Avaliação de sistemas de telhados verdes: análise térmica e hídrica nos diferentes sistemas cultivados com Callisia repens
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Data
2018-06-28
Autores
Carvalho, Gustavo de Castro
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Universidade Estadual Paulista (Unesp)
Resumo
A crescente urbanização, faz com que problemas ambientais tornem-se cada vez mais frequentes e, dessa forma, alternativas como o uso de coberturas vegetais mostram-se como importantes ferramentas para a melhoria ambiental nos centros urbanos. Telhados verdes são sistemas construtivos que quando utilizados, trazem inúmeros benefícios à população, dentre os quais se destacam: melhoria no conforto térmico em edificações, diminuição da poluição atmosférica, acústica e visual, além de menor escoamento superficial, reduzindo enchentes. Diante disso, a presente pesquisa buscou avaliar a temperatura em protótipos com diferentes sistemas de telhados verdes comerciais (Sistema FLAT, Sistema Modular e Sistema MacDrain) cultivados com Callisia repens, para quantificar a melhoria no que diz respeito ao conforto térmico que esses sistemas proporcionam, comparando-os entre si e com um sistema testemunha, totalizando 4 protótipos. A coleta dos dados ocorreu no período de 09/08/2017 à 22/11/2017 através de sensores de temperatura automatizados, em três diferentes horários: 08:00, 13:00 e às 22:00 horas. Adotouse o delineamento experimental de blocos ao acaso, e foram realizadas análises estatísticas para a comparação dos resultados, através do Teste de Tukey a 5% de significância. Os resultados mostraram que em horários com valores maiores de temperatura, os sistemas conseguem atenuar a radiação solar, diminuindo a transferência de calor do meio externo para o compartimento instalado logo abaixo dos sistemas. Já em temperaturas amenas, como o período noturno, o sistema funciona de forma a manter o calor absorvido durante o dia no compartimento abaixo, isolando a perda de calor. Apesar da maior parte dos dados de temperatura interna não estarem dentro dos limites da zona de conforto térmico, a diferença mensurada entre os valores de temperatura dos sensores posicionados no protótipo testemunha e os protótipos com os sistemas instalados de telhados verdes chegou a 23 °C no dia 14/10/2017. Realizando-se as análises estatísticas, o protótipo testemunha apresentou diferença significativa, em relação aos sistemas com telhados verdes, nos três horários, mostrando o potencial do sistema com cobertura vegetal no isolamento térmico. Para os horários das 08:00 e 22:00 horas, os protótipos com diferentes sistemas instalados não apresentaram diferença significativa entre si, entretanto, às 13:00 horas, o sistema FLAT diferiu do sistema Modular. Além das análises térmicas, foram realizadas também análises físicoquímicas da água utilizada no sistema de irrigação após a drenagem no Sistema FLAT, com a finalidade de verificar a possibilidade de reúso em sistemas de irrigação. Os parâmetros analisados foram: pH, carbono orgânico, nitrogênio, fósforo e potássio, sólidos totais, DBO, turbidez e cor. Os resultados mostraram que a qualidade da água drenada foi pouco alterada em relação à água utilizada na irrigação. Dessa forma, a água escoada poderia ser reutilizada para irrigar o próprio sistema de telhado verde, ou ainda, jardins do entorno, contribuindo para o menor consumo de água e preservação deste bem.
The crescent urbanization makes that environmental problems become more frequent and, therefore, alternatives as the use of plant cover are important for the environmental improvement. The green roofs are constructive systems that when used bring countless benefits to the population, to name but a few, thermal comfort improvement in buildings, decrease of the atmosphere pollution, acoustic and visual, besides a larger surface flow reducing floods. Therefore, the present dissertation has evaluated the temperature in different green roof systems prototypes cultivated with Callisia repens, to quantify the improvement related to the thermal comfort that these systems provide, comparing them with each other and with a control system, totaling 4 prototypes. Data were collected from 09/08/2017 to 11/22/2017 by automated alerts, at three different times: 08:00am, 01:00pm and 10:00pm. To compare statistically the results, critical analyses were carried out using the Tukey test at 5% significance level. The results have showed that with higher temperatures, the systems are able to weaken the solar radiation, reducing the heat transfer from the external environment to the compartment just below the prototypes. On the other hand, at night, normally with mild temperatures, the system works by keeping the heat absorbed during the day in the compartment below, isolating the loss of heat. Although most of the internal temperature levels are not within the limits of thermal comfort zone, the difference between the temperature measured in both the temperature values of the sensors placed on the main prototype and the ones placed on the green roof prototypes systems reached 73,4 °F on 10/14/2017. Statistically, the control prototype was different from the green roof systems in the three measured times, showing the potential of them in the thermal comfort. At 08:00am and 10:00pm, the prototypes were statistically equal, but at 01:00pm, the FLAT system differred from the Modular system. Besides the thermal analysis, water tests were carried out with the water that passed through the FLAT system during the drainage, to analyze the possibility of reusing the water for irrigation systems. The parameters considered were: pH, organic carbon, nitrogen, phosphorus and potassium, total solids, BOD, turbidity and color. The results have showed that the quality of the drained water was not changed in comparison to the water used in the irrigation. Therefore, the water could be reused to irrigate the green system itself, or even surrounding gardens, contributing to a lower water consumption and preserving it.
The crescent urbanization makes that environmental problems become more frequent and, therefore, alternatives as the use of plant cover are important for the environmental improvement. The green roofs are constructive systems that when used bring countless benefits to the population, to name but a few, thermal comfort improvement in buildings, decrease of the atmosphere pollution, acoustic and visual, besides a larger surface flow reducing floods. Therefore, the present dissertation has evaluated the temperature in different green roof systems prototypes cultivated with Callisia repens, to quantify the improvement related to the thermal comfort that these systems provide, comparing them with each other and with a control system, totaling 4 prototypes. Data were collected from 09/08/2017 to 11/22/2017 by automated alerts, at three different times: 08:00am, 01:00pm and 10:00pm. To compare statistically the results, critical analyses were carried out using the Tukey test at 5% significance level. The results have showed that with higher temperatures, the systems are able to weaken the solar radiation, reducing the heat transfer from the external environment to the compartment just below the prototypes. On the other hand, at night, normally with mild temperatures, the system works by keeping the heat absorbed during the day in the compartment below, isolating the loss of heat. Although most of the internal temperature levels are not within the limits of thermal comfort zone, the difference between the temperature measured in both the temperature values of the sensors placed on the main prototype and the ones placed on the green roof prototypes systems reached 73,4 °F on 10/14/2017. Statistically, the control prototype was different from the green roof systems in the three measured times, showing the potential of them in the thermal comfort. At 08:00am and 10:00pm, the prototypes were statistically equal, but at 01:00pm, the FLAT system differred from the Modular system. Besides the thermal analysis, water tests were carried out with the water that passed through the FLAT system during the drainage, to analyze the possibility of reusing the water for irrigation systems. The parameters considered were: pH, organic carbon, nitrogen, phosphorus and potassium, total solids, BOD, turbidity and color. The results have showed that the quality of the drained water was not changed in comparison to the water used in the irrigation. Therefore, the water could be reused to irrigate the green system itself, or even surrounding gardens, contributing to a lower water consumption and preserving it.
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Palavras-chave
Telhado verde, Reuso da água, Conforto térmico, Callisia repens, Green roof, Water reuse, Thermal comfort