Energy and Parametric Analysis of Organic Rankine Cycle Combined with a Vapor Compression Refrigeration Cycle (ORC-VCR) System using Natural Refrigerants

Abstract

The dependency on fossil fuels for power generation can be reduced by enhancing the energy efficiency of power generating systems. The refrigeration systems that typically use electricity consume a significant portion of the electricity supplied to cities. The STAND-ALONE refrigeration system which consists of a combined Organic Rankine Cycle and Vapor Compression (ORC-VCR) system is analyzed using the first law of thermodynamics. Dry natural hydrocarbons such as n-Dodecane is used as the working fluid in Organic Rankine Cycle (ORC) and natural Working fluid such as isobutane (R600a) is utilized in Vapor Compression Refrigeration (VCR) Cycle. The study shows that the system can be driven efficiently with Low-grade waste heat from industries or thermal energy from renewable energy sources typically in the range from 1000C to 3500C thus reducing reliance on fossil fuel sources. The results also show that the overall Coefficient of performance COP overall of the system and the energy efficiency of the ORC was greatly affected by the evaporation temperature of ORC, Teva_ORC followed by, the evaporation temperature of VCR, Teva_VCR. The maximum COP overall of the system was found to be 0.558 and the energy efficiency of ORC was found to be 20.69% for Teva_ORC of 315 degree C and Teva_VCR of -30 degree C.