An innovative thermal comfort meter has been developed. It can simulate the human body evaporative losses. The sensor has been calibrated in a climatic chamber with different air temperature, velocity and humidity.
This paper defines a new parameter : the equivalent frequency used for the description of the frequency characteristics of air velocity in turbulent flows.Analyses were performed to identify how much the accuracy of determination of the equivalent frequency depends on the characteristics of the velocity. Results of the analyses identified that the equivalent frequency of the velocity fluctuations in rooms is between 0.1 et 1 Hz, and 90 % of those records were between 0.2 and 0.6 Hz which is the frequency range identified to have most significant impact on people's draught sensation.
The authors introduce a new airflow characteristic, the equivalent frequency, as an integral measure for the frequency of the random velocity fluctuations in rooms. The aim of that study was to test the impact of the equivalent frequency on draught sensation for human subjects. Further investigation at different air temperatures along with different turbulence intensities of air velocity is recommended.
16 segmental and all body heat transfer convective coefficients were determined in tests performed with a thermal mannequin placed in the test chamber of a large wind-tunnel.This paper presents a general table with the numerical coefficients of the equations representing the evolution of the convective coefficient with the flow velocity for all the studied cases (front, back and side flow - at seated and standing postures) . The effect of natural convection is more obvious on the central part of the body. Peripheric parts have stronger losses.
For that study , an heated manikin, in a seated position, is exposed to a local thermo ventilator that promotes a non-uniform horizontal flow ( front , behind and right side) ; an interior climate analyser measures the environmental variables around the manikin. Those data are used as inputs of the numerical program.
A numerical model simulates the human and clothing thermal systems and evaluates the thermal comfort level. Verification was made that when the ventilator is places in front of the manikin, acceptable thermal comfort conditions are fullfilled.
The aim of that study is to make a database of the local convective heat transfer coefficients for each part of a human body in sedentary and standing environments through the use of an experimental thermal manikin and an analysis of the radiative heat transfer rate. The results are applicable to both indoor and outdoor environments.
The paper also discusses the influences of wind velocity, sensible heat loss, posture and furniture arrangements on local convective heat transfer coefficients values.
This paper investigates the possibilities to create velocity variations of that type : (change from "low" to "high" velocity and then back "low" velocity again) in a whole room using standard velocity components. The results show large differences at individual points, but the mean value of all 8 positions in the room shows an expected behaviour.
This paper proposes a simple mathematical model for calculation of the convective air flow rate induced by humans. That model has been then compared to a more complex one and to experimental data with satisfactory results.
That paper presents the results of a thermal comfort evaluation research in a brazilian office building : the measurements show that an underfloor air distribution system can provide comfortable conditions for both sitting and standing occupants along with a reduction of the energy consumption .
Measurements are made first in a full-scale room ventilated with a mixing ventilation, and later with a displacement ventilation. A new method to design mixing ventilation is established. A comparison shows the thermal comfort obtained with the two systems.
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