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Heat output and uniformity of surface temperature distribution are primarily concerned by designers and users of radiant floor heating. The testing approach, testing conditions and calculation of the heat output at each stage of program are different among the test standards. In this paper, a mathematical model to calculate surface temperature and heat output of radiant floor heating system was proposed. Measured data from experiments was used to validate the proposed model. Based on this simulation model, four current test standards in China, Europe, America and Japan were simulated. The simulation results show that the heat output of the same sample is different under the four test standards. Meanwhile, simulations were carried out at various non-heating surface temperatures. The results indicate that the non-heating surface temperature has a significant impact on the heat output of the radiant floor. The differences in the simulations of heating capacity vary from 2% to 7%. Hence, a parameter, the temperature difference between average water temperature of test sample and area weighted average temperature of non-heating surfaces, is introduced to revise the heat output characteristic equation based on the Chinese test standard. [ABSTRACT FROM AUTHOR]

• The effects of diffuse solar radiation on indoor thermal comfort are studied. • CPMV is found to deviate from TSV at high diffuse solar radiation intensity. • CPMV* is proposed to assess thermal comfort under direct and diffuse solar radiation. • CPMV* is verified to be consistent with TSV through field experiments. • Thermal acceptability in solar conditions is analyzed and compared with Fanger's PPD. With the wide application of curtain walls in modern buildings, the effect of solar radiation on indoor thermal comfort becomes significant. To assess the thermal comfort under solar conditions, the corrected predicted mean vote (CPMV) was proposed due to the neglect of solar radiation in the predicted mean vote (PMV) developed by Fanger. However, CPMV only considers direct solar radiation and ignores diffuse solar radiation. Therefore, the effects of diffuse solar radiation on thermal comfort are studied in this research, and field experiments are conducted in transparent envelope buildings. 916 thermal responses are collected in summer. The results reveal that CPMV deviates from the thermal sensation vote (TSV) at high diffuse solar radiation. Then the CPMV* is proposed to consider both direct and diffuse solar radiation, and it is validated to be accurate in quantitatively predicting the thermal sensation under global solar radiation. The thermal acceptability in solar conditions is obtained through questionnaire. The results of thermal unacceptability are different from the predicted percentage dissatisfied (PPD) developed by Fanger. The minimum percentage of dissatisfaction is 12% instead of 5% based on Fanger's PPD, and occurs at the CPMV* of −0.34 other than 0. [ABSTRACT FROM AUTHOR]