This article is about comfort zones in building construction. For other uses, see Comfort zone (disambiguation).
Thermal comfort is the condition of mind that expresses subjective satisfaction with the thermal environment.[1] The human body can be viewed as a heat engine where food is the input energy. The human body will release excess heat into the environment, so the body can continue to operate. The heat transfer is proportional to temperature difference. In cold environments, the body loses more heat to the environment and in hot environments the body does not release enough heat. Both the hot and cold scenarios lead to discomfort.[2] Maintaining this standard of thermal comfort for occupants of buildings or other enclosures is one of the important goals of HVAC (heating, ventilation, and air conditioning) design engineers.
Thermal neutrality is maintained when the heat generated by human metabolism is allowed to dissipate, thus maintaining thermal equilibrium with the surroundings. The main factors that influence thermal comfort are those that determine heat gain and loss, namely metabolic rate, clothing insulation, air temperature, mean radiant temperature, air speed and relative humidity. Psychological parameters, such as individual expectations, also affect thermal comfort.[3] The thermal comfort temperature may vary greatly between individuals and depending on factors such as activity level, clothing, and humidity. People are highly sensitive to even small differences in environmental temperature. At 24 °C, a difference of 0.38 °C can be detected between the temperature of two rooms.[4]
The Predicted Mean Vote (PMV) model stands among the most recognized thermal comfort models. It was developed using principles of heat balance and experimental data collected in a controlled climate chamber under steady state conditions.[5] The adaptive model, on the other hand, was developed based on hundreds of field studies with the idea that occupants dynamically interact with their environment. Occupants control their thermal environment by means of clothing, operable windows, fans, personal heaters, and sun shades.[3][6] The PMV model can be applied to air-conditioned buildings, while the adaptive model can be applied only to buildings where no mechanical systems have been installed.[1] There is no consensus about which comfort model should be applied for buildings that are partially air-conditioned spatially or temporally.
Thermal comfort calculations in accordance with the ANSI/ASHRAE Standard 55,[1] the ISO 7730 Standard[7] and the EN 16798-1 Standard[8] can be freely performed with either the CBE Thermal Comfort Tool for ASHRAE 55,[9] with the Python package pythermalcomfort[10] or with the R package comf.
^ abcANSI/ASHRAE Standard 55-2017, Thermal Environmental Conditions for Human Occupancy
^Çengel, Yunus A.; Boles, Michael A. (2015). Thermodynamics: An Engineering Approach (8th ed.). New York, NY: McGraw-Hill Education. ISBN 978-0-07-339817-4.
^ abde Dear, Richard; Brager, Gail (1998). "Developing an adaptive model of thermal comfort and preference". ASHRAE Transactions. 104 (1): 145–67.
^Fanger, P Ole (1970). Thermal Comfort: Analysis and applications in environmental engineering. McGraw-Hill.[page needed]
^Nicol, Fergus; Humphreys, Michael (2002). "Adaptive thermal comfort and sustainable thermal standards for buildings" (PDF). Energy and Buildings. 34 (6): 563–572. doi:10.1016/S0378-7788(02)00006-3. S2CID 17571584.[permanent dead link]
^ISO, 2005. ISO 7730 - Ergonomics of the thermal environment — Analytical determination and interpretation of thermal comfort using calculation of the PMV and PPD indices and local thermal comfort criteria.
^CEN, 2019. EN 16798-1 - Energy performance of buildings - Ventilation for buildings. Part 1: Indoor environmental input parameters for design and assessment of energy performance of buildings addressing indoor air quality, thermal environment, lighting and acoustics.
Thermalcomfort is the condition of mind that expresses subjective satisfaction with the thermal environment. The human body can be viewed as a heat engine...
the ranges of indoor environmental conditions to achieve acceptable thermalcomfort for occupants of buildings. It was first published in 1966, and since...
of comfort that apply to everyone. Most of these universal themes falls under the physical comfort such as contact comfort, comfort food, and thermal comfort...
conducted in Jaipur, India among healthy young men showed that the neutral thermalcomfort temperature was analyzed to be 30.15 °C (86 °F), although a range of...
through radiant exchange with people and objects and not air, occupant thermalcomfort can be achieved with warmer interior air temperatures than with air...
maintain thermalcomfort conditions. The CBE ThermalComfort Tool can be used to demonstrate the effect of relative humidity for specific thermalcomfort conditions...
Thermal radiation is electromagnetic radiation emitted by the thermal motion of particles in matter. Thermal radiation transmits as an electromagnetic...
the level of humidity in the air. This is done usually for health or thermalcomfort reasons, or to eliminate musty odor and to prevent the growth of mildew...
central heating and cooling that achieves indoor climate control for thermalcomfort using hydronic or electrical heating elements embedded in a floor....
metallurgical workers or firemen. As regards thermalcomfort, only the first case is considered. Thermophysiological comfort is the capacity of the clothing material...
transfer coefficients. The instrument used for assessing environmental thermalcomfort in terms of operative temperature is called a eupatheoscope and was...
acceptance and perceived comfort of a garment cannot be attributed solely to its thermal properties. Rather, the sensation of comfort when wearing a garment...
materials, the thermal masses for the different components can just be added together. Thermal mass is effective in improving building comfort in any place...
Thermal insulation is the reduction of heat transfer (i.e., the transfer of thermal energy between objects of differing temperature) between objects in...
ThermalComfort Monitoring with dry-bulb temperature data or it can be only thermalcomfort surveys by achieving 2 points from T02 Verified Thermal Comfort...
patterns. Airflow is a factor of concern when designing to meet occupant thermalcomfort standards (such as ASHRAE 55). Varying rates of air movement may positively...
spread of fire, thermal insulation and structural strength, which in severe cases, must be guaranteed for 180 minutes. The thermalcomfort is a requirement...
thermophysiological comfort indexes such as physiological equivalent temperature (PET) or predicted mean vote (PMV). What we experience and feel relating to thermal comfort...
and heat dissipation in a building in order to improve the indoor thermalcomfort with low or no energy consumption. This approach works either by preventing...
A thermal expansion valve or thermostatic expansion valve (often abbreviated as TEV, TXV, or TX valve) is a component in vapor-compression refrigeration...
climatic regions rely heavily upon natural ventilation for maintaining thermalcomfort conditions in the enclosed spaces. Design guidelines are offered in...
airflow minimums are selected to avoid the risk of under-ventilation and thermalcomfort issues. However, published research supporting the efficacy of this...
inhabitants of hot and humid areas may not find this uncomfortable. Thermalcomfort depends not just on physical environmental factors, but also on psychological...
atmospheric moisture (humidity), thus providing only a limited estimate of thermalcomfort. Additional factors such as wind, sunshine and individual clothing...
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