Transcript (BRE) – S - PU

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Sustainable Building 2010, Prague
Sustainability of Polyurethane
Thermal Insulation – Performance
Assessment at building and
component level in “low energy”
buildings
Shpresa Kotaji
30/06/2010
Sustainable development
EU’s 20-20-20 target
• By 2020:
– 20 % decrease in energy consumption
– 20 % reduction in greenhouse gas emissions
– 20 % share of renewable
• Key drivers:
– Environment: climate change mitigation
– Economic: energy supply security
– Social: job creation
2
Buildings
Europe’s highest contribution potential
Energy consumption
(Mtoe) 2005
332
Energy saving potential
(%) 2020
24%
25%
280
Residential
buildings
Commercial
buildings
Manufacturing
industry
297
157
Transport
23%
28%
Source: COM(2006)545 final, 2006
Between 280,000 and 450,000 new jobs by 2020
3
Sustainable Construction
The crucial role of insulation
•
•
•
Economic:
– highest negative abatement costs
(savings of € 29 billion by 2015)
– increases energy supply security
and keeps value chain in EU
– short pay back periods and lower
energy bills
Environmental:
– highest CO2 savings potential
Social:
– Reduces fuel poverty and creates
jobs within the EU
– Comfort, well-being
Insulation
Source: CEPS, Tackling Climate Change
4
Insulation for environmental
sustainability
Key selection criteria
#1
#2
#3
Design building with low
thermal conductivity to
optimise energy and CO2
savings
Maintain thermal
performance over
building lifetime –
reduce failure risks by
using fit for purpose
insulation and adequate
detailing
Assess life cycle
environmental
performance at building or
building component level
Insulation critical design issues
5
PU-Europe study: LCA and LCC of low
energy buildings
• Third party: BRE (UK Building Research Establishment)
– Choose model house, insulation solution and construction materials from
BRE LCA and LCC databases
– “simulate” designer approach
• 3 case studies
– Case 1: whole new building at fixed u-values for pitched roof, cavity wall
and ground floor
– Case 2: refurbishment of wall with internal lining at fixed thickness
– Case 3: warm deck flat roof at fixed u-value
• 3 climate zones
– Temperate Mediterranean
– Temperate Oceanic
– Cool Continental
• Heating energy source: natural gas
6
Building insulation - The basics
Standard house
Low energy house
Thermal
conductivity
(W/m.K)
λ
U=
d Thickness
Heat loss rate
(W/m2.K)
(m)
R=
1
U
Thermal resistance
(m2.K/W)
 Two possible functional
references can be used to
compare insulation solutions:
– Same U-value
– Same insulation thickness
(design constraints)
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Case study 1: Whole building
Polyurethane (PU)
Stone wool (SW)
Glass wool (GW)
3-bedroom, 2-storey detached house
U-values: roof=0.13, wall=0.15, ground floor=0.18
Fixed internal floor area of 52 m2 and fixed attic volume
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Case study 1: Whole building
LCA Results - Normalised data
Construction materials and insulation
GWP
4
3
2
AP
ODP
1
0
EP
POCP
PU
SW
 Similar environmental
performance for all
insulation solutions
Environmental Indicators
GWP global warming potential (kg CO2 eq)
ODP ozone depletion potential (kg CFC11 eq)
EP
eutrophication potential (kg PO4)
AP
acidification potential (kg SO2 eq)
POCP photochemical ozone creation potential (kg ethene eq)
GW
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Case study 1: Whole building
LCA Results - Normalised data
Energy use, Construction materials and insulation
AP
Energy use Cool continental
Energy use Temperate Oceanic
Energy use Temperate Mediterranean
Construction materials
POCP
Insulation materials
EP
ODP
GWP
Normalized to EU citizen
0
2
4
6
8
10
12
 Insulation has limited impact on total building
environmental performance
 Construction materials dominate AP, POCP and EP impacts
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Case study 1: Whole building
LCC Results
Cumulative costs @3.5% discount rate
Temperate oceanic climate
Cavity wall SW and GW solutions 4%
more costly: more external brick wall,
longer wall ties and larger foundation
100
Pitched roof SW and GW solutions
20% more costly: deeper rafters and
larger roof covering surface area
80
%
60
40
20
0
Cavity wall total cost
PU solution
Pitched roof total cost
SW solution
Note: the study excluded the cost of
additional land unable to be utilised
because of larger building footprints
GW solution
 PU solution more cost effective
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Case study 1: Whole house
Conclusions
• LCA
– All insulation solutions give similar environmental
performance
– Insulation material has limited contribution to overall
building environmental performance
– Energy use GWP dominates over material GWP
contribution
– Construction material related AP, EP and POCP
dominate over energy AP, EP and POCP contribution
• LCC
– PU solution lowest life cycle cost
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Case study 2: Insulation of wall with
internal lining
Insulation thickness:5 cm, wall surface: 134 m
U-value
U-value
Polyurethane (PU)
0.36
Stone wool (SW)
0.54
Expanded Polystyrene (EPS)
0.47
Glass wool (GW)
0.54
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Case study 2: Internal lining
LCA Results - Normalised data
Energy use, lining installation materials and
insulation (temperate continental climate)
GWP
12
10
8
6
4
2
0
AP
ODP
POCP
PU
EP
SW
GW
 Similar environmental
performance for all
insulation solutions
Environmental Indicators
GWP global warming potential (kg CO2 eq)
ODP ozone depletion potential (kg CFC11 eq)
EP
eutrophication potential (kg PO4)
AP
acidification potential (kg SO2 eq)
POCP photochemical ozone creation potential (kg ethene eq)
EPS
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Case study 2: Internal lining
LCA Results expressed as normalised data
Analysis of energy and material contribution
Example temperate oceanic climate
SW solution
Energy use
Installation material
Insulation
AP
POCP
PU solution
Energy use
Installation material
Insulation
EP
GW solution
Energy use
Installation material
Insulation
ODP
EPS solution
Energy use
Installation material
Insulation
GWP
0
2
4
6
8
15
10
12
Case study 2: Internal lining
LCA Results expressed as characterized data
Analysis of energy and material contribution
Characterized data (relative to maximum value in each impact category)
Example temperate oceanic climate
SW solution
Energy use
Installation material
Insulation
AP
POCP
PU solution
Energy use
Installation material
Insulation
POCP
EP
80
GW solution
Energy use
Installation material
Insulation
100
ODP
GWP
0
20
40
60
80
100
EPS solution
Energy use
Installation material
Insulation
 The greater energy saving achieved with PU offsets the
higher environmental impacts of the PU material itself
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Case study 2: Internal lining
LCC Results
Cumulative costs @3.5% discount rate
35000
Cool
continental
30000
25000
Temperate
oceanic
₤
20000
15000
10000
5000
0
0
10
20
30
40
50
60
years
PU
XY (Scatter) 5
SW
XY (Scatter) 6
GW
XY (Scatter) 7
EPS
XY (Scatter) 8
 PU solution most cost effective
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Case study 2: Internal lining
Conclusions
• LCA
– All insulation solutions give similar environmental
performance
– The greater energy saving achieved with PU offsets the
higher impacts of the PU material itself for all impact
indicators
• LCC
– PU solution has the lowest life cycle cost
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Case study 3: Warm deck flat roof
Polyurethane (PU)
Stone wool (SW)
U-value = 0.15 W/m2K
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Expanded
Polystyrene (EPS)
Case study 3 – Flat roof
LCA Results - Normalised data
Roof material and insulation
GWP
0.8
Insulation
0.6
Density
0.4
AP
Lambda
ODP
0.2
Thickness
mm
Roof surface m2
0
Weight
POCP
EP
PU
kg/m3
SW
kg
PU
EPS
SW
32
30
130
0.023
0.034
0.038
150
220
255
64
64
64
307
422
2121
 PU solution has low GWP, POCP and
AP
EPS
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Case study 3 – Flat roof
LCC results
₤
Cumulative costs @3.5% discount rate, 50 years)
100
90
80
70
60
50
40
30
20
10
0
PU solution
SW solution
EPS solution
 PU solution more cost effective
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Case study 3: Flat roof
Conclusions
• LCA
– Where specific mechanical properties need to be
achieved, the use of polyurethane, with its low density
and low thickness brings environmental performance
improvement
• LCC
– PU solution has the lowest life cycle cost
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Overall conclusions
•
Insulation is a key contributor to sustainable construction
•
Insulation material selection cannot be disconnected from the
specific building context
•
The choice of the insulation materials has limited impact on the
overall building environmental footprint
•
There is not sufficient publicly available LCA data on “natural” plant
or animal derived insulation materials to perform meaningful LCA
comparisons
•
Insulation density and thermal conductivity are critical properties to
consider in LCA and LCC assessment since they define the material
intensity and knock-on effects on the building structure and
footprint, hence the overall building performance
•
Where specific mechanical properties need to be achieved, such as
in a flat roof, the use of polyurethane can bring both environmental
performance improvement and cost benefits
•
From a life cycle cost perspective, PU is a logical choice to consider
in low energy buildings
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Recommendations for choosing
insulation for sustainability
1#Perform insulation choice based on the insulation ability to
optimize efficiently the building thermal performance, especially
where there are thickness constraints
2#Make sure the choice will provide adequate performance
longevity by taking into account potential failure risks – for any
type of insulant specify grades which are fit for the application,
are moisture resistant, are dimensionally stable, will not slump
or sag and will not be affected by adverse and extreme weather
conditions
3#Assess cost performance over the life time for the whole
component or building in order to take into account any hidden
and additional costs related to the insulation specific installation
requirements
4#Assess environmental performance at the building life cycle
level
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Thank you for your attention
www.excellence-in-insulation.eu
www.pu-europe.eu
[email protected]