Performance Evaluation of Centrifugal Chillers in an Air-Conditioning Plant with The Building Automation System (BAS)

Abstract

A thermodynamic model with a novel method of describing the performances of centrifugal chillers for air-conditioning is presented. It is based on the first and second laws of thermodynamics which captures the overall entropy change due to non-isentropic compression and expansion of the thermodynamic cycle. The model gives the fundamental relation between the coefficient of performance (COP) and the cooling rates (Q_e) for (a) the modulating and (b) the throttling actions of the inlet guide-vanes of the compressor. The usefulness and the accuracy of the model are demonstrated here by analysing the in situ performance of two commercial, installed centrifugal chillers of an air-conditioning plant as well as comparing the available performance data of another chiller in the literature.