Thermal comfort indices in individual shelters for dairy calves with different types of roofs

Abstract

Among the building materials used in rural facilities, roofs are noteworthy for being largely responsible for thermal comfort, influencing the thermal balance within the shelter. This study aimed to evaluate the influence of roof on the Enthalpy (H), Thermal Load of Radiation (TLR), and Black Globe Temperature and Humidity Index (BGHI) in individual shelters for dairy calves. The design was completely randomized with three treatments: Z -zinc tile, AC -asbestoscement tile and ACW -asbestos-cement tile painted white on the upper side. The averages were compared by the Scott Knott test at 1% probability. The results showed no statistical difference between treatments (P<0.01) and the external environment for H. For TLR, there was statistical difference among all treatments, where ACW showed the lowest TLR, 489.28 W m -2 , followed by AC with 506.72 W m -2 and Z with the highest TLR, 523.55 W m -2 . For BGHI, the lowest values were observed for ACW (76.8) and AC (77.4), differing significantly from Z, which obtained the highest value (81.6). The tiles with white paint on the upper side promoted the lowest TLR and the lowest BGHI, favoring the thermal environment in the shelter.KEYWORDS: thermal indices, construction materials and type of roof. AMBIENTE TÉRMICO NO INTERIOR DE ABRIGOS INDIVIDUAIS PARA BEZERROS COM A UTILIZAÇÃO DE DIFERENTES TIPOS DE COBERTURASRESUMO: Dentre os materiais de construção utilizados nas instalações rurais, merecem destaque as coberturas, pois são grandes responsáveis pelo conforto térmico, influenciando no balanço térmico no interior das instalações. Este trabalho objetivou avaliar a influência das coberturas sobre a entalpia (H), Carga Térmica Radiante (CTR) e no Índice de Temperatura de Globo Negro e Umidade (ITGU), em abrigos individuais para bezerros leiteiros. O delineamento foi o inteiramente casualizado com três tratamentos: Z -telha de zinco; CA -telha de cimento amianto, e CAB -telha de cimento amianto pintada de branco na face superior.

Thermal behavior of metallic and fiber cement tiles with simple and double layers

“…Abreu et al (2011) observed lower IST for fiber cement tiles in relation to metallic tiles at 14h. Fonseca et al (2011) also verified similar results when studying fiber cement tiles and zinc tiles, where fiber cement tile presented better thermal efficiency than the metallic tile studied (zinc). Sampaio et al (2011) studied the superficial temperature of roofing and their relation to the building thermal environment.…”

Conforto térmico e desempenho de bezerras Girolando alojadas em abrigos individuais com diferentes coberturas

“…Variação média diária da temperatura de bulbo seco (Tbs, °C) no interior dos abrigos nos diferentes tratamentos e no abrigo meteorológico nos dias de maior (A) e menor entalpia (B), temperatura crítica inferior (TCI), zona de conforto térmico (ZCT) e temperatura crítica superior (TCS) para bezerros Não houve diferença estatística (p > 0,05) entre os tipos de cobertura e o ambiente externo para o ITGU; no entanto e de acordo com Baêta & Souza (2010) os valores verificados (Tabela 1) indicam condição de conforto (ITGU < 74) para os bovinos, proporcionado pelo efeito do sombreamento promovido pela cobertura. O valor do ITGU obtido no abrigo com cobertura de fibrocimento está dentro do intervalo encontrado por Sampaio et al (2011) entre 64,2 e 73,5 e menores que os obtidos por Fonseca et al (2011) que avaliaram coberturas de telha de zinco (81,63); telha de cimento amianto (77,41) e telha de cimento amianto pintada de branco na face superior (76,84), em abrigos individuais para bezerros leiteiros.…”

“…Tais valores foram inferiores aos encontrados por Fonseca et al (2011) que verificaram valor mínimo de 63,94 e máximo de 70,38 kJ kg -1 ar seco, principalmente pela baixa umidade relativa do ar entre as 10 e 16 h (Figura 4A).…”

Thermal Efficiency of Different Coverage Materials in Reduced Models of Animal Husbandry Facilities: A Case Study

“…However, FONSECA et al (2011) found a statistical difference between treatments when assessing facilities with tiles of zinc, asbestos cement, and asbestos cement white painted on the upper face. These authors observed that the lowest values of RHL and BGHI (489.28 W m −2 and 76.8, respectively) were found in facilities covered with asbestos cement tiles white painted on the upper face whereas the highest values were found in facilities with zinc tiles (523.55 W m −2 and 81.6, respectively).…”