Experimental study on the thermal performance of a hollow block ventilation wall

A hollow block ventilation wall (HBVW) is an innovative construction where the block cavity of the wall is used as a ventilation duct. Low-grade energy can be used to remove heat stored in the structure in summer and warm the structure in winter. Therefore, the cooling and heating loads of buildings can be significantly reduced. Therefore, an experimental study was conducted to investigate the thermal performance of HBVW under different airflow temperatures and rates. The temperatures and heat flux of HBVW surfaces and the airflow temperatures in cavity were tested on a typical summer day. The results show that the air velocity in the cavity has a great influence on the thermal performance. Compared with a non-ventilation wall, the thermal resistance increases from 0.637 m2K/W to 1.61, 3.06, 3.86, and 4.12 m2K/W when the air velocity is 0.3, 0.9, 1.5, and 1.9 m/s, respectively, and the heat flux transferred through the inner surface can be decreased by 40.5%, 73.3%, 79.4%, and 82.6%. The average temperature of the inner surface can be respectively decreased by 1.8, 2.8, 3.0, and 3.1 °C. The airflow temperature has little effect on the equivalent heat resistance, but it does greatly affect the inner surface temperature.