Research On Indoor Thermal Comfort Index Of Human Body Under Direct Solar Radiation

The predicted mean vote(PMV)model proposed by Prof.Fanger of Technical University of Denmark is the authority of thermal comfort evaluation.However,this model does not consider solar radiation and it is not suitable for thermal comfort evaluation of transparent envelope buildings.Indoor parameters are determined by thermal comfort model,so the use of Fanger's model in transparent envelope buildings will lead to inaccurate indoor parameter setting.To solve this problem,a Corrected Predicted Mean Vote(CPMV)which is applicable for indoor environments with direct solar radiation is proposed in this paper.Considering the solar radiation,the thermal comfort model is corrected by theoretical derivation.Firstly,the mathematical model of CPMV considering solar radiation is established;secondly,the expression of clothing surface temperature is also corrected;finally,the corrected operative temperature considering the effect of solar radiation is proposed.A large number of field experiments were conducted in three typical transparent envelope buildings in Tianjin to validate the accuracy of CPMV model propose in this paper.The experimental sites were Tianjin West Railway Station,the library of Tianjin University new campus and the 43 rd Building of Tianjin University.The experimental methods in this study include environmental parameters monitoring and questionnaire survey.A total of 1888 thermal responses in the three buildings were obtained by questionnaires.Experimental data in buildings with transparent envelope reveals a lack of agreement between PMV and Thermal Sensation Vote(TSV)because it ignores the effect of solar radiation.It was found that the predicted values of CPMV agree quite well with the TSV obtained from the subjects.According to the experimental results,the maximum deviation of PMV is 2.03 while the deviation of CPMV is within 0.20.To explore the influence of each parameter on thermal comfort,the thermal preferences under solar radiation conditions are discussed in this paper.The gender differences on thermal preferences were also studied.Taking Tianjin West Railway Station as an application example of CPMV,the recommended value of transparent envelope transmittance is given according to the CFD simulation results and CPMV method.Moreover,the operating parameters should respond to changes in solar radiation intensity on the basis of CPMV index.This method can be used in any building.