Experiments were conducted on the operating characteristics and performance of various types of working fluid, filling amount and heat flow rate of a loop thermosyphon for cooling ESS battery container. As results of performance test on various working fluids, HFE-7100 and R-134a as a working fluids showed unstable operating and low performance due to vapor pressure drop, and performance was improved by increasing the number of vapor lines for reducing a pressure drop. In this study, n-pentane was more stable and showed better thermal performance among various working fluids.

The performance of organic Rankine cycle was numerically investigated to recover heat from the exhaust of a heavy-duty diesel engine. Exhaust flow rates and temperatures are obtained from the simulation of diesel cycle by using GT-Power. The net power outputs of organic Rankine cycle for 9 working fluids were calculated by cycle simulations. The results showed that as for the net power outputs and the pressure of working fluids, R21 and R245fa are suitable as working fluids for ORC in diesel engine.