The effects of solar radiation on thermal comfort

Abstract

The aim of this study was to investigate the relationship between simulated solar radiation and thermal comfort. Three studies investigated the effects of (1) the intensity of direct simulated solar radiation, (2) spectral content of simulated solar radiation and (3) glazing type on human thermal sensation responses. Eight male subjects were exposed in each of the three studies. In Study 1, subjects were exposed to four levels of simulated solar radiation: 0, 200, 400 and 600 Wm(-2). In Study 2, subjects were exposed to simulated solar radiation with four different spectral contents, each with a total intensity of 400 Wm(-2) on the subject. In Study 3, subjects were exposed through glass to radiation caused by 1,000 Wm(-2) of simulated solar radiation on the exterior surface of four different glazing types. The environment was otherwise thermally neutral where there was no direct radiation, predicted mean vote (PMV)=0+/-0.5, [International Standards Organisation (ISO) standard 7730]. Ratings of thermal sensation, comfort, stickiness and preference and measures of mean skin temperature (t(sk)) were taken. Increase in the total intensity of simulated solar radiation rather than the specific wavelength of the radiation is the critical factor affecting thermal comfort. Thermal sensation votes showed that there was a sensation scale increase of 1 scale unit for each increase of direct radiation of around 200 Wm(-2). The specific spectral content of the radiation has no direct effect on thermal sensation. The results contribute to models for determining the effects of solar radiation on thermal comfort in vehicles, buildings and outdoors.

Estimating the radiation absorbed by a human

“…Traditional approaches to estimating R in outdoor thermal comfort research can be time-consuming, expensive, cumbersome, and may not adequately address the contribution of the short-and long-wave radiation fluxes on the human body (Hodder and Parsons 2007;La Gennusa et al 2005). Although R can be modeled based on planar measurements of incoming and outgoing short-and long-wave radiation fluxes, readily available radiation data can often be difficult to obtain, as the incoming and outgoing solar and terrestrial radiation fluxes are not all commonly observed variables at many meteorological stations, and the equipment used to make these measurements is costly and highly specialized (Baigorria et al 2004;Gul et al 1998).…”

Study on the Thermal Accumulation and Distribution Inside a Parked Car Cabin

“…The subjective experiments were carried out on a chamber in order to develop the driver's fatigue model. Hodder and Parsons (2007) have investigated the relation between simulated solar radiation and thermal comfort. In this work, three effects were studied, (1) the intensity of direct simulated solar radiation, (2) spectral content of simulated solar radiation and (3) glazing type on human thermal sensation responses.…”

Modeling the comfort effects of short-wave solar radiation indoors

“…Hodder and Parsons ('H/P') used an automobile mockup ( Figure 6) with moveable heat lamps to emulate four levels of solar radiation impinging on human subjects [8]. Air temperature was between 22.8 and 24.0°C, metabolic rate 1.2 met, and clothing resistance 0.7 clo.…”

“…Although Fanger published projected area factors for the human body in 1970 [7], the subject of shortwave gain and comfort has been almost absent from the research literature until recently. A few studies [8,9,16,19] have addressed the effect of solar heating on comfort.…”