Modeling solar radiation on a human body indoors by a novel mathematical model

Abstract

Solar radiation affects occupant comfort and building energy consumption in ways that have received relatively little attention in environmental design and energy simulation. Direct, diffuse, and reflected irradiation on the body have warming effects that can be equated to increases in the mean radiant temperature (MRT) of the occupant's surroundings. A simplified occupant-centered model (SolarCal Model, i.e., SC Model) has recently been adopted in ASHRAE Standard 55, followed by a comprehensive simulation procedure combining detailed room-and manikin geometries using the Daylight Coefficient Model (DC Model). This paper presents an intermediate-level mathematical model (the HNU Solar Model) capable of rapid annual calculations of the MRT increases. Both the room and occupant geometries are simplified but consistent with those of the SC Model. Novel strategies of the calculation include a sky-annulus fraction, virtual body shadow, and equivalent window. Modeled results are compared with those simulated by the DC Model using Radiance software, which is assumed to be accurate. The differences in the Delta MRT by diffuse, direct, and reflected solar radiation are usually less than 1, 2, and 0.5°C between the DC and HNU Solar Models, respectively. For a given occupant position indoors, the HNU Solar Model only needs five seconds to obtain the annual Delta MRT, while the DC Model needs about seven minutes. The HNU Solar Model provides a simple and practical way to evaluate indoor environments at the room scale, to design fenestration, and to predict set-point changes in annual energy simulation of HVAC systems.

Simple mathematical models to link climate-based daylight metrics with daylight factor metrics and daylighting design implications

“…RADIANCE is a well-established lighting simulation package employing backward ray-tracing technologies to examine high-ranking lighting regimes. It has been used by a number of researchers for predicting outdoor illuminances and solar radiation [ 52 ], indoor daylighting and evaluating lighting and daylighting technologies [ 53 , 54 ]. The primary advantage of RADIANCE is only a few limitations on geometry and the many materials may be simulated.…”

Determination of Climate-Based Daylight Metrics under 15 CIE (International Commission on Illumination) Standard Skies and Three Representative Skies

“…Falian Xie et al imported the sky model, the data of the waiting hall, and environment in cold regions into Ladybug and RADIANCE, and simulated the natural lighting performance index [27]. Other researchers also used RADIANCE to analyze outdoor illuminance and solar radiation [28], daylighting performance assessment [29], and the evaluation of lighting and daylighting technologies [30,31]. In this study, version 5.3 of RADIANCE, developed at Lawrence Berkeley Laboratory and running on a Windows 10 workstation, was utilized for the analysis.…”

Quantification on fuel cell degradation and techno-economic analysis of a hydrogen-based grid-interactive residential energy sharing network with fuel-cell-powered vehicles

“…The study [55] does not provide a detailed method of calculating vehicle's solar heat gain. With the reference to our previous study on indoor solar radiation in buildings [58], a simplified method is adopted to calculate vehicle solar heat gain. To be more specific, when calculating heat gain from solar radiation, the HV geometry is simplified as a horizontal plate which has a size of the cabin's projected area on the horizontal ground (see Fig.…”