Princípios de racionalização energética na arquitectura vernacular

A arquitectura vernacular caracteriza-se por materializar formalmente uma pluralidade de condicionalismos – geográficos, climáticos e económicos – dos locais onde se insere. Estas implicações traduzem-se na diferenciação regional das estratégias usadas para mitigar os efeitos do clima. Apesar das condições de conforto destas construções não se enquadrarem nos parâmetros actuais, as estratégias adoptadas apresentam potencial de evolução e adaptação à contemporaneidade. Na altura, a fragilidade económica de grande parte das famílias levava à adopção de soluções pragmáticas e de profunda racionalização dos recursos disponíveis. O abandono destas abordagens arquitectónicas em detrimento de uma arquitectura universal baseada em materiais industriais, desarraigada do seu meio, levou a um tipo de construção muito dependente de energia para se garantirem os requisitos de conforto dos ocupantes. Num momento de viragem, promovido pelos actuais contextos ambiental e económico, em que se procuram formas de energia mais limpas e edifícios mais eficientes, é pertinente voltar ao passado para estudar e compreender estas formas de construção intrínsecas ao lugar, com o intuito de adaptar e desenvolver as suas mais-valias na descoberta das formas do futuro

Evaluation of solid waste stratified mixtures as constructed wetland fillers under different operation modes

Based on the strategy that all processes can and should be modified to contribute to a circular economy, this work evaluates the recovery of waste solids as filler material in Constructed Wetlands (CWs) used for wastewater treatment. Five sets of lab-scale CWs were assembled with mixtures of five waste solids and operated to evaluate the removal of chemical oxygen demand (COD) and nutrients from urban and industrial-types of wastewater. The adaptation and growth of the macrophyte Phragmites australis in the mixed-filler CWs was also monitored. Although all evaluated waste solids showed to be acceptable substrates for macrophyte development and wastewater treatment, CWs assembled with mixtures of limestone waste and coal slag showed the best plant growth indicators and wastewater treatment efficiencies. The CWs assembled with mixtures of limestone waste and clay brick fragments or cork granulates showed to be suitable alternatives. With exception for CWs filled with mixtures of limestone and snail shells, pollutant removal efficiencies up to 95%, 86% and 83% were obtained respectively for COD, total phosphorous and total nitrogen, depending on the type of wastewater and mode of operation. Removal efficiencies were not significantly affected by increased hydraulic rate. The CWs can be operated to a hydraulic loading rate of 0.056 m/d, which corresponds to a retention time of 1.5 days. The valorisation of solid waste as a filler can contribute to CWs closely participating in the creation of circular flows for the reuse of waste solids.The work was partially supported by COMPETE2020 under the grant POCI-01-0145-FEDER-23314. The authors acknowledge the support of the Lab.IPT staff, particularly, Alcino Serras, Isabel Silva and Pedro Costa, the research fellows Ana Alves and Nuno Graça. The authors also acknowledge the contribution of Carlos Ferreira, from IPT’s maintenance services, and Fátima Paiva, from IPT’s language centre.info:eu-repo/semantics/publishedVersio

Inversión de los patrones estacionales de la absorción de carbono en un stand de eucalipto en Portugal

This paper summarizes results between 2002 and 2010 from eddy covariance measurements of carbon uptake in the 12 month annual growing period eucalypt site of Espirra in Southern Portugal (38° 38’N, 8° 36’ W) . This site, aimed for pulp production is part of an intensively 300 ha eucalypt coppice, with about 1100 trees ha–1. The climate is of Mediterranean type. During the measurement period (2002-2010) two main events changed the annual sink pattern of the forest: a drought period of two years (2004-2005) and a tree felling (November and December 2006). Before the felling, annual net ecosystem exchange (NEE) diminished from 865.56 gCm–2 in 2002 to 356.64 gCm–2 in 2005 together with a deep decrease in rainfall from 748 mm in 2002 to 378.58 mm and 396.64 mm in 2004 and 2005, respectively. The eucalypt stand recovered its carbon sink ability in June 2007 with a cumulated NEE of 151 gCm–2 from January to September 2010. A quantitative approach using generalized estimating equations (GEEs) was made to relate monthly NEE, gross primary production (GPP) and soil moisture with the main meteorological variables. Seasonal patterns of carbon uptake were almost opposite in the periods before and after the felling with maxima in April and August, respectively, and this seasonal change is gradually reversing to the pattern before 2006. Drought was the main meteorological driver of these temporal tendencies in carbon uptake.Este documento resume los resultados entre 2002 y 2010 a partir de mediciones de covarianza turbulenta de la absorción de carbono en los 12 meses anuales a los sitios de crecimiento de eucalipto período de Espirra en el sur de Portugal (38° 38’N, 8° 36’ W). Este sitio, con el objetivo para la producción de celulosa es parte de un monte bajo de intensidad 300 hectáreas de eucaliptos, con cerca de 1.100 árboles ha–1. El clima es de tipo mediterráneo. Durante el período de medición (2002-2010) dos eventos principales cambiado el patrón fregadero anual de la selva: un período de sequía de dos años (2004-2005) y la tala de árboles (noviembre y diciembre de 2006). Antes de la tala, el intercambio anual neta de los ecosistemas (NEE) se redujo de 865,56 g cm–2 en 2002 a 356,64 g cm–2 en 2005, junto con una disminución profunda de las precipitaciones de 748 mm en 2002 a 378,58 mm y 396,64 en 2004 y 2005, respectivamente. El eucalipto de pie recupera su capacidad de sumidero de carbono en junio de 2007 con un acumulado de 151 gcm NEE–2 de enero a septiembre de 2010.Una aproximación cuantitativa mediante ecuaciones de estimación generalizada (GEES) se hizo para relacionar mensual NEE, la producción primaria bruta (GPP) y la humedad del suelo con las variables meteorológicas principales.Los patrones estacionales de la absorción de carbono eran casi opuestas en los períodos antes y después de la tala, con máximos en abril y agosto, respectivamente, y este cambio de temporada se va de marcha atrás para el patrón antes de 2006. La sequía fue el principal impulsor de estas tendencias meteorológicas temporal en la absorción de carbono