Strategies for improving the microclimate and thermal comfort of a classical Chinese garden in the hot-summer and cold-winter zone

The current study reports on strategies for improving the microclimate and thermal comfort modification effect of urban green spaces in the hot-summer and cold-winter zone. A classical Chinese garden (Lingering Garden) located south of the Yangtze River, China was selected as the study area. The microclimate parameters of the garden, including air temperature, relative humidity, and wind speed, as well as the standard effective temperature (SET*) were obtained using field-measurement-validated ENVI-met model simulations. The water bodies, trees, and buildings in the garden were redesigned by varying their coverage or density. The microclimate parameters and SET* values of the redesigned scenarios were then compared with those of the actual garden. The results indicated that the garden generally exhibited a modification effect. A number of available design strategies were proposed. The microclimate and thermal comfort of a classical Chinese garden can generally be improved by increasing the water coverage and decreasing the building coverage, as well as optimizing the tree coverage. The SET* value can be decreased by more than 1 °C on hot summer days if the water body coverage is increased from 10% to 40%; the SET* value can be reduced by approximately 0.5 °C if the tree coverage is increased from 35% to 70%, while the SET* value is approximately 0.25 °C lower for 15% tree coverage than it is for of 35% tree coverage. In addition, the difference of SET* values between the cases of 10% and 30% building coverage can reach as much as 1 °C. Therefore, various landscape elements should be comprehensively considered in order to achieve more comfortable thermal conditions.