This study attempts clarify the ventilation performance of fixed-type and turbine-type ventilation equipment frequently used in houses and factories in other countries such as Korea through experiments. In particular, the air supply opening area of the ventilation target space and the position and distance of the surrounding obstacles which affect the ventilation performance of both ventilation devices were compared. As experimental results, it was found that the ventilation rate of both ventilators increases with the outdoor wind speed increases and the air supply opening area becomes larger. In addition, it was found that backflow occurs when the obstacle is in front of the fixed-type equipment and the obstacle is on front and right sides of the turbine-type equipment. In addition, the backflow volume increases as the distance decreases.

In this study, convective heat transfer coefficients at steady state in rooms with room air conditioners were investigated using the Low－Reynolds－number k－ε model (Low Re model ). The rooms had areas of 9.72 m², 20 m², and 36 m². Small, medium, and large differences were investigated as the air conditioner controlled the air flow rate into the room. In addition, differences in cooling and heating were examined for different directions of air flow, i.e., in the supply direction, horizontal direction, 45 degree direction and right down direction. The guidelines of the database of the convective heat transfer coefficients were shown. The cooling and heating loads of the air conditioner were calculated using a thermal load calculation method when the area-weighted average convective heat transfer coefficients were applied to all surfaces and each surface for the calculation results of the Low Re model. Upon comparing the calculated cooling and heating loads of the Low Re model, the mean absolute errors were 5 % and 0.4 %, respectively. The total heat transfer coefficients during the thermal load calculation were 8 W/(m²·K), 7 W/(m²·K), 6～7 W/(m²·K) are suitable for the rooms with areas of 9.72 m², 20 m² and 36 m² , respectively when the air flow rate is medium and the supply direction is 45 degree.