Algorithms for the calculation of the view factors between human body and rectangular surfaces in parallelepiped environments

Cannistraro, G.; Franzitta, Giulio; Giaconia, C.; Rizzo, Gianfranco

doi:10.1016/0378-7788(92)90035-f

Cited by 48 publications

(34 citation statements)

References 2 publications

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“…Although in indoor environments the calculation of the angle factors between the human body and the surfaces of the environment requires the acquaintance of the shape and the posture of the subject [11][12][13][14], on the contrary, angle factors between the test area and the same surfaces of the environment may be calculated by means of simpler equations. As a matter of fact, in case of rectangular surfaces, considering the configurations reported in Figure 1 and Figure 2, the view factor → can be estimated by means of the equations (3) and (4) respectively.…”

Section: Evaluation Methodsmentioning

confidence: 99%

The effect of the climatic condition on the radiant asymmetry

Marino¹,

Misiani²,

Nucara³

et al. 2017

IJHT

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This paper analyzes the influence of solar radiation, considering both its direct and diffuse component, on the local thermal comfort of subjects in indoor environments. In fact, as well as too hot or too cold climatic conditions may cause global thermal discomfort, an unwanted cooling or heating of a particular confined area of the body may cause local thermal discomfort, which may occur for vertical air temperature differences, unsuitable temperatures of the floor, drafts and radiant asymmetries. In this context, this work is focused on radiant asymmetry issues and it aims to analyze the radiant asymmetry dependence on outdoor climate parameters, with special regard to the solar radiation. To this purpose, a specific experimental campaign of measurements was conducted. The analysis of the results shows that the solar radiation alters the radiant field and produces a high radiant asymmetry in correspondence of the points of the environment directly irradiated by sunrays.

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Section: Evaluation Methodsmentioning

confidence: 99%

The effect of the climatic condition on the radiant asymmetry

Marino¹,

Misiani²,

Nucara³

et al. 2017

IJHT

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“…After the room interior surface temperatures measurement, the mean radiant temperature is determined at time t for different subjects s1, s2, si in the room. To perform this task, an embedded algorithm has been implemented to automatically apply the calculation of MRT using the angle factors methodology according to the absolute coordinates (Xi, Yi) of the i-th person [3,4]. The algorithms proposed have been implemented in a C++ programming language and turned into a library that is called by the main program uploaded into the microcontroller.…”

Section: System Functionalitiesmentioning

confidence: 99%

A Low-Cost Sensor for Real-Time Monitoring of Indoor Thermal Comfort for Ambient Assisted Living

Revel

Arnesano

Pietroni

2014

Ambient Assisted Living

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The present paper illustrates an innovative low cost solution for the monitoring of indoor thermal comfort by means of Predictive Mean Vote (PMV ) index for multiple positions. This is particularly interesting in an Ambient Assisted Living environment as replacement of typical thermostat used for the climate control. In fact, the system proposed considers also personal parameters, as metabolic rate (M) and clothing level (I cl ), instead of the merely environmental parameters. If this is important for normal living conditions, it becomes crucial in case of elderly people and long-term care patients where a reduction of M or I cl causes a high sensitivity to thermal conditions (especially for cold sensation), or where the disability does not allow the subject re-action (e.g. shading opening/closing when solar radiation occurs). The device proposed uses a set of low-cost non-contact sensors to determine, based on algorithms provided by ISO 7726 and 7730, Mean Radiant Temperature (MRT ) and PMV, which are provided as output of the device through wireless or wired connection. The capability of predicting thermal comfort conditions for multiple positions of the occupant in the room has been tested and validated in a real case study: it resulted in a discrepancy of ±0.5 • C in the MRT measurement and ±0.1 for the PMV with respect to a reference measurement system (microclimate station). The sensitivity to the metabolic rate and clothing level for AAL applications is also discussed together with a procedure for an estimation of these parameters. The accuracy achieved allows a better measurement of the real thermal sensation for a more comfortable environment with lower energy consumption.

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“…These factors Fi,j, for subjects sitting or standing can be calculated with the graphs proposed by Fanger in his study on indoor comfort [1], or with the equation 3) proposed by the author [8,9] and adopted by ISO7726, [16].…”

Section: Heat Exchanges In the Presence Of Radiating Surfacesmentioning

confidence: 99%

The Local Media Radiant Temperature for the Calculation of Comfort in Areas Characterized by Radiant Surfaces

Cannistraro¹,

Cannistraro²,

Restivo³

2015

IJHT

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Thermo-hygrometric indoor conditions, as well known in literature, depend on the indices directly measurable in the place (Tba, Tbu, φa, va) and analytical solutions (Tmr, Top) and also on subjective assessments, metabolic activity carried out, and thermal resistance of clothing. They are tied to the subject occupied position within the work environment, substantially. In air conditioned rooms designed by systems with average parameters, it may happen that an individual, in some places or times, may feel sensations of thermal discomfort.These phenomena can be exacerbated by heat exchanges occurring in the presence of sources of radiation, such as radiant floors or ceilings or large glass surfaces sunny; these surfaces accentuate the radiative heat exchange with the body surfaces of the exposed individual. This paper proposes a "local mean radiant temperature" valid for the regular calculation of comfort in environments characterized by the presence of radiating surfaces. The present study compares the values of the parameters representing the hygrothermal comfort punctual, PMV, in environments characterized by radiating surfaces located in specific positions (ceiling, floor or walls), calculated with the local radiant temperature suggested in this study, with the corresponding values obtained with the mean radiant temperature proposed by the literature.

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Algorithms for the calculation of the view factors between human body and rectangular surfaces in parallelepiped environments

Cited by 48 publications

References 2 publications

The effect of the climatic condition on the radiant asymmetry

The effect of the climatic condition on the radiant asymmetry

A Low-Cost Sensor for Real-Time Monitoring of Indoor Thermal Comfort for Ambient Assisted Living

The Local Media Radiant Temperature for the Calculation of Comfort in Areas Characterized by Radiant Surfaces

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