Development and evaluation of effect for reducing method of summer heat in the environment of urban and biological production

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Air temperatures in the big city such as Fukuoka and Tokyo have been raised more than 2℃ in these 100 years. These heat island phenomena are the sign of global warming at the last half of 21st century. Those are caused by the structure of city covered with concrete and asphalt and the increasing energy consumption associated with condensation of human population. The most important one is the replacement of vegetation to concrete, which brought decreasing of evapotranspiration from ground surface. The purpose of the study is to develop methods of recovering of minus condition brought by structural changes.We conducted experimental studies on the characteristics of evaporative cooling using water retentive ceramic tiles and vegetation on the roof. By the comparisons of surface temperatures between roof with iron material of warehouse and water-retentive ceramic tiles, the temperature decreased was found to be about 20℃ at noon. At this time, the evaporation rate was 0.75 mm/h.As for bio … More logical production environment, we conducted field experiment to improve summer heat in domestic animals's house. Here, we tried to ask goats their feeling about heat. The two types of roof with water retentive ceramic tiles and corrugated iron plate were set. When the sunshine was strong, three goats stayed under the ceramic roof but one goat stayed under the iron roof more than 30 minutes. This was caused by less heat radiation from ceramic roof reacting on lower surface temperature. The wet ceramic roof acts as heat radiation absorber, while the original roof does as heat radiator. Thus, wet ceramics can avoid thermal stress on domestic animal's body, human body as well.Next, we analyzed effect of greenery cover over roofs of a building to thermal environment. On the building 38000 plants are planted shaping step gradens. The surface temperature of vegetation was lower about 30℃ at the highest than that of the concrete surface. We made comparative observation about evapotranspiration using the heat balance method and water balance method. We founded most of net radiation was converted into latent heat by evapotranspiration, and the values estimated from both methods were agree with well. In this case, vegetation acts as heat radiation absorber to a human body. Less