Cascade control for supply air temperature in a variable air volume system

4th Asia Conference of International Building Performance Simulation Association

土木建筑工程

Zhuang, Junhua^1^2 ; Chen, Yimin^1^2^3 ; Wu, Jie^4

School of Electrical and Information Engineering, Beijing University of Civil Engineering and Architecture, Beijing, China^1

Beijing Key Laboratory of Intelligent Processing for Building Big Data, Beijing, China^2

Department of Civil Architectural and Environmental Engineering, Drexel University, Philadelphia

PA

19104, United States^3

Beijing ZXT MandE Engineering Consultant Co. Ltd, China^4

关键词: Air handling units;    Cascade structures;    Indoor temperature;    Internal controls;    Outdoor temperature;    Quality of controls;    Supply air temperature;    Variable-air-volume systems;   

Others  :  https://iopscience.iop.org/article/10.1088/1755-1315/238/1/012021/pdf
DOI  :  10.1088/1755-1315/238/1/012021

学科分类：土木及结构工程学

来源: IOP

【 摘 要 】

Most supply air temperature in variable air volume systems is typically set at 55F(13 ?C) that is design value in these systems. However, sometimes the load of cooling varies greatly in different zones, and it means the indoor temperature of low-load zones is lower than comfortable value, even if the supply air damper is at the minimum value that is not closed for minimum outside air requirement. Meanwhile, in transition season, the indoor temperature is also lower due to low outdoor temperature. These factors provided an opportunity to apply higher supply air temperature to reduce air handling unit (AHU) cooling load and box reheating. In this paper, a cascade control method is used to raise the supply air temperature. The external control loop controls the setting value of supply air temperature with the minimum supply air volume as the control target. And the internal control loop controls the supply air temperature by regulating valve. The cascade structure can solve the problem that the time constant of the system is too large. The simulation results show that the quality of control is good and the reheating can be cancelled.