Search results for "Projected area"
showing 8 items of 8 documents
Evaluating human body area factors from digital images: A measurement tool for a better evaluation of the ergonomics of working places
2006
The evaluation of comfort conditions of people in confined environments requires a knowledge of the human body's radiation data. This is essentially represented by the projected area of the body in a given direction. From this factor, other important parameters can be computed, such as projected area factors and angle factors. Presently, these parameters are evaluated using graphs deriving from a pioneering field study carried out by P.O. Fanger for which a piece of apparatus using mirrors and weight operations on film negatives is used. Obviously, these graphs, apart from referring to a limited number of subjects, also involve some reading errors. With the aim of enlarging the number of ex…
An Anthropometric Analysis of Seated and Standing People
2012
Thermal radiative exchanges of the human body with surrounding surfaces play an essential role in describing the thermal conditions of people in a given environment. Moreover, they could be induced by, among other causes, the presence of high intensity radiant sources, like lighting spots or infrared heating panels. This implies that a suitable set of radiation data related to human body anthropometry is required. This set of data mainly comprises the body surface area, the clothing area factor, the effective radiation area factor, and projected area factors. Several analytical or experimental methods may be utilized in order to compute these parameters. A detailed description of the most c…
A comparison of direct and indirect methods for measuring leaf and surface areas of individual bushes
1995
Indirect estimates of leaf area from measurements with three commercially available instruments (DEMON, LAI-2000 and Sunfleck Ceptometer) were compared with directly measured areas of individual Retama sphaerocarpa bushes. The three indirect methods gave good estimates of the total surface area of individual bushes. For the DEMON, the method of log-linear averaging of transmitted radiation gave estimates closer to directly measured surface area than the method of averaging transmission linearly. For the LAI-2000, estimated surface area index multiplied by canopy projected area gave the best agreement with directly measured values. For measurements with the Sunfleck Ceptometer, values of sur…
Algorithms for the calculation of the projected area factors of seated and standing persons
1991
Moderate thermal environments, other than being affected by the mutual radiative heat exchange at low frequency among the internal surfaces, are often characterized by the presence of high intensity sources, that is, radiant sources showing a small area, a high emission temperature and a strongly directional beam. The sun's direct radiation can be considered to be among these radiant sources. In these cases, the computation of the mean radiant temperature and, consequently, the evaluation of the thermal comfort conditions, require knowledge of the “project area factor”, fp, of the subject. Moreover, the fp parameters are also applicable to derivation of the shape factors between subjects an…
The spatial evaluation of the radiative human body heat exchanges: An effective contribution for limiting energy consumption and achieving better ind…
2018
Abstract Radiative heat exchanges inside buildings remarkably affect the thermal balance of the human body in confined spaces and the related thermal comfort sensations of people. The mean radiant temperature is an important component of this balance. Unfortunately, it is usually computed by means of too simplified relationships, which significantly influence the comfort evaluations. Such simplified approaches are also accountable for a less effective design of HVAC systems which, in turn, could result in high energy consumption in the climatization of buildings. However, an accurate evaluation of the mean radiant temperature, especially when high intensity sources are present in a given in…
Angle Factors and Projected Area Factors for Comfort Analysis of Subjects in Complex Confined Enclosures: Analytical Relations and Experimental Resul…
2008
This paper addresses an important problem in the evaluation of the thermal comfort of people living or working in the sort of confined spaces typical of current architecture. In the details, a new algorithm is proposed for the evaluation of the angle factors of people within rooms characterized by complex shapes, where the envelope components are not always mutually orthogonal. The algorithm is based on field data obtained by means of an experimental photographic apparatus which allows measurements of projected area factors of seated or standing people in such complex confined environments.
Measurements of projected areas of seated and standing people of southern Italy based on a statistical analysis
2006
One of the most important components affecting the human thermal balance is represented by its radiative exchange with the surrounding surfaces. The projected area of the human body is an important parameter of these thermal exchanges. Unfortunately, although the anthropometric measures of people are characterized by significant differences among various populations, the experimental data currently available in the literature refers to a small group of people. Moreover, measurements are generally performed regardless of the statistical significance of the involved subjects with respect to the population to which they belong. In this study, a statistical study is introduced that is based on …
A generalized model of human body radiative heat exchanges for optimal design of indoor thermal comfort conditions
2018
Abstract Human thermal sensation depends heavily on radiative exchanges between the human body and the surrounding environment. Because these exchanges play a crucial role in the thermal balance of the human body, about 35% of the process, human thermal sensation should draw the attention of planners when designing both indoor environments and equipment. The present study aims to contribute to this field by proposing a procedure for delineating the optimal comfort conditions for occupants in most of the articulate and realistic configurations of actual indoor environments. Specifically, this procedure enables accurate assessment of the radiant field surrounding a subject in a given indoor r…