Thermal insulation of walls by using multiple air gaps separated by aluminum sheets

Thermal insulation in the building walls is an important factor to reduce heat transfer from the external environment, thus reducing the demand for air conditioning and achieving thermal comfort. In order to improve the thermal performance of building walls, the present work aims to construct hollow (double) walls experimentally; which are made of several air layers separated by thin aluminum sheets, and to find the extent of their impact on improving or reducing heat gain. Tests were conducted on a model room of sandwich panel with dimensions of 2 m length and 2 m width, and 2.4 m height (32.5 latitudes) in kut city, Iraq, in August. A hole was drilled in the southwest wall with the following dimensions: (1 m long, 0.3 m wide). Three models of hollow walls with a 6 cm air gap were built in this hole; one was left with a 6 cm air gap (without dividing), the second was divided into two parts by placing a thin sheet of aluminum 1 mm thick, and the third wall's air gap was divided into three parts by placing two thin sheets of aluminum. The experimental results showed that the quantity of heat gain was lowered when the air layers were increased. The heat gain decrease was 11.5 % and 21 %, respectively, when comparing the wall with a cavity of 6 cm (without splitting) with the two walls in which the air gap was divided into two and three layers.