Study On Enhacing The Adjustability And Hydraulic Balance Of HVAC Chilled Water Systems

As an important part of HVAC systems the chilled water system decide the operation mode and the energy-saving level of HVAC system. So the optimized design of chilled water system bring social benefit and economical benefit. The chilled water system has been developed in operational flexibility and efficiency in recent years. But all the chilled water system, especially in our country, still remains many problems unresolved, such as: regardless of adjustability and hydraulic balance of hydraulic networks leads to some troubles in practical running.In this paper means of enhancing adjustability and hydraulic balance of hydraulic networks were deeply studied based on the existed HVAC systems and actual projects. The research includes: analyzing the application and selection of all kinds of valves in chilled water system, especially balancing valve and differential pressure by-pass valve, applying Network Graph Theory to simulate the chilled water system, writing a program which can educe the flux distribution data in the chilled water system, drawing a conclusion that direct return system is feasible in medium-sized projects, writing a program to calculate the adjustability of branches in hydraulic networks according to the structure of networks, optimizing the design of networks and selection of valves according to the calculated adjustability. Furthermore in this paper several optimizing measures which can ensure the paralleled multi-chillers chilled water system run reliably in part load mode were presented.