Minimal irreversibility and optimal distributions of heat transfer surface area and heat load in heat transfer systems

A minimum possible rate of entropy production together with corresponding distributions of heat transfer surface areas and contact temperatures is estimated for heat transfer systems with given values of heat loads and heat transfer coefficients. It is proved that the ratio of the temperatures of contacting flows at any point of the system should be the same when the heat flux in the system is proportional to the difference of temperatures. It is also proved that in this case the temperatures of heating flows at the system outlet should be the same.