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

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