Exergy-method analysis of a two-stage vapour-compression refrigeration-plants performance

The behaviour of two-stage compound compression-cycle, with flash intercool ing, using refrigerant R22, has been investigated by the exergy method. The condenser's saturation-temperature was varied from 298 to 308 K and the ev aporator's saturation-temperature from 238 to 228 K, The effects of tempera ture changes in the condenser and evaporator on the plant's irreversibility rate were determined. The greater the temperature difference between eithe r (i) the condenser and the environment, or (ii) the evaporator and the col d room, the higher the irreversibility rate. Any reduction in the irreversi bility rate of the condenser gives approximately 2.40 times greater reducti on in the irreversibility rate for the whole plant, and any reduction in th e evaporator's irreversibility rate gives a 2.87 times greater mean reducti on in the irreversibility rate of the whole plant. Because the changes in t he temperatures in the condenser and the evaporator contribute so significa ntly to the plant's overall irreversibility, there is considerable scope fo r optimising the conditions imposed upon the condenser and evaporator. (C) 1998 Elsevier Science Ltd. All rights reserved.