HEAT TRANSFER IN UNSTEADY GAS FLOW: OPTIMIZATION OF HEAT EXCHANGERS FOR THE ROTO-COOLER AIR CONDITIONING SYSTEM

The Roto-Cooler rotary vane air cycle air conditioning system is simpler and cheaper than conventional vapor compression air conditioning systems with comparable performance. Therefore, the system is worthy of further development. A prototype Roto-Cooler system was built and tested in 1970 by Edwards, based on parametric studies with a steady flow mathematical model. Edwards\u27 test results showed that the prototype heat exchanger was over designed. The purpose of this work was to include the unsteady flow effects in the heat exchanger and other components to complete the gas dynamic analysis of the Roto-Cooler system. A uniform interval calculation scheme is used with the method of characteristics to obtain the air properties in the heat exchanger, as functions of time and position. Using the computer programs developed and presented here, the effects of heat exchanger geometry on performance can be studied, and the heat exchanger can be optimized to provide the best performance. Complete numerical results are presented for the specific operating conditions of Edwards\u27 prototype Roto-Cooler air conditioning system. The results suggest that the heat exchanger can be reduced significantly in size with no loss in system performance