Browsing by Author "Morales-Vera, Rodrigo"

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    (33, 33) Morales-Vera, Rodrigo; Vásquez-Ibarra, Leonardo; Scott, Felipe; Puettmann, Maureen; Gustafson, Richard; 33
    Biomass appears to be one of the most prominent renewable resources for biofuels such as bioethanol, mainly due to its better environmental performance compared with fossil fuels. This study addresses a comprehensive environmental performance of bioethanol production, employing empirical data from hybrid poplar grown in the U.S. The study considers 1 MJ as a functional unit and employs a cradle-to-grave approach, which entails the feedstock and harvesting production of poplar, transport to a biorefinery, bioconversion of the biomass process, and fuel use. On average, bioconversion is the main contributor to environmental degradation in all the categories evaluated (77%). The second main contributor is either the feedstock and harvesting production of poplar (17%) or fuel use (6%), depending on the environmental category. Thus, focusing on only one category may induce a misinterpretation of the environmental performance of bioethanol production. Finally, environmental credits in the global warming potential (GWP) category were obtained from the carbon sequestered in the biomass during the growing period and from avoided fossil fuel emissions due to electricity production from a renewable source. This means that the net GWP of the life cycle of bioethanol from poplar biomass is slightly negative (?1.05 × 10?3 kg CO2-eq·MJ?1).
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    (33, 33) Felmer, Gabriel; Morales-Vera, Rodrigo; Astroza, Rodrigo; González, Ignacio; Puettmann, Maureen; Wishnie, Mark; 33
    While high-rise mass-timber construction is booming worldwide as a more sustainable alternative to mainstream cement and steel, in South America, there are still many gaps to overcome regarding sourcing, design, and environmental performance. The aim of this study was to assess the carbon emission footprint of using mass-timber products to build a mid-rise low-energy residential building in central Chile (CCL). The design presented at a solar decathlon contest in Santiago was assessed through lifecycle analysis (LCA) and compared to an equivalent mainstream concrete building. Greenhouse gas emissions, expressed as global warming potential (GWP), from cradle-to-usage over a 50-year life span, were lower for the timber design, with 131 kg CO2 eq/m2 of floor area (compared to 353 kg CO2 eq/m2) and a biogenic carbon storage of 447 tons of CO2 eq/m2 based on sustainable forestry practices. From cradle-to-construction, the embodied emissions of the masstimber building were 42% lower (101 kg CO2 eq/m2) than those of the equivalent concrete building (167 kg CO2 eq/m2). The embodied energy of the mass-timber building was 37% higher than that of its equivalent concrete building and its envelope design helped reduce space-conditioning emissions by as much as 83%, from 187 kg CO2 eq/m2 as estimated for the equivalent concrete building to 31 kg CO2 eq/m2 50-yr. Overall, provided that further efforts are made to address residual energy end-uses and end-of-life waste management options, the use of mass-timber products offers a promising potential in CCL for delivering zero carbon residential multistory buildings.