Thermal performance of ceramic hollow brick modified with low emissivity coating

There are still requirements in the building energy research and thermal engineering field to increase the thermal performance of a building and its structural elements. Building envelope made of hollow ceramic bricks are widely used in building engineering for their thermal, acoustic, and structural properties. This type of building element can be considered as one of the most used technologies for the present walls of building envelopes in European region. Various aspects that affect the resulting geometry of brick hollows, changes in the configuration of cavities and currently also the application of filling material with low thermal conductivity may contribute to the increase of thermal properties of these bricks. Another potential approach and further improvements can be based on the reduction of heat loss during heat transfer through the brick cavities aimed at reducing heat transfer by thermal radiation. Therefore, the effect of low emissivity on the thermal performance of ceramic hollow brick is the key subject of this paper. For his reason, inner surfaces of brick cavities were modified with low emissivity coating, experimentally tested using a heat flow meter method and to provide a consequent numerical analysis. Results presented in this study reveals, that depending on the emissivity, the decrease of the thermal conductivity of up to 20% can be theoretically achieved when particular hollow bricks are modelled however this effectivity is not followed by experimental measurement.