Thermal and ventilation performance of a curved double-skin facade model

Curved architectural forms are becoming popular in modern building designs, resulting in more demanding requirements of curved double-skin façades (CDSF). However, CDSF’s natural ventilation performance is barely known, as most current studies investigate planar DSF (PDSF). This paper experimentally evaluated the thermal performance of a reduced scale CDSF model. Experimental results show that CDSF can form natural ventilation by buoyancy, however, with significant discrepancies in the distribution of solar irradiances on the curved surface. Observed nonuniformity shows 30.05 % on average vertically and 9.12 % on average horizontally. The thermal pressures vary at different horizontal positions with a fluctuation range between 0.056 Pa and 0.063 Pa, indicating the influence of gradients and the existence of transverse flows and heat transfers in the cavity. Moreover, the effects of solar irradiation and outdoor air temperature on the CDSF are discussed. The results show that solar irradiation is the main influencing factor on the thermal performance of a CDSF, which are correlated with air velocities in the form of power functions. The influence of solar irradiation on CDSF is similar to that of PDSFs, but CDSF exhibits a bigger exponent. In comparison, outdoor air temperature shows very limited effects, and the influence of outdoor air temperature on CDSF is similar to that of PDSF. For the analyzed CDSF, the thermal pressures only fluctuate from 0.053 Pa to 0.055 Pa when the outdoor air temperature raises from 24 °C to 36 °C.