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Abstract:The outdoor open space is used for various purposes, e.g., to walk, rest, talk, meet, study, exercise, play, perform, eat, and drink. Therefore, it is desirable to provide various thermal environments according to users' needs and their actual conditions. In this study, the radiation environment was evaluated, focusing on ground cover materials and solar radiation shading, through the examination on the redevelopment buildings in front of Central Osaka Station. The spatial distribution of solar radiation shading was calculated using ArcGIS and building shape data. Surface temperatures on the ground and wall are calculated based on the surface heat budget equation. MRT (Mean Radiant Temperature) of the human body is calculated assuming that the human body is a sphere. The most dominant factor for the radiant environment is solar radiation shielding and the next is the improvement of surface cover. It is difficult to make SET* (Standard new Effective Temperature) comfortable in the afternoon by both solar radiation shielding and improved surface cover because the air temperature is too high on a typical summer day (August). However, particularly in Rooftop Gardens and Green Garden, because the areas of shade grass and water are large, there are several places where people do not feel uncomfortable.

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The effect of upward reflective film applied to a window on the thermal environment inside and outside the window was investigated, considering the reflection and transmission characteristics depending on the angle of incident solar radiation. In terms of controlling the amount of solar radiation on a building’s windows, it is sufficient if the reflected solar radiation returns upward and does not need to be retroreflected in the azimuthal direction. Therefore, in this study, only the incident angle was considered and treated in two dimensions. The amount of incident solar radiation on the vertical façade is greater around 9:00 and around 16:00. Therefore, it is important to take measures in the morning for east-facing windows and in the afternoon for west-facing windows. The indoor MRT in front of upward reflective film is lower than in front of a transparent window due to lower transmittance. The outdoor MRT in front of upward reflective film is suppressed to the same level as in front of a transparent window, because the downward reflectance does not increase as much as in transparent windows. Upward reflective films applied to windows can improve the indoor thermal environment without worsening the outdoor thermal environment compared to thermal barrier films.

Mist spraying is a technique for locally lowering air temperature by spraying fine mist into the air and using the latent heat of evaporation immediately after spraying. This study focuses on the conditions under which mist spraying contributes to the increase in sensible heat release from the human body, using the ratio of air temperature decrease and humidity increase in the space where mist is sprayed. From the measurement results in front of the air-conditioning condenser unit, humidity increased by about 10 g/kg(DA), while air temperature decreased by about 10 °C. From the measurement results in an open space in a park, air temperature decreased by about 0.5 to 1 °C within 2 m of the mist spray and humidity increased by about 0.5 to 1 g/kg(DA) at the height of the mist spray, regardless of the distance from the mist spray. From the measurement results at semi-open bus stops, air temperature decreased slightly to 1 °C and humidity increased slightly to 1 g/kg(DA) under low-wind conditions. Unfortunately, the measured results of air temperature decrease in relation to humidity increase, which the human body perceives as cooler, were not available.