Computation of effectiveness of two-stream heat exchanger networks based on concepts of entropy generation, entransy dissipation and entransy-dissipation-based thermal resistance

The two-stream heat exchanger networks (THENs) are widely used in industry. The effectiveness of the THENs is analyzed in this paper. The general expressions for the entransy dissipation, the entransy-dissipation-based thermal resistance and the entropy generation for a generalized THEN are developed. It is found that the expressions are independent of the specific constitution of the THENs. Only the entransy-dissipation-based thermal resistance always decreases monotonously with the increase in effectiveness, while the entransy dissipation and the entropy generation do not. Therefore, the entransy-dissipation-based thermal resistance is most applicable for the optimization of the THENs.

► The effectiveness of the THENs is defined.
► Thermal resistance decreases monotonously with the increase in effectiveness.
► Entropy generation is not always appropriate to optimize THENs.
► Application of entransy dissipation to THEN optimization is conditional.