Study On Optimal Control Strategies Of VWV Chilled Water System In Building

With development of the world economy, HVAC systems have gain more extensive application than ever before. Currently, it is not only demanded to improve indoor thermal comfort and indoor air quality, but also it is in accord with the concerning rules of energy saving and environment protection. Now the key issue to improve the level of HVAC systems is to improve its controls, i.e., to develop the optimal strategies for its controls.The aim of the paper is to study the optimal control based on MATLAB simulation of typical VWV chilled water system. The content of the paper is to develop and analyze the effect of the sets of local controls in system performance and control performance. First, the model of each part of VWV chilled water system was given, each characteristics was analyzed, and control strategies and methods of VWV chilled water system were given. Then, according to the characteristics of continuity loads of air conditioning and uncontinuity of chilled water system, and COP (Coefficient of Performance) and PLR(Part Load Ratio) of VAV chilled water system, load distribution method was given based on minimum energy consuming, so optimal load distribution ratio was obtained. For VWV system, due to its characteristics of more control variables and more complicated system structure, set point of supply head value of secondary pump in chilled water system was optimized by using position information of AHU valve and controlling the valve whose position value is the highest to approach maximum position as possible, and corresponding optimal strategies were proposed; Finally, optimal control strategies of VWV chilled water system was simulated and analyzed.Simulation results show that the optimal control strategies in the dissertation can optimize running of chilled water system and save energy, so the strategies are feasible.