Method for efficient counter-current heat exchange using optimized mixtures

摘要

A method is disclosed for maximizing the thermodynamic efficiency and the heat transfer capacity of a counter-current heat exchanger through the use of an optimized multi-component working fluid. Given the operational temperatures and pressures of the heat exchanger, the disclosure teaches a method for selecting the components for the working fluid and for determining the molar fractions of the components that determine the optimal mixture for the working fluid. Because the effective specific heat of a high pressure stream of this mixture is equal to the effective specific heat of a low pressure stream throughout the entire temperature range of the heat exchanger, the thermodynamic efficiency of the heat exchange process is maximized. In addition, because the difference between the enthalpies per unit mass of the two streams are maximized throughout the temperature range of the exchanger, this mixture provides optimal capacity for heat transfer in the heat exchanger. Such an optimal working fluid can dramatically improve the performance of a heat engine or heat pump, and is especially effective in cryogenic refrigeration systems.