Differences

This shows you the differences between two versions of the page.

--- basics:building_physics_-_basics:thermal_bridges:tbcalculation:examples:heatedb [2016/08/09 14:31] – created mschueren
+++ basics:building_physics_-_basics:thermal_bridges:tbcalculation:examples:heatedb [2022/02/15 18:35] (current) – admin
@@ Line 1: / Line 1: @@
-to be translated
-{{ :picprivate:passipedia_mitgliederbereich_artikel_neu.png?500 }}
 ====== Heated basement ======
 In the norms DIN EN ISO 13370 and DIN EN ISO 10211, only one Ψ-value is determined for a heated basement. This includes the upper connection of the basement ceiling and the connection of the basement wall to the basement floor slab. In the Ground worksheet of the [[planning:calculating_energy_efficiency:phpp_-_the_passive_house_planning_package |PHPP]] it is sufficient to enter $\Psi_{total}$  (as a perimeter thermal bridge). Alternatively, both connections ($\Psi_{upper}$ und $\Psi_{lower}$) can be examined separately for the criterion relating to absence of thermal bridges.
-{{ :picprivate:beheizter_keller_abb_1.png?nolink&400 |}}
+{{ :picopen:beheizter_keller_abb_1.png?400 |}}
 The procedure for determining the mentioned linear thermal transmittance is given below. Here it should be mentioned that in the Ground worksheet of the [[planning:calculating_energy_efficiency:phpp_-_the_passive_house_planning_package |PHPP]], U-values for the basement floor slab and the basement wall are determined using the approximation function in the DIN EN ISO 13370, with consideration of the ground. In this way, Option A or Option B can also be applied for heated basements. In the context of certification for a construction system however, Option B should also be applied here for determining the Ψ-values.
-{{ :picprivate:beheizter_keller_abb_2.png?nolink&400 |}}
+{{ :picopen:beheizter_keller_abb_2.png?400 |}}
-Acoording to the figure above, the U-values of the building components that are relevant for determining the Ψ-value can be ascertained as follows:
+According to the figure above, the U-values of the building components that are relevant for determining the Ψ-value can be ascertained as follows:
-{{ :picprivate:beheizter_keller_abb_3a.png?nolink&800 |}}
+{{ :picopen:beheizter_keller_abb_3a.png?800 |}}
-{{ :picprivate:beheizter_keller_abb_3b.png?nolink&800 |}}
+{{ :picopen:beheizter_keller_abb_3b.png?800 |}}
+{{ :picopen:beheizter_keller_abb_3c.png?800 |}}
-{{ :picprivate:beheizter_keller_abb_3c.png?nolink&800 |}}
 \\
@@ Line 27: / Line 23: @@
 <WRAP centeralign>
 **Calculating the conductance**
-<latex>
 $L_{2d}$
-</latex>
 </WRAP>
-{{ :picprivate:beheizter_keller_abb_4a.png?nolink&600 |}}
+{{ :picopen:beheizter_keller_abb_4a.png?600 |}}
 \\
-{{ :picprivate:beheizter_keller_abb_4b.png?nolink&600 |}}
+{{ :picopen:beheizter_keller_abb_4b.png?600 |}}
 <WRAP centeralign>
-<latex>
+$$
-$$\.q = 38{,}123 \, \frac{\text{W}}{\text{m}}$$ \\
+\large{\dot{q} = 38{,}123 \, \dfrac{\text{W}}{\text{m}}}\\
-$$L_{2d} = \frac{\.q}{T_i-T_e} = \frac{38{,}123}{30} = 1{,}2708 \, \frac{\text{W}}{\text{m} \cdot \text{K}}}$$
+$$
-</latex>
+</WRAP>
+<WRAP centeralign>
+$$
+\large{L_{2d} = \dfrac{\dot{q}}{T_i-T_e} = \dfrac{38{,}123}{30} = 1{,}2708 \, \dfrac{\text{W}}{\text{m} \cdot \text{K}}}
+$$
 </WRAP>
@@ Line 47: / Line 46: @@
 <WRAP centeralign>
 **Conductance of the basement floor slab and the basement wall**
-<latex>
 $L_{BP,KW}$
-</latex>
 </WRAP>
-{{ :picprivate:beheizter_keller_abb_5a.png?nolink&600 |}}
+{{ :picopen:beheizter_keller_abb_5a.png?600 |}}
 \\
-{{ :picprivate:beheizter_keller_abb_5b.png?nolink&600 |}}
+{{ :picopen:beheizter_keller_abb_5b.png?600 |}}
-<WRAP centeralign>
-<latex>
+<WRAP centeralign>
-$$\.q = 22{,}190 \, \frac{\text{W}}{\text{m}}$$ \\
+$$
-$$L_{BP,KW} = \frac{\.q}{T_i-T_e} = \frac{22{,}190}{30} = 0{,}7397 \, \frac{\text{W}}{\text{m} \cdot \text{K}}}$$
+\large{\dot{q} = 22{,}190 \, \dfrac{\text{W}}{\text{m}}}\\
-</latex>
+$$
+</WRAP>
+<WRAP centeralign>
+$$
+\large{L_{BP,KW} = \dfrac{\dot{q}}{T_i-T_e} = \dfrac{22{,}190}{30} = 0{,}7397 \, \dfrac{\text{W}}{\text{m} \cdot \text{K}}}
+$$
 </WRAP>
@@ Line 66: / Line 69: @@
 <WRAP centeralign>
 **Calculating the conductance of the exterior wall**
-<latex>
 $L_{AW}$
-</latex>
 </WRAP>
 <WRAP centeralign>
-<latex>
+$$
-$$U_{AW} = 0{,}1205 \, \frac{\text{W}}{\text{m}^2 \cdot \text{K}}$$
+\large{U_{AW} = 0{,}1205 \, \dfrac{\text{W}}{\text{m}^2 \cdot \text{K}}}
-$$L_{AW} = l_{AW} \cdot U_{AW} = 1{,}83 \cdot 0{,}1205 = 0{,}2205 \, \frac{\text{W}}{\text{m} \cdot \text{K}}}$$
+$$
-</latex>
+</WRAP>
+<WRAP centeralign>
+$$
+\large{L_{AW} = l_{AW} \cdot U_{AW} = 1{,}83 \cdot 0{,}1205 = 0{,}2205 \, \dfrac{\text{W}}{\text{m} \cdot \text{K}}}
+$$
 </WRAP>
@@ Line 84: / Line 90: @@
 </WRAP>
 <WRAP centeralign>
-<latex>
+$$
-$$\Psi_{gesamt} = L_{2d}-L_{AW}-L_{BP,KW}=1{,}2708-0{,}2205-0{,}7397=0{,}311 \, \frac{\text{W}}{\text{m} \cdot \text{K}}}$$
+\Psi_{overall} = L_{2d}-L_{AW}-L_{BP,KW}=1{,}2708-0{,}2205-0{,}7397=0{,}311 \, \dfrac{\text{W}}{\text{m} \cdot \text{K}}
-</latex>
+$$
 </WRAP>
@@ Line 93: / Line 99: @@
 In practice, pre-prepared Excel templates are used here also for determining the Ψ-values. The heat flows and necessary lengths can be entered here and the desired Ψ-value is received as the result directly:
-{{ :picprivate:beheizter_keller_abb_6.png?nolink&500 |}}
+{{ :picopen:beheizter_keller_abb_6.png?500 |}}
 Note: this is not a thermal bridge free connection. In the example given here it is relatively clear that the basement wall connection to the basement floor slab has not been implemented in an ideal manner.  One would advise the client to install insulation under the foundation as well (see AkKP 35). Regardless of that, the question that arises is, what about the upper connection? Can the floor/ceiling connection be regarded as thermal bridge free? Strictly speaking, one cannot consider both these connections separately from each other. The ground represents a thermal connection between the basement wall and the floor slab. Heat flow through the floor slab thus influences the heat transfer through the basement wall and vice versa. In most cases however, the basement wall to exterior wall connection is near or even above ground level. For this reason there are less interactions, and separate specification of $\Psi_{lower}$ and $\Psi_{upper }$, which is desirable in practical application, is justified.
@@ Line 100: / Line 106: @@
 <WRAP centeralign>
 **Determining the conductance**
-<latex>
 $L_{2d}$
-</latex>
 </WRAP>
-{{ :picprivate:beheizter_keller_abb_7a.png?nolink&600 |}}
+{{ :picopen:beheizter_keller_abb_7a.png?600 |}}
 \\
-{{ :picprivate:beheizter_keller_abb_7b.png?nolink&600 |}}
+{{ :picopen:beheizter_keller_abb_7b.png?600 |}}
 <WRAP centeralign>
-<latex>
+$$
-$$\.q = 29{,}588 \, \frac{\text{W}}{\text{m}}$$ \\
+\Large{\dot{q} = 29{,}588 \, \dfrac{\text{W}}{\text{m}}} \\
-$$L_{2d} = \frac{\.q}{T_i-T_e} = \frac{29{,}588}{30} = 0{,}9863 \, \frac{\text{W}}{\text{m} \cdot \text{K}}}$$
+$$
-</latex>
+</WRAP>
+<WRAP centeralign>
+$$
+\large{L_{2d} = \dfrac{\dot{q}}{T_i-T_e} = \dfrac{29{,}588}{30} = 0{,}9863 \, \dfrac{\text{W}}{\text{m} \cdot \text{K}}}
+$$
 </WRAP>
@@ Line 122: / Line 131: @@
 </WRAP>
 <WRAP centeralign>
-<latex>
+$$
-$$\Psi_{unten} = L_{2d}-L_{BP,KW}=0{,}9863-0{,}7397 = 0{,}247 \, \frac{\text{W}}{\text{m} \cdot \text{K}}}$$
+\large{\Psi_{lower} = L_{2d}-L_{BP,KW}=0{,}9863-0{,}7397 = 0{,}247 \, \dfrac{\text{W}}{\text{m} \cdot \text{K}}}
-</latex>
+$$
 </WRAP>
@@ Line 135: / Line 144: @@
 <WRAP centeralign>
-<latex>
+$$
-$$\Psi_{upper} = \Psi_{overall}-\Psi_{lower} = 0{,}311-0{,}247 = 0{,}064 \, \frac{\text{W}}{\text{m} \cdot \text{K}}}$$
+\large{\Psi_{upper} = \Psi_{overall}-\Psi_{lower} = 0{,}311-0{,}247 = 0{,}064 \, \frac{\text{W}}{\text{m} \cdot \text{K}}}
-</latex>
+$$
 </WRAP>
@@ Line 149: / Line 158: @@
 <WRAP centeralign>
 **Determining the minimum surface temperature **
-<latex>
 $f_{Rsi}$
-</latex>
 </WRAP>
-{{ :picprivate:beheizter_keller_abb_8a.png?nolink&600 |}}
+{{ :picopen:beheizter_keller_abb_8a.png?600 |}}
 {{ :picprivate:beheizter_keller_abb_8b.png?nolink&600 |}}
+{{ :picopen:beheizter_keller_abb_8b.png?600 |}}
 <WRAP centeralign>
-<latex>
+$$
-$$f_{Rsi,A} = \frac{18{,}5-(-10)}{20-(-10)} = 0{,}94$$
+\large{f_{Rsi,A} = \dfrac{18{,}5-(-10)}{20-(-10)} = 0{,}94}
-$$f_{Rsi,B} = \frac{16{,}9-(-10)}{20-(-10)} = 0{,}89$$
+$$
-$$f_{Rsi,C} = \frac{11{,}6-(-10)}{20-(-10)} = 0{,}72$$
-</latex>
 </WRAP>
+<WRAP centeralign>
+$$
+\large{f_{Rsi,B} = \dfrac{16{,}9-(-10)}{20-(-10)} = 0{,}89}
+$$
+</WRAP>
+<WRAP centeralign>
+$$
+\large{f_{Rsi,C} = \dfrac{11{,}6-(-10)}{20-(-10)} = 0{,}72}
+$$
+</WRAP>
 **Note!** //areas which are near the ground surface are subject to bigger temperature fluctuations than those which are further away from the surface. The steady-state calculated surface temperatures of areas further away are therefore less meaningful, but are usually on the safe side because in reality the boundary conditions necessary for this would have had to prevail for months. If more exact surface temperatures are required, then the solution may lie in two or three-dimensional transient calculations.//
 ===== See also =====
-  * [[basics:building_physics_-_basics:heat_transfer:thermal_bridges:thermal_ bridge_calculation|Thermal bridge calculation]]
-  * [[basics:building_physics_-_basics:heat_transfer:what_defines_thermal_bridge_free_design:thermal bridges:thermal_bridge_calculation:recommended procedure]]
+  * [[basics:building_physics_-_basics:thermal_bridges:tbcalculation|Thermal bridge calculation]]
-  * [[basics:building_physics_-_basics:heat_transfer:thermal_bridges:thermal_bridge_calculation:examples]]
+  * [[basics:building_physics_-_basics:thermal_bridges:tbcalculation:thermal_bridge_software|Software for calculating thermal bridges]]
+  * [[basics:building_physics_-_basics:thermal_bridges:tbcalculation:examples|Examples]]