The conditions for minimum dissipation and the dependence of the minimum possible entropy production on the heat load are obtained for heat exchange systems with a given heat load and total heat transfer coefficient. The case of variable heat capacity of streams is considered. Distributions of heat exchange coefficients and heat capacity rates of the streams for which this minimum of irreversibility can be achieved are found. The problem is solved for a wide class of heat transfer kinetic laws in which the heat flow is proportional to the contact surface. The possibility of evaporation and condensation of streams is investigated. The concept of thermodynamic equivalence of dual-stream and multi-stream systems is introduced and the conditions that lead to such equivalence are obtained. Using this equivalence for Newtonian kinetics, optimal synthesis conditions are obtained for dual-stream and multi-stream systems with a given total heat transfer coefficient and heat load. It is shown how the solution can be implemented in a system of dual-stream heat exchangers.

对于具有给定热负荷和总传热系数的热交换系统，获得了最小耗散条件和最小可能熵产生对热负荷的依赖性。考虑了流的热容量可变的情况。找到了可以实现这种最小不可逆性的流的热交换系数和热容率的分布。该问题通过一大类传热动力学定律得到解决，其中热流与接触面成正比。研究了物流蒸发和冷凝的可能性。介绍了双流和多流系统热力学等效的概念，并获得了导致这种等效的条件。使用牛顿动力学的这个等价，在给定的总传热系数和热负荷的情况下，可为双流和多流系统获得最佳合成条件。显示了如何在双流换热器系统中实施该解决方案。