Please use this identifier to cite or link to this item: http://hdl.handle.net/10397/65338
Title: Analysis of centrifugal chillers with oil-free magnetic bearings for enhancing building energy performance
Authors: Yu, FW
Chan, KT
Sit, RKY
Issue Date: 2017
Publisher: Taylor & Francis
Source: Science and technology for the built environment, 2017, v. 23, no. 2, p. 334-344 How to cite?
Journal: Science and technology for the built environment 
Abstract: This article examines the actual operating performance of centrifugal chillers with oil-free magnetic bearings (hereafter oil-free chillers) to analyze energy saving potentials for commercial buildings. A chiller system retrofit for a shopping arcade involved replacing three existing constant speed water-cooled centrifugal chillers by three oil-free centrifugal chillers of the same capacity. The coefficient of performance was calculated based on operating data logged at 1-h intervals for over 1 year before and after replacement. Oil-free chillers with variable speed control operated at a higher coefficient of performance under part load conditions, reducing the total electricity consumption of the shopping arcade by 9.6%. If the average technical efficiency in data envelopment analysis was improved to 1 from 0.6 in the existing case, the average system coefficient of performance could increase from 6.2 to 10.3. The improvement involved controlling the temperature of supply chilled water at a lower boundary curve and operating an equal percentage of capacity among chillers. It is economically viable to design an all-variable speed chiller system with oil-free chillers instead of the conventional constant speed system for a reference office building in a subtropical climate.
URI: http://hdl.handle.net/10397/65338
ISSN: 2374-4731
DOI: 10.1080/23744731.2016.1232112
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