Energy Conversion and Management: X (Dec 2021)

Numerical study for energy performance optimization of hollow concrete blocks for roofing in a hot climate of Morocco

  • Yassine Chihab,
  • Lahcen Essaleh,
  • Rachid Bouferra,
  • Abdeltif Bouchehma

Journal volume & issue
Vol. 12
p. 100113

Abstract

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The roof is the component of the envelope more subjected to climatic excitations, and it contributes to a significant part of the total building's cooling load in hot climates. Therefore, the thermal optimization of hollow concrete blocks for roofing can considerably reduce the enormous energy consumption used for cooling buildings. For this purpose, the thermal inertia of different configurations of roofs built with traditional concrete blocks used in Morocco with three and six cavities was studied numerically. First, a two-dimensional coupled heat transfer by conduction, convection, and radiation was investigated in the steady-state using the Galerkin finite element method to generate an equivalent homogeneous monolayer block with similar thermal behaviour to the original hollow-block roof. After that, the transient heat conduction equation under real thermal solicitations is solved using a numerical inversion of the Laplace domain solution by utilizing the De Hoog algorithm to evaluate the dynamic thermal characteristics of the roofs. The results report that the emissivity and inside combined convection and radiation heat transfer coefficients significantly impact the roof's thermal inertia. In addition, it is shown that the configuration based on using a low emissivity coating and inserting an insulating material between the outer surface of the block and the slab could reduce the total thermal load over 24-hours by about 93.1% compared to the traditional configuration, which is beneficial to minimize the energy consumption used for cooling buildings.

Keywords