Research On Constant-variable Flow Control Of Time-sharing And Partitions Heating Mode For Secondary System

Under the background of promoting vigorously energy conservation of building in China, energy-saving retrofit for heating system is extraordinary important. There is a phenomenon that a large number of public buildings and residential buildings share the same heat source of secondary system in traditional heating system with indirect connection. Most of existing urban heating system is still not installed heating metering equipment, and end users aren’t installed temperature control equipment, making the reform of heating metering system slow. Under the premise of thermal comfort for different heating rule users, to make heating system stays energy-saving operation, needs to do further research work in aspects of heating characteristics, management and control based on existing studies.For secondary heating system, time-sharing and partitions heating control can be used. This article obtained that characteristic of time-sharing and partitions heating system in different building district types by simulating users load response under ideal control using TRNSYS. And combining the theory of operation regulation, confirm adjustment methods combined by centralized regulation and topical regulation. And proposed universal time-sharing and partitions heating system with constant-variable flow control strategy from preheat control of heat source, control of operational parameters, the minimum flow control, end actuator control and night shift temperature control.Built secondary heating system models in TRNSYS program, and simulated heating results and system energy consumption in different constant-variable flow control schemes and obtained the best solution. For different building district types, proposed the range of controlled flow is various. Compared with the results of constant flow control, proportion of thermal comfort increased by4.2%～6%, proportion of overheating decreased1.5%～5%, and energy saving rate reached3.85%～7.4%in different areas. The greater the proportion of residential building is, the more obvious the improvement of thermal comfort to the system by constant-variable flow control is, and the greater system energy saving rate is.By using the constant-variable flow control based on heat load forecasting method for different building district types, it shows that proportion of thermal comfort increased by5.9%～10.2%, proportion of overheating decreased4.2%～11.1%, and energy saving rate reached3.85%～7.4%by original constant-variable flow control.