The Influence of Availability Costs on Optimal Heat Exchanger Size

Abstract

Optimizing heat exchangers based on second law rather than first law considerations ensures that the most efficient use of available energy is being made. Techniques for second-law optimizing heat exchangers have been developed recently that are straightforward and simple. The main difficulty lies in determining the proper cost of irrreversibility that is to be used in the optimization process. This paper demonstrates how this issue can be handled by including the irreversibility cost in a dimensionless parameter that represents the ratio of annual ownership costs to annual operating costs that include irreversibility costs. In this way, each heat exchanger designer can estimate the costs of irreversibilities for his particular system, and use the generalized method for determining the optimal heat exchanger size.