The compressed air from main compressor of an air-craft cooling system is bled off at 4.5 bar and 200°C. It is then passed through heat exchanger in which the ram air is forced through for cooling purposes by the fan driven by cooling turbine. The condition of the inlet to cooling turbine is 4 bar and 30°C. The air expands in cooling turbine upto 0.7 bar, this isentropic efficiency of cooling turbine is 80% and flow rate through cooling turbine is 30 kg/min. By drawing the system and showing the process on T-s diagram. Find
(i) The actual exit temperature from the cooling turbine.
(ii) The power delivered to the ram air blow fan.
(iii) The tons of refrigeration, if the cold air is tempered by mixing with by passed warm air and delivered to the cabin cockpit area where it warms upto 25°C before exhausting out to waste.