Optimum Operation of Air-Cooled Chillers with Multiple Refrigeration Circuits
Air-cooled chillers are generally the major electricity consumers in air-conditioned buildings in the subtropical climate. To improve the energy efficiency of the air-cooled chillers at part load conditions, two or more refrigeration circuits are designed for water chillers. This paper considers how the use of circuit loading sequence (CLS) enables these chillers to operate more efficiently. A thermodynamic model for the air-cooled chillers with multiple refrigeration circuits was developed and validated using a wide range of operating data. The chiller model considered real process phenomena, integrating the control algorithms for compressors staging, refrigeration circuits switching, condenser fan cycling and expansion valve. Under the optimum CLS, the chiller coefficient of performance (COP) can increase by up to 27.6％ compared with the traditional CLS, depending on the operating conditions. A cooling load profile of an office building in a subtropical climate was considered to assess the potential electricity savings by use of CLS. With regard to the building requiring an annual cooling energy of 9.94x106 kWh, optimal CLS enables the annual electricity consumption of chillers to drop by 3.1％. When condensing temperature control (CTC) are applied to the optimum CLS, an electricity saving of up to 14.8％ could be achieved in the chiller plant. The results of this paper provide useful information on how to implement an air-cooled chiller plant more efficiently.
Air-cooled chiller Multiple refrigeration circuits Circuit loading sequence Condensing temperature control
Jia Yang K.T.Chan Xiangsheng Wu
Department of Building Services Engineering,The Hong Kong Polytechnic University,Hong Kong,China Dep Department of Building Services Engineering,The Hong Kong Polytechnic University,Hong Kong,China Department of Real Estate Management and Environmental Engineering,Logistical Engineering University
国际会议
The 6th International Symposium on Heating,Ventilating and Air Conditioning(第六届国际暖通空调学术会议)
南京
英文
460-467
2009-11-06（万方平台首次上网日期，不代表论文的发表时间）