A radiative heat network method for accurate indoor radiant field and thermal comfort evaluation

Abstract

Solar radiation entering the interior through windows has a significant impact on the indoor radiation environment. Previous studies have proposed models to quantify the effects of direct solar radiation on the radiation environment and human thermal comfort. However, little attention has been given to the additional long-wave radiation effects generated by sunlight-heated wall surfaces. To address this gap, this study developed a radiative heat network model combined with a one-dimensional finite volume method. By dividing walls into multiple surface units, the model enhances resolution, improves the ability to capture localized heating effects from solar radiation, and significantly increases the accuracy of wall temperature distribution calculations. Model validation shows that the surface temperature error is less than 0.32 °C, and the ΔMRT error induced by solar radiation is below 1.9 °C. The results indicate that under high-resolution conditions, wall temperatures can increase by up to 16.6 °C, resulting in localized MRT and SMRT increases of 7.3 °C and 8.8 °C, respectively. Based on this model, the study further explored the combined effects of thermochromic and Low-E glass on regulating radiation environments. The results demonstrate that this combination effectively reduces summer cooling energy consumption by 57.8 %, increases thermal comfort probabilities by 4 %, and significantly improves the uniformity of indoor thermal comfort distribution. This work provides foundational technical support for the evaluation and design of indoor thermal environments.