Research On Optimization Of Capillary Pipe Network Air Conditioning In Residential Buildings In Cold Areas

In 2020,China proposed a dual-carbon policy,reducing carbon emissions and traditional energy consumption is imperative,and with the development of the economy and the improvement of living standards,people’s requirements for indoor air temperature and quality are getting higher and higher.The requirements of energy system balance and the extensive demand of air conditioning have challenged the current form of air conditioning system.How to improve air conditioning system to create a comfortable and energy-saving indoor environment has become a hot topic for scholars to study.As a representative form of temperature and humidity independent control air conditioning system,capillary mesh has gradually been recognized by virtue of its advantages of beauty,energy saving and comfort.However,the capillary network radiation cooling started relatively late in China,and there are few engineering applications.Therefore,starting from the practical application,this thesis optimized the cooling parameters and load distribution ratio of the combined system of capillary network radiation cooling and independent fresh air,aiming at providing basic data and theoretical guidance for the design and application of capillary network air conditioning.Firstly,an experimental study is carried out on the composite system of capillary network radiation cooling plus fan coil.By reasonably simplifying the model,the numerical simulation of experimental conditions is carried out by Airpak software.The accuracy of the established model is verified by comparing the simulation with the experiment.Secondly,the physical model of bedroom and living room was established,and the experiment scheme of 4 factors and 4 levels was designed by orthogonal experiment.The significance of influence of each cooling parameter on indoor thermal comfort was studied by range analysis and variance analysis.The results show that the location of capillary network in the bedroom has a significant effect on PMV and PPD values,and the location of air outlet has a significant effect on PMV and average radiation temperature.Because the bedroom space is small and the fresh air volume is small,the fresh air supply velocity and temperature within the set range have no significant effect on the evaluation index.The location of the capillary network in the living room has a significant effect on PMV,PPD,vertical temperature difference in the active area and mean radiant temperature,while the air supply temperature has a significant effect on PMV and mean radiant temperature.According to the comprehensive balance method,the optimal combination scheme is obtained and verified by simulation.Finally,through orthogonal test,it is found that the location of capillary network has the most significant influence on indoor thermal environment,and the indoor comfort is poor under the condition of ground cooling.In order to improve the indoor thermal environment under the condition of ground cooling of capillary network,the load distribution ratio of the composite system of radiant cooling of capillary network and independent fresh air is optimized on the basis of ensuring the minimum fresh air volume.By comparing and analyzing indoor thermal environment under different working conditions,the optimal proportion of cooling load borne by radiation terminal is obtained.The results show that when the radiation end of the bedroom bears the cooling load of 60～80%,and the radiation end of the living room bears the cooling load of 60～70%,the comfort index of indoor personnel activity area can be controlled within the standard allowable range.When the radiation end of the bedroom and the living room bear the cooling load of 80% and 70%,the best indoor thermal comfort can be obtained.From the point of view of avoiding local discomfort,the cooling load borne by the radiation end of the living room should be limited.Too low floor temperature is easy to cause discomfort.This thesis can provide some reference for the practical engineering application of capillary net radiant air conditioning in residential buildings in cold area.