Static and dynamic thermal characterisation of a hollow brick wall: Tests and numerical analysis

Sala, J.M.; Urresti, A.; Martín-Escudero, Koldobika; Flores, I.; Apaolaza, A.

doi:10.1016/j.enbuild.2008.02.011

Cited by 65 publications

(50 citation statements)

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“…(9) Plotting time lag for the considered blocks against their equivalent thermal diffusivity, there emerged a clear correlation, as depicted in Figure 10. Plotting time lag values against the reciprocal of equivalent thermal diffusivity of each block showed a straight correlation, as depicted in Figure 11.…”

Section: Discussionmentioning

confidence: 97%

“…Lacarrière et al [8] found that the effective heat capacity per unit volume of a brick is of the same order of that of the solid part of the brick in an experimental study on the response of a single vertically perforated brick subjected to a step temperature change. On the contrary, Sala et al [9], in an experimental study on the response of a three-layered wall made of a Expanded Polystyrene (EPS) insulating layer, a hollow brick layer, and a gypsum layer, subject to a triangular temperature-pulse, found that the effective heat capacity per unit volume of the brick was nearly half of that of the clay which the solid part of the brick consisted of. Moreover, Zhang and Wachenfeldt [10] calculated that the heat capacity per unit volume of the equivalent homogeneous layer was about two times that of the solid part of a slab with a cavity area fraction about 50%, through numerical simulations.…”

Section: Introductionmentioning

confidence: 99%

“…Triangular pulse excitation was used to check the dynamic heat transfer characteristics, applied to face S, as proposed in Reference [9]. This kind of solicitation allows us to evaluate the time lag as the delay between the peak of the temperature pulse and the peak of heat transfer on the other Energies 2017, 10, 1807 3 of 11 side, as well as the decrement factor, which is the ratio of the actual peak heat transfer to that with constant temperature equal to the peak value, as defined in Reference [4], as depicted in Figure 2.…”

Section: Mathematical Formulationmentioning

confidence: 99%

“…Martín et al [11] and the cited paper from Sala et al [9] provided experimental results of triangular pulse temperature solicitation on multilayer walls containing hollow bricks. In the former, the time lag is 4.4 h with a 180-mm thick brick layer, while the latter presents a time lag less than one hour for a 40-mm thick brick layer.…”

Section: Introductionmentioning

confidence: 99%

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Dynamic Thermal Features of Insulated Blocks: Actual Behavior and Myths

2017

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Abstract:The latest updates in the European directive on energy performance of buildings have introduced the fundamental "nearly zero-energy building (NZEB)" concept. Thus, a special focus needs to be addressed to the thermal performance of building envelopes, especially concerning the role played by thermal inertia in the energy requirements for cooling applications. In fact, a high thermal inertia of the outer walls results in a mitigation of the daily heat wave, which reduces the cooling peak load and the related energy demand. The common assumption that high mass means high thermal inertia typically leads to the use of high-mass blocks. Numerical and experimental studies on thermal inertia of hollow envelope components have not confirmed this general assumption, even though no systematic analysis is readily available in the open literature. Yet, the usually employed methods for the calculation of unsteady heat transfer through walls are based on the hypothesis that such walls are composed of homogeneous layers. In this framework, a study of the dynamic thermal performance of insulated blocks is brought forth in the present paper. A finite-volume method is used to solve the two-dimensional equation of conduction heat transfer, using a triangular-pulse temperature excitation to analyze the heat flux response. The effects of both the type of clay and the insulating filler are investigated and discussed at length. The results obtained show that the wall front mass is not the basic independent variable, since clay and insulating filler thermal diffusivities are more important controlling parameters.

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Section: Discussionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Section: Mathematical Formulationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Dynamic Thermal Features of Insulated Blocks: Actual Behavior and Myths

2017

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“…Researchers (DEMIRDA; GUNDUZ, 2008;SALA et al, 2008;UTAMA;GHEEWAL, 2009) seem to agree that the thermal transmittance of a material used in building construction depends mainly on the material density, permanent moisture content and mineralogical composition.…”

Section: -Introductionmentioning

confidence: 99%

Mechanical and thermal behaviors of stabilized compressed earth blocks

Ferreira

Ulhôa

2016

Cieng

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The effect of lime and Portland cement associated to sodium silicate (Na2SiO3) on the mechanical and thermal behavior of compressed earth blocks was analyzed. Mini panels were molded and their mechanical and thermal properties were determined in laboratory. For such, sandy and clayey soils were added with Portland cement and lime at 6% and 10% contents, and sodium silicate at dosage of 4%. The compressed earth blocks were cured in a humidity chamber for seven, 28, 56 and 91 days. At the ages of 28, 56 and 91 days the specimens were submitted to the compressive test and water absorption tests at seven days. The thermal conductivity was obtained by the guarded hot plate method and the specific heat value by the calorimeter method. Afterwards, the main thermophysical properties were calculated and analyzed by means of walls thermal behaviors. The best compressive strength and water absorption capacity results were reached by the sandy soil with addition of Portland cement or lime at 10% content, both added of sodium silicate. Regarding to the thermal behavior, the results pointed out that the stabilized compressed earth blocks reached the best thermal behavior when compared to the conventional ones under the same use conditions. Keywords: Stabilized earth, Soil-cement, Mechanical properties, Thermophysical properties. RESUMOFoi analisado o efeito da adição de cimento e cal associados ao silicato de sódio (Na2SiO3) sobre o comportamento mecânico e térmico de tijolos prensados de terra crua. Mini painéis foram moldados e suas propriedades mecânicas e térmicas foram determinadas em laboratório. Para tal, cimento Portland e cal, nas dosagens de 6% e 10% e silicato de sódio, na dosagem de 4% foram adicionados a dois tipos de solos, um arenoso e outro argiloso. Os tijolos foram curados em câmara úmida por sete, 28, 56 e 91 dias. Os ensaios de compressão simples foram realizados nas idades de 28, 56 e 91 dias e os de absorção de água aos sete dias. A condutividade térmica foi obtida pelo método da placa quente e o calor específico foi determinado por calorímetro. As principais propriedades termofísicas foram calculadas e analisadas por meio do comportamento térmico de paredes. Os melhores resultados em termos de compressão simples e absorção de água foram alcançados pela mistura solo arenoso e cimento ou cal na dosagem de 10% associados ao silicato de sódio. Os resultados apontaram que os tijolos prensados de terra crua alcançaram melhor comportamento térmico comparados aos tijolos cerâmicos convencionais.

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