Improving the Accuracy of the Low-Order Models for Heat Exchangers

Abstract

For both counter current and parallel heat exchangers, the transfer functions from the partial differential equations are simplified. The accuracy of these low-order models can be increased through a step-by-step procedure. For counter current heat exchangers, this is done by taking more terms from the Taylor expansion of some specific terms in the transfer functions. For parallel. heat exchangers, a new model, which is called the sectionally-distributed model, is proposed. The accuracy of these low-order models are compared with their original transfer functions in the frequency domain and with the high-order lumped models in the time domain.