Browsing by Keyword "Environmental and economic life-cycle assessment"

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    Analysis of life-cycle boundaries for environmental and economic assessment of building energy refurbishment projects
    (2017-02-01) Oregi, Xabat; Hernandez, Patxi; Hernandez, Rufino; Tecnalia Research & Innovation; PLANIFICACIÓN ENERGÉTICA
    Despite the standardization of the life-cycle assessment methodology for the construction sector, analysts tend to apply some simplifications in relation to the system boundaries, omitting some of the life-cycle stages. In particular, for building energy refurbishment projects, there is a general focus on the operational stage, linked to the main objective of reducing operational energy use. This paper evaluates the relevance of each life-cycle stage in relation to the overall environmental and economic impact on residential building energy refurbishment projects. The results from the analysis of the refurbishment strategies at a case study in Spain show the relatively minor importance of the transport and end of life stages. The construction process stage is also of relatively minor importance regarding the environmental performance. The product, maintenance and replacement stages are generally of higher importance, particularly for economic evaluation. An extensive sensitivity analysis demonstrates the difficulties of simplifying the life-cycle boundaries, suggesting that potential simplifications should take into account various parameters, including the climate region, building typologies, and expected service life. As an example, the results have shown that for cold climate zones and buildings, where large energy savings from energy refurbishment strategies can be achieved, the other life-cycle phases are less important and, in most cases, represent less than 10% of life-cycle environmental impacts.
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    Environmental and Economic Prioritization of Building Energy Refurbishment Strategies with Life-Cycle Approach
    (2020-05-11) Oregi, Xabat; Hernández, Rufino Javier; Hernandez, Patxi; PLANIFICACIÓN ENERGÉTICA
    An increasing number of studies apply life-cycle assessment methodology to assess the impact of a new building or to prioritize between different building refurbishment strategies. Among the different hypotheses to consider during the application of this methodology, the selection of the impact indicator is critical, as this choice will completely change the interpretation of the results. This article proposes applying four indicators that allow analysing the results of a refurbishment project of a residential building with the life-cycle approach: non-renewable primary energy use reduction (NRPER), net energy ratio (NER), internal rate of return (IRR), and life-cycle payback (LC-PB). The combination of environmental and economic indicators when evaluating the results has allowed to prioritize among the different strategies defined for this case study. Furthermore, an extensive sensitivity assessment reflects the high uncertainty of some of the parameters and their high influence on the final results. To this end, new hypotheses related to the following parameters have been considered: reference service life of the building, estimated service life of material, operational energy use, conversion factor, energy price, and inflation rate. The results show that the NRPE use reduction value could vary up to −44%. The variation of the other indicators is also very relevant, reaching variation rates such as 100% in the NER, 450% in the IRR, and 300% in the LC-PB. Finally, the results allow to define the type of input or hypothesis that influences each indicator the most, which is relevant when calibrating the prioritization process for the refurbishment strategy.