Field experimental study of the impact of solar radiation on the thermal comfort of occupants near the glazing area in an office building

Abstract

The ultimate goal of indoor environment design in office buildings is to create a comfortable thermal environment. To satisfy diverse needs, there has been a notable increase in the use of exterior windows in building facades in recent years. This typically results in severe indoor thermal-comfort issues. In this study, a long-term field experiment was conducted in a typical south-facing office during winter, spring, and summer to investigate the thermal comfort of occupants in proximity to glazing. The results indicate that solar radiation transmitted indoors exerts a considerable influence on the thermal comfort of occupants in proximity to glazing. The intensity of solar radiation transmitted indoors has a pronounced impact on the nonuniform thermal environment, wherein the mean radiant temperature distribution is spatially inhomogeneous and exhibits a degree of asymmetric radiant temperature. This effect is observed to diminish as the occupants’ proximity to the window diminishes. The solar-adjusted operative temperature provides an appropriate approach for evaluating or predicting human comfort with direct solar radiation. The sensitivity of occupants to elevated ambient temperature was greater when they were exposed to solar radiation. In the absence of direct solar radiation, the acceptable range of operative temperature ought to be maintained within the range of 22.5 to 25.5 °C. In the presence of direct solar radiation, the acceptable range of solar-adjusted operative temperature should be maintained within the range of 22.0 to 24.5 °C. The deviation between thermal neutrality and thermal comfort is apparent; the deviation between the upper and lower comfort limits is 2.0 °C and 1.6 °C respectively, when occupants are exposed to solar radiation. This deviation indicates that although the thermal sensation reaches neutrality, the occupant may not remain in a comfortable state. Given the crucial function of windows in shaping the indoor thermal environment, the outcomes of this study may assist researchers and designers in selecting more reasonable strategies for improving the indoor thermal environment in buildings with extensive glazing.