Numerical study on dynamic thermal characteristics and optimum configuration of internal walls for intermittently heated rooms with different heating durations

Numerical simulations are carried out to investigate the heating load of intermittently heated rooms and dynamic thermal characteristics of the internal walls in residential buildings by employing CFD techniques. The buildings are located in the lower reaches of the Yangtze River region of China. Moreover, thorough experiments on temperature distributions of thermal mass and indoor air were conducted to validate the simulation model. The results show that the heating load caused by the internal walls accounts for more than 65% of the room heating load. Furthermore, for the intermittently heated room with heating duration shorter than 2 h, the heating load of the internal walls increases linearly with the increase of the surface thermal absorption coefficient, which can be reduced by placing thermal insulation on the surface of the internal walls. When the heating duration is longer than 2 h, the heating load of the internal walls grows linearly with the inside thermal storage coefficient, which can be reduced by increasing the thermal resistance of the thermal insulation or decreasing heat capacity of the internal walls.