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Although humidity is an important factor for thermal comfort, humans are more sensitive to variations in temperature than they are to changes in relative humidity. [29] Humidity has a small effect on thermal comfort outdoors when air temperatures are low, a slightly more pronounced effect at moderate air temperatures, and a much stronger ...
The results are displayed on a psychrometric or a temperature-relative humidity chart and indicate the ranges of temperature and relative humidity that will be comfortable with the given the values input for the remaining four parameters. [44] The PMV/PPD model has a low prediction accuracy. [45]
The representation is made on a temperature-relative humidity, instead of a standard psychrometric chart. The comfort zone in blue represents the 90% of acceptability, which means the conditions between -0.5 and +0.5 PMV, or PPD < 10%.
For humidity ratios above 0.012 kg H 2 O/kg dry air (0.012 lb H 2 O/lb dry air), or for metabolic rates up to 2.0 met, the analytical model must be used to determine thermal comfort sensation. Also based on the PMV model, this method uses tools such as the ASHRAE Thermal Comfort Tool or the online CBE Thermal Comfort Tool for ASHRAE 55 [ 2 ] to ...
Comfortable temperatures can be extended beyond this range depending on humidity, air circulation, and other factors. In certain fields, like science and engineering , and within a particular context, room temperature can mean different agreed-upon ranges.
Plot of humidex depending on temperature and relative humidity. The humidex (short for humidity index) is an index number used by Canadian meteorologists to describe how hot the weather feels to the average person, by combining the effect of heat and humidity. The term humidex was coined in 1965. [1]
If all the other factors influencing humidity remain constant, at ground level the relative humidity rises as the temperature falls; this is because less vapor is needed to saturate the air. In normal conditions, the dew point temperature will not be greater than the air temperature, since relative humidity typically [5] does not exceed 100%. [6]
The wet-bulb temperature is the lowest temperature that may be achieved by evaporative cooling of a water-wetted, ventilated surface.. By contrast, the dew point is the temperature to which the ambient air must be cooled to reach 100% relative humidity assuming there is no further evaporation into the air; it is the temperature where condensation (dew) and clouds would form.