Research On Operation Optimization Control Strategy Of Central Air Conditioning Water System

In order to improve the energy efficiency of the building of the building of a resource-saving society,the energy consumption of the air-conditioning system is concentrated,which has caused extensive research in society.At present,the use of centralized air-conditioning water systems in large public buildings cannot achieve a complete matching of cooling capacity and cooling load.Through theoretical analysis and experimental research,this paper establishes the mathematical model and energy consumption model of each main equipment in the air-conditioning system,uses TRNSYS software to perform integrated simulation of the air-conditioning system,and sets up an air-conditioning water system simulation experiment platform for different air-conditioning variable water systems Energy consumption simulation and analysis of optimized control strategies.This article first establishes a central air-conditioning chilled water system equipment model,which lays the foundation for the study of energy efficiency optimization of chilled water system operation.And analyze the parameters of the key equipment that forms the central air-conditioning chilled water system,including:chiller units,variable frequency pumps,valves,etc.When using TRNSYS software to build an air-conditioning water system simulation platform,based on the module’s energy characteristics and control characteristics,analyze the hydraulic characteristics of modules such as pumps and chiller units,and determine the logical relationship between parameters such as pressure,flow and head in each device It provides a theoretical basis for the subsequent creation of modules and programming in TRNSYS software.A frequency conversion control strategy for the chilled water pump of the central air conditioning water system is proposed,and the temperature difference and pressure difference control strategies of the variable flow system are considered in particular.The air conditioning water system adopts two different control strategies.The control parameters come from the pressure difference between the main supplyand the main return pipes,and the temperature difference between the chilled water outlet and the return water main of the chilled water system.The input signal calculates the deviation according to a preset control algorithm and generates an output signal to control the frequency or rotation speed of the motor of the chilled water pump,so as to adapt to changes in air conditioning load by changing parameters such as the water supply of the chilled water pump.Use TRNSYS software to build a simulation platform for a centralized air-conditioning variable flow water system,conduct simulation analysis of energy-saving optimization strategies,collect data for a comprehensive building’s centralized air-conditioning water system as a research object,and perform dynamic load models and equipment operation of the centralized air-conditioning variable flow system.The experimental conditions were systematically studied.The energy consumption of each component in the system of the central air-conditioning variable flow system under two control strategies of constant temperature difference and constant pressure difference is adopted and analyzed.The simulation test results show that adopting the constant temperature difference control strategy can make the system energy saving rate reach 26.37%,and the annual power consumption of the building is reduced by 8.07 k W · h/ ㎡;adopting the constant pressure difference control strategy,the system energy saving rate reaches 9.28% The annual power consumption is reduced by 2.8 k W·h/㎡.Compared with the constant pressure difference control system,the total energy consumption of the constant temperature difference control can be reduced by about 18.7%.It is proved that the constant temperature difference control method is feasible.