Mathematical modeling of a prototype of parabolic trough solar collector

In this paper, a mathematical model of a parabolic trough collector (PTC) is described in detail and tested by comparing the efficiency predicted by the model with the efficiency measured through outdoor tests on a PTC prototype. The model accounts for optical and thermal losses, thus allowing the calculation of optical, thermal, and global efficiencies, and of all working parameters such as temperatures or heat fluxes on all parts of the receiver. The model is presented in detail and its implementation in a specific ambient for technical computation is also described. The application of the model to a specific prototype of parabolic trough collector is described: this prototype has been developed and tested at Universita Politecnica delle Marche and is intended for industrial process heat production. The comparison between experimental and calculated results shows an average error of about 3.82% and a maximum error of 14% on global efficiencies for tests with water in the temperature range 25–75 °C.

[1]  Richard Bannerot,et al.  Determination of error tolerances for the optical design of parabolic troughs for developing countries , 1986 .

[2]  Soteris A. Kalogirou,et al.  Solar thermal collectors and applications , 2004 .

[3]  Stuart W. Churchill,et al.  Correlating equations for laminar and turbulent free convection from a horizontal cylinder , 1975 .

[4]  T. Sornakumar,et al.  Design, manufacture and testing of fiberglass reinforced parabola trough for parabolic trough solar collectors , 2007 .

[5]  Sheldon M. Jeter,et al.  Geometrical effects on the performance of trough collectors , 1983 .

[6]  Eduardo Zarza,et al.  Parabolic-trough solar collectors and their applications , 2010 .

[7]  K.G.T. Hollands,et al.  A General Method of Obtaining Approximate Solutions to Laminar and Turbulent Free Convection Problems , 1975 .

[8]  Halil M. Guven,et al.  Parabolic trough concentrators—design, construction and evaluation , 1993 .

[9]  Sheldon M. Jeter,et al.  Calculation of the concentrated flux density distribution in parabolic trough collectors by a semifinite formulation , 1986 .

[10]  M. Behnia,et al.  Modelling of Parabolic Trough Direct Steam Generation Solar Collectors , 1998, Renewable Energy.

[11]  A. C. Ratzel,et al.  Techniques for reducing thermal conduction and natural convection heat losses in annular receiver geometries , 1979 .

[12]  S. Klein.  Calculation of Flat-Plate Collector Loss Coefficients , 1975, Renewable Energy.

[13]  S. Churchill,et al.  A Correlating Equation for Forced Convection From Gases and Liquids to a Circular Cylinder in Crossflow , 1977 .

[14]  J. Michalsky.  The Astronomical Almanac's algorithm for approximate solar position (1950 - 2050). , 1988 .

[15]  Polyvios Eleftheriou,et al.  Design and performance characteristics of a parabolic-trough solar-collector system , 1994 .

[16]  Soteris A. Kalogirou,et al.  The potential of solar industrial process heat applications , 2003 .