Study of the geometry of a voided clay brick using rectangular perforations to optimize its thermal properties

Abstract

This study was undertaken to optimize the equivalent transmittance of a wall consisting of voided clay bricks using ceramic material Termoarcilla ® 29 ECO, complying with the Spanish UNE [1] , European EN [2] and international ISO [3] , [4] , [5] , [6] , [7] standards. Various geometries were investigated for the bricks’ cross sections, starting from a commercialized block and improvements in its thermal conductivity were studied by varying parameters such as a number of rows in the brick, the type of tongue and grooving and the alternation between contiguous rows in the brick. Simulations were made using a finite elements application [9] . The conclusions of the study were that the thermal properties of a brick are improved by placing the perforations of the voids in a quincunx (in parallel rows, so that every hole is placed between those of the immediate rows, forming equilateral triangles) and that the greater the number of rows, the better the thermal behaviour. Further, if these perforations are extended to the tongue and groove area and a certain clearance is left between the tongue and groove of each brick, the wall’s equivalent transmittance is reduced. ► This study tries to optimize the equivalent transmittance of a wall of bricks. ► Thermal properties of a brick are improved by placing the perforations in a quincunx. ► If perforations are extended to the tongue the wall’s transmittance is reduced. ► A clearance left in the joint of the bricks, reduces the wall’s transmittance. ► A brick with 26 rows of rectangles with Ueq<0.57 W/m 2 -K is obtained.