Energy modeling and optimization of building condenser water systems with all-variable speed pumps and tower fans:A case study  

作　　者：Yong Cao Chuang Wang Sheng Wang Xiao Fu Xinguo Ming 

机构地区：[1]School of Mechanical Engineering,Shanghai Jiao Tong University,Shanghai 200240,China [2]State Key Laboratory of Air-Conditioning Equipment and System Energy Conservation,Zhuhai 519070,China [3]GREE Electric Appliances,Inc.of Zhuhai,Zhuhai 519070,China [4]School of Environment and Energy Engineering,Beijing University of Civil Engineering and Architecture,Beijing 100044,China [5]Beijing Advanced Innovation Centerfor Future Urban Design,Beijing University of Civil Engineering and Architecture,Beijing 100044,China

出　　处：《Building Simulation》2024年第7期1085-1111,共27页建筑模拟（英文）

基　　金：supported by the State Key Laboratory of Air-Conditioning Equipment and System Energy Conservation(No.ACSKL2019KT13);National Natural Science Foundation of China(No.51608297);Scientific Research Project of Beijing Municipal Education Commission(No.KM201910016009 and No.KZ202110016022);Beijing Advanced Innovation Center for Future Urban Design(No.UDC2019011121);Pyramid Talent Training Project(No.JDYC20220815);Post-Graduate Innovation Project(No.PG2024077)of Beijing University of Civil Engineering and Architecture.

摘　　要：The emergence of building condenser water systems with all-variable speed pumps and tower fans allows for increased efficiency and flexibility of chiller plants in partial load operation but also increases the control complexity of condenser water systems.This study aims to develop an integrated modeling technique for evaluating and optimizing the energy performance of such a condenser water system.The proposed system model is based on the semi-physical semi-empirical chiller,pump,and cooling tower models,with capabilities of fully considering the hydraulic and thermal interactions in the condenser water loop,being solved analytically and much faster than iterative solvers and supporting the explicit optimization of the pump and tower fan frequency.A mathematical approach,based on the system model and constrained optimization technique,is subsequently established to evaluate the energy performance of a typical dual setpoint-based variable speed strategy and find its energy-saving potential and most efficient operation by jointly optimizing pumps and tower fans.An all-variable speed chiller plant from Wuhan,China,is used for a case study to validate the system model’s accuracy and explore its applicability.The results showed that the system model can accurately simulate the condenser water system’s performance under various operating conditions.By optimizing the frequencies of pumps and tower fans,the total system energy consumption can be reduced by 12%–13%compared to the fixed dual setpoint-based strategy with range and approach setpoints of 4℃and 2℃.In contrast,the energy-saving potential of optimizing the cooling tower sequencing is insignificant.A simple joint speed control method for optimizing the pumps and tower fans emerged,i.e.,the optimal pump and fan frequency are linearly correlated(if both are non-extremes)and depend on the chiller part load ratio only,irrespective of the ambient wet-bulb temperature and chilled water supply temperature.It was also found that the oversizing issue has furthe

关 键 词：all-variable speed chiller plant model-based optimization hydraulic and thermal coupling analytical solution dual setpoint-based variable speed control optimal joint speed control 

分 类 号：TQ051.61[化学工程]