basics:building_physics_-_basics:what_defines_thermal_bridge_free_design
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basics:building_physics_-_basics:what_defines_thermal_bridge_free_design [2016/08/22 17:20] – [How to achieve a thermal bridge free design] kdreimane | basics:building_physics_-_basics:what_defines_thermal_bridge_free_design [2022/02/15 19:13] (current) – admin | ||
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====== What defines thermal bridge free design? ====== | ====== What defines thermal bridge free design? ====== | ||
- | A building envelope is considered to be free of thermal bridges if the transmission losses under consideration of all [[basics: | + | A building envelope is considered to be free of thermal bridges if the transmission losses under consideration of all [[basics: |
\\ | \\ | ||
[{{ : | [{{ : | ||
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<WRAP centeralign > | <WRAP centeralign > | ||
- | $$H_{T} = \sum_{i}A_{i}U_{i}+\sum_{k}l_{k}\varPsi_{k}+\sum_{j}\chi_{j}$$ | + | $$ |
+ | \Large{H_{T} = \sum_{i}A_{i}U_{i}+\sum_{k}l_{k}\varPsi_{k}+\sum_{j}\chi_{j}} | ||
+ | $$ | ||
</ | </ | ||
| | ||
<WRAP centeralign | <WRAP centeralign | ||
- | $$\sum\varPsi \cdot l + \sum\chi | + | $$ |
+ | \Large{\sum\varPsi \cdot l + \sum\chi | ||
+ | $$\\ | ||
+ | \\ | ||
+ | \\ | ||
** [defined as thermal bridge free]** | ** [defined as thermal bridge free]** | ||
</ | </ | ||
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It will then be admissible to disregard the thermal bridge effects in the PHPP, thus simplifying the calculation quite considerably. This equates to the statement $ \Delta U_{WB} \leq 0$, where $\Delta U_{WB}$ is the thermal bridge correction addend (as used in the German energy saving regulations for example)\\ | It will then be admissible to disregard the thermal bridge effects in the PHPP, thus simplifying the calculation quite considerably. This equates to the statement $ \Delta U_{WB} \leq 0$, where $\Delta U_{WB}$ is the thermal bridge correction addend (as used in the German energy saving regulations for example)\\ | ||
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- | [{{ : | ||
===== Simplified criterion ===== | ===== Simplified criterion ===== | ||
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Verification using this definition of thermal bridge free design would imply that all details would have to be calculated in a multi-dimensional way. Therefore, simplified criteria for “thermal bridge free design” should be devised. It was found that for ordinary building geometries, the “thermal bridge free” requirement was almost always adequately met for all linear disturbances only if | Verification using this definition of thermal bridge free design would imply that all details would have to be calculated in a multi-dimensional way. Therefore, simplified criteria for “thermal bridge free design” should be devised. It was found that for ordinary building geometries, the “thermal bridge free” requirement was almost always adequately met for all linear disturbances only if | ||
<WRAP centeralign | <WRAP centeralign | ||
- | $$\varPsi \leq 0.01 \quad W/(mK)$$ **[TbCrit]** | + | $$ |
+ | \Large{\varPsi \leq 0.01 \quad W/(mK)} | ||
+ | $$ | ||
+ | \\ | ||
+ | **[TbCrit]** | ||
</ | </ | ||
These may still result in certain positive contributions, | These may still result in certain positive contributions, | ||
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Besides, the remaining contributions are compensated to a certain extent by other connections where there are negative linear thermal transmittances. The // | Besides, the remaining contributions are compensated to a certain extent by other connections where there are negative linear thermal transmittances. The // | ||
- | With the simplified criterion, planning and construction become significantly easier: for a particular category of connection details, it only has to be verified once in advance that the // | + | With the simplified criterion, planning and construction become significantly easier: for a particular category of connection details, it only has to be verified once in advance that the // |
On the [[http:// | On the [[http:// | ||
<WRAP center 100%> | <WRAP center 100%> | ||
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[{{: | [{{: | ||
- | [{{: | + | [{{: |
</ | </ | ||
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* Solid constructions with solid bricks, | * Solid constructions with solid bricks, | ||
+ | |||
* Solid constructions with low-conductivity blocks (e.g. porous concrete blocks), | * Solid constructions with low-conductivity blocks (e.g. porous concrete blocks), | ||
+ | |||
* Timber constructions (solid wood beams as well as lightweight beams), | * Timber constructions (solid wood beams as well as lightweight beams), | ||
+ | |||
* Constructions using formwork elements, | * Constructions using formwork elements, | ||
- | * Constructions using prefabricated lightweight concrete elements. | ||
- | |||
- | Details for solid constructions, | ||
+ | * Constructions using prefabricated lightweight concrete elements. | ||
- | [[basics: | + | Details for solid constructions, |
+ | | ||
The Passive House Institute provides advice for manufacturers regarding the development of thermal bridge free constructions.\\ | The Passive House Institute provides advice for manufacturers regarding the development of thermal bridge free constructions.\\ | ||
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\\ | \\ | ||
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- | \\ | + | |
<WRAP centeralign 90% > | <WRAP centeralign 90% > | ||
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===== References ===== | ===== References ===== | ||
- | **[AkkP 16]** Wärmebrückenfreies Konstruieren ; Protokollband Nr. 16 des Arbeitskreises kostengünstige Passivhäuser, | + | **[AkkP 16]** Wärmebrückenfreies Konstruieren ; Protokollband Nr. 16 des Arbeitskreises kostengünstige Passivhäuser, |
**[Kaufmann 2002]** Das Passivhaus – Energie-Effizientes-Bauen, | **[Kaufmann 2002]** Das Passivhaus – Energie-Effizientes-Bauen, | ||
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[[basics: | [[basics: | ||
+ | [[basics: | ||
+ | |||
+ | [[basics: | ||
- | * [[basics: | ||
- | * [[basics: | ||
basics/building_physics_-_basics/what_defines_thermal_bridge_free_design.1471879247.txt.gz · Last modified: 2016/08/22 17:20 by kdreimane