SuReReEnMaHo - Central Europe experience and knowledge Prof. Dr.-Ing. Dieter Bunte

SuReReEnMaHo - Central Europe experience and knowledge

Prof. Dr.-Ing. Dieter Bunte

Central Europe experienceand knowledge about sustainable rehabilitation

of housings and energymanagement

1.Social background and expectations2.Overview about reached rehabilitation status3.Expected transitions (shifts)



1.Social background and expectations

- europe-wide the operation of buildings count for round about 40% of the final energy consumption

- in Germany round about 30% of the final energy consumption is related to housing

- round about 80% of this energy is needed for heating (warm water, cooking, ligthning, and so on is the rest)



Generally mind-set of dweller concerning rehabilitation [1]:

good

very good

Ex ante in between ex post retrospectivequestioning



Generally mind-set of dweller concerning rehabilitation [1]:

Advantages:

?

Disadvantages/Burden:

- construction site dirt- site noise- constriction in using the rooms- untidiness- enduring presence of craftsman- insufficient information about coordination,

kind and amount of rehabilitation workflow

5



Expectations of dwellers [1]:

Improvement of the residential building

very important not important at all

CO2 reduction

Increasement of comfort of living

energy saving

Improvement of the building climate

Reduction of heating costs

6



Age structure of buildings respectively flats [2]:

buildingsflats

7



Ownership conditions [2]:buildings dwellings

All buildings % %

Private ownership 88.3 62.4

Community of owners 5.5 15.6

Housing company 5.5 20.7

others 0.7 1.2

One and two family houses

private 95.9 95.2



Multi family houses

private 50.9 33.0



8



Building size and floor numbers [2]:One and two family houses Share of buildings in %

One dwelling 73.0

Two dwellings 27.0

One floor 39.2

Two floors 55.7

More then two floors 5.1

Multi family houses

3 – 4 dwellings 53.7



More then 12 dwellings 8.8

1 – 2 floors 41.3

3 – 4 floors 51.1

5 – 9 floors 7.3

More then 9 floors 0.3

9



Heat insulation status [2]:

Buildings (%) with insulation of

Exterior walls Roof / upper floor ceiling

Basement ceiling / ground floor

All buildings 42.1 76.4 37.1

Old buildings constructed before 1978

35.7 68.2 23.3

Year of construction 1979 - 2004

53.2 92.1 62.1

New buildings constructed after 2005

66.0 98.5 87.3

10



Heat insulation status [2]: ex post insulationBuildings (%) with insulation of





35.7 68.2 23.3

Year of construction 1979 - 2004

53.2 92.1 62.1

New buildings constructed after 2005

66.0 98.5 87.3

Buildings (%) with ex post insulation of





27.6 52.2 12.5

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Ex post insulation of multi family houses constructed before 1978 [2]: geographical

differences

Multi family houses (%) with with es post insulation of



Northern parts of Germany 22.5 42.4 6.8

Southern parts of Germany 21.2 43.0 8.7

Formerly GDR 39.5 64.9 22.3

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Exterior walls: kind of wall construction in % [2]

Kind of wall construction whole Germany north south east

brick, one layer 61.3 32.4 85.1 63.4

brick, two layers 29.9 61.2 6.5 21.5

truss wall 3.1 2.4 2.9 4.9

timber frame construction 3.7 3.3 4.3 3.2

concrete, prefabricated elements 1.9 0.7 1.0 6.7

Kind of wall construction before 1978 1979 - 2004 2005 until now

brick, one layer 63.8 56.0 57.5

brick, two layers 28.7 32.8 27.8

truss wall 4.4 0.4 0.6

timber frame construction 1.5 7.5 13.0

concrete, prefabricated elements 1.5 3.1 0.8

13



Insulation thickness (exterior walls) [2]:

Insulation thickness

percentage

AllOld buildings before 1978Between 1979 and 2004New buildings after 2004

14



Insulation thickness (exterior wall, old buildings before 1978) [2]:


percentage

All old buildings

Constructed with insulation

Ex post insulation

15



Insulation thickness (exterior wall, old buildings before 1978) [2]:


percentage

Brick, one layer

Brick, two layers

Truss wall

Prefabricated concrete elements

16



Thickness of upper floor ceiling / roof insulation[2]:


percentage

All housing buildingsOld buildings before 1978Buildings from 1979 – 2004New buildings from 2005 to now

17



Ex post insulation thickness of roof / upper floor ceiling (old buildings before 1978) [2]:


percentage

Roof not heated

Roof heated

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Insulation thickness of ground floor / basement ceiling [2]:


percentage

All housing buildingsOld buildings before 1978Buildings from 1979 – 2004New buildings from 2005 to now

19



Height of the basement [2] (old buildings before 1978):

Heating situation in the basement [2] (old buildings before 1978):

percentage

High basement (a person 1.80 m tall can use it erectly) 75.9

Low basement (a person 1.80 m tall can use it barely) 19.3

Very low basement (a person 1,80 m tall have to crouch down) 4.8

Percentage

No basement 12.6

Not heated basement 61.9

Partly heated basement 22.2

Completely heated basement 3.3

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Frequency distribution of window age [2]:

Installation age

percentage

All buildingsOld buildings before 1979

21



Thermal insulation glass production in Germany [2]:

Triple glazing (U=0.7 W/m2K)Duplex glazing (U=1.1 W/m2K)Duplex glazing (U=1.2 W/m2K)Duplex glazing (U=1.4 W/m2K)

22



Kind of glazing and window installation year [2]:

All buildings Old buildings before 1978

New buildings from 2005 until now

Windows installed before 1994

Single glazing 2.2 4.1

Douplex glazing 41.2 56.8

Trippel glazing 0.5 0.4

Windows installed after 1995

Single glazing 0.3 0.2 0.3

Douplex glazing 52.6 36.4 85.0

Tripel glazing 3.2 2.0 14.7

sum 100 100 100

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Kind of heating and energy source [2]:Old buildings before 1978

Buildings from 1979 until 2004

New buildings after 2004

Kind of heating

district heating 3.9 4.0 3.6

central heating 79.9 92.4 92.2

seperate dwelling heating 6.3 1.5 1.6

individual room heating 9.9 2.1 2.5

Kind of energy source

district heating 3.9 4.0 3.6

gas 47.9 59.8 60.1

oil 37.2 29.4 5.9

biomass 6.5 2.6 9.2

coal 1.0 0.0 0.0

electricity 3.5 4.3 21.1

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Amount of modernisation (year of construction before 2004) [2]:

Number of energy saving measures Percentage

Only one energy saving measure 66.4

Two energy saving measures 20.9

Three energy saving measures 6.4

Four energy saving measures 4.2

Five energy saving measures 1.9

Six energy saving measures 0.3

100

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Amount of energetically rehabilitation intentions during the next five years [2]:

Intention All buildings Old buildings before 1978

Exterior wall insulation 7.5 9.6

Roof or upper floor ceiling insulation 8.5 11.0

Basement ceiling or ground floor insulation 3.7 5.0

Installation of new windows 7.5 9.5

Installation of photovoltaic elements 2.5 1.9

Installation of solar heating elements 4.7 4.3

Installation of district heating connection 0.1 0.1

Replacement of the heating system 10.2 10.4

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3.Expected Transitions

Thinking about energy demand or energy consumption calculation in a different way as

it is done today

- by establishing such calculations as a sustainability criteria,

- integrating user/owner behaviour an consider this as an important aspect,

- combining energy calculation with economical calculations (costs, value, finance)

and

- establishing new policy instruments if they are more effective.

27



In Germany nowadays used energy certificate:

28



But, what's the real situation (1)?

Calculated energy demand in kWh/(m2a)

Measured energy consum

ption in kWh/(m

2a)

29



But, what's the real situation (2)?Low energy housing district Niedernhausen

Measured energy consumption per m² in 1994

heating energy

average

30



European and German climate protection and energy saving goals

- goals 2020 (European council, March 2007)- 20 % reduction in green house gases compared to 2005- 20 % share of renewable energy- 20 % reduction of the energy consumption

- goals of the German government until 2050 (German energy concept 2011)- 80 % reduction of green house gases- 50 % reduction of the primary energy consumption- 25 % reduction of the electrical power consumption (wattage, end energy)- 40 % reduction of the traffic related energy consumption

- 80 % reduction of the head demand of buildings- 60 % share of renewable energy of the energy consumption (end energy)- 80 % share of renewable energy of the the electrical power consumption (gross value)

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Some statistical data (Germany 2009, Federal Ministry of Economics and Technology):

First orientation:

Total primary energy consumption: 13,300 PJ/year = 163 GJ/(capita·year) = 5,170 W/capita

Head energy consumption (private households): 2,300 PJ/year =

28 GJ/(capita·year) =

900 W/capita

Can you imagine 900 W?

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Architects and engineers are not so familiar with this 900 W/inhabitant

Their key number is something in kWh/(m2∙year):

Total amount of head floor space (only residential buildings): 34.85 Gm2

This lead to annually: 2,300 PJ/34.85 Gm2 = 660 MJ/m2

or with 365∙24∙3600 = 31,536,000 seconds per year to

660 MJ/(m2∙31,536,000s) = 20.9 W/m2 .

One year is equal to 8,760 h so that there is an average head energy consumption of:

20.9 W/m2∙8,760 h/year = 183,084 W∙h/(m2·year) = 183 kWh/(m2·year).

33



German Goal: 80 % reduction

Target value for 2050: average head energy consumption: 0.2∙183 kWh/(m2∙year) =

36.6 kWh/(m2∙year)

or:

0.2∙900 W/inhabitant = 180 W/inhabitant

(reachable or hallucination?)

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Prof. Dr.-Ing. Dieter BunteInfluence of rehabilitation done in the past on energy consumption

(Berlin buildings)

precast concrete slabs anddistrict heating

brick buildings andheating with gas or oil

Energy consum

ption in kWh/(m

2a)

before rehabilitationafter rehabilitation (average)best value

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References:

[1] Institut Wohnen und Umwelt: Akzeptanz energetischer Maßnahmen im Rahmen der nachhaltigen Modernisierung des Wohnungsbestandes,

Forschungsbericht, Darmstadt, 2006.

[2] N. Diefenbach, H. Cischinsky, M. Rodenfels, K.D. Clausnitzer: Datenbasis Gebäudebestand, Forschungsbericht, Darmstadt, 2010

Documents

SuReReEnMaHo - Central Europe experience and knowledge Prof. Dr.-Ing. Dieter Bunte