Analysis of Heat Transfer Phenomena inside Concrete Hollow Blocks

During both hot and cold seasons,masonry walls play an important role in the thermal performance between the interior and the exterior of occupied spaces.It is thus essential to analyze the thermal behavior at the hollow block’s level in order to better understand the temperature and heat flux distribution in its structure and potentially limit as much as possible the heat transfer through the block.In this scope,this paper offers an experimental and numerical in-depth analysis of heat transfer phenomena inside a hollow block using a dedicated experimental setup including a well-insulated reference box and several thermocouples and fluxmeters distributed at the boundaries and inside the hollow block.The block was then numerically 3D modelled and simulated using COMSOL Multiphysics under the same conditions,properties,and dimensions as the experimentally tested block.The comparison between the numerical and experimental results provides very satisfactory results with relative difference of less than 4%for the computed thermal resistance.

Thermal Analysis of Concrete Mixtures with Recycled EPS Aggregates

Reusing recycled waste materials in buildings is gaining more and more attention for what it offers economic,environmental,and energy benefits;and many researchers are nowadays working on producing new sustainable construction materials incorporating recycled wastes.In this scope,this work uses an experimental approach aiming at understanding the effect of incorporating Expanded Polystyrene(EPS)beads in concrete and proposing thermally improved concrete mixtures for the production of hollow blocks in Lebanese constructions by substituting fine aggregates with recycled products such as EPS in order to promote their insulating properties.Three different diameters of EPS beads(2 mm~3 mm,3 mm~4 mm and 4 mm~5 mm)are studied with different volumetric ratios(20%,40%,60%and 80%)in order to investigate the effect of EPS on the thermal properties of concrete.The results showed that the only the percentage of incorporated EPS beads impacted the thermal performance of the concrete mixtures while the EPS diameters have a negligible effect on the thermal properties of the concrete samples.

Thermal performance of lightweight concrete applications in building envelopes in Lebanon

Innovative building materials are being used in building envelopes for reducing their heating and cooling needs.This paper aims to assess the thermal impact of using lightweight concrete in Lebanese building constructions by pouring an 8 cm thickness of lightweight concrete on the roof and the slab and replacing traditional hollow concrete block by lightweight concrete blocks.Thermal properties of two different samples were experimentally determined:the first one(558 kg/m^(3))used for the roof and the slab and the second one(1074 kg/m^(3))used for the walls.Then numerical simulations were carried out for a Lebanese traditional detached house using the characteristics of these two samples.The thermally improved Light Weight Concrete building(LWC)was compared to a traditional Lebanese house base case(BC)using a dynamic building energy simulation tool in the four different Lebanese climate zones:coastal,mid-mountain,mountain,and inland zones.The results highlight the effectiveness of integrating LWC to building envelopes by reducing energy consumption and improving thermal comfort in both winter and summer climate conditions and in the different Lebanese climatic zones.The paper demonstrates that the use of LWC in the vertical walls replacing the traditional hollow blocks can reduce the heating needs by up to 9%and by up to 13%for cooling needs.On the other hand,adding a LWC roof screed has a very high impact on cooling and heating energy consumption,which can reach up to 74%in cooling energy savings and up to 24%in heating energy savings.