Abstract Parabolic trough collector (PTC) is the most established solar concentrating technology worldwide. The conventional parabolic trough collectors are used in various applications of medium and high-temperature levels. However, there are numerous studies which investigate alternative designs. The reasons for examining different PTC configurations regard the thermal efficiency increase, the reduction of the manufacturing cost and the development of more compact designs. The objective of this review paper is to summarize the existing alternative designs of PTC and to suggest the future trends in this area. Optical and thermal modifications are examined, as well as the use of concentrating thermal photovoltaic collectors. The optical modifications include designs with secondary concentrators, stationary concentrators and strategies for achieving uniform heat flux. The thermal modifications regard the use of nanofluids, turbulators and the use of thermally modified receivers with insulation, double-coating and radiation shields. The concentrating thermal photovoltaics are systems with flat or triangular receivers which can operate in low or in medium temperature levels with the proper alternative designs. It has been found that there are many promising choices for designing PTC with higher thermal performance and lower cost. The conclusions of this work can be used as guidelines for future trends in linear parabolic concentrating technologies.

中文翻译：

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抛物槽式太阳能集热器的替代设计

摘要 抛物槽式集热器 (PTC) 是全球最成熟的太阳能聚光技术。传统的抛物线槽式集热器用于中高温级别的各种应用。然而，有许多研究调查了替代设计。检查不同 PTC 配置的原因涉及热效率的提高、制造成本的降低和更紧凑设计的开发。本评论文件的目的是总结 PTC 的现有替代设计，并提出该领域的未来趋势。检查了光学和热修改，以及聚光热光伏收集器的使用。光学修改包括带有二次聚光器的设计，固定集中器和实现均匀热通量的策略。热修改涉及纳米流体、湍流器的使用以及具有绝缘、双层涂层和辐射屏蔽的热修改接收器的使用。聚光热光伏系统是带有平面或三角形接收器的系统，它们可以通过适当的替代设计在低温或中等温度水平下运行。已经发现，对于设计具有更高热性能和更低成本的 PTC，有许多有希望的选择。这项工作的结论可用作线性抛物线聚光技术未来趋势的指导方针。聚光热光伏系统是带有平面或三角形接收器的系统，它们可以通过适当的替代设计在低温或中等温度水平下运行。已经发现，对于设计具有更高热性能和更低成本的 PTC，有许多有希望的选择。这项工作的结论可用作线性抛物线聚光技术未来趋势的指导方针。聚光热光伏系统是带有平面或三角形接收器的系统，可以在低温或中等温度水平下通过适当的替代设计运行。已经发现，对于设计具有更高热性能和更低成本的 PTC，有许多有希望的选择。这项工作的结论可用作线性抛物线聚光技术未来趋势的指导方针。