水分気化熱を利用した屋外暑熱環境緩和技術の検討
保水性壁体による暑熱緩和効果
我が国では,夏季の気温上昇が顕著になるヒートアイランド現象が発生し,人体の健康と生態系への深刻な被害や冷房ピーク時の電力需要増加が大きな社会問題になっている｡ヒートアイランド現象の緩和対策として,都市の被覆面からの水分蒸散量を促進させる方法がある。水分蒸散における気化熱で都市の被覆面を冷却する結果, 昼間の暑熱環境が緩和され,さらに,地中への蓄熱量が減少するので夜間の暑熱環境も緩和できる｡
本研究では,屋外側の暑熱環境を緩和することを目的として,壁体内部に水平方向に埋設した管から給水して壁体を湿潤状態に保持できる保水性壁体を提案し検討を行った。本報では,保水性壁体の熱特性の実験による確認結果と,街区に適用した場合の暑熱緩和効果の解析結果について報告する。
キーワード： 水分気化熱，都市暑熱環境，保水性壁体，保水性舗装
＊１ 技術センター建築技術研究所環境研究室
＊２ 技術センター建築技術開発部建築生産技術開発室
＊３ 建築本部技術部技術計画部
Research on the Evaporative Cooling Technology of Water for the Mitigation of Hot Urban Micro-Climatic Environment
The Mitigation Effects to the Thermal Environment of Water Retentive Wall
In Japan, heat island phenomena, in which the air temperature in the central part of a city is higher than that in suburban areas, are considered as a severe social problem with concerns for human health and eco-systems and high power demand during peak periods of air-conditioning load.
As a possible generation mechanism of heat island phenomena, a decrease in vapor release from the surface soil cover may be raised. By promoting vapor release, heat of vaporization generated during vapor release will suppress surface temperature in daytime, thereby leading to climatic mitigation of hot environment during day. It is further expected to mitigate hot climate during night time by reducing heat storage under the ground.
For the purpose of mitigation effects to the hot urban micro-climatic environment, water retentive wall was proposed and this study was conducted. The condition of this wall is wet by supplying water from water pipe in this wall. This paper reports the results of experiments on heat behavior of water retentive wall and the results of analysis on mitigation effects in the city block constructed with building using this wall.
Keywords: evaporative cooling effect of water, hot urban micro-climatic environment, water retentive wall, water retentive pavement
*1 Environmental Engineering Research Section, Building Engineering Research Institute, Technology Center
*2 Construction Technology Development Section, Building Technology Development Department, Technology Center
*3 Technology Planning Section, Technology Promotion Department, Building Construction Division
