Suitability of STERG’s HelioPOD for Azelio’s CSP tower technology

Azelio is developing a unique distributed solution able to provide dispatchable solar energy by concentrating solar power (CSP) technology. Azelio solution provides a relatively small, modular CSP product using a central receiver setup. There, solar irradiation is concentrated onto the receiver using a heliostat field. Heliostats are the largest capital cost driver of CSP plants and their optical performance is at the same time integral to the plant’s efficiency. Therefore, the heliostats may comply the thermal requirements at competitive cost. The objective of this work is to investigate the potential of adapting the heliostat technology developed at Solar Thermal Energy Research Group (STERG) to suit Azelio’s tower technology and needs. STERG technology raised interest due to an innovative system of six heliostats sharing a common mounting structure. Such a system is referred to as a HelioPod. A study of the optical efficiency of the heliostat fields is conducted to design four dedicated layouts able to reach Azelio heat flow rate requirements with the highest annual energy collection. The development of a performance assessment based on Monte Carlo ray-tracing model provides a high accuracy analysis and points out what is possible to achieve. AMonte Carlo raytracing model was set up to simulate the performance of the heliostat field layouts and analyze the individual heliostat and HelioPod performance. The ray-tracing model was further used to investigate the benefit of utilizing different heliostat focal length to those currently deployed on the HelioPod for the purpose of the Azelio plant. The findings showthat a small set of facet focal lengths may provide excellent heliostat imaging accuracy. Finally, a preliminary analysis of the facet surface slope error sets the boundary of the minimum acceptable requirements. This thesis suggests that, as a next step, prototype facets with shorter focal length of 15mshould be designed and manufactured