Optical performance of solar power towers with conical secondary concentrators

Solar power towers are a type of concentrating solar power system that enable temperatures of over 1500° C, allowing high efficiency electrical conversion and the creation of solar fuels which can replace CO2 emitting resources such as oil. Efficient operation of solar towers is achieved through solar concentration in the form of heliostats and conical secondary concentrators. A multi-focus field is proposed allowing for a single tower to have three separate cavity receivers each with its own accompanying polar field of heliostats. Multi-focus fields proved to have comparable power and efficiency levels to single tower north facing fields and were more resilient to slope error. Conical secondary concentrators are a viable alternative to compound parabolic concentrators and have more variability in both concentration ratio as well as acceptance angle. A design map is presented to allow for cones to match either the optical efficiency or concentration ratio of CPCs.