Heat exchanger

摘要

A heat exchanger ( 50 ) is provided for transferring heat between first and second fluids ( 52 ) and ( 54 ) having a maximum operating mass flow rate through the heat exchanger ( 50 ) and mass flow rates that are substantially proportional to each other. The heat exchanger ( 50 ) provides essentially constant outlet temperatures for the first and second fluids ( 52,54 ) for all of the flow rates within the operating spectrum of the heat exchanger ( 50 ) without the use of an active control system. The heat exchanger ( 50 ) is of particular use in the fuel processing system ( 36 ) of proton exchange membrane type fuel cell systems.