Experimental and Numerical Investigation on Design Optimization of a Roof Skylight Combined with Solar Chimney

Abstract

The integration of roof skylight and solar chimney can provide daylight, induce ventilation, and reduce heat gain admission. This paper reports experimental and numerical investigation to determine the optimum design of a new roof configuration we introduced recently combining skylight with solar chimney (SSC). SSC is composed of a clear acrylic layer on the top, an intermediate layer composed of a set of distanced aluminium slats and a third layer composed of a combination of clear acrylic and aluminium slats. More precisely, we focus on the optimal position of the intermediate layer. Experimental investigation was conducted using two small rooms of 2.52 m 3 volume built using commercial materials. The 30 degrees south facing roof included 0.50 m × 1.50 m × 0.15 m (W × L × H) SSC unit. A 0.025 m 2 outlet opening was located at the top lateral side and another inlet opening of similar surface area was installed on the bottom lower layer inside the room for ventilation. The first room, used as a reference, included SSC with intermediate layer located at the middle between the top and lower layers. Whereas in the second room, the position of intermediate was varied to be near the top layer (second configuration) and near the lower layer (third configuration). Solidworks flow simulation software package is used to simulate the thermal performance of SSC. Field tests and numerical simulations results showed that the position of intermediate layer did not affect indoor temperature significantly as temperatures were not much different. However, lowest heat flux transmitted through SSC and lower illuminance are observed when located near the lower layer. The induced air change was relatively similar for the three positions considered. Therefore, it is recommended that for practical application, the appropriate position for SSC intermediate layer should be located between the middle and lower layer as it will lead to good ventilation rate, lower indoor temperature, and less heat gain transmission without glare.