An investigation of air and water dual adjustment decoupling control of surface heat exchanger

• Published in: Applied thermal engineering 2018-03, Vol.133, p.418-427
• Main Authors: Fang, Zhaosong, Xu, Xiaoning, Li, Qiao, You, Xiuhua, Oladokun, Majeed Olaide
• Format: Article
• Language: English
• Subjects: Air conditioners; Air conditioning; Central air-conditioning; Computer simulation; Control equipment; Cooling; Decoupling; Decoupling control; Energy consumption; Energy saving; Feedback control; Flow velocity; Heat exchanger; Heat exchangers; Heat transfer; Simulation; Studies; Water flow
• ISSN: 1359-4311; 1873-5606
• DOI: 10.1016/j.applthermaleng.2018.01.045

•The model of heat transfer of surface cooler was established by Matlab/Simulink.•A serial of experiments were conducted to variation of the model of heat transfer of surface cooler.•The decoupled control pattern can shorten the system regulation time and improve performance. The terminal equipment of central cooling system accounts for a significant proportion of the total system’s energy consumption. Therefore, it is important to reduce the terminal equipment energy consumption in central air conditioning system. In this study, the difference of the effect of the chilled water flow rate and air supply rate on the surface cooler during the heat transfer process is taken into full account. Matlab/Simulink simulation software is used to model and simulate the heat transfer of surface cooler of the main terminal equipment of air conditioning system. Simulation tests and experimental validations are conducted by using variable chilled water flow rate and variable air supply rate control mode separately. The experiment results show that the simulation model can effectively predict the heat transfer performance of heat exchanger. Further, the study introduced a dual feedback control mode, which synchronously regulates the chilled water flow rate and air supply rate. Also, under certain conditions, the complex heat transfer process of the surface cooler can be decoupled, and single variable control pattern is used to separately regulate the chilled water flow rate and air supply rate. This can effectively shorten the system regulation time, reduce overshoot and improve control performance.