Numerical investigation of the influence of room factors on HAM transport in a full-scale experimental room

To model the indoor environment influenced by room factors including moisture loads and ventilation conditions, the governing equations of heat, air and moisture (HAM) transport inside the room and through the envelope, including the coupling process of the interaction of heat and moisture between indoor air and envelope, need to be solved. This paper presents a CFD model of the indoor environment that takes into account the heat and moisture transfer through the envelope in a single simulation environment. The comparisons between experimental data and simulation results show close agreement. This model is then implemented in 12 cases to study the influence of moisture loads, ventilation rates, and positions of the air inlet and outlet on the indoor environment and on the heat and moisture transport through the envelope. Simulation results show that the humidity responses of the test room vary significantly for different moisture loads from 42 g/h to 91 g/h and for different ventilation rates from 0.5 air change per hour (ach) to 1 ach. Changing the positions of the ventilation vents alters the air flow pattern significantly, thus affecting the ventilation efficiency. With a heat and moisture source inside the test room, the changed ventilation efficiency influences the indoor environment significantly, especially under low ventilation rates. The increased ventilation rate carries away more heat and moisture, which reduces both temperature and moisture levels inside the room. Under the mixed convection condition, the indoor temperature and moisture levels dominate the heat and moisture transport through the wall system.

► A directly coupled CFD model is developed for HAM transport in room air and walls.
► Simulation results are compared with experimental data of a large-scale test room.
► Influences on indoor RH by ventilation, vent locations and moisture loads are shown.
► Heat and moisture transport of wall system under different room condition are studied.