Evaluation and optimisation of the optical performance of low-concentrating dielectric compound parabolic concentrator using ray-tracing methods

We present a detailed design concept and optical performance evaluation of stationary dielectric asym- metric compound parabolic concentrators (DiACPCs) using ray-tracing methods. Three DiACPC designs, DiACPC-55, DiACPC-66, and DiACPC-77, of acceptance half-angles (0° and 55°), (0° and 66°), and (0° and 77°), respectively, are designed in order to optimize the concentrator for building façade photovoltaic applications in northern latitudes (>55°N). The dielectric concentrator profiles have been realized via truncation of the complete compound parabolic concentrator profiles to achieve a geometric concen- tration ratio of 2.82. Ray-tracing simulation results show that all rays entering the designed concentra- tors within the acceptance half-angle range can be collected without escaping from the parabolic sides and aperture. The maximum optical efficiency of the designed concentrators is found to be 83%, which tends to decrease with the increase in incidence angle. The intensity is found to be distributed at the receiver (solar cell) area in an inhomogeneous pattern for a wide range of incident angles of direct solar irradiance with high-intensity peaks at certain points of the receiver. However, peaks become more intense for the irradiation incident close to the extreme acceptance angles, shifting the peaks to the edge of the receiver. Energy flux distribution at the receiver for diffuse radiation is found to be homogeneous within 12% with an average intensity of 520W=m2.