Q7 : A cascade refrigeration system is designed to supply 10 tonnes of refrigeration at an evaporator temperature of -40°C and a condenser temperature of 36°C.
Q7 : A cascade refrigeration system is designed to supply 10 tonnes of refrigeration at an evaporator temperature of -40°C and a condenser temperature of 36°C. The load at -40°C is absorbed by a unit using R-22 as the refrigerant and is rejected to a cascade condenser at -10°C. The cascade condenser is cooled by a unit using R-12 as the refrigerant and operating between – 20°C evaporating temperature and 36°C condenser temperature. The refrigerant leaving the R-22 condenser is subcooled by 6°C but there is no subcooling of R-12 refrigerant. The gas leaving both the evaporators is dry and saturated and the compressions are isentropic. Neglecting losses. calculate the COP of whole system
