Review of software for optical analyzing and optimizing heliostat fields

Solar Central Receiver power facilities are complex industrial systems which require a very important initial investment. The heliostat field is a key factor for both the initial deployment costs and for taking the maximum benefit from the incoming solar energy. Consequently, numerous software packages have been developed through the years to help designers in the designing process of this kind of facilities. In this context, software packages are commonly divided into two main categories: (i) tools prepared for precise and deep optical performance analyses of given fields and, (ii) tools focused on proposing optimal heliostat field layouts according to particular requirements. Although there is a traditional and stable kernel of modeling tools dating from late seventies and eighties, this is an active field under continuous development. In this work, a review of existing software tools from this sector is done, ranging from the original ones (DELSOL, HFLCAL, etc), to some modern and powerful utilities (Tonatiuh, HOps, NSPOC etc). Additionally, some interesting ideas and algorithms are also commented as promising experimental tools and proofs of concept. The review shows the existence of mature and accessible tools for detailed optical analyses and a certain lack of modern open tools for field optimization.