Browsing by Author "Vera Araya, Sergio Eduardo"

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    A novel stomatal resistance equation for modeling heat and mass transfer of extensive vegetative roofs
    (Elsevier GMBH, 2024) Rojas Mondaca, Aldo Nicolás; Steinfort Needham, Úrsula Carla; Vera Araya, Sergio Eduardo; CEDEUS (Chile)
    The cooling potential of vegetated roofs depends on the stomatal resistance (rs), leaf area index, and other factors. Sailor (2008) and Tabares-Velasco and Srebric (2012) are among the most cited heat and mass transfer vegetative roof models. They include different equations to estimate rs, which show large differences, and significantly overestimate rs under certain conditions. Therefore, their models offer particular opportunities for improvement to reflect the actual vegetation cooling potential. This is necessary to predict the impact of vegetative roofs more accurately on the building energy performance and the urban heat island effect. The rs of both vegetative roof heat and mass transfer models have been developed based on studies with species that are not commonly planted on vegetative roofs. It was found that both models overestimate the rs under certain conditions that could turn into the underestimation of the transpiration rates and the cooling potential. Consequently, this paper aims to develop a novel equation for rs based on field measurements in a semiarid climate. The species tested were Glandularia berterii (C3), Selliera radicans (C3), Phyla reptans (C3), Aptenia cor-difolia (CAM), Sedum palmeri (CAM), and Sedum spurium (CAM). A New Linear Model (NLM) was formulated to estimate rs. The regressors of NLM are minimum stomatal resistance (rs,min), incident solar radiation (Rsh), leaf area index (LAI), substrate volumetric water content (VWC), and vapor pressure difference (VPD). The results show that rs,min and Rsh reflect 64 % of rs; the species with higher cooling potential were Selliera radicans, Sedum palmeri, and Sedum spurium due to higher LAI and lower/moderate rs,min; and, the NLM showed a better agree-ment with the measured rs, correcting points where Sailor (2008) and Tabares-Velasco and Srebric (2012) equations significantly overestimated rs. Finally, it was demonstrated that the developed NLM better represents the stomatal behavior and distinguishes the responses between C3 and CAM species.
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    A quantitative and qualitative evaluation of the sustainability of industrialised building systems: A bibliographic review and analysis of case studies
    (Elsevier Ltd, 2022) López Guerrero, Rafael Eduardo; Vera Araya, Sergio Eduardo; Carpio Martínez, Manuel; CEDEUS (Chile)
    The building construction has a significant impact on sustainability worldwide. However, industrialised building systems (IBS) might reduce these impacts compared to traditional building systems (TBS). Previous literature reviews have analysed IBS's sustainability, based primarily on environmental aspects and through qualitative indicators, disregarding a detailed quantitative comparison between both technologies and nor considering economic and social sustainability indicators. To fill this gap, this paper aims to evaluate vis-à-vis IBS's sustainability in relation to TBS, based on the quantitative and qualitative indicators studied in the literature. Thus, an exhaustive bibliographic review of IBS and TBS case studies was conducted. In total, 67 scientific papers were selected (papers, book chapters and reports), containing 86 case studies. Major findings indicated that IBS are more sustainable in almost all studied values – except construction costs. Nevertheless, this advantage depends on material design, prefabrication levels, transportation, work management and each author's methodological approaches. These factors are discussed to explain the reasons for IBS′ sustainability. Furthermore, main conclusions indicate that sustainability assessments have been unbalanced in literature, with few analyses of economic and social performance, and some indicators have been poorly studied (e.g., water and acidification potential), so their results are not yet representative. Similarly, reusability, prefabrication levels and the social indicators of IBS were insufficiently analysed in the reviewed case studies. Finally, the current review highlights IBS sustainability indicators that have been less studied in order to motivate new investigations in the broader field, exposing the IBS sustainability outlook and other research gaps.
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    Influences of Recycled Polyethylene Terephthalate Microplastic on the Hygrothermal and Mechanical Performance of Plasterboard with Polymethylhydrosiloxane Content
    (MDPI, 2024) Romano Matos, Victoria Enriqueta; Tundidor Camba, Alain; Vera Araya, Sergio Eduardo; Navarrete Leschot, Iván Ignacio; Videla Leiva, Álvaro Rodrigo; CEDEUS (Chile)
    New composites produced with recycled waste are needed to manufacture more sustainable construction materials. This paper aimed to analyze the hygrothermal and mechanical performance of plasterboard with a polymethylhydrosiloxane (PMHS) content, incorporating recycled PET microplastic waste and varying factors such as PMHS dose, homogenization time, and drying temperature after setting. A cube-centered experimental design matrix was performed. The crystal morphology, porosity, fluidity, water absorption, flexural strength, and thermal conductivity of plasterboards were measured. The results showed that incorporating recycled PET microplastics does not produce a significant difference in the absorption and flexural strength of plasterboards. However, the addition of recycled PET reduced the thermal conductivity of plasterboards by around 10%.
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    Sustainable Water Management in Urban Environment: Green Roof Experience in Semiarid Climate
    (IAHR-International Association of Hydro-Environment Engineering Research, 2015) Reyes Piña, Fermín Rodolfo; Vera Araya, Sergio Eduardo; Victorero Castaño, Felipe Andres; Bustamante Gómez, Waldo; Gironás León, Jorge Alfredo; Rojas, Victoria; Bonilla Meléndez, Carlos Alberto; CEDEUS (Chile)
    Most green roofs have been studied and built in humid climates, with many benefits such as thermal isolation and biodiversity. However, little is known about their performance in arid and semiarid climates where irrigation system affects the sustainability of this technology. In order to improve the water efficiency and get a sustainable water management, five 4-m2 modules of vegetated roofs were instrumented and monitored to evaluate the irrigation water requirements during the first year in Santiago, Chile (33 degrees 26 ' S, 70 degrees 39 ' W, 570 MASL). Based on the water retention properties, the maximum soil available water was 10%, the permanent wilting point was 17% and 27% at field capacity. Three substrate depths (5-cm, 10-cm and 20-cm) and three commercial drainage systems found in Chile were evaluated. The results showed that with the same drainage system and irrigation conditions, the substrate depth controls both, stored water and daily temperature oscillation during summer. While 5 and 10-cm substrates showed low water contents ( close to the minimum for plant survival) and peak temperatures (54 degrees C and 38 degrees C respectively), 20-cm substrate reached the minimum soil moisture only in days with high atmospheric demands reaching a peak soil temperature of 27 degrees C. To provide a better and sustainable condition for the 5-cm green roof modules, water retention capacity was incremented to resist the harsh summer atmospheric conditions. With a proper drainage system, substrate moisture in 5-cm green roof was equal or higher than the measured in the 20-cm green roof. However, peak temperatures were not reduced. Therefore, in addition to water requirements and plant species tolerance to drought and high temperatures, it is crucial to know the soil water retention properties and selecting a suitable type of drainage. These factors, along with the irrigation criterion, must be considered in order to get a sustainable water management on an urban green roof when built in semiarid climate.
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    Techos y muros vegetativos en chile: propuesta de política pública basada en i+d para la implementación de techos y muros vegetativos en chile
    (Centro de Desarrollo Urbano Sustentable, 2023) Vera Araya, Sergio Eduardo; Rojas Mondaca, Aldo Nicolás; Viecco Márquez, Margareth; Bustamante Gómez, Waldo Enrique; CEDEUS (Chile)
    La infraestructura verde de edificios, tales como techos y muros vegetativos, son tecnologías reconocidas por proporcionar diferentes beneficios ecosistémicos a nivel de edificios, pero por sobre todo a nivel urbano. En el año 2010 nos motivó el poder cuantificar algunos de estos beneficios ecosistémicos en climas semiáridos como el de la zona central de Chile, caracterizada por altas temperaturas y radiación solar durante gran parte del año, y muy bajas precipitaciones concentradas en pocos días, sumado a la tremenda escasez hídrica de hace más de dos décadas. Estas condiciones imponen desafíos complejos a los techos y muros vegetativos, que son muy importantes comprender y cuantificar para apoyar el diseño, construcción y mantención de estos, tal que provean uno o más beneficios ecosistémicos, que potencialmente pueden generar enormes beneficios socioambientales en las urbes.