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Abstract(s)
O trabalho aqui apresentado abordou o estudo de um sistema solar passivo aplicado em fachadas com parede de trombe, a qual constitui uma tecnologia construtiva que permite a redução do consumo energético dos edifícios. Avaliou-se, em particular, o efeito da incorporação de materiais de mudança de fase (PCM’s), nomeadamente um PCM à base de Parafina e outro à base de Octadecano.
Este estudo baseou-se, fundamentalmente, na conceção, análise experimental e comparação de resultados obtidos em modelos de teste.
Para tal, foi previamente efetuada, uma campanha experimental no Instituto Politécnico de Bragança de maneira a aferir o modo de mistura de todos os constituintes da argamassa, a percentagem de PCM a incorporar na argamassa, bem como a quantidade de água. Estes estudos prévios incluíram ainda uma caracterização mecânica das argamassas com e sem PCM. Os dados obtidos indicam que com a adição de 30% de PCM na constituição da argamassa, obtêm-se melhores resultados comparativamente com outras percentagens.
A segunda parte do trabalho foi dedicada ao estudo de seis modelos de teste construídos com argamassa cimentícia e uma geometria apropriada. Um dos modelos serviu para comparação de resultados, outro modelo de teste foi realizado considerando a fachada principal em vão envidraçado e os outros quatro foram executados com a fachada principal no sistema construtivo parede de trombe. As paredes de trombe foram construídas com quatro materiais distintos: argamassa cimentícia, argamassa cimentícia com Octadecano, argamassa cimentícia com Parafina e ainda granito.
Todos os modelos foram monitorizados e ensaiados. Em três dos ensaios os modelos foram monitorizados ao mesmo tempo e nas mesmas condições, cada um deles com duração de quatro dias. Fez-se variar de ensaio para ensaio a cor na parede de granito e a ventilação imposta aos modelos. Durante a monitorização dos modelos obtiveram-se valores de temperaturas e da condutividade térmica dos elementos da fachada principal de 10 em 10 minutos e foi deste modo, possível estabelecer uma análise comparativa entre os modelos ensaiados.
Concluiu-se com este trabalho que a incorporação de PCM’s em argamassas térmicas pode trazer vantagens a nível de conforto térmico, maior eficiência e sustentabilidade aos edifícios, para além de melhorar a eficiência do sistema construtivo – parede de trombe.
The work presented here is related to the study of a passive solar system applied in facades with trombe wall, which is a construction technology that allows reducing the energy consumption of buildings. In particular, it was evaluated the effect of the incorporation of phase changing materials (PCM's) was evaluated using, namely, PCM based on Paraffin and another one based on Octadecane. This study is primarily based in the execution, experimental analysis and comparison of results obtained in test models. For this purpose, an experimental campaign conducted at Bragança Polytechnic Institute was previously performed in order to evaluate the blending mode of all the constituents of the mortar, the content of PCM to incorporate in the mortar as well as the involved water quantity. These early studies included the mechanical characterization of the mortar with and without PCM. The obtained data indicate that the best results were achieved with the addition of 30% of PCM in the mortar. The second part or current work was devoted to the study of six test models built using cement mortar and an appropriate geometry. One of the models served as a reference, another sample model was tested considering that the main facade will simulate a window, while the remaining models were executed as a main facade using the Trombe wall building system. Trombe walls were built with four different materials: cement mortar, cement mortar with Octadecane, cement mortar with Paraffin and granite. All models were monitored and tested. Three of the walls testing samples were tested simultaneously under the same conditions, for four days. The differences between the tests are related to the granite wall colour and the ventilation around the models. During the monitoring of the models it was possible to obtain temperature records and thermal conductivity of the main facade elements in 10 to 10 minutes intervals and so it was possible to establish a comparison between the tested models. Main conclusions of this work are that the incorporation of PCM's into thermal mortars can bring benefits in terms of thermal comfort, greater efficiency and sustainability to buildings, as well as improve the efficiency of trombe wall building system.
The work presented here is related to the study of a passive solar system applied in facades with trombe wall, which is a construction technology that allows reducing the energy consumption of buildings. In particular, it was evaluated the effect of the incorporation of phase changing materials (PCM's) was evaluated using, namely, PCM based on Paraffin and another one based on Octadecane. This study is primarily based in the execution, experimental analysis and comparison of results obtained in test models. For this purpose, an experimental campaign conducted at Bragança Polytechnic Institute was previously performed in order to evaluate the blending mode of all the constituents of the mortar, the content of PCM to incorporate in the mortar as well as the involved water quantity. These early studies included the mechanical characterization of the mortar with and without PCM. The obtained data indicate that the best results were achieved with the addition of 30% of PCM in the mortar. The second part or current work was devoted to the study of six test models built using cement mortar and an appropriate geometry. One of the models served as a reference, another sample model was tested considering that the main facade will simulate a window, while the remaining models were executed as a main facade using the Trombe wall building system. Trombe walls were built with four different materials: cement mortar, cement mortar with Octadecane, cement mortar with Paraffin and granite. All models were monitored and tested. Three of the walls testing samples were tested simultaneously under the same conditions, for four days. The differences between the tests are related to the granite wall colour and the ventilation around the models. During the monitoring of the models it was possible to obtain temperature records and thermal conductivity of the main facade elements in 10 to 10 minutes intervals and so it was possible to establish a comparison between the tested models. Main conclusions of this work are that the incorporation of PCM's into thermal mortars can bring benefits in terms of thermal comfort, greater efficiency and sustainability to buildings, as well as improve the efficiency of trombe wall building system.
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Keywords
PCM Argamassa térmica Parede de trombe Modelos de teste