Wind engineering analysis of parabolic trough solar collectors: The effects of varying the trough depth

Abstract

Wind affects parabolic trough solar collectors on both the structural and performance levels. With the need for higher temperatures, larger apertures of the troughs are required to increase the concentration ratio, however, this also increases the wind loads on the structure. Additionally, airflow around the receiver tube adversely affects the performance of the plant by increasing convective heat losses.This paper presents the results of research into the effects of the wind on parabolic trough solar collectors. The airflow is investigated in a parametric study aiming at a reduction of the wind loads and thermal losses in the receiver tubes to provide a basis for higher concentration ratios and thus higher efficiencies of parabolic trough power plants. Validated against experimental data from wind tunnel tests and previous studies on the wind effects on parabolic troughs, a series of three-dimensional simulations was conducted using the commercial CFD program ANSYS ® CFX 14.5. The parameter that was varied is the depth of the trough, i.e. the focal length of the paraboloid. Simulations were performed over a large range of pitch angles for three different trough geometries as periodic simulations of an individual trough, representing a single collector row. Time-averaged data on aerodynamic loads and heat transfer are presented.While a deep trough leads to higher forces than a shallow trough, when facing the wind, due to increased curvature, the wind speed around the receiver is significantly lower with a lower focal length, which can minimise the heat loss in the receiver tube leading to overall higher efficiencies due to higher possible temperatures in the solar field.