Vortex Tube Heat Booster to Improve Performance of Heat Driven Cooling Cycles for Automotive Applications

Increasing energy costs justify research on how to improve utilization of low-grade energy that is abundantly available as waste heat from many thermodynamic processes such as internal combustion engine cycles. One option is to directly generate cooling through absorption/adsorption or vapor jet ejector cycles. As in the case of power generation cycles, cooling cycle efficiencies would increase if the heat input were available at higher temperature. This paper assesses the feasibility of a novel idea that uses a vortex tube to increase the available temperature levels of low-grade heat sources. The desired temperature increase is achieved by sending a stream of vapor that was heated by the waste heat source through a vortex tube, which further elevates the temperature used in a heat driven ejector cooling cycle. Simulation results show that COP can be increased by 40% with the use of the vortex tube heat booster when the cycle is operating with low entrainment ratio at conditions where baseline performance and COP are low.