半地下試験家屋における透過日射を阻止した状態での熱環境性能に関する長期実測

Abstract

In order to obtain the fundamental data on the thermal performance of semi-underground house, a twin-type test house was constructed in the campus of Tohoku University in September 1984. The test house has two rooms with the southfacing windows above the grade and the corridor situated between two rooms. The floor plan is the same as that of the passive solar test house already constructed in 1981. The floor level is 1.3 meter below the ground surface. The insulation of 0.1 meter depth and 1.35 meter width horizontally installed at the level of 0.3 meter below the ground surface surrounding the room on the east designated Room D. This insulation is called the Horizontal Insulation. The room on the west designated Room C has not such insulation. Total heat transmission factor of the construction above the grade is about 1 kcal/h℃ per floor area. The equivalent leakage areas per floor area for ΔP=1.0mmAq of Rooms C and D are 1.86 and 1.45cm^2/m^2, respectively. Both of the two rooms were remarkably airtight, compared to other recently constructed detached houses in Japan. Before the long-term field measurement, the profiles of two room temperatures and isotherms of soil surrounding the construction below the ground surface were estimated by computer simulation using two-dimensional finite element method, in order to investigate the effect of falling in of ground surface from the point of 4 meters apart from the east side of Room D. Calculations were made hourly for a year under the standard Sendai climate conditions. As calculated results, it was estimated that falling in of ground surface has little effect on room temperatures. All windows were insulated with weather shutters to avoid disturbing the heat gain due to solar radiation since October 1984. The outdoor air temperature, room temperatures, soil temperatures surrounding the construction, etc. were measured from 2 December 1984 to 8 October 1985. The results of the long-term field measurement are shown as follows : (1) The amplitude of yearly fluctuation of room temperature is half that of outdoor air temperature. Room D installed with the Horizontal Insulation is warmer in winter and cooler in summer than Room C. The difference of temperatures between Rooms C and D is less than 1.6℃ at the maximum, appearing in February. (2) The amplitude of daily fluctuation of outdoor air temperature is about 15℃. But that of room temperatures is less than 2℃. (3) The isotherms in the soil covered with the Horizontal Insulation at the level of 0.3 meter below the ground surface is very different from that without such insulation. Generally, the temperature of soil covered with the insulation is higher in winter and lower in summer.