2018 Volume 43 Issue 250 Pages 11-19
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.
