sustainable building 2010, prague sustainability of polyurethane thermal insulation – performance...
TRANSCRIPT
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
10/199
2
Sustainable developmentEU’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
3
Buildings Europe’s highest contribution potential
280
157297
332
Between 280,000 and 450,000 new jobs by 2020
Source: COM(2006)545 final, 2006
25%
28%23%
24%Residentialbuildings
Commercialbuildings
Manufacturingindustry
Transport
Energy consumption (Mtoe) 2005
Energy saving potential (%) 2020
4
Sustainable ConstructionThe 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 Source: CEPS, Tackling Climate Change
Insulation
5
Insulation for environmental sustainabilityKey selection criteria
#1 Design building with low thermal conductivity to optimise energy and CO2
savings#2 Maintain thermal
performance overbuilding lifetime – reduce failure risks by using fit for purpose insulation and adequate detailing
#3 Assess life cycle environmental performance at building or building component level
Insulation critical design issues
6
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
7
Building insulation - The basics
U =λ
dHeat loss rate
(W/m2.K)
Thermal conductivity
(W/m.K)
Thickness(m)
Two possible functional references can be used to compare insulation solutions:
– Same U-value
– Same insulation thickness (design constraints)
Standard house Low energy house
R =1
UThermal resistance
(m2.K/W)
8
Case study 1: Whole building
3-bedroom, 2-storey detached houseU-values: roof=0.13, wall=0.15, ground floor=0.18Fixed internal floor area of 52 m2 and fixed attic volume
Polyurethane (PU) Stone wool (SW) Glass wool (GW)
9
Case study 1: Whole buildingLCA Results - Normalised dataConstruction materials and insulation
Similar environmental performance for all insulation solutions
Environmental IndicatorsGWP 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)
0
1
2
3
4GWP
ODP
EPPOCP
AP
PU SW GW
10
Case study 1: Whole buildingLCA Results - Normalised dataEnergy use, Construction materials and insulation
Normalized to EU citizen
0 2 4 6 8 10 12
Energy use Cool continental
Energy use Temperate Oceanic
Energy use Temperate Mediterranean
Construction materials
Insulation materials
GWP
ODP
EP
POCP
AP
Insulation has limited impact on total building environmental performance
Construction materials dominate AP, POCP and EP impacts
11
Case study 1: Whole buildingLCC Results
Cavity wall SW and GW solutions 4% more costly: more external brick wall, longer wall ties and larger foundation
Pitched roof SW and GW solutions 20% more costly: deeper rafters and larger roof covering surface area
Note: the study excluded the cost of additional land unable to be utilised because of larger building footprints 0
20
40
60
80
100
Cavity wall total cost Pitched roof total cost
%
PU solution SW solution GW solution
PU solution more cost effective
Cumulative costs @3.5% discount rateTemperate oceanic climate
12
Case study 1: Whole houseConclusions
• 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
13
Case study 2: Insulation of wall with internal lining
U-value U-value
Polyurethane (PU) 0.36 Stone wool (SW) 0.54
Expanded Polystyrene (EPS) 0.47 Glass wool (GW) 0.54
Insulation thickness:5 cm, wall surface: 134 m
14
Case study 2: Internal liningLCA Results - Normalised dataEnergy use, lining installation materials and insulation (temperate continental climate)
Similar environmental performance for all insulation solutions
Environmental IndicatorsGWP 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)
0
2
4
6
8
10
12GWP
ODP
EPPOCP
AP
PU SW GW EPS
15
GW solutionEnergy useInstallation materialInsulation
PU solutionEnergy useInstallation materialInsulation
SW solutionEnergy use Installation materialInsulation
EPS solutionEnergy useInstallation materialInsulation
Case study 2: Internal liningLCA Results expressed as normalised dataAnalysis of energy and material contributionExample temperate oceanic climate
0 2 4 6 8 10 12
GWP
ODP
EP
POCP
AP
16
Case study 2: Internal liningLCA Results expressed as characterized dataAnalysis of energy and material contributionCharacterized data (relative to maximum value in each impact category)Example temperate oceanic climate
GW solutionEnergy useInstallation materialInsulation
PU solutionEnergy useInstallation materialInsulation
SW solutionEnergy use Installation materialInsulation
EPS solutionEnergy useInstallation materialInsulation
The greater energy saving achieved with PU offsets the higher environmental impacts of the PU material itself
0 20 40 60 80 100
GWP
ODP
EP
POCP
AP
80 100
POCP
17
Case study 2: Internal liningLCC Results
0
5000
10000
15000
20000
25000
30000
35000
0 10 20 30 40 50 60
years
₤
PU SW GW EPSXY (Scatter) 5 XY (Scatter) 6 XY (Scatter) 7 XY (Scatter) 8
Temperate oceanic
Cool continental
PU solution most cost effective
Cumulative costs @3.5% discount rate
18
Case study 2: Internal liningConclusions
• 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
19
Case study 3: Warm deck flat roof
Polyurethane (PU) Stone wool (SW)Expanded
Polystyrene (EPS)
U-value = 0.15 W/m2K
20
Case study 3 – Flat roofLCA Results - Normalised dataRoof material and insulation
Insulation PU EPS SW
Density kg/m3 32 30 130
Lambda 0.023 0.034 0.038
Thickness mm 150 220 255
Roof surface m2 64 64 64
Weight kg 307 422 2121
PU solution has low GWP, POCP and AP
0
0.2
0.4
0.6
0.8GWP
ODP
EPPOCP
AP
PU SW EPS
21
Case study 3 – Flat roofLCC results
0102030405060708090
100
PU solution SW solution EPS solution
₤
PU solution more cost effective
Cumulative costs @3.5% discount rate, 50 years)
22
Case study 3: Flat roofConclusions
• 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
23
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
24
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
Thank you for your attention
www.excellence-in-insulation.euwww.pu-europe.eu