Extensive green roofs in Porto Alegre, Brazil : effect on indoor thermal comfort in residential buildings

This research aims to develop further understanding of the effect of extensive green roofs on the indoor thermal comfort in naturally ventilated low-income houses, in the Brazilian subtropical city of Porto Alegre. This is achieved by studying the influence of a set of variables, to comprehend the best combinations of elements to a climate responsive green roof design. Moreover, in order to create more realistic results, different scenarios with green roofs and other elements (as grass on the ground and trees) are created, to evaluate the influence of the local microclimate on the indoor thermal comfort. Additionally, understanding how the extensive green roofs affect the outdoor microclimate in Porto Alegre is also a part of the aim. Evaluations are made for the whole year as well as for the summer and winter seasons. The study estimates the effect of extensive green roofs on the indoor thermal comfort and on the outdoor microclimate by calculations through computer simulations. The simulations are performed with EnergyPlus for the indoor thermal comfort and with ENVI-met for the microclimate simulations. The studied houses are conceived for urban or suburban areas, to be implemented in any Brazilian city, as long as some adjustments are made to better respond to the climate, complying with the Brazilian Standards 15.575 and 15.220. The indoor thermal comfort is evaluated primarily with the Adaptive thermal comfort model of the ASHRAE Standard 55, and the calculation of heating and cooling degree-hours. For the outdoor microclimate, the variables air temperature and mean radiant temperature are evaluated. The research shows that green roofs increase the indoor thermal comfort in the studied one-storey houses. For the whole year, the best combination of features is low-density plants and a thick soil layer (150mm). For the winter season, extra-insulation in the building envelope would improve indoor thermal comfort. The extensive green roofs would be beneficial both to new projects, complying with the minimum level of insulation from the Brazilian Standards, and to the existing building stock, which is typically poorly insulated. The microclimate around the buildings affects the indoor thermal comfort, and this investigation shows that, when the green roofs are integrated in a green strategy at the site (with trees and grass on the ground), their cooling effect increases compared to when they are the only green strategy. This study also confirms the advantages of performing coupled simulations, where the results of the microclimate simulations are used as input to the building simulations, to have more realistic predictions of the indoor thermal comfort. Concerning the effect of the extensive green roofs on the microclimate, a minor and local cooling effect is observed, especially at pedestrian level. That indicates that the effect of extensive green roofs as a strategy for reducing the outdoor air temperature in an urban context might be overestimated. The study showed that in the climate of Porto Alegre, a trade-off is needed: the best configuration of vegetation for the indoor thermal comfort over the whole year (trees with a lower density) is not the best configuration for providing a cooling effect on the microclimate. Since the use of green roofs are advantageous to low-income housing projects, this work contributes to meeting the Sustainable Development Goals of the United Nations, especially goal 11: “Make cities and human settlements inclusive, safe, resilient and sustainable”

HABITAÇÃO EM CONTAINER: UM ESTUDO PARAMÉTRICO PARA A ZONA BIOCLIMÁTICA 3

Dado o crescente interesse em soluções construtivas mais sustentáveis, as oportunidades de reciclagem de componentes vêm ganhando cada vez mais espaço em construções no Brasil. Assim, diversos estudos vêm sendo realizados no sentido de investigar as potencialidades de adaptação dos containers navais para diferentes usos na construção civil, incluindo o uso residencial. Este artigo apresenta um estudo paramétrico de dois projetos de container adaptados à moradia unifamiliar: um originalmente proposto e outro modificado, visando aumentar seu desempenho termoenergético pela qualificação do envelope construtivo. O projeto está localizado na cidade de Porto Alegre - RS (Zona Bioclimática 03). Para a modelagem e apuração do consumo energético do edifício foram adotados os programas SketchUp e EnergyPlus, com o plugin Legacy OpenStudio. Os resultados permitiram confirmar a importância das estratégias projetuais (decisões arquitetônicas) para o aumento do conforto interno aliado à redução de consumo energético. Este trabalho busca contribuir para a avaliação de soluções mais sustentáveis em edificações, em especial aquelas que se utilizam de estratégias passivas para o incremento no desempenho termoenergético

Efeitos do Adensamento Construtivo Sobre Microclimas Urbanos

Tradicionalmente, o aumento do adensamento construtivo em cidades brasileiras ocorre sem a devida atenção aos efeitos sobre os microclimas, o que potencializa a criação de espaços abertos termicamente desconfortáveis. Esse estudo analisou os efeitos do aumento da densidade construída para o conforto térmico de pedestres em Bagé-RS, cidade de médio porte de clima subtropical úmido com verões quentes. A metodologia é quali-quantitativa com estudo de caso e simulação computacional dos microclimas em um recorte urbano central no período atual (cenário 1) e em um prognóstico de adensamento para 2060 (cenário 2). As análises foram feitas para os extremos de verão e de inverno. A análise de insolação e sombreamentos demonstrou que o cenário 2 reduz o tempo de insolação das calçadas ao longo do dia, o que diminui a TRM, desfavorável ao conforto no inverno e benéfico no verão. Os resultados demonstraram que o aumento do adensamento construtivo limitado a edificações com três pavimentos no período mais quente do dia (às 14:00h) altera minimamente o microclima na quadra analisada, sem alterações significativas nos fluxos de ventos

Violência e desenvolvimento sustentável: o papel da universidade

This paper is an essay that resulted from reflections on sustainable development and its connections with university extension programs and violence. The paper discusses the four extents of sustainable development - ethical, temporal, social, and practical and the ethical principles of sustainability, essential for a culture of peace. It proposes a new praxis in the university to reevaluate the institution departmentalization, in order to open space for the construction of a cross-disciplinary environment which will produce graduates prepared for a sustainable future. It introduces an extension program of the Federal University of Rio Grande do Sul (UFRGS), which studies violent behavior and acts to decrease the problem effectively. The work concludes that it is the university's role to educate professionals according to sustainable development values, prepared to act in an ethical and responsible way concerning natural and human resources, capable of understanding and interacting with the complexity of problems such as poverty, social inequities and violence, which threaten human rights and the future generations.Este é um trabalho de natureza ensaística, resultado de reflexões sobre o desenvolvimento sustentável e a sua conexão com as ações de extensão universitárias e a violência. Discute as quatro dimensões básicas do desenvolvimento sustentável - a ética, a temporal, a social e a prática - e os princípios éticos da sustentabilidade, necessários para uma cultura de paz. Propõe uma nova práxis universitária, em que a departamentalização da instituição seja repensada a fim de abrir espaço para a construção de um ambiente de atuação transdisciplinar, formador de profissionais preparados para um futuro sustentável. Apresenta um serviço da Universidade Federal do Rio Grande do Sul (UFRGS), que, por meio da ação de extensão Projeto Proteger, estuda o comportamento violento e age para diminuir efetivamente a violência. Conclui que é papel da universidade formar profissionais em compasso com os valores do desenvolvimento sustentável, preparados para agir de forma ética e responsável com os recursos naturais e humanos, capazes de entender e interagir com a complexidade de problemas como a pobreza, as desigualdades sociais e a violência, que ameaçam os direitos humanos e as futuras gerações

Coberturas vivas extensivas : análise da utilização em projetos na região metropolitana de Porto Alegre e serra gaúcha

Os processos tradicionais de produção na indústria da construção civil estão entre os maiores causadores de impactos ambientais ao planeta. A transformação do ambiente natural em ambiente construído consome consideráveis volumes de recursos naturais não-renováveis, e gera também consideráveis volumes de resíduos. Pesquisas recentes, nacionais e internacionais, têm buscado alternativas construtivas que minimizem esses aspectos negativos, identificando sistemas e técnicas construtivas que diminuam o consumo destes recursos, e que prolonguem o tempo de vida útil dos materiais. As coberturas vivas representam uma opção que, juntamente com outras técnicas, possibilitam uma mudança de paradigmas projetuais. Estas coberturas são uma alternativa construtiva que oferece a possibilidade de utilização de materiais locais, apresentam comprovados benefícios térmicos e acústicos. A possibilidade de utilização de coberturas vivas nas cidades pode promover, também, ganhos na umidificação e filtragem de partículas do ar, e na suavização de um meio térmico fortemente aquecido, sobretudo onde se encontram grandes aglomerações edificadas. A bibliografia existente sobre o assunto é, em sua maioria, estrangeira. O emprego de coberturas vivas em edificações ainda é bastante incipiente no Brasil, o que gera poucos registros de exemplares para pesquisas. Por outro lado, o pouco registro de pesquisas científicas sobre essa tecnologia no Brasil também dificulta sua divulgação e maior utilização, havendo ainda muitos mitos sobre o assunto. Sendo assim, as questões técnicas de desempenho ao longo dos anos e a adaptação às variações climáticas em locais com climas sub-tropicais, como é o caso de Porto Alegre, ainda são raras para quem procura informações sobre o assunto. O trabalho pretende contribuir para verificar a possibilidade de utilização de coberturas vivas na região metropolitana de Porto Alegre e Serra Gaúcha, levantando, registrando e analisando os exemplares existentes. Analisa, também, os benefícios percebidos por profissionais e usuários com seu uso, assim como os cuidados necessários à sua construção e manutenção nestes locais.The tradicional production processes in the civil construction industry are among the greatest environmental impact causers in the planet. The transformation of the natural environment into the built environment consumes considerable amouts of non-renewable natural resorces and also generates a great volume of residue. Recent national and international researches have looked for constructive alteratives which could minimize these negative aspects, identifying constructive systems and technics that could diminish these resorces consumtion and lengthen the materials life time. The living roofs represent and option which, along with other technics, provide a change in the projectual paradigms. These roofs are a constructive alternative that offers the posibility of use of local materials, presents proved thermic and acoustic benefits. The possibility of use of living roofs in the cities can also promote gains in the humidification and filtrage of air particules and in the smoothening of a highly warmed thermic surface, specially where there are large built getherings. The existing bibliography about the subject is, mostly, foreign. The applying of living roofs on buildings is still incipient in Brazil, what generates few research sample records. Yet, the few records of cientific research about this technology in Brazil also makes it difficult to be disclosed and to increase its use while there are still a lot of miths about the subject. Therefore, the performance technical issues along the years and the adaptation to climate variations in sub-tropical environments , which is the case of Porto Alegre, are still rare to the ones who search for data about the subject. The study intends to contribute to verification of the living roofs applicability in the metropolitan área of Porto Alegre and in the gaúcha high-lands, retrieving data, registering and analizing the existing samples. It also analizes the benefits recognized by professionals and users, as well as the necessary concerns towards their construction en manteinnance in these places

Extensive green roofs in Porto Alegre, Brazil : Effect on indoor thermal comfort in residential buildings

Brazil had a significant quantitative housing deficit of 7.7 million residences in 2015, especially in low-income housing. Traditionally, these projects have low levels of thermal insulation which can result in discomfort caused by warmth or cold. The residential sector is responsible for a significant part of the energy use in Brazil. A green roof, a rooftop system with the addition of vegetation in the upper layer, is a way of reducing heat gain in the summer and heat loss in the winter. That is why green roofs are considered as a passive technique worldwide – that is, a technique not using energy for heating or cooling – to improve the indoor thermal comfort. There is a growing use of green roofs in Brazil. A more comprehensive understanding of the effect of green roofs on thermal comfort will help to identify key design aspects to improve their efficiency. This thesis investigates the effect of the thinner and most common type of green roof, called extensive, on the indoor thermal comfort in Porto Alegre, a city in Southern Brazil with a subtropical climate. The indoor thermal comfort in naturally ventilated low-income houses was calculated using computer simulations. Three groups of factors influencing the thermal performance of green roofs were analysed: the first was related to the building envelope (level of insulation), the second was associated with the green roof composition (soil thickness and vegetation density), and, finally, the third was related to the outdoor environment (presence of trees near the houses). For the last group of factors, calculations of outdoor microclimate and indoor thermal comfort were linked in a process called coupled simulation. The results confirmed the suitability of green roofs to increase the indoor thermal comfort in low-income housing projects in Porto Alegre, especially in one-story buildings. Green roofs would be beneficial to new projects, complying with the minimum level of insulation requirements in the Brazilian Standards, and to the existing poorly insulated building stock. Extra insulation in the building envelope would increase the benefits provided by the green roofs in the winter season even more. For the whole year, the best combination of features was low-density plants and a thicker soil layer (150mm thick). The vegetation around the building influences the microclimate and also affects the indoor climate. However, the shade provided by trees is helpful in the summer but disadvantageous in the winter. Both the green roof and the garden landscape should not consist of too dense vegetation in the climate of Porto Alegre, because it reduces the solar heat gain which is beneficial in the winter. The effect of green roofs on the microclimate was also evaluated. Results from this investigation revealed a minimal and local cooling effect from the green roofs on the outdoor temperature. Green roofs alone are thus not effective in reducing the high temperatures during the summer season in Porto Alegre. This work contributes to meeting the goals of the 2030 Agenda for Sustainable Development from the United Nations General Assembly (2015), especially the 11th Sustainable Development Goal: “Make cities and human settlements inclusive, safe, resilient and sustainable”. The findings of this study that the use of green roofs increases indoor thermal comfort meets the aim of adopting local and affordable resources, being relevant to low-income housing projects

Extensive green roofs in Porto Alegre, Brazil : effect on indoor thermal comfort in residential buildings

This research aims to develop further understanding of the effect of extensive green roofs on the indoor thermal comfort in naturally ventilated low-income houses, in the Brazilian subtropical city of Porto Alegre. This is achieved by studying the influence of a set of variables, to comprehend the best combinations of elements to a climate responsive green roof design. Moreover, in order to create more realistic results, different scenarios with green roofs and other elements (as grass on the ground and trees) are created, to evaluate the influence of the local microclimate on the indoor thermal comfort. Additionally, understanding how the extensive green roofs affect the outdoor microclimate in Porto Alegre is also a part of the aim. Evaluations are made for the whole year as well as for the summer and winter seasons. The study estimates the effect of extensive green roofs on the indoor thermal comfort and on the outdoor microclimate by calculations through computer simulations. The simulations are performed with EnergyPlus for the indoor thermal comfort and with ENVI-met for the microclimate simulations. The studied houses are conceived for urban or suburban areas, to be implemented in any Brazilian city, as long as some adjustments are made to better respond to the climate, complying with the Brazilian Standards 15.575 and 15.220. The indoor thermal comfort is evaluated primarily with the Adaptive thermal comfort model of the ASHRAE Standard 55, and the calculation of heating and cooling degree-hours. For the outdoor microclimate, the variables air temperature and mean radiant temperature are evaluated. The research shows that green roofs increase the indoor thermal comfort in the studied one-storey houses. For the whole year, the best combination of features is low-density plants and a thick soil layer (150mm). For the winter season, extra-insulation in the building envelope would improve indoor thermal comfort. The extensive green roofs would be beneficial both to new projects, complying with the minimum level of insulation from the Brazilian Standards, and to the existing building stock, which is typically poorly insulated. The microclimate around the buildings affects the indoor thermal comfort, and this investigation shows that, when the green roofs are integrated in a green strategy at the site (with trees and grass on the ground), their cooling effect increases compared to when they are the only green strategy. This study also confirms the advantages of performing coupled simulations, where the results of the microclimate simulations are used as input to the building simulations, to have more realistic predictions of the indoor thermal comfort. Concerning the effect of the extensive green roofs on the microclimate, a minor and local cooling effect is observed, especially at pedestrian level. That indicates that the effect of extensive green roofs as a strategy for reducing the outdoor air temperature in an urban context might be overestimated. The study showed that in the climate of Porto Alegre, a trade-off is needed: the best configuration of vegetation for the indoor thermal comfort over the whole year (trees with a lower density) is not the best configuration for providing a cooling effect on the microclimate. Since the use of green roofs are advantageous to low-income housing projects, this work contributes to meeting the Sustainable Development Goals of the United Nations, especially goal 11: “Make cities and human settlements inclusive, safe, resilient and sustainable”

Coberturas vivas extensivas : análise da utilização em projetos na região metropolitana de Porto Alegre e serra gaúcha

Os processos tradicionais de produção na indústria da construção civil estão entre os maiores causadores de impactos ambientais ao planeta. A transformação do ambiente natural em ambiente construído consome consideráveis volumes de recursos naturais não-renováveis, e gera também consideráveis volumes de resíduos. Pesquisas recentes, nacionais e internacionais, têm buscado alternativas construtivas que minimizem esses aspectos negativos, identificando sistemas e técnicas construtivas que diminuam o consumo destes recursos, e que prolonguem o tempo de vida útil dos materiais. As coberturas vivas representam uma opção que, juntamente com outras técnicas, possibilitam uma mudança de paradigmas projetuais. Estas coberturas são uma alternativa construtiva que oferece a possibilidade de utilização de materiais locais, apresentam comprovados benefícios térmicos e acústicos. A possibilidade de utilização de coberturas vivas nas cidades pode promover, também, ganhos na umidificação e filtragem de partículas do ar, e na suavização de um meio térmico fortemente aquecido, sobretudo onde se encontram grandes aglomerações edificadas. A bibliografia existente sobre o assunto é, em sua maioria, estrangeira. O emprego de coberturas vivas em edificações ainda é bastante incipiente no Brasil, o que gera poucos registros de exemplares para pesquisas. Por outro lado, o pouco registro de pesquisas científicas sobre essa tecnologia no Brasil também dificulta sua divulgação e maior utilização, havendo ainda muitos mitos sobre o assunto. Sendo assim, as questões técnicas de desempenho ao longo dos anos e a adaptação às variações climáticas em locais com climas sub-tropicais, como é o caso de Porto Alegre, ainda são raras para quem procura informações sobre o assunto. O trabalho pretende contribuir para verificar a possibilidade de utilização de coberturas vivas na região metropolitana de Porto Alegre e Serra Gaúcha, levantando, registrando e analisando os exemplares existentes. Analisa, também, os benefícios percebidos por profissionais e usuários com seu uso, assim como os cuidados necessários à sua construção e manutenção nestes locais.The tradicional production processes in the civil construction industry are among the greatest environmental impact causers in the planet. The transformation of the natural environment into the built environment consumes considerable amouts of non-renewable natural resorces and also generates a great volume of residue. Recent national and international researches have looked for constructive alteratives which could minimize these negative aspects, identifying constructive systems and technics that could diminish these resorces consumtion and lengthen the materials life time. The living roofs represent and option which, along with other technics, provide a change in the projectual paradigms. These roofs are a constructive alternative that offers the posibility of use of local materials, presents proved thermic and acoustic benefits. The possibility of use of living roofs in the cities can also promote gains in the humidification and filtrage of air particules and in the smoothening of a highly warmed thermic surface, specially where there are large built getherings. The existing bibliography about the subject is, mostly, foreign. The applying of living roofs on buildings is still incipient in Brazil, what generates few research sample records. Yet, the few records of cientific research about this technology in Brazil also makes it difficult to be disclosed and to increase its use while there are still a lot of miths about the subject. Therefore, the performance technical issues along the years and the adaptation to climate variations in sub-tropical environments , which is the case of Porto Alegre, are still rare to the ones who search for data about the subject. The study intends to contribute to verification of the living roofs applicability in the metropolitan área of Porto Alegre and in the gaúcha high-lands, retrieving data, registering and analizing the existing samples. It also analizes the benefits recognized by professionals and users, as well as the necessary concerns towards their construction en manteinnance in these places

Influence of microclimate on the effect of green roofs in Southern Brazil – A study coupling outdoor and indoor thermal simulations

A comprehensive understanding of the effect of green roofs on the indoor thermal comfort, under different microclimates, will help to identify key design aspects. In this study, which is the first of its kind in Brazil, the indoor thermal comfort for two different types of roofs, under different microclimates in Porto Alegre in Southern Brazil, have been compared. Coupled simulations using ENVI-met and EnergyPlus linked calculations of outdoor microclimate and indoor thermal comfort. The site was approximately 100 m by 100 m with 24 one-story, naturally ventilated semi-detached houses with an area of 39 m2. One of the houses, located approximately in the middle of the site, represented the building scale. In the original site (with no tree shadings), the substitution of the ceramic by the green roof led to an increase of 9.1% of the time within the thermal comfort zone. This study helps to bridge the current gap between thermal simulations in different scales. Moreover, this investigation concluded that green roofs performed better when in a green environment: for the summer season, with trees partially shading the roof, the green roof resulted in a reduction of the maximum operative temperature by 4.3 °C, whereas for the site without trees, the reduction was 2.8 °C

A variabilidade climática causada pelo adensamento urbano: estudo de caso na cidade de Pelotas-RS

O objetivo deste recorte do estudo é analisar os efeitos sobre a variável climática da temperatura radiante média (TMR), ao nível do pedestre, no miolo da quadra durante o período do inverno. Na próxima etapa do trabalho será realizada a análise de todas as variáveis climáticos e o impacto delas no conforto térmico em ambientes abertos