Energy and exergy analysis of a combined system: cascade organic Rankine cycle and cascade refrigeration cycle

Abstract

In this paper, a new combined system is proposed for recovering thermal energy at medium temperature using a cascade organic Rankine cycle to feed a cascade refrigeration cycle. Energy and exergy analysis is applied to the combined system to determine its performance using different working fluids under the same operating conditions taking into account the effect of some operating parameters and the selection of organic fluids on cycle performance. The pair of organic fluid (Toluene/R245fa) used for the cascade organic Rankine cycle and the pairs (R717/R744, R717/R23, R134a/R23) used for the cascade refrigeration cycles. The results show that the combined system function with the couple (R717/R23) for cascade refrigeration cycle gives better exergy efficiency 50.03% compared to other couples, 49.57% for the couple (R717/R744), and 48.01% for the couple (R134a/R23). The thermodynamic evaluation shows that the operating temperatures, such as the cascade organic Rankine cycle evaporation temperature and the cascade refrigeration cycle evaporation temperature influence the performance of the combined system.

Parametric study on the exergy analysis of a dual evaporator cooling cy-cle powered by the organic Rankine cycle

“…Kaşka et al, made a study on the performance of the refrigeration cycle combined with the ORC cycle, which allows cooling hydrogen at the inlet of the compressor providing compression at constant temperature in the Claude cycle intended for liquefaction of hydrogen from a geothermal source [20]. Rabah et al carried out a novel study on a combined system that was proposed to recuperate thermal energy at moderate temperature through the use of a cascaded ORC cycle to feed a cascaded cooling cycle; An energy and exergy analysis is performed on the studied system in order to determine its performance using diverse working fluids under the same experimental conditions, considering the effect of some operating parameters on the cycle performance [21].…”