Parameter Estimation and the Use of Catalog Data in Modeling Heat Exchangers and Coils

Abstract

This paper presents a technique for developing models that can accurately replicate equipment performance of heat exchangers and coils. The technique employs mechanistic relations with unspecified parameters as the basis for the model relations. Catalog information is then used to estimate the best value of the parameters. Only a few geometric specifications are required and only a small number of parameters need to be fit. The technique is robust and accurately replicates catalog information over the entire operating range. Major advantages are that the use of mechanistic relations allows extension to different heat transfer fluids, different temperature ranges, and different temperature levels. The performance of the models developed with this technique is compared to that using the models of the ASHRAE HVAC 2 Toolkit (Brandemuehl 1992) and the historical ASHRAE approach (Stoecker 1975). The technique is illustrated for the heat transfer and pressure drop characteristics of a specific set of chilled water cooling coils. Results for a number of different heat exchanger types from different manufacturers such as shell-in-tube heat exchangers, heating and cooling coils, and direct expansion coils are also reported.