Design and optimization of a small scale portable solar tower with different configurations

• The design, analysis and optimization of a small solar concentrator is presented. • The concentrator uses a compact heliostat field of 2 m × 5 m in size, allowing it to be towed on public roads in a utility trailer to off-grid rural areas or places affected by natural disasters. • The optical efficiency of the concentrator is studied by considering blocking, shadowing, and cosine efficiency for a target geographical location in southern Peru. • The estimated hourly efficiency variation as well as reflected power output for the proposed concentrator are presented. • Different parabolic side profiles of the heliostat are compared against the conventional flat arrangement. This paper presents the design and modeling of a small and mobile solar concentrator. The concentrator uses a compact heliostat field of 2 m × 5 m in size, allowing it to be towed on public roads in a utility trailer to off-grid rural areas or places affected by natural disasters. The concentrator consists of a receiver and a field of reflective heliostats uniformly spaced in a rectangular grid. Parabolic and flat side profiles of the heliostat field are analyzed, and their performance is compared in this work. A computer algorithm was developed to place each heliostat to optimize their quantity for a given area. The cosine efficiency of every heliostat was calculated by taking into account the relative position between each heliostat and the receiver as well as the solar angle for every hour. A similar analysis was done for the attenuation factor, the shadowing factor and the blocking factor between heliostats. A concept from computational geometry was adapted to compute these factors. Furthermore, an algorithm capable of computing multiple instances of blocking or shadowing on a heliostat was developed and implemented. Heat maps of the shadowing factor and the cosine efficiency are presented for parabolic and flat side profiles of the heliostat field. The mean field efficiency of the solar concentrator for each side profile is also compared. It was found that the mean field efficiency of the different profiles is very similar. However, the flat profile shows slightly better performance. In our calculations and simulations, we have considered the mountainous region of Arequipa in southern Peru as the target geographical area. However, our analysis is applicable to other regions provided that hourly solar radiation data is available for that region.