Exergy, economic and environmental analysis of organic Rankine cycle based vapor compression refrigeration system

Abstract

This study analyzed, and optimized to address energy, cost, and environmental concerns across the globe of low-grade heat source driven combined organic Rankine cycle and vapor compression refrigeration (ORC-VCR) for multifunctional utility. The exergetic efficiency, total cost, and environmental cost of the system are taken as the indicators of the thermodynamic, economic, and environmental performance of the system, respectively. The results obtained by employing the technique for order of preference by similarity to ideal solution (TOPSIS) indicate the optimal exergetic efficiency, total cost and environmental cost be 28.4%, $69949 and, $3491 respectively. The optimal combination of the operating parameters is R602 as working fluid, 75%, and 85% isentropic efficiencies of the compressor and expander, the outlet temperature of chilled fluid at 276 K, and inlet temperatures of the ORC evaporator and the cooling water at 393 K and 313 K. Moreover, the proposed system is compared with a commercially available 66.67 kW vapor compression chiller and this comparison led to the conclusion that the higher cost ($69949) of the ORC-VCR system is a major drawback in the commercial competitiveness of these systems. However, the reduction in emission of CO2 can lead the annual saving of environmental costs up to $3491.