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--- planning:thermal_protection:thermal_protection_works:thermal_protection_vs._thermal_storage [2019/02/21 10:18] – cblagojevic
+++ planning:thermal_protection:thermal_protection_works:thermal_protection_vs._thermal_storage [2022/02/15 19:57] (current) – admin
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 In some publications, including various articles on the internet, emphasis is placed on the influence of the thermal storage capacity of buildings, claiming that improving the thermal insulation of external walls is pointless or even damaging. Allegedly, the effects of the thermal storage capacity of a wall and the heat gains from solar radiation are insufficiently, or not at all, taken into account by scientists.
-The author of this article has already dealt with this topic systematically in 1987, under the same title. In the meantime, many new findings have become available, all of which support this publication. The full (German) version of the summary given here can be ordered from the following link: [[http://passipedia.passiv.de/passipedia_de/_media/picopen/faxb.pdf|[Feist 2000] Feist, Wolfgang: Ist Wärmespeichern wichtiger als Wärmedämmen? (Is thermal storage more important than thermal protection?) Passivhaus Institut, Darmstadt 2000]]\\
+The author of this article has already dealt with this topic systematically in 1987, under the same title. In the meantime, many new findings have become available, all of which support this publication. The full (German) version of the summary given here can be ordered from the following link: [[https://shop.passivehouse.com/de/products/ist-warmespeichern-wichtiger-als-warmedammen-90/|[Feist 2000] Feist, Wolfgang: Ist Wärmespeichern wichtiger als Wärmedämmen? (Is thermal storage more important than thermal protection?) Passivhaus Institut, Darmstadt 2000]]\\
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 ===== The main facts =====
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 <WRAP center 60%>
-<latex>
 $$\rho c \dfrac{\delta T}{\delta t} = - div\,(- \Lambda\,grad\,T )$$
-</latex>
 </WRAP>
 The heat equation in general formulation describes the time variation of a temperature field T(x,y,z) in fixed matter (e.g. in a solid body).
-  * Differences in the temperature (gradient //grad//, on the right) propel a heat flux which increases proportional to the relevant component of the thermal conductivity tensor <latex> \Lambda </latex>. ((The most general formulation with which the thermal conductivity can vary for different spatial directions (e.g. in a perforated brick) is represented here. If the thermal conductivity is invariant with respect to direction (isotropic), the scalar value of the conductivity <latex> \lambda </latex> applies instead of the tensor <latex> \Lambda </latex>. The specific heat capacity <latex>\rho c</latex> and thermal conductivity <latex>\Lambda</latex> can depend on the location, without significantly changing the character of the equation. If the coefficients also depend on the temperature (e.g. gases), the equation becomes non-linear – however, even then the numerical solution can still provide useable results under certain conditions.)) (<latex> q = -\Lambda \,grad\,T </latex> is the heat flux).
+  * Differences in the temperature (gradient //grad//, on the right) propel a heat flux which increases proportional to the relevant component of the thermal conductivity tensor $\Lambda$. ((The most general formulation with which the thermal conductivity can vary for different spatial directions (e.g. in a perforated brick) is represented here. If the thermal conductivity is invariant with respect to direction (isotropic), the scalar value of the conductivity $\lambda$ applies instead of the tensor $\Lambda$. The specific heat capacity $\rho c$ and thermal conductivity $\Lambda$ can depend on the location, without significantly changing the character of the equation. If the coefficients also depend on the temperature (e.g. gases), the equation becomes non-linear – however, even then the numerical solution can still provide useable results under certain conditions.)) ($q = -\Lambda \,grad\,T$ is the heat flux).
   * The negative divergence of the heat flow is the change of the heat content in the infinitesimal volume element.
-  * This is the same as the temporal change in temperature <latex>\(\frac{\partial T}{\partial t}\)</latex> multiplied by the heat capacity   <latex>\rho c</latex>(left side of equation).
+  * This is the same as the temporal change in temperature $\frac{\partial T}{\partial t}$ multiplied by the heat capacity $\rho c$(left side of equation).
 This equation has proved to be consistently effective in physics and technology. Such different things like heat transfer in stars, in semi-conductor devices, brake pads and many others can be calculated in good correlation with measurements. This equation also applies in building physics – and the calculations made using it correspond just as well with building physical measurements as shown in [[planning:thermal_protection:thermal_protection_works:Thermal protection vs. thermal storage#Theory and practice (measurement)|the following example]].
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 ===== Literature =====
-**[Feist 1987]** Ist Wärmespeichern wichtiger als Wärmedämmen? 1. Auflage, IWU 1987; 2. Auflage, Passivhaus Institut, 2000 ({{:picopen:faxb.pdf|PHI's list of publications}})\\
+**[Feist 1987]** Ist Wärmespeichern wichtiger als Wärmedämmen? 1. Auflage, IWU 1987; 2. Auflage, Passivhaus Institut, 2000 [[https://shop.passivehouse.com/en/products/ist-warmespeichern-wichtiger-als-warmedammen-90/|Link to PHI Publication]]\\
 (**“Is thermal storage more important than thermal insulation?”**, 1st edition, IWU 1987; 2nd edition, Passive House Institute, 2000)\\
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 (**“Passive houses in Central Europe”**; Dissertation, University of Kassel, 1993)\\
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-**[AkkP 5]** Energiebilanz und Temperaturverhalten; Protokollband Nr. 5 des Arbeitskreises kostengünstige Passivhäuser, 1. Auflage, Passivhaus Institut, Darmstadt 1997 ({{:picopen:faxb.pdf|PHI's list of publications}})\\
+**[AkkP 5]** Energiebilanz und Temperaturverhalten; Protokollband Nr. 5 des Arbeitskreises kostengünstige Passivhäuser, 1. Auflage, Passivhaus Institut, Darmstadt 1997 [[https://shop.passivehouse.com/en/products/05-energiebilanz-und-temperaturverhalten-24/|Link to PHI Publication]]\\
 (**“Energy balance and temperature behaviour”**; Protocol Volume No. 5 of the Research Group for cost-efficient Passive Houses, 1st edition, Passive House Institute, Darmstadt 1997)