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The general factor of thermal insulation G

This factor of thermal insulation reflects the sum of all thermal loss troughall the building envelope elements for a thermal difference of 1 Kelvin () plus the lossesbecause of ventilation and air infiltration.

GGN

The minimal values GN are given in the following table:

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Where:V represents the inside volume of the building V[m3] ;Rm - represents the average corrected thermal resistance of the building element,

[m2K/W];

;1

==

j

j

j

med

m

R

AUR

[W/m3K];

A The area of the element with the specific main thermal resistance Rm;A[m2];

n represents the ventilation rate (the number of volume changes per hour.n=0,7; 0,8; 0,9 [h-1] according to the degree of win exposure of the building);

The temperature correction factor

;)()(

ei

ui

TTTT

=

Ti=+20CTe represents the external temperature and it is in function of the zone.Tu= +5C;

Tu represents the temperature for indoor un-wormed spaces;

A

l

RRU +=

=

)(11 ;

where:

represents the linear coefficient of temperature losses trough thermal bridges anddepends on the constructive detail of the linear thermal bridge.l- represents the length of the linear thermal bridge where the specific measure the heat

losses (lis determined for one floor and than multiplied with the nr. of similar floors).

F th j t th i th ifi th l b id th t b i l d d i th

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3Vertical joint between envelope wall andinternal shear wall near an opening

1=0.0362=0.20

4Vertical joint between end shear wall andinternal shear wall.

=0.035

5 Horizontal joint at the roof.

1=0.145

2=0.168

6 Current floor horizontal joint.1=0.112=0.10

7 Current floor with balcony horizontal joint.1=0.212=0.20

8 Horizontal joint at the wall base.1=0.152=0.20

9Horizontal joint between internal wall andfloor over basement floor.

=0.029

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The steps to follow in order to determine the general factor of thermal insulation Gare:

1. Elaboration of the building plans and the characteristic cross (vertical) section throughthe building with the specification of the heated spaces perimeter;

2. Estimation of all the specific areas for the elements from the perimeter (envelope) ofthe building.

3. Calculation of the building envelope area and ( A=Aj) the building heated volume (V);4. Evaluation of the indoor unheated temperatures (Tu) by the equations of thermal

balance (for the case of in the project Tu=+5 C) ;5. Estimation of temperature correction factor j;6. Computation of the corrected thermal resistance of the building elements from the eq:

jj A

l

RRU

+=

=

)(11

7. Calculation of the mean thermal resistance of the building elements ;)/(.

=

jj

j

jm RA

AR ;

8. Estimation of the ventilation rate n in the project will consider n=0,7. . . 0,9;9. Assessment of the expression

jjm

j

R

A

,

;

10.Estimation of nR

A

VG

m

+

= 34.0

1 ;

11.Calculation of (A/V) and the resultant GN;

12.Comparison between G and GN

Recommendation:

For a simple and a better conduction of the estimation procedure we recommendorganizing the data and the results in tables, and we suggest some models for the tables

to use in the evaluation process.

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Linearheat loss

Linear bridgelength

AreaThermalresist.

Correctedthermalresist.

Meanthermalresist.

Temp.Correct.factor

Specificpower

Bridge

Detail

l *l A R (*l) R' Rm' (A )Rm'

Currentnum

ber

BuildingElem

ent

_W

m*Km

WK

mm*K

WWK

m*KW

m*KW

1 2 3 4 5 6=4*5 7 8 9=611=1/(1/8+7/

9)12=7/(7/9) 13 14=7*13/12

10,065

0,2844,8

3,588

15,456

2

4

6

1 External Wall

5

586,08

3,39

(arithmeticmean of R)

(R1+R2+R3)/3

1

52

Floor over thebasement

8

(R1+R)/2

3 Roof 5 1

4 Windows & Doors 9 1

Need for G . . . . . . . . . .