Experimental and theoretical analysis on thermal performance of solar thermal curtain wall in building envelope

The need for energy efficient building design has stimulated the integrating buildings with energy systems. In this paper, a novel solar thermal curtain wall (STCW), which is the solar collector installed as a building envelope or integrated to normal facades, is developed. A stand-alone house with the STCW was constructed and thermal performance of the STCW was tested and theoretically analyzed. The results showed that the STCW combined energy production for hot water supply with other functional features of architectural, structural and aesthetic as a new kind of building component. In typical summer day and winter day, the efficiency of the STCW system were 56.8% and 41.0%, respectively. The heat transfer coefficient of the STCW varied monthly, with the maximum value recorded being 1.99 W m−2 K−1 in August and the minimum value recorded being 0.86 W m−2 K−1 in January. A sensitivity analysis was made to investigate variations on the heat transmission load of the solar curtain wall. The results show that the transmission heating load can be reduced by about 39% when the insulation is increased from 25 mm to 50 mm. A comparison between the solar collector integrated with traditional wall and solar curtain wall only was made. Integrated solar collector to wall provides more damping of load fluctuation and smaller peak load, compared with traditional walls, the heating load of façade-integrated walls are less and the walls even contribute heating for the building. Though the cooling load was increased, the comprehensive performance for the façade-integrate walls are superior to the traditional walls.