Thermal Environment Design of Outdoor Spaces by Examining Redevelopment Buildings Opposite Central Osaka Station

Abstract

Thermal environmental design in an outdoor space is discussed by focusing on the proper selection and arrangement of buildings, trees, and covering materials via the examination of redevelopment buildings in front of Central Osaka Station, where several heat island countermeasure technologies have been introduced. Surface temperatures on the ground and wall were calculated based on the surface heat budget equation in each 2 m size mesh of the ground and building wall surface. Incident solar radiation was calculated using ArcGIS and building shape data. Mean radiant temperature (MRT) of the human body was calculated using these results. Distribution of wind velocity was calculated by computational fluid dynamics (CFD) reproducing buildings, obstacles, trees, and the surroundings. The effect of MRT on SET* was greater than that of wind velocity at 13:00 and 17:00 on a typical summer day. SET* reduction was the highest by solar radiation shading, followed by surface material change and ventilation. The largest ratio of the area considered for the thermal environment was 83% on Green Garden, which consists of 44% of building shade, 21% of tree shade, 7% of water surface, and 11% of green cover. It is appropriate to consider the thermal environment design of outdoor space in the order of shade by buildings, shading by trees, and improvement of surface materials.

Thermal Environment Map in Street Canyon for Implementing Extreme High Temperature Measures

“…Since the urban blocks were not configured with surface materials with high reflectivity, the error due to this was considered to be small. Surface temperature was calculated on each ground and wall surface by the surface heat budget equation which balances radiation, convection, evaporation, and conduction heat flux, by given the physical properties of each surface [16]. Radiation heat flux was calculated by incident solar radiation and mutual infrared radiation by using building shape data.…”

“…Convection and evaporation heat flux were calculated by air temperature, relative humidity, wind velocity, and surface temperature on each ground and wall surface, by using the heat and moisture transfer coefficients between the air and each surface. Conduction heat flux was calculated by the one-dimensional transient heat conduction equation with internal temperature as boundary condition on each surface material [16]. Since long-term calculations were not carried out, the effect of the stored heat of solar radiation in the morning on the surface temperature from afternoon to evening was considered, but the effect of the previous day's effect on the surface temperature in the morning was not considered.…”

The Impact of Street Trees on a Typical Urban Canyon in Eastern Cairo Region

“…4&5. This ,in turn, led to a variation of wall temperature of the façade [25], [26]. For example, the edge evergreen arrangement on the SW façade lowered SW radiation by 85 w/m 2 and wall temperature by 6°C when compared to the no vegetation scenario midday.…”

Introducing the Built Environment in a Changing Climate: Interactions, Challenges, and Perspectives

“…It requires a comfort-oriented selection and allocation of built elements (e.g., buildings, pavements, roads), vegetated areas (e.g., parks, tree-lined avenues, gardens, green roofs), and water features (e.g., fountains, pools, sprinklers, ponds). In [20], a redevelopment plan for Central Osaka Station is proposed by combining different heat island countermeasures and by applying computational fluid dynamics, surface heat budget equation, and GIS to track wind distribution, surface temperatures, and mean radiant temperatures. The results are compared in terms of standard new effective temperature (SET*) on a typical summer day.…”