WHY SKIN MODEL TESTERS OF THERMAL COMFORT OF FABRICS SOMETIMES DISPLAY NEGATIVE VALUES OF THERMAL RESISTANCE?

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F46747885%3A24410%2F16%3A00003705" target="_blank" >RIV/46747885:24410/16:00003705 - isvavai.cz</a>

Výsledek na webu

<a href="http://www.aachen-dresden-denkendorf.de/en/itc/" target="_blank" >http://www.aachen-dresden-denkendorf.de/en/itc/</a>

DOI - Digital Object Identifier

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Jazyk výsledku

angličtina

Název v původním jazyce

WHY SKIN MODEL TESTERS OF THERMAL COMFORT OF FABRICS SOMETIMES DISPLAY NEGATIVE VALUES OF THERMAL RESISTANCE?

Popis výsledku v původním jazyce

The most important standard for testing of thermo-physiological comfort of fabrics presents the ISO 11092. For the determination of thermal and evaporation resistance of textile fabrics according to this standard, Skin Models are widely used instruments. During the measurement in these instruments, one surface of the tested fabric is exposed to air flow with different humidity or temperature then the other surface. However, when measuring the fabric thermal resistance of hydrophilic fabrics on the this type instruments, sometimes the instrument displays very low or negative values of thermal resistance. The explanation of this effect and the possible solutions of this is presented in the paper. It was found, that when exposing the tested sample in the Skin model to the temperature higher then the previous laboratory temperature, the sample gets relatively “overdryed” and its free surface absorbs water vapour from the running air. The heat of water vapour condensation is very high and may cause the effect of negative values of thermal resistance. However, when the time of measurement is long enough, or when the free surface is covered by very thin impermeable foil, then the effect of the reduced of even negative thermal resitance disappears, as proved experimentally.

Název v anglickém jazyce

WHY SKIN MODEL TESTERS OF THERMAL COMFORT OF FABRICS SOMETIMES DISPLAY NEGATIVE VALUES OF THERMAL RESISTANCE?

Popis výsledku anglicky

The most important standard for testing of thermo-physiological comfort of fabrics presents the ISO 11092. For the determination of thermal and evaporation resistance of textile fabrics according to this standard, Skin Models are widely used instruments. During the measurement in these instruments, one surface of the tested fabric is exposed to air flow with different humidity or temperature then the other surface. However, when measuring the fabric thermal resistance of hydrophilic fabrics on the this type instruments, sometimes the instrument displays very low or negative values of thermal resistance. The explanation of this effect and the possible solutions of this is presented in the paper. It was found, that when exposing the tested sample in the Skin model to the temperature higher then the previous laboratory temperature, the sample gets relatively “overdryed” and its free surface absorbs water vapour from the running air. The heat of water vapour condensation is very high and may cause the effect of negative values of thermal resistance. However, when the time of measurement is long enough, or when the free surface is covered by very thin impermeable foil, then the effect of the reduced of even negative thermal resitance disappears, as proved experimentally.

Druh

O - Ostatní výsledky

CEP obor

JJ - Ostatní materiály

OECD FORD obor

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Projekt

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Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2016

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů