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basics:building_physics_-_basics:thermal_comfort:thermal_comfort_parameters [2019/02/21 09:33]
cblagojevic
basics:building_physics_-_basics:thermal_comfort:thermal_comfort_parameters [2020/08/13 21:18] (current)
wfeist [Thermal comfort parameters]
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 ====== Thermal comfort parameters ====== ====== Thermal comfort parameters ======
 Many subjective perceptions determine living comfort, even the colour of the surroundings plays a certain role – particularly for the mood of person who thereby expresses his or her perceptions. ​ Living comfort mainly depends on the "​thermal comfort"​. This has been well-researched and the results have been incorporated into international standards (DIN ISO 7730). A large part of the information available to us today is due to the work of the Danish scientist [[http://​en.wikipedia.org/​wiki/​P._Ole_Fanger|P. O. Fanger (Wikipedia Seite)]].\\ Many subjective perceptions determine living comfort, even the colour of the surroundings plays a certain role – particularly for the mood of person who thereby expresses his or her perceptions. ​ Living comfort mainly depends on the "​thermal comfort"​. This has been well-researched and the results have been incorporated into international standards (DIN ISO 7730). A large part of the information available to us today is due to the work of the Danish scientist [[http://​en.wikipedia.org/​wiki/​P._Ole_Fanger|P. O. Fanger (Wikipedia Seite)]].\\
 +
 +In Passipedia we also have a [[phi_publications:​pb_25:​comfort_criteria_according_to_international_standards_especially_for_use_in_passive_houses|comprehensive explanation of Fangers comfort research and ISO 7730]] for those interested in the scientific background [5],​[6]. ​
  
 [{{:​picopen:​fig._1_air_movement_near_to_a_passive_house_window.jpg?​520 | **Fig. 1** Air movement near to a Passive House window: Due to the small temperature difference between window surface and room air, the speed of air sinking at the window is small. At the floor, approximately 10 cm horizontally from the passive house window (U=0.8 W/(m²K)) the maximum air speed is a barely noticeable 0.11 m/s. If the insulating value of the window is worse, then air speed rises to disturbingly high values. Therefore it is recommended,​ with "​normal windows",​ to position a heating element under the window.(CFD simulation: J. Schnieders, PHI)}}] [{{:​picopen:​fig._1_air_movement_near_to_a_passive_house_window.jpg?​520 | **Fig. 1** Air movement near to a Passive House window: Due to the small temperature difference between window surface and room air, the speed of air sinking at the window is small. At the floor, approximately 10 cm horizontally from the passive house window (U=0.8 W/(m²K)) the maximum air speed is a barely noticeable 0.11 m/s. If the insulating value of the window is worse, then air speed rises to disturbingly high values. Therefore it is recommended,​ with "​normal windows",​ to position a heating element under the window.(CFD simulation: J. Schnieders, PHI)}}]
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     * air humidity.\\     * air humidity.\\
-There is a complete range of combinations of these four comfort factors where the level of comfort is very good, this is known as the **comfort range**. ​ It can be determined by Fanger’s equation, documented in ISO 7730.  Furthermore,​ according to this standard it is essential that+There is a complete range of combinations of these four comfort factors where the level of comfort is very good, this is known as the **comfort range**. ​ It can be determined by Fanger’s equation, documented in ISO 7730 (see also [[phi_publications:​pb_25:​comfort_criteria_according_to_international_standards_especially_for_use_in_passive_houses#​Appendix:​ Calculation of the PMV according to DIN EN ISO 7730|Fangers comfort equation]]). Furthermore,​ according to this standard it is essential that
  
     * the sultriness limit in relation to the air humidity is not exceeded,     * the sultriness limit in relation to the air humidity is not exceeded,
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 \\ \\
  
-The practical consequence:​ With highly insulating external construction components, the temperature of the interior surface is only slightly different from the other temperatures ​in the area; this applies both in summer and winter. In the winter, the interior surfaces of the external construction components are comfortably warm (external walls, roofs etc. at the most 1 °C under the ambient temperature,​ window surfaces maximally 3 to 3.5 °C under it [ 1 ]). The definition of "​Passive House quality"​ windows is straightforward:​ The insulating efficiency of a window suitable for Passive Houses must be so good that under the coldest design conditions, the equation: +The practical consequence:​ With highly insulating external construction components, the temperature of the interior surface is only slightly different from the other indoor ​temperatures;​ this applies both in summer and winter. In the winter, the interior surfaces of the external construction components are comfortably warm (external walls, roofs etc. at the most 1 °C lower than the ambient temperature,​ window surfaces maximally 3 to 3.5 °C below [ 1 ]). The definition of "​Passive House quality"​ windows is straightforward:​ The insulating efficiency of a window suitable for Passive Houses must be so good that under the coldest design conditions, the equation: ​
-                                       θ area - θ Oberfl ≤ 3.5 °C+
  
-still holds trueThese small temperature differences have the following affects on the comfort criteria:+θ<​sub>​air</​sub>​ - θ<​sub>​surf</​sub>​ ≤ 3.5 °C
  
-      ​Air speeds ​in the area (apart from leaks) are due to free convection at cooler surfaces. Due to the small temperature differences the convective currents, and consequently air speeds, are now very small. Fig. 1 in the left column shows a CFD (Computational Fluid Dynamic) simulation result: There is no draft in the room, even without a heating element under the window.+still holds true. These small temperature differences have the following effects on the comfort criteria: 
 + 
 +      ​Indoor air speeds (apart from leaks) are created by free convection at cooler surfaces. Due to the small temperature differences the convective currents, and consequently air speeds, are now very small. Fig. 1 in the left column shows a CFD (Computational Fluid Dynamic) simulation result: There is no draft in the room, even without a heating element under the window.
  
       * If the external surface temperature is not more than 3.5 °C below the ambient temperature,​ then the radiant temperature difference in different directions cannot be greater than 3.5 °C. The thermography photographs in Fig. 3 to Fig. 5 show the difference between windows of various insulating quality.       * If the external surface temperature is not more than 3.5 °C below the ambient temperature,​ then the radiant temperature difference in different directions cannot be greater than 3.5 °C. The thermography photographs in Fig. 3 to Fig. 5 show the difference between windows of various insulating quality.
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 [[Planning:​thermal_protection:​windows:​Types of glazing and their specific values]] ​ {{:​picopen:​members_only.png?​25|}} [[Planning:​thermal_protection:​windows:​Types of glazing and their specific values]] ​ {{:​picopen:​members_only.png?​25|}}
 +
 +[[phi_publications:​pb_25:​comfort_criteria_according_to_international_standards_especially_for_use_in_passive_houses| A comprehensive explanation of Fangers theory of "​thermal comfort"​ and the implementation in ISO 7730]] [5],[6]
  
 [[Basics:​Summer|Thermal comfort - in summer too]] [[Basics:​Summer|Thermal comfort - in summer too]]
  
  
-==== Literature ​====+==== References ​====
  
 \\ \\
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 [ 4 ] Hermelink, Andreas: Do desires become true? Temperatures in passive houses for tenants; in: AkkP proceedings NR. 25, Darmstadt, 2004 [ 4 ] Hermelink, Andreas: Do desires become true? Temperatures in passive houses for tenants; in: AkkP proceedings NR. 25, Darmstadt, 2004
 +
 +[ 5 ] DIN EN ISO 7730: Gemäßigtes Umgebungsklima (Moderate thermal environments);​ Beuth Verlag, Berlin 1987.
 +
 +[ 6 ] Fanger, P.O.: Thermal Comfort. Analysis and Applications in Environmental Engineering;​ USA: New York 1972, © P.O. Fanger 1970.
  
  
  
basics/building_physics_-_basics/thermal_comfort/thermal_comfort_parameters.1550738019.txt.gz · Last modified: 2019/02/21 09:33 by cblagojevic