The Economic Operation Research Of District Cooling System

District cooling system is adopted more and more because of the complexity and variety of the terminal users. In order to meet the complicate demand of the system, VWV system is brought from abroad. But the design of VWV system is based on the experience and materials of foreign countries. There are many problems in the design and actual operation. The paper discusses the efficient operation of VWV system, based on the investigation of an air conditioning system of an airport in Shanghai and calculation, analysis of some examples.The paper analyzes VWV system from four aspects, as follows: 1. analyzes the hydraulic imbalance based on the investigation of an air conditioning system of an airport in Shanghai. The indoor temperature of some hot region can be reduced by 1-2 ℃ after regulating. 2.analyzes and summaries the principles, right setting of the balancing valves, static balancing valve can meet the demand of CWVsystem; while in the VWVsystem, it is neccessary to install static balancing valve, auto-flow balancing valve, differential pressure balancing valve rightly, according to their different functions. 3.researches the dynamic characteristics of pipe network. Terminal users usually operate under overflow in the pressure-control system. But for the terminal pressure-control system, the operating condition depends on the distribution of the users in operation, the down-stream users usually operate under design condition, the upper-stream users' flow is less than the design one. For the primary pump system, pipe network resistance factor S is constant under higher load operation. 4.discusses the efficient operation methods of parallel pump. For a system, it is better to adopt the operation method that several pumps with VFD are paralleled than the one that one constant speed parallel with several pumps with VFD, when most users of the system operates.