Difference between revisions of "Heating consumption of buildings"

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where A<sub>f</sub> is area of floor, A<sub>r</sub> is area of roof, A<sub>w</sub> is area of walls, A is area of building, which emits heat, n is number of floors in the building and U<sub>f</sub> is the overall heat transfer coefficient of floor, U<sub>w</sub> the overall heat transfer coefficient of walls, and U<sub>r</sub> is the overall heat transfer coefficient of roof. Unit of areas are m<sup>2</sup>, unit of the overall heat transfer coefficients are kW/(m<sup>2</sup> K).
 
where A<sub>f</sub> is area of floor, A<sub>r</sub> is area of roof, A<sub>w</sub> is area of walls, A is area of building, which emits heat, n is number of floors in the building and U<sub>f</sub> is the overall heat transfer coefficient of floor, U<sub>w</sub> the overall heat transfer coefficient of walls, and U<sub>r</sub> is the overall heat transfer coefficient of roof. Unit of areas are m<sup>2</sup>, unit of the overall heat transfer coefficients are kW/(m<sup>2</sup> K).
 +
 +
Building overall heat transfer coefficients are regulated in Finnish building regulations, which are presented in following table
 +
{| {{prettytable}}
 +
| Part of building
 +
| 1978-1985
 +
|
 +
| 1985-2002
 +
|
 +
| 2003-2006
 +
|
 +
| 2007-2010
 +
|
 +
| 2010-?
 +
|
 +
|----
 +
| ,
 +
| Mass less than
 +
| Mass over
 +
| Warm area
 +
| Half warm area
 +
| Warm area
 +
| Half warm area
 +
| Warm area
 +
| Half warm area
 +
| Warm area
 +
| Half warm area
 +
|----
 +
| ,
 +
| 100 kg / m2
 +
| 100 kg / m2
 +
| &gt; 17 °C
 +
| &gt; 5 °C
 +
| &gt; 17 °C
 +
| &gt; 5 °C
 +
| &gt; 17 °C
 +
| &gt; 5 °C
 +
| &gt; 17 °C
 +
| &gt; 5 °C
 +
|----
 +
| ,
 +
| [W / m2 K]
 +
| [W / m2 K]
 +
| [W / m2 K]
 +
| [W / m2 K]
 +
| [W / m2 K]
 +
| [W / m2 K]
 +
| [W / m2 K]
 +
| [W / m2 K]
 +
| [W / m2 K]
 +
| [W / m2 K]
 +
|----
 +
| Walls
 +
| 0,29
 +
| 0,35
 +
| 0,28
 +
| 0,45
 +
| 0,25
 +
| 0,45
 +
| 0,24
 +
| 0,38
 +
| 0,17
 +
| 0,26
 +
|----
 +
| Roof
 +
| 0,23
 +
| 0,29
 +
| 0,22
 +
| 0,45
 +
| 0,16
 +
| 0,45
 +
| 0,15
 +
| 0,28
 +
| 0,09
 +
| 0,14
 +
|----
 +
| Floor
 +
| 0,23
 +
| 0,29
 +
| 0,22
 +
| 0,45
 +
| 0,16
 +
| 0,45
 +
| 0,15
 +
| 0,28
 +
| 0,09
 +
| 0,26
 +
|----
 +
| Part which is against ground
 +
| 0,4
 +
| 0,4
 +
| 0,36
 +
| 0,45
 +
| 0,25
 +
| 0,45
 +
| 0,24
 +
| 0,34
 +
| 0,16
 +
| 0,24
 +
|----
 +
| Window
 +
|
 +
|
 +
| 2,1
 +
| 3,1
 +
| 1,4
 +
| 2,1
 +
| 1,4
 +
| 1,8
 +
| 1
 +
| 1,4
 +
|----
 +
| Door
 +
|
 +
|
 +
| 0,7
 +
| 2,9
 +
| 1,4
 +
| 2,1
 +
| 1,4
 +
| 1,8
 +
| 1
 +
| 1,4
 +
|----
 +
|}
  
 
Heating consumptions of building is calculated as:
 
Heating consumptions of building is calculated as:

Revision as of 10:39, 7 April 2009

Scope

To define heating consumption of buildings.

Definition

Heating consumption (Q) of buildings can be defined with knowledge of surface area of building, inside and outside temperature in certain time period, and heat permeability factors. Easiest way to use heating consumption is to define it as floor area weighted calculation.

Assumptions: 

Af = Ar
Aw = nAf
A = Af+Aw+Ar=(n+2)*Af

Buildings overall heat transfer coefficient per floor area is calculated as: 

Uf = (Af/Af*Uf + Aw/Af*Uw + Ar/Af*Ur)/(Af/Af)
=[(1/n)*Uf + n*Uw + (1/n)*Ur)]/(n+2)

where Af is area of floor, Ar is area of roof, Aw is area of walls, A is area of building, which emits heat, n is number of floors in the building and Uf is the overall heat transfer coefficient of floor, Uw the overall heat transfer coefficient of walls, and Ur is the overall heat transfer coefficient of roof. Unit of areas are m2, unit of the overall heat transfer coefficients are kW/(m2 K).

Building overall heat transfer coefficients are regulated in Finnish building regulations, which are presented in following table

Part of building 1978-1985 1985-2002 2003-2006 2007-2010 2010-?
, Mass less than Mass over Warm area Half warm area Warm area Half warm area Warm area Half warm area Warm area Half warm area
, 100 kg / m2 100 kg / m2 > 17 °C > 5 °C > 17 °C > 5 °C > 17 °C > 5 °C > 17 °C > 5 °C
, [W / m2 K] [W / m2 K] [W / m2 K] [W / m2 K] [W / m2 K] [W / m2 K] [W / m2 K] [W / m2 K] [W / m2 K] [W / m2 K]
Walls 0,29 0,35 0,28 0,45 0,25 0,45 0,24 0,38 0,17 0,26
Roof 0,23 0,29 0,22 0,45 0,16 0,45 0,15 0,28 0,09 0,14
Floor 0,23 0,29 0,22 0,45 0,16 0,45 0,15 0,28 0,09 0,26
Part which is against ground 0,4 0,4 0,36 0,45 0,25 0,45 0,24 0,34 0,16 0,24
Window 2,1 3,1 1,4 2,1 1,4 1,8 1 1,4
Door 0,7 2,9 1,4 2,1 1,4 1,8 1 1,4

Heating consumptions of building is calculated as: 

Q = Uf * Af * (Tin-Tout)dt

where Uf is floor weighted overall heat transfer coefficient per floor area of building, Af is area of floor, and Tin is inside temperature and Tout outside temperature in time dt.Unit of areas are m2, unit of heating permeability factors are kW/(m2 K).

Unit

kW/year

Result

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