Entransy dissipation-based thermal resistance method for heat exchanger performance design and optimization

Optimal design of heat exchanger performance is of the key issue in energy conservation. Based on the entransy theory, this study deduced the formula of entransy dissipation-based thermal resistance (EDTR) for different types of heat exchangers, analyzed the factors influencing heat exchanger performance and, more importantly, developed an alternative EDTR method for the design and optimization of heat exchanger performance. The results indicate that the EDTR of parallelflow, counterflow and TEMA E-type shell-and-tube heat exchangers have a general formula, which directly connects heat exchanger performance to heat capacity rates of fluids, thermal conductance and flow arrangement of heat exchanger without introducing any phenomenological non-dimensional parameter. From this formula, it is clear that there are three factors influencing heat exchanger performance, including finite thermal conductance, different heat capacity rates of hot and cold fluids, and non-counterflow arrangement of heat exchangers. Furthermore, based on the relation among heat transfer rate, arithmetical mean temperature difference and EDTR, the total heat transfer rate in a heat exchanger can be easily calculated by the thermal conductance of heat exchanger and the heat capacity rates of fluids. Therefore, the EDTR method can analyze, compare and optimize heat exchanger performance conveniently. (C) 2013 Elsevier Ltd. All rights reserved.