Visual performance of building with dielectric crossed compound parabolic concentrator (dCCPC) panel as skylights

The benefits of daylighting on visual comfort, human health and energy saving have been discussed for decades. With the rising of energy problems, daylighting becomes a significant part in new building design for the purpose of sustainability. The compound parabolic concentrator (CPC) belonging to nonimaging optics is regarded as a highly potential and appealing option for solar energy concentration and illumination. It has been mainly and widely applied in solar energy like photovoltaic (PV) and solar thermal system as a significant component. CPC has been used for concentration application in the past, however its potential in daylighting was discovered in recent years. This paper investigated the indoor visual environment of example buildings utilizing dCCPC as skylights. The indoor illuminance distribution of using dCCPC, double glazing and other diffuse panels are compared first. Then the effects on indoor illuminance distribution of different roof types mounting skylights are discussed. Finally the glare analysis are provided by high dynamic range images (HDRIs) that compares the indoor visual environment of using dCCPC as skylights with double glazing and low-E glazing. Results show that dCCPC provides effective control on strong direct sunlight and the lowest values of daylight glare probability (DGP). It also make the light distributed more uniformly owing to its significant diffusing effect.