As the artificial environment, the cities are on the opposite side of the nature. Air temperatures in the big city such as Fukuoka and Tokyo have been raised about 2ィイD1゜ィエD1cC in these 100 years. This is the sign of global warming at the last half of 21 century. Those were caused by the increasing energy consumption associated with condensation of human population and the structure of city covered with concrete and asphalt. The later is the replacement of vegetation to concrete, which brought decreasing of evaportranspiration.
The purpose of the study is to develop the methods of recovering of minus condition brought by structural changes. I conducted experimental study on the characteristics of ability evaporative cooling using water retentive ceramic tile.
The comparisons of surface temperatures among water-retentive ceramic tiles rice plants and the original concrete roof surface were examined on fare summer days. Here, the ceramic tiles were laid horizontally and vertically on the r
oof of 6 storied building. The temperature difference between those wet ceramics and the original concrete roof surface were about 20ィイD1゜ィエD1cC at noon. Temperatures of wet ceramics and rice plants were nearly equal each other, but their daily time course changed slightly depending on the time, if it was fare, or the amount of solar radiation. Heat balance and radiation balance was analyzed. The wet ceramics could consume most of net radiation by changing into latent heat.
Next, I discussed on the folding type of ceramic roof of warehouse, which can extend surface evaporative area comparing with flat type roof. The surface temperatures outer side and inner side were much decreased than the original steel roof, and direction of heat radiation from human body inside the room was reversed at noon. The inner thermal pollution was greatly improved.
At the same time, the amount of evaporation of flat and slopes facing south and north are 0.86, 0.74 and 0.46 mm/h respectively. Those values are easily converted into latent heat energy.
From the points of the characteristics of heat radiation, wet ceramic roof acts as heat radiation absorber, while the original roof does as heat radiator. Thus, wet ceramics can avoid thermal stress on human body. As the effect of decreasing temperature of flat ceramics is enough, so the folding type is not always needed for open wide area. We can achieve a lot of decreasing of thermal pollution in urban area, if we can apply this method to the city. Less