Design And Application Of Air Comfort Control For VAV Air Conditioning

With the rapid development of science and technology increased,people's living standards of comfortable indoor environment is also increasing.As the most important equipment to affect the air comfort,air conditioner plays a main role in daily life.Because of its flexibility and energy efficiency,Variable air volume?VAV?air conditioner gradually become the mainstream of central air conditioning systems,and has been quickly promoted and applied.Temperature,humidity and CO₂ concentration of air are main factors that affect comfort and energy consumption of air-conditioned room.Accurate and intelligent control of the central air conditioning temperature,humidity and CO₂ concentration for improving comfort,energy saving and even create greater economic value has a significant meaning.Because of the multivariable,strong coupling,non-linearity and time-varying characteristics of VAV air conditioning system,PID control is difficult to meet the requirements of energy saving,high efficiency and air comfort at the same time.The traditional VAV control system adopts PID control.The purpose of this paper is to build a control system which can meet the requirements of multivariable and fast control for VAV air conditioning based on the traditional PID control algorithm.Firstly,air conditioning system is a typical complex control system with large inertia,large delay,time-varying and nonlinear.According to the operation characteristics of VAV system,the main factors that affect the operation and energy-saving effect are analyzed.Importance of integrated control method for variable air volume air conditioning system is pointed out.Secondly,the advantages and disadvantages of the traditional PID control method are analyzed and the advantages of the fuzzy control are analyzed.The fuzzy control algorithm is adopted to control the variable air volume air conditioning system and meet air comfort and other requirements.Thirdly,the priority of temperature,humidity and air freshness of VAV air conditioning are divided into different levels.Based on the VAV system of Chengdu Teda Time Center,the control system has been improved.Finally,the system modeling and simulation experiments are carried out.The simulation results show that the design scheme can improve the fastness on the basis of satisfying the comfort,and prove that the scheme is reasonable and feasible.