Experimental Investigation of a Small-Scale Parabolic Trough Concentrated Solar Power ‎Systems

Abstract

Large-scale systems have a lower levelized cost of electricity than small-scale concentrated solar power systems. Thus, the purpose of the present study is to evaluate the potential of using standalone small-‎scale ‎concentrated ‎solar power collectors in order to generate process ‎heat ‎at ‎a ‎moderate ‎temperature, which directly utilizes thermal energy without the need to generate electricity. ‎A ‎parabolic trough ‎collector (3.6m2) ‎was ‎designed ‎and ‎manufactured, including a dual-axis solar tracking system with and without an insulating function. An ‎insulating ‎cavity ‎was incorporated to ‎minimize the heat ‎losses collected by the absorbed ‎tube. ‎The experiments ‎were ‎carried out during a time of high winds and unfavorable weather ‎in ‎Sabratha City. The findings of the experiments demonstrated that the produced temperature and the collected heat energy progressively increase until they reach their maximum value, and then gradually decrease. The maximum water ‎temperature ‎was 96ºC at ‎a ‎flow rate ‎of ‎‎0.5L/min, and ‎the highest amount of ‎heat energy was 550W/m². ‎Wind speed showed an important impact on the produced temperature; therefore, various comparative experiments were carried out in the same climate condition; ‎the experiment with the insulating function ‎presented the least heat loss, and it takes a higher edge of 11% in terms of efficiency. ‎In addition, the water temperature rose to 120°C where steam was generated at a zero flow rate, while the oil ‎reached 194ºC. In addition, a mathematical model was also implemented to theoretically study energy balance; with little expected discrepancy, its predictions and the experimental results agreed. In conclusion, the results presented reasonable markers of interest despite the poor environmental conditions during the experiments.‎