The air flow in a room of a building contains in-room wind particular to the room which is accommodated with various fittings, unlike natural convection in a closed spase. In order to get a clue to obtain the surface heat transfer coefficient in a room under such conditions, I set up a nozzle-shaped or slit-like air inlet and outlet in the upper and lower portions of the wall of a room model (3m×3m×3m) and carried out cooling and heating experiments. The heat transfer coefficient becomes larger as compared to that of natural convection, and it becomes larger as the ventilation frequency increases. The heat transfer coefficient of each wall surface shows an almost constant value both during cooling and heating regardless of how to measure the air temperature for the calculation of the heat transfer coefficient. The heat transfer coefficient of the ceiling surface and the floor surface vary greatly depending on how to measure the air temperature; during coolig the vicinity of the ceiling surface gives the minimum air temperature value and during heating it gives the maximum air temperature value. Also, I attempted to arrange the heat transfer coefficient by the Archimedes' number.
