Hot Summer Region Of China Research Articles

Prediction of the temperature profiles for shallow ground in cold region and cold winter hot summer region of China

The lacking of ground temperature measurement data has been preventing the development of underground engineering in China. Therefore, this paper proposed and validated a numerical prediction model that comprehensively considered the effects of short-wave solar radiation, long-wave radiation, latent evaporation energy, heat convection, heat conduction, soil freezing and thawing latent heat on ground temperature. Three frequently-used typical meteorological year databases were used to provide the weather parameters for the numerical model. Comparison of three city cases showed that the model using the “Chinese typical year weather” performed best in accuracy. Moreover, due to the much calculation time required for the numerical model, the two-harmonic analytical correlation (THAC) with higher accuracy than Kusada correlation and Baggs correlation was introduced to obtain ground temperature rapidly. Considering the variety of soil types, the universal correction formulas about the relationship between the THAC coefficients and the soil thermal diffusivity were developed through a series of typical city cases. Simultaneously, THACs of main cities in two climate regions corresponding to soil thermal diffusivity of 8.13*10-2 m2/day were provided as the standard THACs. The THACs of other types of soil were proved to be derived according to the universal correction formulas and the standard THACs.

Performance-driven optimization of urban open space configuration in the cold-winter and hot-summer region of China

Urbanization has led to changes in urban morphology and climate, while urban open space has become an important ecological factor for evaluating the performance of urban development. This study presents an optimization approach using computational performance simulation. With a genetic algorithm using the Grasshopper tool, this study analyzed the layout and configuration of urban open space and its impact on the urban micro-climate under summer and winter conditions. The outdoor mean Universal Thermal Climate Index (UTCI) was applied as the performance indicator for evaluating the quality of the urban micro-climate. Two cases—one testbed and one real urban block in Nanjing, China—were used to validate the computer-aided simulation process. The optimization results in the testbed showed UTCI values varied from 36.5 to 37.3 °C in summer and from −4.9 to −1.9 °C in winter. In the case of the real urban block, optimization results show, for summer, although the average UTCI value increased by 0.6 °C, the average air velocity increased by 0.2 m/s; while in winter, the average UTCI value increased by 1.7 °C and the average air velocity decreased by 0.2 m/s. These results demonstrate that the proposed computer-aided optimization process can improve the thermal comfort conditions of open space in urban blocks. Finally, this study discusses strategies and guidelines for the layout design of urban open space to improve urban environment comfort.