Investigation Of Simulink/Fluent Collaborative Simulation Between The Air Conditioning System And The Thermal Environment Of An Air Conditioned Room

In order to accurately predict the dynamic variation of thermal environment in an air conditioned room and improve the thermal comfort test efficiency of air conditioner devices,a parallel collaborative simulation method was proposed in this study.The efficient coupling and collaborative prediction between air conditioning system and room thermal environment can be realized by utilizing the advantages of Simulink and Fluent.The specific work that has been done is presented in the following aspects.First of all,according to the principle of thermodynamics,the one-dimensional dynamic model of air conditioning system was established by Simulink.The proposed model was validated with steady-state experimental data and the error was within 3%.By considering variations on the operating frequency of the compressor and outdoor conditions,the constructed model of air conditioning system can effectively predict the dynamic characteristics of the air conditioner.Secondly,taking the thermal environment of the air-conditioned room as the research object,the three-dimensional numerical model of room was built by Fluent.The thermal environment model of the air-conditioned room was also solided by experiment and the error was within 10%.By varying the air supply angle and velocity of the indoor unit,the proposed room model can effectively calculate the temperature field and velocity field of the air-conditioned room.Then,based on the principle of sharing data file,the communication interface between Simulink and Fluent was developed by using S-Function and UDF respectively.The parallel collaborative simulation platform was further constructed based on the proposed communication mode.The control strategies of the collaborative simulation model were designed for the studied air conditioner.Finally,the collaborative simulation model was utilized to simulate the operating process of the studied air conditioner and the dynamic response process of room thermal environment.At the same time,the thermal environment of an air conditioned room is predicted and analyzed by varying structural parameters(evaporator structures)and control parameters(control strategies,set temperatures,and air supply angles)of the air conditioner,and the thermal environment was evaluated under such cases.The simulation results are summarized as follows: i)due to the lack of actual control strategy applied in the air conditioner unit,the idealization of the room model and simplification of the air outlet structure,the collaborative simulation model has some deviation with the experimental results when predicting part of the thermal environment evaluation indexes such as temperature deviation,temperature fluctuation,etc.However,it is realized the interactions among system structural parameters,control parameters and the room thermal environment to some extent.Based on this collaborative simulation method,the air conditioning system model and the room thermal environment model can be further optimized to improve the overall prediction accuracy.ii)Within a given parameter range,both the structural parameters and control parameters of the air conditioning system affect the development and variations of the thermal enviroment,as well as the related evaluation indexs.When the structure of evaporator is changed,the influence on temperature uniformity and vertical air temperature difference is stronger,followed by PMV and DR.The sensitivity of related evaluation indexes of thermal environment to evaporator structural parameters is fin spacing,tube spacing,and tube outer diameter in order.When altering the control strategy,the impact on temperature uniformity and vertical air temperature difference is also stronger,followed by PMV and DR.When the set temperature varies,PMV and DR are mainly affected,followed by air cooling rate and temperature deviation.The variations of air supply angle obviously influence the evaluation of the vertical air temperature difference,but the effect on PMV,DR and temperature uniformity does not indicate differences in regularity.