Lara-Cerecedo L.O., Moreno-Cruz I., Pitalúa-Diaz, N., Arancibia-Bulnes, C.A.

Abstract

A novel modeling tool for calculation of central receiver concentrated flux distributions is presented, which takes into account drift effects. This tool is based on a drift model that includes different geometrical error sources in a rigorous manner and on a simple analytic approximation for the individual flux distribution of a heliostat. The model is applied to a group of heliostats of a real field to obtain the resulting flux distribution and its variation along the day. The distributions differ strongly from those obtained assuming the ideal case without drift or a case with a Gaussian tracking error function. The time evolution of peak flux is also calculated to demonstrate the capabilities of the model. The evolution of this parameter also shows strong differences in comparison to the case without drift

Modeling of Drift Effects on Solar Tower Concentrated Flux Distributions

Publicado en Revistas Arbitradas

Valades-Pelayo P.J., Romero-Paredes H., Arancibia-Bulnes C.A., Villafán-Vidales H.I.

Abstract

In the present study, the optimization of a multi-tubular solar thermochemical cavity reactor is carried out. The reactor consists of a cubic cavity made of woven graphite, housing nine 2.54 cm diameter tungsten tubes. A heat transfer model is developed and implemented considering high-temperature radiative transfer at steady state. The temperature distribution on the receiver tubes is determined by using a hybrid Monte Carlo-finite volume approach. The optimization aims at maximizing average tube temperature by varying tube locations. Optimal tube distributions are explored by using a custom-made stochastic, multi-parameter, global optimization algorithm. A considerable increase in average temperature as well as improvement on temperature uniformity is found in the optimized tube arrays. Patterns among the different optimal distributions are found, and general features are discussed

Geometric optimization of a solar cubic-cavity multi-tubular thermochemical reactor using a Monte Carlo-finite element radiative transfer model

Publicado en Revistas Arbitradas

Ricardo Pérez-Enciso, Alessandro Gallo, David Riveros-Rosas, Edward Fuentealba-Vidal, Carlos Pérez-Rábago

Abstract

A method to achieve a uniform flux distribution with a multi-faceted point focus concentrator for laboratory tests is proposed in this work. The method can be applied to different types of receiver - thermal or photovoltaic - and no additional device is required to homogenize the flux. The technique consists in moving the receiver from the focal plane and enlarging the solar spot impinging on it. At the same time, each mirror aim-point is adjusted in order to superimpose the images that have been generated by every facet. To evaluate the method, a real multi-faceted concentrator composed of eighteen spherical mirrors was modeled in a ray-tracing software. The procedure was validated through the comparison of an image of the real solar spot on the receiver generated by three mirrors, and the simulated flux obtained the same way. This way a mean concentrator global optical error of 2.8 mrad was estimated. This value was used then for further analyses. Results show that the concentration factor can be varied in a range of 150–900 suns over a receiver diameter of up to 7 cm. Hence, according to the receiver requirements, it is possible to expand the distribution and to alter the intensity of the flux. Finally, optical parametrical analyses were carried out, from which it is inferred that good quality optics give rise to a more homogeneous solar flux on the receiver.

A simple method to achieve a uniform flux distribution in a multi-faceted point focus concentrator

Publicado en Revistas Arbitradas

Videos HoSIER

Entrevista HoSIER Factor Ciencia Canal Once (14/12/2015)