Performance Evaluation Criteria and Selection Utility Function for Compact Air-to-Refrigerant Heat Exchangers

摘要

The issue of Performance Evaluation Criteria (PEC) for Heat eXchangers (HX) is widely discussed in the literature. However, not often is discussed some deeper meanings of each PEC metric and the consequences they potentially have in the design and selection of HX's when using one or another. There are two main evaluation approaches: energy-based and entropy-based PEC's. The main difference between them is that the first objectively compares the quantities of energy coming in and out of the HX, whilst the second quantifies and qualifies all the factors that affect the overall performance. Furthermore, with the advances in computational capabilities and manufacturing technologies, there is an increasing development of novel HX concepts, and large data sets from multi-objective optimization studies. When the options multiply, the more challenging is to compare and select the best alternative. In this paper, we provide a brief review on the existing PEC from the literature. Additionally, we present a set of PEC that purposely addresses the HX performance in a fundamentally consistent way, however general allowing a fair comparison between different HX's. We compare how different metrics affect the outcomes of an optimization and discuss the results. Lastly, we describe a procedure for translating the optimization results into a Multi-Attribute Utility Function that serves for HX selection method, based on existing methods in the engineering decision-making literature. All the analyses presented in this paper are valid for single-phase HX applications using fixed heat transfer rates and fixed heat capacitance rates.