Thermophysiological clothing comfort

2021 ◽  
Vol 7 (3) ◽  
pp. 98-103
Author(s):  
Devanand Uttam ◽  
Ramratan .

The clothing is not worn only for protecting the human body, but it helps to obtain comfort during high level activities or in unfavorable environmental conditions. Heat generated by the working human body in hot climate or high physical activity, which must be dissipated to the environment. Similarly, in the cold environment, the body is going to be shielded from cold feeling. Thermophysiological clothing comfort related to warmth and moisture transport behaviour of clothing. Good clothing helps to maintain body temperature during various level of physical activities and surrounding environmental condition. Therefore, some improved functional properties are desirable in the clothing. For clothing comfort, thermophysiological comfort properties of fabrics which are related to heat and moisture transport properties play very vital role. These properties can be introduced in the clothing by using various fibrous material and modifying the structure of yarns, fabrics and garments.

2012 ◽  
Vol 49 (6-I) ◽  
pp. 32-43 ◽  
Author(s):  
A. Ozolinsh ◽  
A. Jakovich

Abstract The heat and moisture transport in multi-layer walls is analysed for five building units. Using the developed program, a typical of Latvian conditions temperature and relative humidity profiles in multi-layered constructions has been obtained and the indoor heat losses estimated. Consideration is also given to the risk of condensate formation and to the influence of moisture on the U-value. The created mathematical model allows forecasting the energy efficiency and sustainability of different technical solutions as refer to the heat and moisture transport in buildings.


Author(s):  
N. Ghaddar ◽  
K. Ghali ◽  
E. Jaroudi

A dynamic thermal model is developed using the 2D cylinder model of Ghaddar et al [1] of ventilated fabric-skin system where a microclimate air annulus separates an outer cylindrical fabric boundary and an inner human body solid boundary for closed and open apertures. The cylinder model solves for the radial, and angular flow rates in the microclimate air annulus domain where the inner cylinder is oscillating within an outer fixed cylinder of porous fabric boundary. The 2-D cylinder model is further developed in the radial and angular directions to incorporate the heat and moisture transport from the inner cylinder when the fabric touches the skin boundary at repetitive finite intervals during the motion cycle. The touch model is based on a lumped fabric transient approach based on the fabric dry and evaporative resistances at the localized touch regions at the top and bottom of points of the cylinder. The film coefficients at the inner cylinder are needed for the model simulation. Experiments are conducted in an environmental chamber under controlled conditions to measure the mass transfer coefficient at the skin to the air annulus separating the wet skin and the fabric in the cylindrical geometry. In addition, experiments have also been conducted at ventilation frequencies of 30, 40, and 60 rpm to measure the sensible heat loss from the inner cylinder to validate the predictions of sensible and latent heat losses of the 2-D ventilation model for the two cases when fabric is in contact with the skin surface and when no contact is present for close aperture. The model prediction of time-averaged steady-periodic sensible heat loss agreed well with the experimentally measured values. A parametric study is performed to predict sensible and latent heat losses from the system by ventilation at different frequencies, fabric skin contact times during the motion cycle measured by a dimensionless amplitude parameter (ζ = amplitude/mean annular spacing). The rate of heat loss increases with increased ventilation frequency at fixed ζ. The latent heat loss in the contact region increases by almost 40% due to increase in fabric temperature during contact. The sensible heat loss decreases between 3% at f = 60 rpm, and 5% at f = 25 rpm in the contact region due to higher air temperature and lack of heat loss by radiation during the contact between fabric and skin.


2020 ◽  
Vol 1472 (1) ◽  
pp. 123-138
Author(s):  
Dominik L. Schumacher ◽  
Jessica Keune ◽  
Diego G. Miralles

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