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)
SuReReEnMaHo - Central Europe experience and knowledge
Prof. Dr.-Ing. Dieter Bunte
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)
SuReReEnMaHo - Central Europe experience and knowledge
Prof. Dr.-Ing. Dieter Bunte
Generally mind-set of dweller concerning rehabilitation [1]:
good
very good
Ex ante in between ex post retrospectivequestioning
SuReReEnMaHo - Central Europe experience and knowledge
Prof. Dr.-Ing. Dieter Bunte
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
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SuReReEnMaHo - Central Europe experience and knowledge
Prof. Dr.-Ing. Dieter Bunte
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
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SuReReEnMaHo - Central Europe experience and knowledge
Prof. Dr.-Ing. Dieter Bunte
Age structure of buildings respectively flats [2]:
buildingsflats
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SuReReEnMaHo - Central Europe experience and knowledge
Prof. Dr.-Ing. Dieter Bunte
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
Community of owners 2.8 3.5
Housing company 0.8 0.8
Multi family houses
private 50.9 33.0
Community of owners 18.5 26.5
Housing company 28.7 38.7
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SuReReEnMaHo - Central Europe experience and knowledge
Prof. Dr.-Ing. Dieter Bunte
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
5 – 6 dwellings 18.6
7 – 12 dwellings 19.0
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
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SuReReEnMaHo - Central Europe experience and knowledge
Prof. Dr.-Ing. Dieter Bunte
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
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SuReReEnMaHo - Central Europe experience and knowledge
Prof. Dr.-Ing. Dieter Bunte
Heat insulation status [2]: ex post insulationBuildings (%) 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
Buildings (%) with ex post insulation of
Exterior walls Roof / upper floor ceiling
Basement ceiling / ground floor
All buildings 20.8 40.5 9.5
Old buildings constructed before 1978
27.6 52.2 12.5
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SuReReEnMaHo - Central Europe experience and knowledge
Prof. Dr.-Ing. Dieter Bunte
Ex post insulation of multi family houses constructed before 1978 [2]: geographical
differences
Multi family houses (%) with with es post insulation of
Exterior walls Roof / upper floor ceiling
Basement ceiling / ground floor
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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SuReReEnMaHo - Central Europe experience and knowledge
Prof. Dr.-Ing. Dieter Bunte
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
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SuReReEnMaHo - Central Europe experience and knowledge
Prof. Dr.-Ing. Dieter Bunte
Insulation thickness (exterior walls) [2]:
Insulation thickness
percentage
AllOld buildings before 1978Between 1979 and 2004New buildings after 2004
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SuReReEnMaHo - Central Europe experience and knowledge
Prof. Dr.-Ing. Dieter Bunte
Insulation thickness (exterior wall, old buildings before 1978) [2]:
Insulation thickness
percentage
All old buildings
Constructed with insulation
Ex post insulation
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SuReReEnMaHo - Central Europe experience and knowledge
Prof. Dr.-Ing. Dieter Bunte
Insulation thickness (exterior wall, old buildings before 1978) [2]:
Insulation thickness
percentage
Brick, one layer
Brick, two layers
Truss wall
Prefabricated concrete elements
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SuReReEnMaHo - Central Europe experience and knowledge
Prof. Dr.-Ing. Dieter Bunte
Thickness of upper floor ceiling / roof insulation[2]:
Insulation thickness
percentage
All housing buildingsOld buildings before 1978Buildings from 1979 – 2004New buildings from 2005 to now
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SuReReEnMaHo - Central Europe experience and knowledge
Prof. Dr.-Ing. Dieter Bunte
Ex post insulation thickness of roof / upper floor ceiling (old buildings before 1978) [2]:
Insulation thickness
percentage
Roof not heated
Roof heated
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SuReReEnMaHo - Central Europe experience and knowledge
Prof. Dr.-Ing. Dieter Bunte
Insulation thickness of ground floor / basement ceiling [2]:
Insulation thickness
percentage
All housing buildingsOld buildings before 1978Buildings from 1979 – 2004New buildings from 2005 to now
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SuReReEnMaHo - Central Europe experience and knowledge
Prof. Dr.-Ing. Dieter Bunte
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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SuReReEnMaHo - Central Europe experience and knowledge
Prof. Dr.-Ing. Dieter Bunte
Frequency distribution of window age [2]:
Installation age
percentage
All buildingsOld buildings before 1979
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SuReReEnMaHo - Central Europe experience and knowledge
Prof. Dr.-Ing. Dieter Bunte
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)
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SuReReEnMaHo - Central Europe experience and knowledge
Prof. Dr.-Ing. Dieter Bunte
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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SuReReEnMaHo - Central Europe experience and knowledge
Prof. Dr.-Ing. Dieter Bunte
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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SuReReEnMaHo - Central Europe experience and knowledge
Prof. Dr.-Ing. Dieter Bunte
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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SuReReEnMaHo - Central Europe experience and knowledge
Prof. Dr.-Ing. Dieter Bunte
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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SuReReEnMaHo - Central Europe experience and knowledge
Prof. Dr.-Ing. Dieter Bunte
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.
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SuReReEnMaHo - Central Europe experience and knowledge
Prof. Dr.-Ing. Dieter Bunte
In Germany nowadays used energy certificate:
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SuReReEnMaHo - Central Europe experience and knowledge
Prof. Dr.-Ing. Dieter Bunte
But, what's the real situation (1)?
Calculated energy demand in kWh/(m2a)
Measured energy consum
ption in kWh/(m
2a)
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SuReReEnMaHo - Central Europe experience and knowledge
Prof. Dr.-Ing. Dieter Bunte
But, what's the real situation (2)?Low energy housing district Niedernhausen
Measured energy consumption per m² in 1994
heating energy
average
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SuReReEnMaHo - Central Europe experience and knowledge
Prof. Dr.-Ing. Dieter Bunte
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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SuReReEnMaHo - Central Europe experience and knowledge
Prof. Dr.-Ing. Dieter Bunte
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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SuReReEnMaHo - Central Europe experience and knowledge
Prof. Dr.-Ing. Dieter Bunte
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).
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SuReReEnMaHo - Central Europe experience and knowledge
Prof. Dr.-Ing. Dieter Bunte
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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SuReReEnMaHo - Central Europe experience and knowledge
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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SuReReEnMaHo - Central Europe experience and knowledge
Prof. Dr.-Ing. Dieter Bunte
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