Reduced Order Modeling of Heat Exchangers Using High Order Finite Control Volume Models

Abstract

A distributed parameter approach for dynamic modeling of heat exchangers and using it to obtain low order models have been presented in this report. The finite control volume (FCV) approach accurately captures the distributed nature of the system parameters, but the models obtained are complex and have a high order. This report presents a FCV approach to multi-phase flow heat exchanger dynamics as a set of Ordinary Differential Equations (ODEs), rather than a set of Differential-Algebraic-Equations (DAEs) that are typically used in this paradigm. It also presents an approach to apply model reduction techniques to FCV models to obtain low order models. A key advantage of these approaches is retention of the physical nature of the system states which are lost when using standard model reduction procedures. The low order models obtained are control oriented and can be utilized for analysis and improvement of the efficiency of heating, ventilation and air-conditioning devices.