Study on appropriate heat mitigation technologies for urban block redevelopment based on demonstration experiments in Kobe city

Abstract

In order to promote the redevelopment of cities in consideration of measures against extreme heat, the effectiveness of various heat mitigation technologies introduced by Kobe City was evaluated. We introduced each technology for heat countermeasures to the central part of Kobe city, clarified their effects by measurement, and discussed issues and evaluations for the implementation. Watering on road, sunshade with mist spray, water surface, watering on pavement, and mist spray in a park were introduced, and their effects were evaluated using the thermal environment index SET* based on the measurement results. Since it is necessary to compare and evaluate multiple technologies, the thermal environment index of the human body was adopted as a common index. The reduction in surface temperature, MRT and SET* by watering on the roadway were about 10 °C, 1.9 °C and 0.8 °C, respectively, and the effects lasted for at least 30 min. SET* was greatly decreased when the upper fractal sunshade blocked solar radiation to the central measurement point under the sunshade. The reduction of MRT and SET* on the watered on the pavement were larger than that on the water surface because the watered area was larger than the water surface area. MRT reduction due to wetting of the globe ball sensor by the mist spray had a greater effect on SET* reduction than air temperature reduction due to evaporation of the mist.