Experimental validation of a prototype compound parabolic concentrator as a viable façade-mounted daylighting system

While compound parabolic concentrators (CPCs) have been widely explored for solar concentration in photovoltaic applications, their potential for daylighting is still not fully explored. Their capacity to redirect sunlight and integration with light transport systems are fundamental to their role in daylighting systems. They can be deployed as façade-mounted devices to enable deep daylight penetration into buildings, as they capture both direct and diffuse light. This is useful as diffuse light is pronounced under overcast sky conditions, common in northern latitude climates such as in Ireland. With the installation of CPC at the façade, the brightness near the window can be lower while increasing the brightness at the end of the room, resulting in a more uniformly-distributed brightness for all unshaded rooms. This project aims to experimentally test and evaluate the efficiency of CPCs in collecting and concentrating the light for daylighting purposes. The simulation-optimised configuration of a small-scale reflector CPC and a dielectric CPC was manufactured to validate the simulation results. Initial results of the prototype dielectric CPC system have shown that the light intensity at the end of the channel is more than the required 5% daylight factor recommended for indoor spaces. This shows that despite the losses, sufficiently bright light can be provided deep into the room through a CPC daylighting system. This study aims to present the experimental results and explore the viability and limitations of a CPC daylighting system.