Experimental study of a linear Fresnel concentrator: A new procedure for optical and heat losses characterization

This paper describes a set of iterative procedures developed in Matlab and Engineering Equation Solver, used to experimentally obtain the optical and heat loss characterization of a small-scale linear Fresnel concentrator. These procedures were created for a prototype designed and built for direct steam generation by the LEPTEN laboratory, at the Federal University of Santa Catarina. Two different sets of experimental data were considered. First, the heat transfer fluid was at the lowest temperature achievable using the experimental setup available and was used to obtain the optical peak efficiency and the incidence angle modifier. The second set, with wider range of fluid temperatures, was used to find the heat losses. Applying the procedures developed, convergence was obtained. The optical peak efficiency ranged from 47 to 52%. Monte Carlo Ray-Tracing software was used to obtain the incidence angle modifier, and these curves were compared with experimental ones. The heat loss curve was constructed for fluid temperatures up to 130 °C. These iterative procedures can be adapted to determine the heat loss and optical efficiency in any linear Fresnel solar concentrator if adequate experimental data is available. Each software used had its role, and the use of both allowed creating a fast easy-to-converge methodology.