A regenerative air refrigeration system is designed to take a load of 30 tons of refrigeration load of an aircraft cabin. The pressure of air is increased from 0.8 bar to 1.2 bar by ramming action. The air required for the refrigeration is bled from the main compressor at 4.8 bar. The effectiveness of the HE-I (when rammed air is used) is 0.6. The air coming out of HE-I is passed through the cooling turbine and some portion of the air coming out from the cooling turbine is used in HE-II (known as regenerative Heat Exchanger) where refrigeration air is cooled to 50oC. The temperature of the air coming out of He-II is 100oC. The cabin is maintained at 1 bar and 25oC. The ambient temperature is 7oC. Assuming ramming is isontropic and ηc1 = 90% and ηt = 80%, find
A regenerative air refrigeration system is designed to take a load of 30 tons of refrigeration
load of an aircraft cabin. The pressure of air is increased from 0.8 bar to 1.2 bar by
ramming action. The air required for the refrigeration is bled from the main compressor at
4.8 bar. The effectiveness of the HE-I (when rammed air is used) is 0.6. The air coming out
of HE-I is passed through the cooling turbine and some portion of the air coming out from
the cooling turbine is used in HE-II (known as regenerative Heat Exchanger) where
refrigeration air is cooled to 50oC. The temperature of the air coming out of He-II is 100oC.
The cabin is maintained at 1 bar and 25oC. The ambient temperature is 7oC. Assuming
ramming is isontropic and ηc1 = 90% and ηt = 80%, find
(a) The percentage of the air extracted from the cooling turbine used in regenerative
heat exchanger.
(b) Power required to run the system.
Assume that the power developed by the cooling turbine is used for running the ram air
exhaust fan.
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