Center for Industrial Ecology, ADAI - LAETA,

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1 Avaliação de Ciclo de Vida de uma moradia unifamiliar em Portugal. Comparação de diferentes paredes exteriores e métodos de avaliação de impacte ambiental Helena Monteiro & Fausto Freire helena.monteiro@dem.uc.pt, fausto.freire@dem.uc.pt Center for Industrial Ecology, ADAI - LAETA, Dep. of Mechanical Eng., University of Coimbra, Portugal.

2 OVERVIEW Motivation s Building Definition Methods 2

3 MOTIVATION Buildings: about 39% of total energy consumption in PT LC thinking quantify tradeoffs between LC phases. BUT it is not currently used. Many LCIA methods but for LCA practitioners it is not obvious: - which LCIA method to choose - whether different LCIA methods lead to coincident or contradictory conclusions 3

4 GOALS -To characterize the LC processes of a dwelling (energy and environmental impacts), considering two alternative operational patterns (OP) - To assess 7 exterior walls for the same house to identify environmentally preferable solutions -To compare the results of 3 LCIA methods (CED, CML 2001, Eco-indicator'99), to determine the extent to which the results of a LCA are influenced by the method 4

5 LIFE CYCLE MODEL INPUT Raw materials Energy Building Life Cycle Phases & Processes CONSTRUCTION Material extraction production Transport OUTPUT Environmental Burdens (emissions, waste) USE Energy Raw materials Heating Cooling Environmental Burdens (emissions, waste) Maintenance End of Life is out of scope 5

6 LCI - BUILDING DEFINITION - Single family house 132m 2 -Location: Coimbra Functional unit: Building living area over life span (132m 2 x 50 years) Background data: Average European data for building materials (ecoinvent v2), ITE50, Producer Technical data Transport of materials: by truck(average European fleet) 6

7 LCI - BUILDING DEFINITION Alternative exterior wall scenarios Similar U-values Average operational requirements (RCCTE): Heating 71,8 kwh/m2.ano Cooling 3,8 kwh/m2.ano House Exterior wall (EW) description EW insulation (cm) H0 Double hollow brick masonry (base scenario) XPS 4 H1 Double facing and hollow brick masonry XPS 4 H2 Lightweight concrete blocks masonry EPS 5 H3 Thermal concrete blocks masonry EPS 4 H4 Autoclaved aerated concrete block masonry EPS 3 H5 Hollow brick masonry & exterior wood cladding XPS 4 H6 Wood frame and cladding XPS 5 7

8 LCI - BUILDING DEFINITION Use phase - Alternative Operational Patterns (OP) OP1, 50% of the maximum heating and cooling requirements 35,9 kwh/m 2.y heating; 1,9 kwh/m 2.y cooling. OP2, 10% of the maximum heating and cooling requirements 7,2 kwh/m 2.y heating; 0,4 kwh/m 2.y cooling; Heating & Cooling system: 10 kw heat pump (COPh=2.8, COPc=2.0) Maintenance activities: - Painting - Varnishing - Water proof layer substitution 8

9 LCIA METHODS CED - Cumulative Energy Demand, Primary energy (MJeq) CML 2001 mid-point; Problem-oriented Eco-indicator 99 end-point; damaged-oriented CML Category Unit EI 99 Category Unit Abiotic Depletion kg Sb eq Fossil Fuels Minerals Acidification Eutrophication kg SO 2 eq kg PO 4 eq MJ surplus MJ surplus Acidific./Eutrophi. PDF*m 2.y Global warming kg CO 2 eq Climate change DALY Ozone layer depletion kg CFC-11 eq Ozone layer DALY Photochemical oxidation kg C 2 H 4 Resp. organics DALY Freshwater ecotoxicity Marine ecotoxicity Terrestrial ecotoxicity Human toxicity kg 1,4-DB eq Ecotoxicity PDF*m 2.y kg 1,4-DB eq Carcinogens Resp.inorganics Radiation Land Use DALY DALY DALY PDF*m 2.y 9

10 LCIA METHODS (UNEP/SETAC Life Cycle Initiative in 2003) LCI results Midpoint categories (environmental problems) Photochemical oxidant formation Human toxicity Ozone depletion Climate change Acidification Eutrophication Ecotoxicity Land use impacts Abiotic resources deplection Biotic resources deplection Endpoint categories (environmental damages) Human Health Biotic & abiotic natural environment Biotic & abiotic natural resources Biotic & abiotic manmade resources

11 LCIA METHODS Midpoint versus endpoint Endpoint simplifies weighting between impact categories Endpoint simplifies comparison of stressors with different modes of action But high uncertainty in the modeling of the full causeeffect chain in endpoint assessment Midpoint characterisation factors are considered more robust comparted to endpoint characterisation factors 11

12 LC RESULTS Base case house (H0) 12

13 LC CED RESULTS Base case house (H0) 13

14 LC CML 2001 RESULTS Base case house (H0) 14

15 LC EI 99 RESULTS Base case house (H0) 15

16 RESULTS House scenarios 16

17 LC CED RESULTS House scenarios 17

18 LC CML 2001 RESULTS House scenarios Environmental Impact categories 18

19 LC EI 99 RESULTS House scenarios H6: lower Environmental impacts (except OLD, LU) H1: Higher Env. impacts (for most categories) 19

20 Comparison of CED, CML, and EI'99 LC results (excluding heating and cooling requirements) 20

21 CONCLUSIONS The LCIA results for the 3 methods show: - The most significant LC process depends on the OP assumed - The wood wall house (H6) as the preferable solution Comparing CED, CML 2001 and EI 99 methods - The Non-R results (CED) are close to AD (CML) and Resources (EI 99) - The GWP, OLD, AD, Acidification, Eutrophication present robust results that permit a straightforward comparison between CML 2001 and EI 99 methods - Nevertheless, CML results present slightly higher impacts for the use phase, while EI'99 for material production - The two methods can present different ranking of alternatives between similar categories, which ultimately can influence the choice between solutions 21

22 Life-Cycle Assessment of a house with alternative exterior walls: comparison of three impact assessment methods Avaliação de Ciclo de Vida de uma moradia unifamiliar Comparação de diferentes paredes exteriores e métodos de avaliação de impacte ambiental Helena Monteiro & Fausto Freire helena.monteiro@dem.uc.pt, fausto.freire@dem.uc.pt Center for Industrial Ecology, ADAI - LAETA, Dep. of Mechanical Eng., University of Coimbra, Portugal.