text:
Thermal comfort
From Wikipedia, the free encyclopedia
Jump to: navigation, search
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 satisfaction with the thermal environment and is assessed by subjective evaluation (ANSI/ASHRAE Standard 55).[1] The human body can be viewed as a heat engine where food is the input energy. The human body will generate 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 no exert 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. Most people will feel comfortable at room temperature, colloquially a range of temperatures around 20 to 22 °C (68 to 72 °F),[3] but this may vary greatly between individuals and depending on factors such as activity level, clothing, and humidity.
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.[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.[4][6]
The PMV model can be applied to air-conditioned buildings, while the adaptive model can be generally 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 according to ANSI/ASHRAE Standard 55[1] can be freely performed with the CBE Thermal Comfort Tool for ASHRAE 55.
Similar to ASHRAE Standard 55 there are other comfort standards like EN 15251[7] and the ISO 7730 standard.[8][9]
Contents
[hide]
1 Significance
2 Influencing factors
2.1 Metabolic rate
2.2 Clothing insulation
2.3 Air temperature
2.4 Mean radiant temperature
2.5 Air speed
2.6 Relative humidity
2.6.1 Skin wettedness
2.6.2 Interplay of temperature and humidity
2.7 Natural ventilation
3 Models
3.1 PMV/PPD method
3.1.1 Elevated air speed method
3.1.2 Virtual Energy for Thermal Comfort
3.1.3 Standard effective temperature
3.1.4 Local thermal discomfort
3.1.4.1 Radiant temperature asymmetry
3.1.4.2 Draft
3.1.4.3 Vertical air temperature difference
3.1.4.4 Floor surface temperature
3.2 Adaptive comfort model
3.2.1 Psychological Adaptation
3.2.2 Physiological Adaptation
3.2.3 Behavioral Adaptation
4 Specificity and sensitivity
4.1 Individual differences
4.2 Biological gender differences
4.3 Regional differences
5 Thermal stress
6 Research
6.1 Medical environments
6.2 Personal comfort systems
7 See also
8 References
9 Further reading
Significance[edit]
Satisfaction with the thermal environment is important for its own sake and because it influences productivity and health. Office workers who are satisfied with their thermal environment are more productive.[10] Thermal discomfort has also been known to lead to sick building syndrome symptoms.[11] The combination of high temperature and high relative humidity serves to reduce thermal comfort and indoor air quality.[12]
Although a single static temperature can be comfortable, thermal delight, alliesthesia is usually caused by varying thermal sensations. Adaptive models of thermal comfort allow flexibility in designing naturally ventilated buildings that have more varying indoor conditions.[13] Such buildings may save energy and have the potential to create more satisfied occupants.[4]
Influencing factors[edit]
Since there are large variations from person to person in terms of physiological and psychological satisfaction, it is hard to find an optimal temperature for everyone in a given space. Laboratory and field data have been collected to define conditions that will be found comfortable for a specified percentage of occupants.[1]
There are six primary factors that directly affect thermal comfort that can be grouped in two categories: personal factors - because they are characteristics of the occupants - and environmental factors - which are conditions of the thermal environment. The former are metabolic rate and clothing level, the latter are air temperature, mean radiant temperature, air speed and humidity. Even if all these factors may vary with time, standards usually refer to a steady state to study thermal comfort, just allowing limited temperature variations.
Metabolic rate[edit]
People have different metabolic rates that can fluctuate due to activity level and environmental conditions.[14][15][16] The ASHRAE 55-2010 Standard defines metabolic rate as the level of transformation of chemical energy into heat and mechanical work by metabolic activities within an organism, usually expressed in terms of unit area of the total body surface. Metabolic rate is expressed in met units, which are defined as follows:
1 met = 58.2 W/m² (18.4 Btu/h·ft²), which is equal to the energy produced per unit surface area of an average person seated at rest. The surface area of an average person is 1.8 m² (19 ft²).[1]
ASHRAE Standard 55 provides a table of met rates for a variety of activities. Some common values are 0.7 met for sleeping, 1.0 met for a seated and quiet position, 1.2-1.4 met for light activities standing, 2.0 met or more for activities that involve movement, walking, lifting heavy loads or operating machinery. For intermittent activity, the Standard states that is permissible to use a time-weighted average metabolic rate if individuals are performing activities that vary over a period of one hour or less. For longer periods, different metabolic rates must be considered.[1]
According to ASHRAE Handbook of Fundamentals, estimating metabolic rates is complex, and for levels above 2 or 3 met – especially if there are various ways of performing such activities – the accuracy is low. Therefore, the Standard is not applicable for activities with an average level higher than 2 met. Met values can also be determined more accurately than the tabulated ones, using an empirical equation that takes into account the rate of respiratory oxygen consumption and carbon dioxide production. Another physiological yet less accurate method is related to the heart rate, since there is a relationship between the latter and oxygen production.[17]
The Compendium of Physical Activities is used by physicians to record physical activities. It has a different definition of met that is the ratio of the metabolic rate of the activity in question to a resting metabolic rate.[18] As the formulation of the concept is different from the one that ASHRAE uses, these met values cannot be used directly in PMV calculations, but it opens up a new way of quantifying physical activities.
Food and drink habits may have an influence on metabolic rates, which indirectly influences thermal preferences. These effects may change depending on food and drink intake.[19] Body shape is another factor that affects thermal comfort. Heat dissipation depends on body surface area. A tall and skinny person has a larger surface-to-volume ratio, can dissipate heat more easily, and can tolerate higher temperatures more than a person with a rounded body shape.[19]
Clothing insulation[edit]
Main article: Clothing insulation
The amount of thermal insulation worn by a person has a substantial impact on thermal comfort, because it influences the heat loss and consequently the thermal balance. Layers of insulating clothing prevent heat loss and can either help keep a person warm or lead to overheating. Generally, the thicker the garment is, the greater insulating ability it has. Depending on the type of material the clothing is made out of, air movement and relative humidity can decrease the insulating ability of the material.[20][21]
1 clo is equal to 0.155 m²·K/W (0.88 °F·ft²·h/Btu). This corresponds to trousers, a long sleeved shirt, and a jacket. Clothing insulation values for other common ensembles or single garments can be found in ASHRAE 55.[1]
Air temperature[edit]
Main article: Dry-bulb temperature
The air temperature is the average temperature of the air surrounding the occupant, with respect to location and time. According to ASHRAE 55 standard, the spatial average takes into account the ankle, waist and head levels, which vary for seated or standing occupants. The temporal average is based on three-minutes intervals with at least 18 equally spaced points in time. Air temperature is measured with a dry-bulb thermometer and for this reason it is also known as dry-bulb temperature.
Mean radiant temperature[edit]
Main article: Mean radiant temperature
The radiant temperature is related to the amount of radiant heat transferred from a surface, and it depends on the material’s ability to absorb or emit heat, or its emissivity. The mean radiant temperature depends on the temperatures and emissivities of the surrounding surfaces as well as the view factor, or the amount of the surface that is “seen” by the object. So the mean radiant temperature experienced by a person in a room with the sunlight streaming in varies based on how much of his/her body is in the sun.
Air speed[edit]
In HVAC, air speed is defined as the rate of air movement at a point, without regard to direction. According to ANSI/ASHRAE Standard 55, it is the average speed of the air to which the body is exposed, with respect to location and time. The temporal average is the same as the air temperature, while the spatial average is based on the assumption that the body is exposed to a uniform air speed, according to the SET thermo-physiological model. However, some spaces might provide strongly nonuniform air velocity fields and consequent skin heat losses that cannot be considered uniform. Therefore, the designer shall decide the proper averaging, especially including air speeds incident on unclothed body parts, that have greater cooling effect and potential for local discomfort.[1]
Relative humidity[edit]
Main article: Relative humidity
Relative humidity (dH) is the ratio of the amount of water vapor in the air to the amount of water vapor that the air could hold at the specific temperature and pressure. While the human body has sensors within the skin that are fairly efficient at feeling heat and cold, relative humidity is detected indirectly. Sweating is an effective heat loss mechanism that relies on evaporation from the skin. However at high RH, the air has close to the maximum water vapor that it can hold, so evaporation, and therefore heat loss, is decreased. On the other hand, very dry environments (RH < 20-30%) are also uncomfortable because of their effect on the mucous membranes. The recommended level of indoor humidity is in the range of 30-60% in air conditioned buildings,[22][23] but new standards such as the adaptive model allow lower and higher humidities, depending on the other factors involved in thermal comfort.
Recently, the effects of low relative humidity and high air velocity were tested on humans after bathing. Researchers found that low relative humidity engendered thermal discomfort as well as the sensation of dryness and itching. It is recommended to keep relative humidity levels higher in a bathroom than other rooms in the house for optimal conditions.[24]
Skin wettedness[edit]
Skin wettedness is defined as "the proportion of the total skin surface area of the body covered with sweat."[25] The wetness of skin in different areas also affects perceived thermal comfort. Humidity can increase wetness on different areas of the body, leading to a perception of discomfort. This is usually localized in different parts of the body, and local thermal comfort limits for skin wettedness differ by locations of the body.[26] The extremities are much more sensitive to thermal discomfort from wetness than the trunk of the body. Although local thermal discomfort can be caused from wetness, the thermal comfort of the whole body will not be affected by the wetness of certain parts.
Interplay of temperature and humidity[edit]
Various types of apparent temperature have been developed to combine air temperature and air humidity. For higher temperatures, there are quantitative scales, such as the heat index. For lower temperatures, a related interplay was identified only qualitatively:
High humidity and low temperatures cause the air to feel chilly.[27]
Cold air with high relative humidity "feels" colder than dry air of the same temperature because high humidity in cold weather increases the conduction of heat from the body.[28]
There has been controversy over why damp cold air feels colder than dry cold air. Some believe it is because when the humidity is high, our skin and clothing become moist and are better conductors of heat, so there is more cooling by conduction.[29]
Natural ventilation[edit]
Main article: Natural ventilation
Many buildings use an HVAC unit to control their thermal environment. Other buildings are naturally ventilated and do not rely on such mechanical systems to provide thermal comfort. Depending on the climate, this can drastically reduce energy consumption. It is sometimes seen as a risk, though, since indoor temperatures can be too extreme if the building is poorly designed. Properly designed, naturally ventilated buildings keep indoor conditions within the range where opening windows and using fans in the summer, and wearing extra clothing in the winter, can keep people thermally comfortable[citation needed].
Models[edit]
When discussing thermal comfort, there are two main different models that can be used: the static model (PMV/PPD) and the adaptive model.
PMV/PPD method[edit]
Psychrometric Chart
Temperature-relative humidity chart
Two alternative representations of thermal comfort for the PMV/PPD method
The PMV/PPD model was developed by P.O. Fanger using heat-balance equations and empirical studies about skin temperature to define comfort. Standard thermal comfort surveys ask subjects about their thermal sensation on a seven-point scale from cold (-3) to hot (+3). Fanger’s equations are used to calculate the Predicted Mean Vote (PMV) of a large group of subjects for a particular combination of air temperature, mean radiant temperature, relative humidity, air speed, metabolic rate, and clothing insulation.[5] Zero is the ideal value, representing thermal neutrality, and the comfort zone is defined by the combinations of the six parameters for which the PMV is within the recommended limits (-0.5<PMV<+0.5).[1] Although predicting the thermal sensation of a population is an important step in determining what conditions are comfortable, it is more useful to consider whether or not people will be satisfied. Fanger developed another equation to relate the PMV to the Predicted Percentage of Dissatisfied (PPD). This relation was based on studies that surveyed subjects in a chamber where the indoor conditions could be precisely controlled.[5]
This method treats all occupants the same and disregards location and adaptation to the thermal environment.[30] It basically states that the indoor temperature should not change as the seasons do. Rather, there should be one set temperature year-round. This is taking a more passive stand that humans do not have to adapt to different temperatures since it would always be constant.[31][32]
ASHRAE Standard 55-2010 uses the PMV model to set the requirements for indoor thermal conditions. It requires that at least 80% of the occupants be satisfied.[1]
The CBE Thermal Comfort Tool for ASHRAE 55 allows users to input the six comfort parameters to determine whether a certain combination complies with ASHRAE 55. 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.[33]
Elevated air speed method[edit]
ASHRAE 55 2013 accounts for air speeds above 0.2 metres per second (0.66 ft/s) separately than the baseline model. Because air movement can provide direct cooling to people, particularly if they are not wearing much clothing, higher temperatures can be more comfortable than the PMV model predicts. Air speeds up to 0.8 m/s (2.6 ft/s) are allowed without local control, and 1.2 m/s is possible with local control. This elevated air movement increases the maximum temperature for an office space in the summer to 30 °C from 27.5 °C (86.0–81.5 °F).[1]
Virtual Energy for Thermal Comfort[edit]
"Virtual Energy for Thermal Comfort" is the amount of energy that will be required to make a non-air-conditioned building relatively as comfortable as one with air-conditioning. This is based on the assumption that the home will eventually install air-conditioning or heating.[34] Passive design improves thermal comfort in a building, thus reducing demand for heating or cooling. In many developing countries, however, most occupants do not currently heat or cool, due to economic constraints, as well as climate conditions which border lines comfort conditions such as cold winter nights in Johannesburg (South Africa) or warm summer days in San Jose, Costa Rica. At the same time, as incomes rise, there is a strong tendency to introduce cooling and heating systems. If we recognize and reward passive design features that improve thermal comfort today, we diminish the risk of having to install HVAC systems in the future, or we at least ensure that such systems will be smaller and less frequently used. Or in case the heating or cooling system is not installed due to high cost, at least people should not suffer from discomfort indoors. To provide an example, in San Jose, Costa Rica, if a house were being designed with high level of glazing and small opening sizes, the internal temperature would easily rise above 30 °C (86 °F) and natural ventilation would not be enough to remove the internal heat gains and solar gains. This is why Virtual Energy for Comfort is important.
World Bank's assessment tool the EDGE software (Excellence in Design for Greater Efficiencies) illustrates the potential issues with discomfort in buildings and has created the concept of Virtual Energy for Comfort which provides for a way to present potential thermal discomfort. This approach is used to award for design solutions which improves thermal comfort even in a fully free running building. Despite the inclusion of requirements for overheating in CIBSE, overcooling has not been assessed. However, overcooling can be an issue, mainly in the developing world, for example in cities such as Lima (Peru), Bogota, and Delhi, where cooler indoor temperatures can occur frequently. This may be a new area for research and design guidance for reduction of discomfort.
Standard effective temperature[edit]
Standard effective temperature (SET*) is a model of human response to the thermal environment. Developed by A.P. Gagge and accepted by ASHRAE in 1986,[35] it is also referred to as the Pierce Two-Node model.[36] Its calculation is similar to PMV because it is a comprehensive comfort index based on heat-balance equations that incorporates the personal factors of clothing and metabolic rate. Its fundamental difference is it takes a two-node method to represent human physiology in measuring skin temperature and skin wettedness.[35]
ASHRAE 55-2010 defines SET as "the temperature of an imaginary environment at 50% relative humidity, <0.1 m/s [0.33 ft/s] average air speed, and mean radiant temperature equal to average air temperature, in which total heat loss from the skin of an imaginary occupant with an activity level of 1.0 met and a clothing level of 0.6 clo is the same as that from a person in the actual environment, with actual clothing and activity level."[1]
Research has tested the model against experimental data and found it tends to overestimate skin temperature and underestimate skin wettedness.[36][37] Fountain and Huizenga (1997) developed a thermal sensation prediction tool that computes SET.[38]
Local thermal discomfort[edit]
Although thermal comfort is usually discussed for the body as a whole, thermal dissatisfaction may also occur just for a particular part of the body, due to local sources of unwanted heating, cooling or air movement.[39] According to the ASHRAE 55-2010 standard,[1] there are four main causes of thermal discomfort to be considered. A section of the standard specifies the requirements for these factors, that apply to a lightly clothed person engaged in near sedentary physical activity. This is because people with higher metabolic rates and/or more clothing insulation are less thermally sensitive, and consequently have less risk of thermal discomfort.
Radiant temperature asymmetry[edit]
Large differences in the thermal radiation of the surfaces surrounding a person may cause local discomfort or reduce acceptance of the thermal conditions. ASHRAE Standard 55 sets limits on the allowable temperature differences between various surfaces. Because people are more sensitive to some asymmetries than others, for example that of a warm ceiling versus that of hot and cold vertical surfaces, the limits depend on which surfaces are involved. The ceiling is not allowed to be more than +5 °C (9.0 °F) warmer, whereas a wall may be up to +23 °C (41 °F) warmer than the other surfaces.[1]
Draft[edit]
While air movement can be pleasant and provide comfort in some circumstances, it is sometimes unwanted and causes discomfort. This unwanted air movement is called "draft" and is most prevalent when the thermal sensation of the whole body is cool. People are most likely to feel a draft on uncovered body parts such as their head, neck, shoulders, ankles, feet, and legs, but the sensation also depends on the air speed, air temperature, activity, and clothing.[1]
Vertical air temperature difference[edit]
Thermal stratification that results in the air temperature at the head level being higher than at the ankle level may cause thermal discomfort. ASHRAE Standard 55 recommends that the difference not be greater than 3 °C (5.4 °F) for seated occupants or for standing occupants 4 °C (7.2 °F).[1]
Floor surface temperature[edit]
Floors that are too warm or too cool may cause discomfort, depending on footwear. ASHRAE 55 recommends that floor temperatures stay in the range of 19–29 °C (66–84 °F) in spaces where occupants will be wearing lightweight shoes.[1]
Adaptive comfort model[edit]
Adaptive chart according to ASHRAE Standard 55-2010
The adaptive model is based on the idea that outdoor climate influences indoor comfort because humans can adapt to different temperatures during different times of the year. The adaptive hypothesis predicts that contextual factors, such as having access to environmental controls, and past thermal history can influence building occupants' thermal expectations and preferences.[4] Numerous researchers have conducted field studies worldwide in which they survey building occupants about their thermal comfort while taking simultaneous environmental measurements. Analyzing a database of results from 160 of these buildings revealed that occupants of naturally ventilated buildings accept and even prefer a wider range of temperatures than their counterparts in sealed, air-conditioned buildings because their preferred temperature depends on outdoor conditions.[4] These results were incorporated in the ASHRAE 55-2004 standard as the adaptive comfort model. The adaptive chart relates indoor comfort temperature to prevailing outdoor temperature and defines zones of 80% and 90% satisfaction.[1]
The ASHRAE-55 2010 Standard introduced the prevailing mean outdoor temperature as the input variable for the adaptive model. It is based on the arithmetic average of the mean daily outdoor temperatures over no fewer than 7 and no more than 30 sequential days prior to the day in question.[1] It can also be calculated by weighting the temperatures with different coefficients, assigning increasing importance to the most recent temperatures. In case this weighting is used, there is no need to respect the upper limit for the subsequent days. In order to apply the adaptive model, there should be no mechanical cooling system for the space, occupants should be engaged in sedentary activities with metabolic rates of 1-1.3 met, and a prevailing mean temperature greater than 10 °C (50.0 °F) and less than 33.5 °C (92.3 °F).[1]
This model applies especially to occupant-controlled, natural-conditioned spaces, where the outdoor climate can actually affect the indoor conditions and so the comfort zone. In fact, studies by de Dear and Brager showed that occupants in naturally ventilated buildings were tolerant of a wider range of temperatures.[4] This is due to both behavioral and physiological adjustments, since there are different types of adaptive processes.[30] ASHRAE Standard 55-2010 states that differences in recent thermal experiences, changes in clothing, availability of control options, and shifts in occupant expectations can change people's thermal responses.[1]
Adaptive models of thermal comfort are implemented in other standards, such as European EN 15251 and ISO 7730 standard. While the exact derivation methods and results are slightly different from the ASHRAE 55 adaptive standard, they are substantially the same. A larger difference is in applicability. The ASHRAE adaptive standard only applies to buildings without mechanical cooling installed, while EN15251 can be applied to mixed-mode buildings, provided the system is not running.[7]
There are basically three categories of thermal adaptation, namely: behavioral, physiological, and psychological.
Psychological Adaptation[edit]
An individual's comfort level in a given environment may change and adapt over time due to psychological factors. Subjective perception of thermal comfort may be influenced by the memory of previous experiences. Habituation takes place when repeated exposure moderates future expectations, and responses to sensory input. This is an important factor in explaining the difference between field observations and PMV predictions (based on the static model) in naturally ventilated buildings. In these buildings, the relationship with the outdoor temperatures has been twice as strong as predicted.[4]
Psychological adaptation is subtly different in the static and adaptive models. Laboratory tests of the static model can identify and quantify non-heat transfer (psychological) factors that affect reported comfort. The adaptive model is limited to reporting differences (called psychological) between modeled and reported comfort.[citation needed]
Thermal comfort as a "condition of mind" is defined in psychological terms. Among the factors that affect the condition of mind (in the laboratory) are a sense of control over the temperature, knowledge of the temperature and the appearance of the (test) environment. A thermal test chamber that appeared residential "felt" warmer than one which looked like the inside of a refrigerator.[40]
Physiological Adaptation[edit]
Further information: Thermoregulation
The body has several thermal adjustment mechanisms to survive in drastic temperature environments. In a cold environment the body utilizes vasoconstriction; which reduces blood flow to the skin, skin temperature and heat dissipation. In a warm environment, vasodilation will increase blood flow to the skin, heat transport, and skin temperature and heat dissipation.[41] If there is an imbalance despite the vasomotor adjustments listed above, in a warm environment sweat production will start and provide evaporative cooling. If this is insufficient, hyperthermia will set in, body temperature may reach 40 °C (104 °F), and heat stroke may occur. In a cold environment, shivering will start, involuntarily forcing the muscles to work and increasing the heat production by up to a factor of 10. If equilibrium is not restored, hypothermia can set in, which can be fatal.[41] Long-term adjustments to extreme temperatures, of a few days to six months, may result in cardiovascular and endocrine adjustments. A hot climate may create increased blood volume, improving the effectiveness of vasodilation, enhanced performance of the sweat mechanism, and the readjustment of thermal preferences. In cold or underheated conditions, vasoconstriction can become permanent, resulting in decreased blood volume and increased body metabolic rate.[41]
Behavioral Adaptation[edit]
In naturally ventilated buildings, occupants take numerous actions to keep themselves comfortable when the indoor conditions drift towards discomfort. Operating windows and fans, adjusting blinds/shades, changing clothing, and consuming food and drinks are some of the common adaptive strategies. Among these, adjusting windows is the most common.[42] Those occupants who take these sorts of actions tend to feel cooler at warmer temperatures than those who do not.[43]
These behavioral actions significantly influence energy simulation inputs, and researchers are developing behavior models to improve the accuracy of simulation results. For example, there are many window-opening models that have been developed to date, but there is no consensus over the factors that trigger window opening.[42]
Specificity and sensitivity[edit]
Individual differences[edit]
Further information: Cold sensitivity
The thermal sensitivity of an individual is quantified by the descriptor FS, which takes on higher values for individuals with lower tolerance to non-ideal thermal conditions.[44] This group includes pregnant women, the disabled, as well as individuals whose age is below fourteen or above sixty, which is considered the adult range. Existing literature provides consistent evidence that sensitivity to hot and cold surfaces usually declines with age. There is also some evidence of a gradual reduction in the effectiveness of the body in thermo-regulation after the age of sixty.[44] This is mainly due to a more sluggish response of the counteraction mechanisms in lower parts of the body that are used to maintain the core temperature of the body at ideal values.[44] Seniors prefer warmer temperatures than young adults (76 vs 72 degrees F).[45]
Situational factors include the health, psychological, sociological, and vocational activities of the persons.
Biological gender differences[edit]
While thermal comfort preferences between sexes seems to be small, there are some differences. Studies have found males report discomfort due to rises in temperature much earlier than females. Males also estimate higher levels of their sensation of discomfort than females. One recent study tested males and females in the same cotton clothing, performing mental jobs while using a dial vote to report their thermal comfort to the changing temperature.[46] Many times, females will prefer higher temperatures. But while females were more sensitive to temperatures, males tend to be more sensitive to relative-humidity levels.[47][48]
An extensive field study was carried out in naturally ventilated residential buildings in Kota Kinabalu, Sabah, Malaysia. This investigation explored the sexes thermal sensitivity to the indoor environment in non air-conditioned residential buildings. Multiple hierarchical regression for categorical moderator was selected for data analysis; the result showed that females were slightly more sensitive than males to the indoor air temperatures, whereas, under thermal neutrality, it was found that males and females have similar thermal sensation.[49]
Regional differences[edit]
In different areas of the world, thermal comfort needs may vary based on climate. In China the climate has hot humid summers and cold winters, causing a need for efficient thermal comfort. Energy conservation in relation to thermal comfort has become a large issue in China in the last several decades due to rapid economic and population growth.[50] Researchers are now looking into ways to heat and cool buildings in China for lower costs and also with less harm to the environment.
In tropical areas of Brazil, urbanization is causing a phenomenon called urban heat islands (UHI). These are urban areas that have risen over the thermal comfort limits due to a large influx of people and only drop within the comfortable range during the rainy season.[51] Urban heat islands can occur over any urban city or built-up area with the correct conditions.[52] Urban heat islands are caused by urban areas with few trees and vegetation to block solar radiation or carry out evapotranspiration, many structures with a large proportion of roofs, and sidewalks with low reflectivity that absorb heat, high amounts of ground-level carbon dioxide pollution that retains heat released by surfaces, great amounts of heat generated by air-conditioning systems of densely packed buildings, and a large amount of automobile traffic generating heat from engines and exhaust.[53]
In the hot humid region of Saudi Arabia, the issue of thermal comfort has been important in mosques where Muslims go to pray. They are very large open buildings that are used only intermittently (very busy for the noon prayer on Fridays), making it hard to ventilate them properly. The large size requires a large amount of ventilation, but this requires a lot of energy since the buildings are used only for short periods of time. Some mosques have the issue of being too cold from their HVAC systems running for too long, and others remain too hot. The stack effect also comes into play due to their large size and creates a large layer of hot air above the people in the mosque. New designs have placed the ventilation systems lower in the buildings to provide more temperature control at ground level.[54] New monitoring steps are also being taken to improve efficiency.[55]
Thermal stress[edit]
Not to be confused with Thermal stress.
The concept of thermal comfort is closely related to thermal stress. This attempts to predict the impact of solar radiation, air movement, and humidity for military personnel undergoing training exercises or athletes during competitive events. Values are expressed as the wet bulb globe temperature or the discomfort index.[56] Generally, humans do not perform well under thermal stress. People’s performances under thermal stress is about 11% lower than their performance at normal thermal wet conditions. Also, human performance in relation to thermal stress varies greatly by the type of task which the individual is completing. Some of the physiological effects of thermal heat stress include increased blood flow to the skin, sweating, and increased ventilation.[57][58]
Research[edit]
The factors affecting thermal comfort were explored experimentally in the 1970s. Many of these studies led to the development and refinement of ASHRAE Standard 55 and were performed at Kansas State University by Ole Fanger and others. Perceived comfort was found to be a complex interaction of these variables. It was found that the majority of individuals would be satisfied by an ideal set of values. As the range of values deviated progressively from the ideal, fewer and fewer people were satisfied. This observation could be expressed statistically as the percent of individuals who expressed satisfaction by comfort conditions and the predicted mean vote (PMV). This approach was challenged by the adaptive comfort model, developed from the ASHRAE 884 project, which revealed that occupants were comfortable in a broader range of temperatures.[4]
This research is applied to create Building Energy Simulation (BES) programs for residential buildings. Residential buildings in particular can vary much more in thermal comfort than public and commercial buildings. This is due to their smaller size, the variations in clothing worn, and different uses of each room. The main rooms of concern are bathrooms and bedrooms. Bathrooms need to be at a temperature comfortable for a human with or without clothing. Bedrooms are of importance because they need to accommodate different levels of clothing and also different metabolic rates of people asleep or awake.[59] Discomfort hours is a common metric used to evaluate the thermal performance of a space.
Thermal comfort research in clothing is currently being done by the military. New air-ventilated garments are being researched to improve evaporative cooling in military settings. Some models are being created and tested based on the amount of cooling they provide.[60]
In the last twenty years, researchers have also developed advanced thermal comfort models that divide the human body into many segments, and predict local thermal discomfort by considering heat balance.[61][62][63] This has opened up a new arena of thermal comfort modeling that aims at heating/cooling selected body parts.
Medical environments[edit]
This section relies largely or entirely on a single source. Relevant discussion may be found on the talk page. Please help improve this article by introducing citations to additional sources. (June 2016)
Whenever the studies referenced tried to discuss the thermal conditions for different groups of occupants in one room, the studies ended up simply presenting comparisons of thermal comfort satisfaction based on the subjective studies. No study tried to reconcile the different thermal comfort requirements of different types of occupants who compulsorily must stay in one room. Therefore, it looks to be necessary to investigate the different thermal conditions required by different groups of occupants in hospitals to reconcile their different requirements in this concept. To reconcile the differences in the required thermal comfort conditions it is recommended to test the possibility of using different ranges of local radiant temperature in one room via a suitable mechanical system.
Although different researches are undertaken on thermal comfort for patients in hospitals, it is also necessary to study the effects of thermal comfort conditions on the quality and the quantity of healing for patients in hospitals. There are also original researches that show the link between thermal comfort for staff and their levels of productivity, but no studies have been produced individually in hospitals in this field. Therefore, research for coverage and methods individually for this subject is recommended. Also research in terms of cooling and heating delivery systems for patients with low levels of immune-system protection (such as HIV patients, burned patients, etc.) are recommended. There are important areas, which still need to be focused on including thermal comfort for staff and its relation with their productivity, using different heating systems to prevent hypothermia in the patient and to improve the thermal comfort for hospital staff simultaneously.
Finally, the interaction between people, systems and architectural design in hospitals is a field in which require further work needed to improve the knowledge of how to design buildings and systems to reconcile many conflicting factors for the people occupying these buildings.[64]
Personal comfort systems[edit]
Personal comfort systems (PCS) refer to devices or systems which heat or cool a building occupant personally.[65] This concept is best appreciated in contrast to central HVAC systems which have uniform temperature settings for extensive areas. Personal comfort systems include fans and air diffusers of various kinds (e.g. desk fans, nozzles and slot diffusers, overhead fans, high-volume low-speed fans etc.) and personalized sources of radiant or conductive heat (footwarmers, legwarmers, hot water bottles etc.). PCS has the potential to satisfy individual comfort requirements much better than current HVAC systems, as interpersonal differences in thermal sensation due to age, sex, body mass, metabolic rate, clothing and thermal adaptation can amount to an equivalent temperature variation of 2-5 K, which is impossible for a central, uniform HVAC system to cater to.[65] Besides, research has shown that the perceived ability to control one's thermal environment tends to widen one's range of tolerable temperatures.[4] Traditionally, PCS devices have been used in isolation from one another. However, it has been proposed by Andersen et al. (2016) that a network of PCS devices which generate well-connected microzones of thermal comfort, and report real-time occupant information and respond to programmatic actuation requests (e.g. a party, a conference, a concert etc.) can combine with occupant-aware building applications to enable new methods of comfort maximization.[66]
See also[edit]
ASHRAE
ANSI/ASHRAE Standard 55
Air conditioning
Building insulation
Mean radiant temperature
Mahoney tables
Povl Ole Fanger
Psychrometrics
Ralph G. Nevins
Room air distribution
Room temperature
References[edit]
^ Jump up to: a b c d e f g h i j k l m n o p q r s t u ANSI/ASHRAE Standard 55-2013, Thermal Environmental Conditions for Human Occupancy
Jump up ^ 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.
Jump up ^ The American Heritage Dictionary of the English Language (5th ed.). 2014.
^ Jump up to: a b c d e f g h i de Dear, Richard; Brager, Gail (1998). "Developing an adaptive model of thermal comfort and preference". ASHRAE Transactions. 104 (1): 145–67.
^ Jump up to: a b c Fanger, P Ole (1970). Thermal Comfort: Analysis and applications in environmental engineering. McGraw-Hill. [page needed]
Jump up ^ 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.
^ Jump up to: a b EN 15251 Standard 2007, Indoor environmental input parameters for design and assessment of energy performance of buildings addressing indoor air quality, thermal environment, lighting and acoustics
Jump up ^ Parsons, K C. "Introduction to thermal comfort standards" (PDF). Retrieved 1 December 2013.
Jump up ^ Olesen, B; Parsons, K C (2002). "Introduction to thermal comfort standards and to the proposed new version of EN ISO 7730". Energy and Buildings. 34 (6): 537–548. doi:10.1016/S0378-7788(02)00004-X.
Jump up ^ Huizenga, Charlie; Abbaszadeh, Sahar; Zagreus, Leah; Arens, Ed (2006). Air quality and thermal comfort in office buildings: Results of a large indoor environmental quality survey. Healthy buildings.
Jump up ^ Myhren, Jonn Are; Holmberg, Sture (2008). "Flow patterns and thermal comfort in a room with panel, floor and wall heating". Energy and Buildings. 40 (4): 524. doi:10.1016/j.enbuild.2007.04.011.
Jump up ^ Fang, L; Wyon, DP; Clausen, G; Fanger, PO (2004). "Impact of indoor air temperature and humidity in an office on perceived air quality, SBS symptoms and performance". Indoor air. 14 Suppl 7: 74–81. doi:10.1111/j.1600-0668.2004.00276.x. PMID 15330775.
Jump up ^ Cabanac, Michel (1971). "Physiological role of pleasure". Science. 173 (4002): 1103–7. Bibcode:1971Sci...173.1103C. doi:10.1126/science.173.4002.1103. PMID 5098954.
Jump up ^ Toftum, J. (2005). "Thermal Comfort Indices". Handbook of Human Factors and Ergonomics Methods. Boca Raton, FL, USA: 63.CRC Press. [page needed]
Jump up ^ Smolander, J. (2002). "Effect of Cold Exposure on Older Humans". International Journal of Sports Medicine. 23 (2): 86–92. doi:10.1055/s-2002-20137. PMID 11842354.
Jump up ^ Khodakarami, J. (2009). Achieving thermal comfort. VDM Verlag. ISBN 978-3-639-18292-7. [page needed]
Jump up ^ Thermal Comfort chapter, Fundamentals volume of the ASHRAE Handbook, ASHRAE, Inc., Atlanta, GA, 2005[page needed]
Jump up ^ Ainsworth, BE; Haskell, WL; Whitt, MC; Irwin, ML; Swartz, AM; Strath, SJ; O'Brien, WL; Bassett Jr, DR; Schmitz, KH; Emplaincourt, PO; Jacobs Jr, DR; Leon, AS (2000). "Compendium of physical activities: An update of activity codes and MET intensities". Medicine and science in sports and exercise. 32 (9 Suppl): S498–504. doi:10.1097/00005768-200009001-00009. PMID 10993420.
^ Jump up to: a b Szokolay, Steven V. (2010). Introduction to Architectural Science: The Basis of Sustainable Design (2nd ed.). pp. 16–22.
Jump up ^ Havenith, G (1999). "Heat balance when wearing protective clothing". The Annals of Occupational Hygiene. 43 (5): 289–96. doi:10.1016/S0003-4878(99)00051-4. PMID 10481628.
Jump up ^ McCullough, Elizabeth A.; Eckels, Steve; Harms, Craig (2009). "Determining temperature ratings for children's cold weather clothing". Applied Ergonomics. 40 (5): 870–7. doi:10.1016/j.apergo.2008.12.004. PMID 19272588.
Jump up ^ Balaras, Constantinos A.; Dascalaki, Elena; Gaglia, Athina (2007). "HVAC and indoor thermal conditions in hospital operating rooms". Energy and Buildings. 39 (4): 454. doi:10.1016/j.enbuild.2006.09.004.
Jump up ^ Wolkoff, Peder; Kjaergaard, Søren K. (2007). "The dichotomy of relative humidity on indoor air quality". Environment International. 33 (6): 850–7. doi:10.1016/j.envint.2007.04.004. PMID 17499853.
Jump up ^ Hashiguchi, Nobuko; Tochihara, Yutaka (2009). "Effects of low humidity and high air velocity in a heated room on physiological responses and thermal comfort after bathing: An experimental study". International Journal of Nursing Studies. 46 (2): 172–80. doi:10.1016/j.ijnurstu.2008.09.014. PMID 19004439.
Jump up ^ Frank C. Mooren, ed. (2012). "Skin Wettedness". Encyclopedia of Exercise Medicine in Health and Disease. pp. 790–790. doi:10.1007/978-3-540-29807-6_3041.
Jump up ^ Fukazawa, Takako; Havenith, George (2009). "Differences in comfort perception in relation to local and whole body skin wettedness". European Journal of Applied Physiology. 106 (1): 15–24. doi:10.1007/s00421-009-0983-z. PMID 19159949.
Jump up ^ Randall McMullan (2002). Environmental Science in Building. Palgrave. p. 376.
Jump up ^ "Humidity". The Columbia Electronic Encyclopedia (6th ed.). Columbia University Press. 2012.
Jump up ^ "How the weather makes you hot and cold". Popular Mechanics. July 1935. p. 36.
^ Jump up to: a b La Roche, P. (2011). Carbon-neutral architectural design. CRC Press.[page needed]
Jump up ^ Ye, X. J.; Zhou, Z. P.; Lian, Z. W.; Liu, H. M.; Li, C. Z.; Liu, Y. M. (2006). "Field study of a thermal environment and adaptive model in Shanghai". Indoor Air. 16 (4): 320–6. doi:10.1111/j.1600-0668.2006.00434.x. PMID 16842612.
Jump up ^ Khodakarami, Jamal; Knight, Ian (2008). "Required and Current Thermal Conditions for Occupants in Iranian Hospitals". HVAC&R Research. 14 (2): 175. doi:10.1080/10789669.2008.10391002.
Jump up ^ Hoyt, Tyler; Schiavon, Stefano; Piccioli, Alberto; Moon, Dustin; Steinfeld, Kyle (2013). "CBE Thermal Comfort Tool". Center for the Built Environment, University of California, Berkeley. Retrieved 21 November 2013.
Jump up ^ WC16 Saberi (PDF). p. 1329 (p. 5 in the PDF). Retrieved 31 May 2017.
^ Jump up to: a b Gagge, AP; Fobelets, AP; Berglund, LG (1986). "A standard predictive index of human response to the thermal environment". ASHRAE Transactions (2nd ed.). 92: 709–31.
^ Jump up to: a b Doherty, TJ; Arens, E.A. (1988). "Evaluation of the physiological bases of thermal comfort models". ASHRAE Transactions. 94 (1): 15.
Jump up ^ Berglund, Larry (1978). "Mathematical models for predicting the thermal comfort response of building occupants". ASHRAE Transactions. 84.
Jump up ^ Fountain, Mark; Huizenga, Charlie (1997). "A thermal sensation prediction software tool for use by the profession". ASHRAE Transactions. 103 (2).
Jump up ^ ISO/FDIS 7730:2005, International Standard, 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
Jump up ^ Rohles, Frederick H. (February 2007). "Temperature & Temperament - A Psychologist Looks at Comfort". ASHRAE Journal. ASHRAE: 14–22.
^ Jump up to: a b c Szokolay, Steven V. (2010). Introduction to Architectural Science: The Basis of Sustainable Design (2nd ed.). p. 19.
^ Jump up to: a b Nicol, J Fergus (2001). "Characterising Occupant Behaviour in Buildings" (PDF). Proceedings of the Seventh International IBPSA Conference. Rio de Janeiro, Brazil. pp. 1073–1078.
Jump up ^ Haldi, Frédéric; Robinson, Darren (2008). "On the behaviour and adaptation of office occupants". Building and Environment. 43 (12): 2163. doi:10.1016/j.buildenv.2008.01.003.
^ Jump up to: a b c Lenzuni, P.; Freda, D.; Del Gaudio, M. (2009). "Classification of Thermal Environments for Comfort Assessment". Annals of Occupational Hygiene. 53 (4): 325–32. doi:10.1093/annhyg/mep012. PMID 19299555.
Jump up ^ Rohles, Frederick H. (February 2007). "Temperature & Temperament - A Psychologist Looks at Comfort". ASHRAE Journal. ASHRAE: 14–22.
Jump up ^ Wyon, D.P.; Andersen, I.; Lundqvist, G.R. (2009). "Spontaneous magnitude estimation of thermal discomfort during changes in the ambient temperature*". Journal of Hygiene. 70 (2): 203–21. doi:10.1017/S0022172400022269. PMC 2130040  . PMID 4503865.
Jump up ^ Karjalainen, Sami (2007). "Biological sex differences in thermal comfort and use of thermostats in everyday thermal environments". Building and Environment. 42 (4): 1594. doi:10.1016/j.buildenv.2006.01.009.
Jump up ^ Lan, Li; Lian, Zhiwei; Liu, Weiwei; Liu, Yuanmou (2007). "Investigation of biological sex difference in thermal comfort for Chinese people". European Journal of Applied Physiology. 102 (4): 471–80. doi:10.1007/s00421-007-0609-2. PMID 17994246.
Jump up ^ Harimi Djamila, Chi Chu Ming, Sivakumar Kumaresan, "Assessment of Gender Differences in Their Thermal Sensations to the Indoor Thermal Environment", The 7th CUTSE Conference: Engineering International Conference (CUTSE- Engineering Goes Green), Published by: School of Engineering & Science, Curtin University Sarawak Malaysia,(2012): 262-266.ISBN 978-983-44482-3-3.
Jump up ^ Yu, Jinghua; Yang, Changzhi; Tian, Liwei; Liao, Dan (2009). "Evaluation on energy and thermal performance for residential envelopes in hot summer and cold winter zone of China". Applied Energy. 86 (10): 1970. doi:10.1016/j.apenergy.2009.01.012.
Jump up ^ Silva, Vicente de Paulo Rodrigues; De Azevedo, Pedro Vieira; Brito, Robson Souto; Campos, João Hugo Baracuy (2009). "Evaluating the urban climate of a typically tropical city of northeastern Brazil". Environmental Monitoring and Assessment. 161 (1–4): 45–59. doi:10.1007/s10661-008-0726-3. PMID 19184489. .
Jump up ^ United States Environmental Protection Agency. Office of Air and Radiation. Office of the Administrator.; Smart Growth Network (2003). Smart Growth and Urban Heat Islands.
Jump up ^ Shmaefsky, Brian R. (2006). "One Hot Demonstration: The Urban Heat Island Effect". Journal of College Science Teaching. 35 (7): 52. doi:10.2505/4/jcst06_035_07_52.
Jump up ^ Al-Homoud, Mohammad S.; Abdou, Adel A.; Budaiwi, Ismail M. (2009). "Assessment of monitored energy use and thermal comfort conditions in mosques in hot-humid climates". Energy and Buildings. 41 (6): 607. doi:10.1016/j.enbuild.2008.12.005.
Jump up ^ Nasrollahi, N. (2009). Thermal environments and occupant thermal comfort. VDM Verlag, 2009, ISBN 978-3-639-16978-2.[page needed]
Jump up ^ "About the WBGT and Apparent Temperature Indices".
Jump up ^ Hancock, P. A.; Ross, Jennifer M.; Szalma, James L. (2007). "A Meta-Analysis of Performance Response Under Thermal Stressors". Human Factors: the Journal of the Human Factors and Ergonomics Society. 49 (5): 851. doi:10.1518/001872007X230226.
Jump up ^ Leon, Lisa R. (2008). "Thermoregulatory responses to environmental toxicants: The interaction of thermal stress and toxicant exposure". Toxicology and Applied Pharmacology. 233 (1): 146–61. doi:10.1016/j.taap.2008.01.012. PMID 18313713.
Jump up ^ Peeters, Leen; Dear, Richard de; Hensen, Jan; d’Haeseleer, William (2009). "Thermal comfort in residential buildings: Comfort values and scales for building energy simulation". Applied Energy. 86 (5): 772. doi:10.1016/j.apenergy.2008.07.011.
Jump up ^ Barwood, Martin J.; Newton, Phillip S.; Tipton, Michael J. (2009). "Ventilated Vest and Tolerance for Intermittent Exercise in Hot, Dry Conditions with Military Clothing". Aviation, Space, and Environmental Medicine. 80 (4): 353. doi:10.3357/ASEM.2411.2009.
Jump up ^ Zhang, Hui; Arens, Edward; Huizenga, Charlie; Han, Taeyoung (2010). "Thermal sensation and comfort models for non-uniform and transient environments: Part I: Local sensation of individual body parts". Building and Environment. 45 (2): 380. doi:10.1016/j.buildenv.2009.06.018.
Jump up ^ Zhang, Hui; Arens, Edward; Huizenga, Charlie; Han, Taeyoung (2010). "Thermal sensation and comfort models for non-uniform and transient environments, part II: Local comfort of individual body parts". Building and Environment. 45 (2): 389. doi:10.1016/j.buildenv.2009.06.015.
Jump up ^ Zhang, Hui; Arens, Edward; Huizenga, Charlie; Han, Taeyoung (2010). "Thermal sensation and comfort models for non-uniform and transient environments, part III: Whole-body sensation and comfort". Building and Environment. 45 (2): 399. doi:10.1016/j.buildenv.2009.06.020.
Jump up ^ Khodakarami, Jamal; Nasrollahi, Nazanin (2012). "Thermal comfort in hospitals – A literature review". Renewable and Sustainable Energy Reviews. 16 (6): 4071. doi:10.1016/j.rser.2012.03.054.
^ Jump up to: a b Zhang, H.; Arens, E.; Zhai, Y. (2015). "A review of the corrective power of personal comfort systems in non-neutral ambient environments". Building and Environment. 91: 15–41. doi:10.1016/j.buildenv.2015.03.013.
Jump up ^ Andersen, M.; Fiero, G.; Kumar, S. (2016). "Well-Connected Microzones for Increased Building Efficiency and Occupant Comfort". Proceedings of ACEEE Summer Study on Energy Efficiency in Buildings. Pacific Grove, CA. August 21–26. https://escholarship.org/uc/item/7710g5cb
Further reading[edit]
Thermal Comfort,Fanger, P. O, Danish Technical Press, 1970 (Republished by McGraw-Hill, New York, 1973).
Thermal Comfort chapter, Fundamentals volume of the ASHRAE Handbook, ASHRAE, Inc., Atlanta, GA, 2005.
Weiss, Hal (1998). Secrets of Warmth: For Comfort or Survival. Seattle, WA: Mountaineers Books. ISBN 0-89886-643-X. OCLC 40999076.
Godish, T. Indoor Environmental Quality. Boca Raton: CRC Press, 2001.
Bessoudo, M. Building Facades and Thermal Comfort: The impacts of climate, solar shading, and glazing on the indoor thermal environment. VDM Verlag, 2008
Nicol, Fergus (2012). Adaptive thermal comfort : principles and practice. London New York: Routledge. ISBN 978-0415691598.
Humphreys, Michael (2016). Adaptive thermal comfort : foundations and analysis. Abingdon, U.K. New York, NY: Routledge. ISBN 978-0415691611.
[show]
v
t
e
Heating, ventilation and air conditioning
Fundamental concepts
Air changes per hour
Bake-out
Building envelope
Convection
Dilution
Domestic energy consumption
Enthalpy
Fluid dynamics
Gas compressor
Heat pump and refrigeration cycle
Heat transfer
Humidity
Infiltration
Latent heat
Noise control
Outgassing
Particulates
Psychrometrics
Sensible heat
Stack effect
Thermal comfort
Thermal destratification
Thermal mass
Thermodynamics
Vapour pressure of water
Technology
Absorption refrigerator
Air barrier
Air conditioning
Antifreeze
Automobile air conditioning
Autonomous building
Building insulation materials
Central heating
Central solar heating
Chilled beam
Chilled water
Constant air volume (CAV)
Coolant
Dedicated outdoor air system (DOAS)
Deep water source cooling
Demand-controlled ventilation (DCV)
Displacement ventilation
District cooling
District heating
Electric heating
Energy recovery ventilation (ERV)
Firestop
Forced-air
Forced-air gas
Free cooling
Heat recovery ventilation (HRV)
Hybrid heat
Hydronics
HVAC
Ice storage air conditioning
Kitchen ventilation
Mixed-mode ventilation
Microgeneration
Natural ventilation
Passive cooling
Passive house
Radiant heating and cooling system
Radiant cooling
Radiant heating
Radon mitigation
Refrigeration
Renewable heat
Room air distribution
Solar air heat
Solar combisystem
Solar cooling
Solar heating
Thermal insulation
Underfloor air distribution
Underfloor heating
Vapor barrier
Vapor-compression refrigeration (VCRS)
Variable air volume (VAV)
Variable refrigerant flow (VRF)
Ventilation
Components
Air conditioner inverter
Air door
Air filter
Air handler
Air ionizer
Air-mixing plenum
Air purifier
Air source heat pumps
Automatic balancing valve
Back boiler
Barrier pipe
Blast damper
Boiler
Centrifugal fan
Chiller
Condensate pump
Condenser
Condensing boiler
Convection heater
Cooling tower
Damper
Dehumidifier
Duct
Economizer
Electrostatic precipitator
Evaporative cooler
Evaporator
Exhaust hood
Expansion tank
Fan coil unit
Fan heater
Fire damper
Fireplace
Fireplace insert
Freeze stat
Flue
Freon
Fume hood
Furnace
Furnace room
Gas compressor
Gas heater
Gasoline heater
Geothermal heat pump
Grease duct
Grille
Ground-coupled heat exchanger
Heat exchanger
Heat pipe
Heat pump
Heating film
Heating system
High efficiency glandless circulating pump
High-efficiency particulate air (HEPA)
High pressure cut off switch
Humidifier
Infrared heater
Inverter compressor
Kerosene heater
Louver
Mechanical fan
Mechanical room
Oil heater
Packaged terminal air conditioner
Plenum space
Pressurisation ductwork
Process duct work
Radiator
Radiator reflector
Recuperator
Refrigerant
Register
Reversing valve
Run-around coil
Scroll compressor
Solar chimney
Solar-assisted heat pump
Space heater
Smoke exhaust ductwork
Thermal expansion valve
Thermal wheel
Thermosiphon
Thermostatic radiator valve
Trickle vent
Trombe wall
Turning vanes
Ultra-low particulate air (ULPA)
Whole-house fan
Windcatcher
Wood-burning stove
Measurement
and control
Air flow meter
Aquastat
BACnet
Blower door
Building automation
Carbon dioxide sensor
Clean Air Delivery Rate (CADR)
Gas sensor
Home energy monitor
Humidistat
HVAC control system
Intelligent buildings
LonWorks
Minimum efficiency reporting value (MERV)
OpenTherm
Programmable communicating thermostat
Programmable thermostat
Psychrometrics
Room temperature
Smart thermostat
Thermostat
Thermostatic radiator valve
Professions, trades,
and services
Architectural acoustics
Architectural engineering
Architectural technologist
Building services engineering
Building information modeling (BIM)
Deep energy retrofit
Duct leakage testing
Environmental engineering
Hydronic balancing
Kitchen exhaust cleaning
Mechanical engineering
Mechanical, electrical, and plumbing
Mold growth, assessment, and remediation
Refrigerant reclamation
Testing, adjusting, balancing
Industry organizations
ACCA
AMCA
ASHRAE
ASTM International
BRE
BSRIA
CIBSE
LEED
SMACNA
Health and safety
Indoor air quality (IAQ)
Passive smoking
Sick building syndrome (SBS)
Volatile organic compound (VOC)
See also
ASHRAE Handbook
Building science
Fireproofing
Glossary of HVAC terms
Template:Home automation
Template:Solar energy
Retrieved from "https://en.wikipedia.org/w/index.php?title=Thermal_comfort&oldid=835605881"
Categories:
Heating, ventilating, and air conditioning
Building engineering
Temperature
Heat transfer
Environmental psychology
Hidden categories:
Wikipedia articles needing page number citations from November 2013
All articles with unsourced statements
Articles with unsourced statements from October 2017
Articles with unsourced statements from February 2018
Articles needing additional references from June 2016
All articles needing additional references
Navigation menu
Personal tools
Not logged in
Talk
Contributions
Create account
Log in
Namespaces
Article
Talk
Variants
Views
Read
Edit
View history
More
Search
Navigation
Main page
Contents
Featured content
Current events
Random article
Donate to Wikipedia
Wikipedia store
Interaction
Help
About Wikipedia
Community portal
Recent changes
Contact page
Tools
What links here
Related changes
Upload file
Special pages
Permanent link
Page information
Wikidata item
Cite this page
Print/export
Create a book
Download as PDF
Printable version
Languages
العربية
Čeština
Deutsch
Español
فارسی
Français
עברית
Lietuvių
日本語
Polski
Português
Svenska
粵語
中文
5 more
Edit links
This page was last edited on 9 April 2018, at 18:16.
Text is available under the Creative Commons Attribution-ShareAlike License; additional terms may apply. By using this site, you agree to the Terms of Use and Privacy Policy. Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc., a non-profit organization.
Privacy policy
About Wikipedia
Disclaimers
Contact Wikipedia
Developers
Cookie statement
Mobile view
Enable previews

key: html

type: local

value: div

attrs: id class

values: mw-page-base noprint

values: mw-head-base noprint

value: a

attrs: id class lang

values: firstHeading firstHeading en

values: siteSub noprint

values: jump-to-nav mw-jump

values:
/wiki/Comfort_zone_(disambiguation)
mw-disambig
Comfort zone (disambiguation)

attrs: role class

values:
note
hatnote navigation-not-searchable

attrs: href title

values: /wiki/Heating mw-redirect Heating

values:
/wiki/Metabolic_rate
mw-redirect
Metabolic rate

values:
nofollow
http://comfort.cbe.berkeley.edu/
external text

values: Edit section: Interplay of temperature and humidity

values:
/wiki/Naturally_ventilated
mw-redirect
Naturally ventilated

values: This section has no citations (October 2017)

values:
noprint Inline-Template Template-Fact
white-space:nowrap;

attrs: alt src width height srcset data-file-width data-file-height

values:
/wiki/P._Ole_Fanger
mw-redirect
P. Ole Fanger

values:
/wiki/Psychrometric_chart
mw-redirect
Psychrometric chart

values: Edit section: Virtual Energy for Thermal Comfort

values:
/wiki/Developing_countries
mw-redirect
Developing countries

values:
nofollow
external text
https://www.edgebuildings.com

values: Excellence in Design for Greater Efficiencies

values: Edit section: Standard effective temperature

values: Edit section: Radiant temperature asymmetry

values: Edit section: Vertical air temperature difference

attrs: alt src width height class srcset data-file-width data-file-height

values: This claim needs references to reliable sources. (February 2018)

values: Edit section: Specificity and sensitivity

values: Edit section: Biological gender differences

values:
/wiki/Solar_radiation
mw-redirect
Solar radiation

values:
/wiki/Wet_bulb_globe_temperature
mw-redirect
Wet bulb globe temperature

values:
/wiki/Discomfort_index
mw-redirect
Discomfort index

values: plainlinks metadata ambox ambox-content ambox-one_source

values: This citation requires a reference to the specific page or range of pages in which the material appears. (November 2013)

values:
/wiki/PubMed_Identifier
mw-redirect
PubMed Identifier

values:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/15330775

values:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/5098954

values:
nofollow
external text
//doi.org/10.1055%2Fs-2002-20137

values:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/11842354

values:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/10993420

values:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/10481628

values:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/19272588

values:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/17499853

values:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/19004439

values:
nofollow
external text
//doi.org/10.1007%2Fs00421-009-0983-z

values:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/19159949

values:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/16842612

values:
nofollow
external text
//doi.org/10.1093%2Fannhyg%2Fmep012

values:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/19299555

attrs: alt src title width height srcset data-file-width data-file-height

values:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/4503865

values:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/17994246

values:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/19184489

values:
nofollow
external text
//doi.org/10.1518%2F001872007X230226

values:
nofollow
external text
//doi.org/10.1016%2Fj.taap.2008.01.012

values:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/18313713

values:
nofollow
external text
//doi.org/10.3357%2FASEM.2411.2009

values:
nofollow
external text
//doi.org/10.1016%2Fj.rser.2012.03.054

values: -moz-column-width: 30em; -webkit-column-width: 30em; column-width: 30em; list-style-type: decimal;

values:
nofollow
external text
//www.worldcat.org/oclc/40999076

values:
/wiki/Gas_compressor
mw-redirect
Gas compressor

values:
/wiki/Demand-controlled_ventilation
mw-redirect
Demand-controlled ventilation

values:
/wiki/Solar_cooling
mw-redirect
Solar cooling

values:
/wiki/Solar_heating
mw-redirect
Solar heating

values:
/wiki/Air_conditioner_inverter
mw-redirect
Air conditioner inverter

values: High efficiency glandless circulating pump

values:
/wiki/High-efficiency_particulate_air
mw-redirect
High-efficiency particulate air

values:
/wiki/High_pressure_cut_off_switch
mw-redirect
High pressure cut off switch

values:
/wiki/Mechanical_fan
mw-redirect
Mechanical fan

values:
/wiki/Intelligent_buildings
mw-redirect
Intelligent buildings

values: Mold growth, assessment, and remediation

values: Chartered Institution of Building Services Engineers

values: Leadership in Energy and Environmental Design

values: Sheet Metal and Air Conditioning Contractors' National Association

values: nowraplinks collapsible collapsed navbox-inner

values: Category:Heating, ventilating, and air conditioning

values: Category:Wikipedia articles needing page number citations from November 2013

values: Category:All articles with unsourced statements

values: Category:Articles with unsourced statements from October 2017

values: Category:Articles with unsourced statements from February 2018

values: Category:Articles needing additional references from June 2016

values: Category:All articles needing additional references

values: Discussion about edits from this IP address [ctrl-alt-n]

values: A list of edits made from this IP address [ctrl-alt-y]

values: You are encouraged to create an account and log in; however, it is not mandatory

values: You're encouraged to log in; however, it's not mandatory. [ctrl-alt-o]

values:
/wiki/Thermal_comfort
View the content page [ctrl-alt-c]
c

values: A list of recent changes in the wiki [ctrl-alt-r]

values: portal navigation p-interaction p-interaction-label

values: List of all English Wikipedia pages containing links to this page [ctrl-alt-j]

values: Recent changes in pages linked from this page [ctrl-alt-k]

values:
/wiki/Wikipedia:File_Upload_Wizard
Upload files [ctrl-alt-u]
u

values: A list of all special pages [ctrl-alt-q]

values: Permanent link to this revision of the page

values: Link to connected data repository item [ctrl-alt-g]

values: Printable version of this page [ctrl-alt-p]

values: ارتياح حراري – Arabic

values:
interlanguage-link interwiki-cs
display: none;

values: آسایش حرارتی – Persian

values: נוחות אקלימית – Hebrew

values:
interlanguage-link interwiki-he
display: none;

values:
interlanguage-link interwiki-lt
display: none;

values:
interlanguage-link interwiki-pl
display: none;

values:
interlanguage-link interwiki-zh-yue
display: none;

values: All languages (initial selection from common choices by you and others)

values: /static/images/wikimedia-button-1.5x.png 1.5x, /static/images/wikimedia-button-2x.png 2x

values: /static/images/poweredby_mediawiki_132x47.png 1.5x, /static/images/poweredby_mediawiki_176x62.png 2x

values:
suggestions
display: none; font-size: 13px;

values: mediawiki ltr sitedir-ltr mw-hide-empty-elt ns-0 ns-subject page-Thermal_comfort rootpage-Thermal_comfort skin-vector action-view