Research On Emission Of Ceiling Radiant Cooling Panels And Analysis Of Indoor Thermal Environment

With the intensification of global energy crisis, ceiling radiant cooling panelsand dedicated outdoor air system has attracted great attentions due to its energysaving and thermal comfort. More and more scholars at home and abroad start to studyits performance during these years.Emissivity is one of basic thermal parameters of an object which is important todescribe the object’s thermal radiation character.With important application value andresearch significance in aviation,aerospace, scientific research, national defense,industrial and agricultural production fileds,many scholars at home and abroad areexploring its method of measurement.However,few people carry out the research onthe emissivity applied in radiative transfer in radiation refrigeration and heatingsystem.Ceiling radiant cooling panels and dedicated outdoor air system is described inthis paper systematically,in which analyzes calculation method of heat convection andradiation in the system,and three basic laws of radiation transfer.Especially,theemissivity of the surfaces will be studied for which typical measuring methods ofemissivity and main factors that will impact the emissivity.Meanwhile,a emissivitymathematical model is built based on the radiation heat transfer theory,on which someexperiment is conducted to get some data.Then,the analysis on experimentaldata,experimental thermal loss and errors are studied.At last,based on mathematicalmodes,the emissivity data of all surfaces are got.In this paper,a numerical simulation of thermal environment for ceiling radiantcooling panels and dedicated outdoor air system is conducted by CFD simulation toanalyze the air velocity and temperature,especially, the environment around theworker in the room.The result of this simulation indicates that the air velocity aroundthe worker is below0.3m/s,the indoor air temperature difference between the headand the ankle of a worker when sitting is about1℃.It is within the range of thermalcomfort of the specification as required.From the simulation,the air diffusionperformance index is84.8%,which indicates that people enjoy a good thermal comfortenvironment in ceiling radiant cooling panels and dedicated outdoor air system.