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PERFORMANCE IMPROVEMENT OF WATER-COOLED SCREW CHILLER UNDER PART LOAD OPERATION CONDITIONS BY THE PARALLELING THROTTLE MECHANISM

ABSTRACT
Currently, water-cooled screw chiller is widely applied in commercial and industrial buildings, and the energy consumption of water chiller even could cover 70% of air-conditioning energy consumption in the most adverse operating conditions. Moreover, a number of chillers are running at a low rate under part-load state. In order to reduce the energy consumption of water-cooled screw chillers under part-load state, the paper presents the paralleling throttle mechanism. Through experimental study, under part-load state, it can be found that the by-pass tube diameter Ø16 has the most positive effect on the performance of water-cooled screw chiller in four by-pass tube diameters. The oblique access mode is better than the vertical access mode, while the spiral access mode has little influence on the chiller performance. Because of paralleling throttle using, the exergetic loss of the evaporator and chiller is able to be reduced by 3.4%-15.5% and 0-6.7%, respectively. Meanwhile, the coefficient of performance of chiller can be enhanced by 0.2%-1.6%, and discharge temperature can be reduced by 0.4-2.7°C. In addition, the economic and environmental benefits of the advanced water-cooled screw chiller are more evident than the conventional water-cooled screw chiller's.
KEYWORDS
PAPER SUBMITTED: 2017-10-11
PAPER REVISED: 2017-11-27
PAPER ACCEPTED: 2017-11-28
PUBLISHED ONLINE: 2018-02-18
DOI REFERENCE: https://doi.org/10.2298/TSCI171011043N
CITATION EXPORT: view in browser or download as text file
THERMAL SCIENCE YEAR 2018, VOLUME 22, ISSUE Supplement 2, PAGES [S585 - S596]
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© 2018 Society of Thermal Engineers of Serbia. Published by the Vinča Institute of Nuclear Sciences, Belgrade, Serbia. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International licence