thermal insulation computation
TRANSCRIPT
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Thermal Insulation Computation
The thermal design of the building envelope elements and of the ones which isolate places with
different temperatures are done according to C107/ 1-1997.
necef RR min,
efR - total resistance at the heat exchange
necRmin, - the minimum resistance at the heat exchange
n
j
e
j
j
ief Rd
RR1
;e
e
i
i RR
1;
1
Where:
iR -specific resistance at heat exchange through interior wall surface ]/[ 2
Wkm
eR -specific resistance at heat exchange through exterior wall surface ]/[ 2
Wkm
nnumber of layers
jd - thickness of j layer
j - thermal conductivity of j layer
8i - coefficient of interior superficial thermo transfer
24e
- coefficient of exterior superficial thermo transfer
]/[125.08
11 2wkmR
i
i
]/[042.024
11 2 wkmRe
e
Exterior walls
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According to C107/2005, in case of the external walls we have the following:
Rsi=0.125[m2K/W];
Rse=0.042[m2K/W];
Rmin=1.80[m2K/W]; (from 10.06.2011)
No. Crit. Material d (m) (W/mk) d/
1 Exterior plaster 0.015 0.93 0.0161
2Thermal insulation with
expanded polystyrene0,1 0.035 2.86
3 B.C.A. Masonry 0.25 0.21 1.19
4 Interior plaster 0.015 0.81 0.0185
]/[25.4042.00185.019.186.20161.0125.0 2 wkmRef
Lower slab:
According to C107/2005, for slab over basement we have:
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Rsi=0.125[m2K/W];
Rse=0.042[m2K/W];
Rmin=2.9[m2K/W]; (from 10.06.2011)
Nr.crt Name of the material layer d(m) (W/mK) d/
1 Ceiling plaster 0.015 0.87 0.017
2 Thermal insulation 0.20 0.044 4.545
3 RC Plate 0.15 1.74 0.086
4 Equalizing cement 0.03 0.93 0.032
5 Sand stone 0.01 1.2 0.083
)/(93.4042.0)083.0032.0086.0545.4017.0(125.0 21
WKmRdRRn
j
e
j
jief
Roof floor
According to C107/2005, for slab over basement we have:
Rsi=0.125[m2K/W];
Rse=0.042[m2K/W];
Rmin=5[m2K/W]; (from 10.06.2011)
Nr.crt Name of the
layer
d(mm) (W/mK) d/
1 Ceiling plaster 0.015 0.87 0.017
2 RC plate 0.15 1.74 0.086
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3 Equalizing
cement
0.03 0.93 0.032
4 Vapour barrier - - -
5 Protection layer - - -
6 Support layer 0.03 0.93 0.032
7 Diffusion layer - - -
8 Protection layer - - -
9 Thermal
insulation
0.2 0.048 4.5
10 Protection
screed
0.03 0.91 0.032
11 Waterproofing - - -
12 Gravel - - -
n
j
e
j
j
ief WKmRd
RR1
2 )/(326.5167.0)32.05.4032.0032.0086.0017.0(125.0
The calculus for the global coefi cient of thermal insulation
km
wrefGG
311
1G - the coeficient for thermal insulation for a buildingor a part of a building, representing the
timetables heat looses by transmision via enclosure elements, for a difference of temperature equal to0
1 C
between the interior and the exterior.
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m
jj
R
A
VG
11
V- the wormed volume of the building or of the building part calculated based on the exterior
dimensions of the building ][
3
m .
jA -the elemnts area ofbuilding j, by wich the change of heat is done ][ 2m .
j -the corection factor for the diference of temperature between the isolated
enviroments of the construction element.
V- the wormed volume of the building or of the building part calculated based on the exterior
dimensions of the building ][ 3m .
jA -the elemnts area of building j, by wich the change of heat is done ][ 2m .
j -the corection factor for the diference of temperature between the isolated
enviroments of the construction element.
Windows + interior doors:
][07.1434]1.22.12.1
)9.25875.2875.125.46.19.2[(1.29.02.1)9.200.59.045.21.44.59.2(
2
4
m
A
Exterior walls:
A1=441m2
A2=228m2
A3=441m2
A4=228m2
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Area of the superior plate: 446.88 ][ 2m
Area of the inferior plate: 446.88 ][ 2m
][1332 3mVtotal
Calculation of the heat bridges lengths:
Heat bridges are non homogeneous areas of the building elements with a greater heat transfer.
Usually they are found at the intersection of building elements and in the area of resistance
elements.
a. Vertical bridgescorner
b. Vertical bridgesintersection of column with wall
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c. Vertical bridgeswindow
d. Horizontal bridgesintersection of wall with plate
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e. Horizontal bridgesintersection of wall with plate over ground-floor
f. Horizontal bridgesintersection of wall with plate with balcony
2.02
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Calculation of construction elements area, volume and perimeter:
- the area, perimeter and volume is calculated on the interior faces of the walls
P = 88.8 [m]
Pthe building perimeter
][23.41 2mAw
wA - Window area / floor
][129023.4115*8.88 2mAhPA wop - area of the exterior wall
][8.446 2
mS
SThesurface of floor
][8.222513328.4468.446 2mAbe - building envelope area
][670215*8.446 3
mV -heated volume of the building
5.0)200511072(331.06702
8.22252
NGCofannexfrom
km
w
V
A
NG allowed global coefficient of building thermal insulation
21.01
20.01
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'
1'
UR
R corrected specific thermal resistance
U coefficient of thermal transfer
]/[)(1
' 2 WkmA
L
RU
linear coefficient of thermal transfer
Llength of thermal bridge
Aarea of building element
Rthermal resistance
For exterior wall: ]/[40.01290
)158.8815.018012.0602.0(
25.4
1' 2 WkmU
For window: ]/[24.323.41
5.16531.0
5.0
1' 2 WkmU
For roof plate:]/[491.08.446
8.885.0
55.2
1
'
2
WkmU
For ground-floor plate: ]/[355.08.446
8.8843.0
7.3
1' 2 WkmU
]/[34.0)'
(1 3kmWn
R
A
VG
Gglobal coefficient of building thermal insulation
correction factor of exterior temperatures
n=0.6naturalventilation speed
]/[384.06.034.0)181.2
8.4461
03.2
8.4468.0
308.0
5.1651
22.3
1290(
6702
1 31 kmWG
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SWEAT CALULUS
Sweat calculus - for external wallhas been carried out using the program Isover.
Data input:
We input each layer, their thickness, and thermal conductivity:
NGG 1
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a.Computing the possibility of condensation:
We input:
Internal temperature: 200 C
External termperature: -18
0
C Relative humidity of indoor air: 65%
Relative humidity of outdoor air: 85%
Length of heating season: 210 days;
Data sheet of thermal trasmittance:
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Data sheet of vapour diffusion is shown in the following chart:
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So, no interstitial condensation is expected.