Field study of performance of solar chimney with air-conditioned building

Abstract

The study examines the performance of a solar chimney (SC) within an air-conditioned building. To this end, a single-room house of 25 m 3 volume was used. Two configurations of SC were used: the roof solar collector (RSC) composed of CPAC monier concrete tile, 14 cm air gap and gypsum board, and the modified trombe wall (MTW) composed of a masonry wall, 14 cm air gap and gypsum board. To control the induced air flow rate, as excess incoming hot ambient air will increase air-conditioner (AC) load, the size of the SC inlet opening was used as a means of ventilation control and three opening sizes were considered per each SC configuration. Experiments were performed throughout a period of six months (March–September). A split type AC of 1 t nominal capacity was installed. Comparisons between a common house and a solar chimney house (SCH) conducted using days with relatively similar ambient conditions demonstrated that a SCH could reduce the average daily electrical consumption of an AC by 10–20%, the ventilation fan saving must also be added. The appropriate size of inlet openings of a SC is 5×5 cm 2, which induces about 3–8 m 3/h/SC unit. The SC is very efficient for decreasing the AC load, namely when the AC is turned on at the beginning of afternoon (1 p.m.) as no heat is stored inside the room. In this operating mode the saving is much higher, about 30%. Consequently, the SCH is highly suitable for a hot climate as it could be used for both an AC and a non-AC building. The design recommendations formulated here could be used to conduct a realistic design depending on the requirements of the house’s owner.