The effects of ground cover and shading on an outdoor thermal environment in an apartment complex

A comfortable outdoor environment can be achieved through well-designed physical planning, which includes the layouts of buildings, covering materials, grass, trees, water areas, etc. In this study, the outdoor environments of an apartment complex were measured quantitatively. The paving, grass and water areas were chosen to analyse the effects of ground cover on the outdoor environment. An unsteady-state computational fluid dynamics (CFD) simulation was also conducted with the same conditions as the measurement. In order to obtain the reliability and limitation of the simulation, the results of the measurement and the simulation were compared. The effects of changing the green area, including the grass and the trees, to 15% and 50% were analysed by the simulation method. Depending on the ground cover, the air temperature slightly changed. However, the mean radiant temperature (MRT) of the grass area was lower than that of other areas. Especially the shaded area showed a very low MRT and thus thermal comfort was improved. Because over 75% of MRT was produced by long wave radiation, increasing the green area and reducing surface temperature were reasonable methods to improve the outdoor thermal environment.