Design, manufacture and testing of fiberglass reinforced parabola trough for parabolic trough solar collectors A. Valan Arasu * , T. Sornakumar Department of Mechanical Engineering, Thiagarajar College of Engineering, Madurai 625 015, Tamilnadu, India Received 8 February 2006; received in revised form 26 December 2006; accepted 2 January 2007 Available online 14 February 2007 Communicated by: Associate Editor Brian Norton Abstract The design and manufacture of a smooth 90° rim angle fiberglass reinforced parabolic trough for parabolic trough solar collector hot water generation system by hand lay up method is described in this paper. The total thickness of the parabolic trough is 7 mm. The con- cave surface where the reflector is fixed is manufactured to a high degree of surface finish. The fiberglass reinforced parabolic trough was tested under a load corresponding to the force applied by a blowing wind with 34 m/s. Distortion of the parabola due to wind loading was found to be within acceptable limits. The thermal performance of the newly developed fiberglass reinforced parabolic collector was determined according to ASHRAE Standard 93 [ASHRAE Standard 93, 1986. Method of testing to determine the thermal performance of solar collectors. American Society of Heating, Refrigerating and Air-Conditioning Engineers, Atlanta, GA]. The standard deviation of the distribution of the parabolic surface errors is estimated as 0.0066 rad from the collector performance test according to ASHRAE Standard 93 (1986), which indicates the high accuracy of the parabolic surface. Ó 2007 Elsevier Ltd. All rights reserved. Keywords: Parabolic trough collector; Fiberglass reinforced parabolic trough; Parabolic surface error; Wind load test; Wooden mould; Wind force 1. Introduction Among the family of solar collectors, parabolic trough collector (PTC) is currently receiving considerable atten- tion for a wide range of applications from domestic hot water production (Kalogirou and Lloyd, 1992; Kruger et al., 2000) to steam generation for power (Lippke, 1996; Thomas, 1996) and industrial process heat generation (May and Murphy, 1983; Kalogirou, 2002). The recom- mendation of Bird and Drost (1982) is that the PTC con- cept should receive the highest priority for commercial development for low temperature (65–177 °C) solar process heat applications. The high degree of concentration attain- able with parabolic trough collector offsets the disadvan- tage associated with the requirement of some level of tracking as compared to flat plate collectors. Also, para- bolic trough collectors are structurally simpler than other collectors. One of the important factors that affect the per- formance of a PTC is the accuracy of the parabolic surface. The parabolic structure must be accurate to ensure good efficiency. Concentrator contour-error reduction is impor- tant if higher operating temperatures are to be efficiently attained. The increase in performance that occurs with a concentrator contour error reduction from 6 mrad to 3 mrad outweighs the economic penalty that occurs if the cost of the concentrator is doubled for troughs with concentration ratios of 25 or higher (Gee and Murphy, 1983). Some of the factors to be considered in designing the parabolic structure are that it should not distort significantly due to its own weight and that it should be 0038-092X/$ - see front matter Ó 2007 Elsevier Ltd. All rights reserved. doi:10.1016/j.solener.2007.01.005 * Corresponding author. E-mail addresses: a_valanarasu@yahoo.com (A. Valan Arasu), sorna- kumar2000@yahoo.com (T. Sornakumar). www.elsevier.com/locate/solener Solar Energy 81 (2007) 1273–1279