Design and analysis of multiple parallel-pass condensers

This paper describes and analyzes a novel design of multiple parallel-pass (MPP) microchannel tube condenser and its applications to automotive A/C systems. A flow distributor concept is introduced in MPP condenser in order to enable parallel flow arrangement in adjacent flow paths. Throughout analysis of two-phase flow and heat transfer processes in MPP condenser, a two-phase zone enlargement technique is developed to enhance condensation heat transfer and reduce pressure drop. Visual observation indicates a more uniform refrigerant quality entering the next cooling pass can be achieved in MPP condenser because superheated vapor through a pass-through hole on flow distributor directly injects into the separated liquid–vapor zone in a header tube. Performance test results show MPP condenser is able to improve heat transfer rate as high as 9.5% while its refrigerant mass flow increases 13.34% when comparing to a benchmark PF condenser.