A boot strap cooling system of 20 tons capacity is used for an air plane. The temperature and pressure of atmosphere are 20oC and 0.8 bar. The pressure of air is increased from 0.8 bar to 0.96 bar by ramming action. The pressure of air leaving the main and auxiliary compressor are 3.5 bar and 5.25 bar respectively. 60% of total heat of the air leaving the main compressor is removed in the first heat exchanger and 35% of total heat of the air leaving the auxiliary compressor is removed in second heat exchanger. Assuming ramming is isentropic and ηt = 80%, ηc1 = ηc2 = 85%. Cabin pressure is maintained at1.03 bar and temperature of the air leaving the cabin should not exceed 27oC. Find the following: a.) kW required to take the load in cabin and b.) COP of the system.

A boot strap cooling system of 20 tons capacity is used for an air plane. The temperature and pressure of atmosphere are 20oC and 0.8 bar. The pressure of air is increased from 0.8 bar to 0.96 bar by ramming action. The pressure of air leaving the main and auxiliary compressor are 3.5 bar and 5.25 bar respectively. 60% of total heat of the air leaving the main compressor is removed in the first heat exchanger and 35% of total heat of the air leaving the auxiliary compressor is removed in second heat exchanger. Assuming ramming is isentropic and ηt = 80%, ηc1 = ηc2 = 85%. Cabin pressure is maintained at1.03 bar and temperature of the air leaving the cabin should not exceed 27oC. Find the following: a.) kW required to take the load in cabin and b.) COP of the system.