Research On Air Conditioning Terminals For Chilled Water With Large Temperature Difference

China is a large energy consumer,building energy consumption has gradually become one of the main energy consumption,and air conditioning energy consumption is an important part of building energy consumption.Air conditioning energy consumption can be divided into cold and heat source energy consumption,transmission energy consumption,terminal energy consumption and fresh air energy consumption.Increasing the temperature difference of chilled water can effectively reduce the energy consumption of air conditioning.Through three-stage chiller,15℃large temperature difference air-conditioning system can be realized,it can greatly reduce the flow of chilled water,and saving conveying energy consumption of water pump,water chiller efficiency can be significantly improved.But due to the change of the temperature difference,the existing terminals are not enough to match the operation of the large temperature difference air conditioning system.In view of the problem,this paper is aimed at 15℃ at the terminal of the large temperature difference air-conditioning system a series of research.Firstly based on the existing large temperature difference FCU and dry FCU,and proposed the terminal scheme of the series FCU to match the 15℃ large temperature difference air conditioning system,and preliminarily discusses the feasibility of the series FCU by comparing the various conventional FCU.The analysis shows that the series scheme has reduced water flow,the power consumption is not obvious,and the parameters can be satisfied.On this basis,in order to facilitate the engineering application,combined with the design and calculation of the surface cooler,the design of the series fan coil unit was optimized.Based on the terminal of the series FCU and CFD simulation software to simulate the layout of the series FCU of an air-conditioned room,simulated and calculated the influence of different layouts on the indoor airflow organization including temperature field and velocity field,and the optimal layout form of the series FCU was obtained by comparative analysis.For the single FCU,the orthogonal design method was used to calculate the factors,and the cooling efficiency and enthalpy efficiency were used as the evaluation indexes to analyze the factors and optimize the calculation of the large temperature difference FCU,so as to provide technical support for the design of large temperature difference FCU.Then based on the air conditioning system with large temperature difference of 15℃ for chiller water,this paper analyzes the scheme of conventional air conditioning unit and series surface air cooler,designs and selects the surface air cooler for each scheme in an air conditioning room,and makes a preliminary evaluation of the series surface air cooler scheme.Finally,based on the proposed terminal scheme and combined with the 15℃ large temperature difference three-stage series chiller,makes a preliminary analysis on the engineering design of a building air conditioner,providing reference for the engineering practice of the large temperature difference system.The research in this paper provides the matching idea for the terminal of the chiller water 15℃ large temperature difference air conditioning system,and also provides support for the optimization design of the large temperature difference terminal equipment,which is expected to promote the development of the large temperature difference air conditioning system and promote the building energy saving.