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basics:building_physics_-_basics:heating_load [2016/08/22 14:56] – kdreimanebasics:building_physics_-_basics:heating_load [2019/03/20 10:28] (current) – cblagojevic
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   * The heating loads must be calculated conservatively, i.e. they must ensure a comfortable level of heating for the buildings planned.   * The heating loads must be calculated conservatively, i.e. they must ensure a comfortable level of heating for the buildings planned.
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   * The calculated heating loads should not, however, contain excessive safety margins as this would make the structural and technical requirements unreasonable to reach and the specific advantages of buildings with very small heating loads would no longer be apparent.   * The calculated heating loads should not, however, contain excessive safety margins as this would make the structural and technical requirements unreasonable to reach and the specific advantages of buildings with very small heating loads would no longer be apparent.
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   * If possible, the method should be simple to apply   * If possible, the method should be simple to apply
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   * The boundary conditions required for a particular design should be easily available. It would therefore seem appropriate to apply the existing standards for determining the space heating load [EN 12831]. However, it soon became evident that this standardised method led to extreme over-dimensioning in the case of highly efficient buildings such as Passive Houses. The reasons (besides the easily modifiable "special features" relating to oddly selected additional conditions but not to the method itself, such as U-values that always have to be set at a minimum of 0.3 W/(m²K)) are as follows:   * The boundary conditions required for a particular design should be easily available. It would therefore seem appropriate to apply the existing standards for determining the space heating load [EN 12831]. However, it soon became evident that this standardised method led to extreme over-dimensioning in the case of highly efficient buildings such as Passive Houses. The reasons (besides the easily modifiable "special features" relating to oddly selected additional conditions but not to the method itself, such as U-values that always have to be set at a minimum of 0.3 W/(m²K)) are as follows:
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   * Internal heat sources and solar gains that are especially significant during very low outdoor temperatures are not taken into account adequately in EN 12831. However, even in the design case, these free heat gains play a very significant role, particularly in buildings with a very small heating load. "No internal loads" only applies if there are no occupants present, which in turn leads to very minimal requirements. If occupants requiring a high standard of comfort are present, internal heat gains exist on a regular basis; possibly in small amounts but not zero. This makes a crucial difference, especially in the case of well-insulated buildings.   * Internal heat sources and solar gains that are especially significant during very low outdoor temperatures are not taken into account adequately in EN 12831. However, even in the design case, these free heat gains play a very significant role, particularly in buildings with a very small heating load. "No internal loads" only applies if there are no occupants present, which in turn leads to very minimal requirements. If occupants requiring a high standard of comfort are present, internal heat gains exist on a regular basis; possibly in small amounts but not zero. This makes a crucial difference, especially in the case of well-insulated buildings.
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   * Buildings with very small heating loads often have very high time constants (anywhere from 5 to 30 days or more). Due to this, brief periods of extreme weather conditions are irrelevant for the Passive House (these are virtually disregarded by the building) and the design parameters refer primarily to longer periods of time. This fact was also known to the originators of the older standards (such as DIN 4701), but it was not extended to buildings with very long time constants and, in the end, it was even ignored in the newer standards.   * Buildings with very small heating loads often have very high time constants (anywhere from 5 to 30 days or more). Due to this, brief periods of extreme weather conditions are irrelevant for the Passive House (these are virtually disregarded by the building) and the design parameters refer primarily to longer periods of time. This fact was also known to the originators of the older standards (such as DIN 4701), but it was not extended to buildings with very long time constants and, in the end, it was even ignored in the newer standards.
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   * Room-by-room determination of the heating load is associated with a high degree of uncertainty even in conventional buildings, which results from the fact that the internal heat flows, caused by relatively small temperature differences between rooms, can be more significant than the heat losses towards the outside. This effect is even more significant in the Passive House. For this reason, **room-by-room determination of the heating load usually doesn't make sense in Passive Houses**; individual calculations for each apartment or building are more reliable and are usually sufficient. Details can be found in [AkkP 25].   * Room-by-room determination of the heating load is associated with a high degree of uncertainty even in conventional buildings, which results from the fact that the internal heat flows, caused by relatively small temperature differences between rooms, can be more significant than the heat losses towards the outside. This effect is even more significant in the Passive House. For this reason, **room-by-room determination of the heating load usually doesn't make sense in Passive Houses**; individual calculations for each apartment or building are more reliable and are usually sufficient. Details can be found in [AkkP 25].
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   * Heating load calculations are usually based on floor areas calculated according to interior dimensions, thus disregarding thermal bridge effects and going against the rest of the entire planning procedure, for which the use of exterior dimensions has become established.    * Heating load calculations are usually based on floor areas calculated according to interior dimensions, thus disregarding thermal bridge effects and going against the rest of the entire planning procedure, for which the use of exterior dimensions has become established. 
  
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   * Not only do quality assured Passive Houses built actually meet the extremely small annual heating demand previously calculated by means of simulations and/or balancing procedures, the extremely low heating load resulting from the functional dimensioning is sufficient for the heating of these buildings.   * Not only do quality assured Passive Houses built actually meet the extremely small annual heating demand previously calculated by means of simulations and/or balancing procedures, the extremely low heating load resulting from the functional dimensioning is sufficient for the heating of these buildings.
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   * On the basis of the measured values, it is possible to confirm the fact that internal heat sources and passive solar gains must also be taken into account in the heating load calculation, especially for well-insulated buildings.   * On the basis of the measured values, it is possible to confirm the fact that internal heat sources and passive solar gains must also be taken into account in the heating load calculation, especially for well-insulated buildings.
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   * Performance during special situations can be validated metrologically using measured temperatures and heating loads in very specific individual cases (e.g. unoccupied apartments unheated throughout the winter). These measurements also confirm the simulation.   * Performance during special situations can be validated metrologically using measured temperatures and heating loads in very specific individual cases (e.g. unoccupied apartments unheated throughout the winter). These measurements also confirm the simulation.
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   * Very stable temperatures in buildings with excellent insulation, especially in Passive Houses, are confirmed by the case studies as well as the simulations. This increases error tolerance for extreme weather events ("worst winter in a hundred years") as well as errors in dimensioning. Of course, this knowledge must be handled very carefully: if the cumulated errors exceed a certain level, even the Passive House Standard’s tolerance level will be exceeded and the errors will have an even greater effect. It is therefore advisable to take the planning task and quality assurance seriously and to use the tolerance level resulting from a correctly planned and built Passive House to ensure and account for variances in occupant behaviour.   * Very stable temperatures in buildings with excellent insulation, especially in Passive Houses, are confirmed by the case studies as well as the simulations. This increases error tolerance for extreme weather events ("worst winter in a hundred years") as well as errors in dimensioning. Of course, this knowledge must be handled very carefully: if the cumulated errors exceed a certain level, even the Passive House Standard’s tolerance level will be exceeded and the errors will have an even greater effect. It is therefore advisable to take the planning task and quality assurance seriously and to use the tolerance level resulting from a correctly planned and built Passive House to ensure and account for variances in occupant behaviour.
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   * As regards the central question of this study, the calculation approaches based on the method published in [Bisanz 1999] have proved very successful for all buildings under consideration. This method has thus undergone a special performance test, as Passive House buildings with their extremely small heating loads are particularly susceptible to influencing factors such as solar radiation. Only buildings with such low heating loads allow the testing of such a method, as such small influences are usually masked by other effects in buildings with high heating loads.    * As regards the central question of this study, the calculation approaches based on the method published in [Bisanz 1999] have proved very successful for all buildings under consideration. This method has thus undergone a special performance test, as Passive House buildings with their extremely small heating loads are particularly susceptible to influencing factors such as solar radiation. Only buildings with such low heating loads allow the testing of such a method, as such small influences are usually masked by other effects in buildings with high heating loads. 
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 **[Feist 2005]** Feist, W.: Heizlast in Passivhäusern – Validierung durch Messungen. Endbericht. IEA SHC TASK 28 / ECBCS ANNEX 38. Passivhaus Institut, Darmstadt 2005 \\ **[Feist 2005]** Feist, W.: Heizlast in Passivhäusern – Validierung durch Messungen. Endbericht. IEA SHC TASK 28 / ECBCS ANNEX 38. Passivhaus Institut, Darmstadt 2005 \\
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 **[Feist 2005]** Feist, W.: Heating load in Passive Houses – Validation through measurement. Final Report. IEA SHC TASK 28 / ECBCS ANNEX 38. Passive House Institute, Darmstadt 2005 \\ **[Feist 2005]** Feist, W.: Heating load in Passive Houses – Validation through measurement. Final Report. IEA SHC TASK 28 / ECBCS ANNEX 38. Passive House Institute, Darmstadt 2005 \\
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 **[AkkP 28]** Wärmeübergabe- und Verteilverluste im Passivhaus; Protokollband Nr. 28 des Arbeitskreises kostengünstige Passivhäuser Phase III; Passivhaus Institut; Darmstadt 2004 \\ **[AkkP 28]** Wärmeübergabe- und Verteilverluste im Passivhaus; Protokollband Nr. 28 des Arbeitskreises kostengünstige Passivhäuser Phase III; Passivhaus Institut; Darmstadt 2004 \\
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 **[AkkP 28]** Transmission and distribution heat losses in the Passive House; Research Group for Cost-effective Passive Houses Phase III, Protocol Volume No. 28, Passive House Institute, Darmstadt 2004 \\ **[AkkP 28]** Transmission and distribution heat losses in the Passive House; Research Group for Cost-effective Passive Houses Phase III, Protocol Volume No. 28, Passive House Institute, Darmstadt 2004 \\
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 **[DIN EN 12831]** DIN EN 12831: Heizungssysteme in Gebäuden – Verfahren zur Berechnung der Norm-Heizlast Deutsche Fassung EN 12831; Beuth Verlag; Berlin \\ **[DIN EN 12831]** DIN EN 12831: Heizungssysteme in Gebäuden – Verfahren zur Berechnung der Norm-Heizlast Deutsche Fassung EN 12831; Beuth Verlag; Berlin \\
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 **[DIN EN 12831]** Heating systems in buildings - method for calculation of the design heating load EN 12831; Beuth Verlag; Berlin \\  **[DIN EN 12831]** Heating systems in buildings - method for calculation of the design heating load EN 12831; Beuth Verlag; Berlin \\ 
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 **[AkkP-25]** Temperaturdifferenzierung in der Wohnung; Protokollband Nr. 25 des Arbeitskreises kostengünstige Passivhäuser Phase III; Passivhaus Institut; Darmstadt 2004 \\ **[AkkP-25]** Temperaturdifferenzierung in der Wohnung; Protokollband Nr. 25 des Arbeitskreises kostengünstige Passivhäuser Phase III; Passivhaus Institut; Darmstadt 2004 \\
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 **[AkkP 25]** Temperature differentiation in apartments, Research Group for Cost-effective Passive Houses Phase III, Protocol Volume No. 25, Passive House Institute, Darmstadt 2004 \\  **[AkkP 25]** Temperature differentiation in apartments, Research Group for Cost-effective Passive Houses Phase III, Protocol Volume No. 25, Passive House Institute, Darmstadt 2004 \\ 
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 **[DIN 4701]** Deutsches Institut für Normung: DIN 4701: Regeln für die Berechnung des Wärmebedarfs von Gebäuden; Beuth Verlag; Berlin 1995 \\  **[DIN 4701]** Deutsches Institut für Normung: DIN 4701: Regeln für die Berechnung des Wärmebedarfs von Gebäuden; Beuth Verlag; Berlin 1995 \\ 
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 **[DIN 4701]** German Institute for Standardisation: DIN 4701: Regulations for calculating the heating demand of buildings; Beuth Verlag; Berlin 1995 \\  **[DIN 4701]** German Institute for Standardisation: DIN 4701: Regulations for calculating the heating demand of buildings; Beuth Verlag; Berlin 1995 \\ 
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 **[Feist/Werner 1993]** Feist, W. und Werner, J.: Erste Messergebnisse aus dem Passivhaus Darmstadt Kranichstein; gi 114 (1993) Heft 5 Seite 240 ff \\ **[Feist/Werner 1993]** Feist, W. und Werner, J.: Erste Messergebnisse aus dem Passivhaus Darmstadt Kranichstein; gi 114 (1993) Heft 5 Seite 240 ff \\
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 **[Feist/Werner 1993]** Feist, W. and Werner, J: Initial measurement results from the Passive House in Darmstadt Kranichstein; gi 114 (1993), Issue 5, page 240 ff \\ **[Feist/Werner 1993]** Feist, W. and Werner, J: Initial measurement results from the Passive House in Darmstadt Kranichstein; gi 114 (1993), Issue 5, page 240 ff \\
-**[Feist/Loga 1997]** Feist, W. und Loga, T.: Vergleich von Messung und Simulation. In: Arbeitskreis kostengünstige Passivhäuser, Protokollband Nr. 5, Passivhaus Institut, Darmstadt 1997 \\ + 
 +**[Feist/Loga 1997]** Feist, W. und Loga, T.: Vergleich von Messung und Simulation. In: Arbeitskreis kostengünstige Passivhäuser, Protokollband Nr. 5, Passivhaus Institut, Darmstadt 1997 \\ 
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 **[Feist/Loga 1997]** Feist, W. and Loga, T.: Comparison of measurements and simulation. Research Group for Cost-effective Passive Houses, Protocol Volume No.5, Passive House Institute, Darmstadt 1997 \\  **[Feist/Loga 1997]** Feist, W. and Loga, T.: Comparison of measurements and simulation. Research Group for Cost-effective Passive Houses, Protocol Volume No.5, Passive House Institute, Darmstadt 1997 \\ 
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 **[Kaufmann/Feist 2001]** Kaufmann, B. und Feist, W.: Vergleich von Messung und Simulation am Beispiel eines Passivhauses in Hannover- Kronsberg. CEPHEUS-Projektinformation Nr. 21, Passivhaus Institut, enercity, Hannover 2001 \\  **[Kaufmann/Feist 2001]** Kaufmann, B. und Feist, W.: Vergleich von Messung und Simulation am Beispiel eines Passivhauses in Hannover- Kronsberg. CEPHEUS-Projektinformation Nr. 21, Passivhaus Institut, enercity, Hannover 2001 \\ 
-**[Kaufmann/Feist 2001]** Kaufmann, B. und Feist, W.: Comparison of measurements and simulation using the example of a Passive House in Hannover-Kronsberg. CEPHEUS-Project Information No. 21, Passive House Institute, enercity, Hannover 2001 \\ + 
 +**[Kaufmann/Feist 2001]** Kaufmann, B. und Feist, W.: Comparison of measurements and simulation using the example of a Passive House in Hannover-Kronsberg. CEPHEUS-Project Information No. 21, Passive House Institute, enercity, Hannover 2001 \\ 
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 **[Bisanz 1999]** Bisanz, C.: Heizlastauslegung im Niedrigenergie- und Passivhaus, 1. Auflage, Darmstadt, Januar 1999 \\  **[Bisanz 1999]** Bisanz, C.: Heizlastauslegung im Niedrigenergie- und Passivhaus, 1. Auflage, Darmstadt, Januar 1999 \\ 
-**[Bisanz 1999]** Bisanz, C.: Dimensioning the heating load in low-energy and Passive Houses, 1st edition, Darmstadt, January 1999 \\ + 
 +**[Bisanz 1999]** Bisanz, C.: Dimensioning the heating load in low-energy and Passive Houses, 1st edition, Darmstadt, January 1999 \\ 
 **[PHPP 1999]** Feist, W.; Baffia, E. und Schnieders, J.: Passivhaus Projektierungspaket 1999; Passivhaus Institut, Darmstadt, Januar 1999 \\  **[PHPP 1999]** Feist, W.; Baffia, E. und Schnieders, J.: Passivhaus Projektierungspaket 1999; Passivhaus Institut, Darmstadt, Januar 1999 \\ 
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 **[PHPP 1999]** Feist, W.; Baffia, E. and Schnieders, J.: Passive House Planning Package 1999; Passive House Institute, Darmstadt, January 1999 \\ **[PHPP 1999]** Feist, W.; Baffia, E. and Schnieders, J.: Passive House Planning Package 1999; Passive House Institute, Darmstadt, January 1999 \\
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basics/building_physics_-_basics/heating_load.txt · Last modified: 2019/03/20 10:28 by cblagojevic