Study on actual environmental conscious and healthy houses fit for climate and living environment in subtropical Okinawa

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This study consists of 6 topics, and they were carried out in this three years. The first topic is about historical changes of thermal environment in dwelling houses in subtropical Okinawa. Representative 6 houses from traditional wooden structure to advanced passive cooling system were selected to measure the indoor climate or to analyze measured data to consider the change of the indoor thermal conditions. The second topic is solar protection and heat insulation on rooftop that is a largest cooling load part in low latitude zone. 6 materials that include rooftop garden, ceramic tiles and heat insulation paint for RC slab and galvanized iron sheet roof were set on a real rooftop and measured their thermal performances. Thermal performance of rooftop garden is best and followed by ceramic tiles. Solar protection by the paint is also confirmed. The third topic is about thermal performance of finish mortars on the outside of walls that are made from local materials originate in Okinawa. … More 3 types of the finish mortars were plastered on the west and the north wall of an RC small model house. The results show that they can work as outside insulation though they were just plastered. The latter 3 topics are about outdoor environment surrounding houses. The fourth topic is thermal characteristics of a traditional stone pavement. Old lanes paved by natural limestone are left in Shuri-Kinjo area and one of the lanes is selected as a traditional pavement. Comparative measurement of thermal environments on the stone pavement and on asphalt pavement near the stone pavement was conducted. Surface temperature on the stone pavement is lower than that on the asphalt pavement not only in the daytime but in the nighttime. The fifth topic is about traditional arboreal hedges surrounding houses. Fukugi (Garcinia subelliptina) is a representative tree for the hedge against salty wind in Okinawa. Detailed survey on the old Fukugi hedges were done in Bise area of Motobu town. The survey included the present conditions of old Fukugi hedges and historical changes of them. The residents have an opinion that effects of Fukugi hedges on living environment are good, however when the houses changed from wooden material to RC structure, the Fukugi hedges were cut down and reducing now. The last topic is thermal performance of trees, especially roads de trees. The differences of thermal performance between 8 species of trees were measured in the campus of University of the Ryukyus. The density of leaves have major effect on the temperature in the tree crown. Shading effect by tree crown was quantified by the shape factor in the sky. Less