Theoretical Analysis And Experimental Study On Climate Adaptation Of Direct Expansion Air Conditioning Systems

China has a vast area and the climate varies greatly from region to region.Therefore,in order to meet the requirements of different users for indoor thermal comfort in different climate zones,higher requirements are put forward for the design of air conditioning system.However,in the evaporator of a direct expansion air conditioner,the cooling and dehumidification processes are coupled,so the proportion of the sensible cooling capacity and the latent cooling capacity is mutually restricted.In addition,the heat and humidity loads of buildings in different climatic regions are different,and the distribution rules are not the same.However,at present,most direct expansion air conditioners are designed and selected according to fixed working conditions,and only the total cooling capacity is considered,without distinguishing sensible cooling capacity and latent cooling capacity.Accordingly,the direct expansion air conditioning system only takes the indoor temperature as the control target,and the indoor humidity fluctuates randomly,which leads to its failure to ensure that it can meet the thermal comfort requirements of the indoor environment when used in different climatic regions.In view of the shortage of existing research,this paper carries out theoretical and experimental research on the climate adaptation of direct expansion air conditioning system.In order to comprehensively compare the matching between the output capacity of air conditioning system and the heat and humidity load of buildings,this paper firstly studies the influence of climate on the heat and humidity load of buildings.Aiming at the typical building model in Guangzhou,the hourly thermal load and humidity load of the building are obtained by using the energy consumption simulation software.In this way,the two-dimensional plan of building thermal and humidity load is established and the influence of different influencing factors on the plan is studied.Then,a direct expansion air conditioning prototype was selected to test the output capacity,and the output cooling capacity of the air conditioning system was divided into sensible cooling capacity and latent cooling capacity for separate analysis.Thus,the plane diagram of air conditioning system output capacity is obtained,and the influence of different working conditions on the plane diagram of air conditioning system output capacity is studied.Then,the building load plane and the air conditioning cooling output capacity plane are analyzed in the same coordinate.Taking the percentage of building load point falling on the plane of air conditioning cooling output capacity as the criterion of air conditioning climate adaptation,this paper explores the adaptation of direct expansion air system conditioning to different characteristic loads.Finally,in view of the limitations of the existing direct expansion air conditioning system climate adaptation application,the traditional algorithm and the climate adaptation algorithm of air conditioning system operation comparison experiments.The experimental results show that the climate adaptive algorithm is significantly better than the traditional algorithm in terms of control strategy and indoor thermal comfort in building load plane I area,and it can approach any controllable load with variable control path,so it has certain climate adaptive ability and can meet the needs of different load characteristics.At the same time,this study proposed that the climate adaptation algorithm expanded the optimization range in the load plane,provided the possibility of optimization in a wider range,and also provided research ideas and directions for the further development of the air conditioning system for the simultaneous optimization of climate adaptation and energy consumption.