抄録
This paper reports the experimental results of the performance evaluation of direct gain systems using a twintype passive solar test house. Bricks were used as thermal storage material. For purpose of our investigation, one test room having a brick floor with the depth of 30 cm was used for a reference, while the other for various types of direct gain systems. After the measurement of the temperatures at various points and the amount of solar radiation over a period of two to three weeks, the effects of the depth of bricks, the surface area of bricks in contact with room air, the carpet covering the brick floor, etc., on the room temperature profiles was evaluated by examining the two factors, "difference in daily mean temperature between inside and outside" and "difference between the maximum and minimum temperatures". The results were obtained as follows : (1) The room temperature fluctuation decreases with an increase in brick surface in contact with the room air. When the room has both a brick floor and brick walls 20 cm in depth, the temperature fluctuation decreases by 20 %. In such cases, the heat capacity equals that of the reference room with a 30 cm deep brick floor, and the brick surface area is 1. 5 times larger than that of the reference room. (2) An increase in the amount of thermal storage material is effective in decreasing the room temperature fluctuation. But when the depth of the brick floor is over 20 cm, the heat storage capacity of the portion over 20 cm under the floor surface has no significant effect on the room air temperature fluctuation. Therefore, it is more effective to increase the brick surface area and to decrease the depth of the bricks rather than to increase the depth of bricks. (3) The ratio of the air temperature fluctuation of a room having a brick floor covered with a carpet to that of a room without carpet turned out to be 1.3 to 1.4, because the absorption of solar heat and its release are restrained by the carpet. (4) When a room is equipped with brick floor and brick walls, the volume of which is 1.5 times greater than that of reference room and has an insulated weather shutters used at night as well as windows with triple glazings, the maximum air temperature is 23℃ during the daytime, and the minimum air temperature is 13℃ at day-break. It can be said that auxiliary heating is unnecessary in actual dwellings equipped with the same level of insulation and thermal storage as found in this type under the climatic conditions of Sendai.
