD (pinch point temperature difference) of ORC (Organic Rankine Cycle) system. The Analytic Hierarchy Process (AHP)-Entropy method which based on the comprehensive assessment on the thermal and economic performance of ORC system is applied. Under the considered operating condition, the comprehensive evaluation index is obtained by the indicator and criterion evaluation which performed by thermal and economic performance evaluation. The optimal working fluid of present considered working fluid is determined, and the optimal PPTD ratio (evaporation to condensation) parameter is obtained as well. The results show that the optimal working fluid among present considered is R11, and the most suitable PPTD ratio is 1.25-1.5.