basics:building_physics_-_basics:thermal_comfort:thermal_comfort_parameters
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basics:building_physics_-_basics:thermal_comfort:thermal_comfort_parameters [2017/01/31 17:44] – kdreimane | basics:building_physics_-_basics:thermal_comfort:thermal_comfort_parameters [2020/08/13 21:16] – [Literature] wfeist | ||
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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. | 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. | ||
- | [{{: | + | In Passipedia we also have a [[phi_publications:pb_25:comfort_criteria_according_to_international_standards_especially_for_use_in_passive_houses|comprehensive explanation |
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- | [{{:picopen:fig._2_stratification.jpg? | + | |
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* air temperature | * air temperature | ||
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* the temperature of the surrounding surfaces, this can also be summarised as the " | * the temperature of the surrounding surfaces, this can also be summarised as the " | ||
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* air speed and turbulence | * air speed and turbulence | ||
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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**. |
- | 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**. | + | |
* 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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* air speeds are within closely defined limits (for speeds under 0.08 m/s, the number of dissatisfied due to draughts is less than 6%) | * air speeds are within closely defined limits (for speeds under 0.08 m/s, the number of dissatisfied due to draughts is less than 6%) | ||
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* the difference between radiant temperature and air temperature remains small, | * the difference between radiant temperature and air temperature remains small, | ||
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* the difference in the radiant temperature in various directions remains small (less than 5 °C, known as the " | * the difference in the radiant temperature in various directions remains small (less than 5 °C, known as the " | ||
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* the indoor air temperature stratification is less than 2 °C between the head and ankles of a seated person, | * the indoor air temperature stratification is less than 2 °C between the head and ankles of a seated person, | ||
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* the perceived temperatures in the room change by no more than 0.8 °C at different locations. | * the perceived temperatures in the room change by no more than 0.8 °C at different locations. | ||
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===== What does this have to do with the Passive House?===== | ===== What does this have to do with the Passive House?===== | ||
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+ | (Source: PHI, from the Passive House Kranichstein).}}] | ||
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+ | [{{: | ||
+ | (IR-fotography: | ||
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It is exciting that by the requirements of the passive house standard all comfort criteria are automatically optimally fulfilled - substantially improving the thermal insulation simultaneously improves thermal comfort. This can be understood as follows: | It is exciting that by the requirements of the passive house standard all comfort criteria are automatically optimally fulfilled - substantially improving the thermal insulation simultaneously improves thermal comfort. This can be understood as follows: | ||
* By improving thermal insulation (regardless of which external building building component, e.g. wall, roof, floor, etc.) the heat flow from the inside to the outside is reduced. | * By improving thermal insulation (regardless of which external building building component, e.g. wall, roof, floor, etc.) the heat flow from the inside to the outside is reduced. | ||
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* Therefore the heat flow of the room area to the interior surface of this external building component is also reduced. That heat flow has to flow through the thermal film coefficinet of the surface (radiation and convection). | * Therefore the heat flow of the room area to the interior surface of this external building component is also reduced. That heat flow has to flow through the thermal film coefficinet of the surface (radiation and convection). | ||
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* The smaller heat flow implies a resultant smaller drop of temperature over this thermal resistance. In other words: | * The smaller heat flow implies a resultant smaller drop of temperature over this thermal resistance. In other words: | ||
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* There is a smaller temperature difference between the room area (the surfaces in the area and the room air) and the interior surface of the well insulated building component. | * There is a smaller temperature difference between the room area (the surfaces in the area and the room air) and the interior surface of the well insulated building component. | ||
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\\ | \\ | ||
- | The practical consequence: | + | The practical consequence: |
- | θ area - θ Oberfl ≤ 3.5 °C | + | |
- | still holds true. These small temperature differences have the following | + | θ< |
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+ | still holds true. These small temperature differences have the following | ||
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+ | * 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. | ||
- | * 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. | ||
* If the external surface temperature is not more than 3.5 °C below the ambient temperature, | * If the external surface temperature is not more than 3.5 °C below the ambient temperature, | ||
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* The room air temperature stratification between the head and feet of a sitting person is less than 2 °C - however only under the condition that the effective median U-value of the external building components is under 0.85 W/(m²K). See Fig. 2 in the left column. | * The room air temperature stratification between the head and feet of a sitting person is less than 2 °C - however only under the condition that the effective median U-value of the external building components is under 0.85 W/(m²K). See Fig. 2 in the left column. | ||
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* The percieved temperature varies less than 0.8 °C within the area. | * The percieved temperature varies less than 0.8 °C within the area. | ||
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- Sociological questionings of a sample group of inhabitants revealed good remarks about well insulated buildings. [ 4 ] | - Sociological questionings of a sample group of inhabitants revealed good remarks about well insulated buildings. [ 4 ] | ||
+ | \\ \\ | ||
+ | ===== See also ===== | ||
+ | [[Planning: | ||
- | ===== See also ===== | + | [[phi_publications: |
+ | [[Basics: | ||
- | [[Planning: | ||
- | [[Basics:Summer|Thermal comfort | + | ==== References ==== |
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+ | \\ | ||
+ | [ 1 ] Pfluger, R.; Schnieders, J.; Buyer, B.; , W. Feist: Highly insulating window systems: Investigation and optimization in the installation (appendix to interim report A), | ||
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+ | [ 2 ] Schnieders, J.; Betschart, W.; , W. protects: Room air currents in the passive house: Measurement and simulation HLH 03-2002, page 61 | ||
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+ | [ 3 ] Lipp, B. and Moser, M.: Heating systems and comfort: Is comfort physiologically measurable? | ||
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+ | [ 4 ] Hermelink, Andreas: Do desires become true? Temperatures in passive houses for tenants; in: AkkP proceedings NR. 25, Darmstadt, 2004 | ||
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+ | [ 5 ] DIN EN ISO 7730: Gemäßigtes Umgebungsklima (Moderate thermal environments); | ||
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+ | [ 6 ] Fanger, P.O.: Thermal Comfort. Analysis and Applications in Environmental Engineering; | ||
basics/building_physics_-_basics/thermal_comfort/thermal_comfort_parameters.txt · Last modified: 2020/08/13 21:18 by wfeist