thermal insulation computation

8/12/2019 Thermal Insulation Computation

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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.

thermal insulation computation

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