Research On Optimization Of Operating Strategy Of Dual Temperature Cold Source Air Conditioning System

In the traditional air conditioning system,the sensible heat load and latent heat load of the room are borne by the same cold source.In order to achieve the purpose of dehumidification,low-temperature cold source of 5 ~ 7? is generally adopted.The sensible heat load accounts for more than half of the total air conditioner load,which can be borne by a high-temperature cold source at 15-18°C,but they are processed by the low temperature cold source together with the latent heat load,resulting in the waste of energy utilization grade.In addition,the traditional air conditioning system also has its disadvantages in terms of comfort and air quality.In recent years,the temperature and humidity independent control system due to its advantages in the aspects of comfort and energy-saving received widespread attention,so in this paper,a kind of temperature and humidity independent control system based on dual temperature cold source was studied,and discusses the dual temperature source energy saving mechanism of the air conditioning system,and proposes two kinds of optimal control strategies for the variable operating conditions of its fresh air subsystem.This paper summarizes the disadvantages of the traditional air conditioning system and the principle and advantages of the temperature and humidity independent control system.Taking an office building in Beijing as an object,the physical model of this building was built by SketchUp and Openstudio,and the load calculation was carried out by Energyplus energy consumption simulation software,and the distribution characteristics of room load in the air conditioning season were obtained.The energy consumption simulation model of dual temperature and cold source system using traditional control method was established,and the simulation results were compared with the test data,so as to verify the accuracy of the model.According to the load and operation characteristics of the air-conditioning system based on dual temperature cold source,two optimal control strategies of the fresh air subsystem under variable operating conditions are proposed.Energyplus energy consumption simulation software was used to build simulation models of air-conditioning system based on dual temperature cold source using these two operating strategies,and energy consumption simulation data were obtained.Comparing the energy consumption data of the original system with that of the system using the optimized operation strategy,the research results show that: in terms of the energy consumption comparison on the design day,the energy saving rate of the dual temperature cold source system using operation strategy 1 and operation strategy 2 is7.76% and 6.63%,respectively,compared with the original system.In terms of the energy consumption comparison in the air conditioning season,the energy saving rates of the dual temperature cold source system using operation strategy 1 and operation strategy 2 are 10.25% and 8.91%,respectively.The thermal comfort module was added to the simulation models of air-conditioning system based dual temperature cold source using three operating strategies respectively.Thermal comfort analysis was carried out and thermal comfort indexes were obtained under different operating strategies.The results show that the thermal comfort index of the dual temperature cold source system with operation strategy 1 and operation strategy 2 is better than the traditional operation strategy in cooling season and design day.