Study and Applications of Empirically-based Models for Predicting Energy Performance of Water Chillers

• Main Authors: Wan-Chen Lu, 呂宛蓁
• Other Authors: 蔡尤溪
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/9a34ye

博士 === 國立臺北科技大學 === 機電科技研究所 === 101 === The objective of this study was to investigate the development of the empirically-based performance models for water chillers. Several representative performance models were selected for a total evaluation on the prediction accuracy and the suitability. These models were then used in the verification of energy efficiency measurements for water chillers. Finally these models were used in fault detection and diagnosis of water chiller systems. The prediction accuracy and model suitability of eleven empirically-based performance models for water chillers were studied. Then this study evaluated over 2000 datasets which comprise operating data for constant or variable chilled water flow rates, and for fixed or variable speed drive centrifugal liquid chillers. The results show that among the eleven empirical-based models, the Bi-quadratic regression model, the multivariate polynomial regression model, the simple multivariate polynomial regression model, and the modified DOE-2 model, all have prediction CV values under 1% for all datasets. These models were shown to achieve good prediction accuracy. Then these six models were further evaluated in terms of energy saving potential using the data sets that comprise of short-term measurement data and long-term monitoring data. These models were evaluated for the performance prediction ability, model suitability, and energy saving analysis. This study found that (1) modified Gordon-Ng universal model cannot be used for external data, (2) the Gordon-Ng universal model has the best prediction accuracy, (3) performance prediction ability of chiller performance model will affect the analysis of energy efficiency analysis greatly, and (4) the proposed model in the ASHRAE Guideline 14 must be re-evaluated. The results of this study provide important reference for selecting empirically-based performance models for energy analysis, optimal operating control, energy efficiency measurement and verification (M&V), and the development of fault detection and diagnosis (FDD) systems for centrifugal water chillers.