Nanofluids in Solar Thermal Parabolic Trough Collectors (PTCs)

Solar thermal parabolic trough collectors (ST-PTCs or simply PTCs) consist of a parabolic mirror which concentrate solar radiation on the receiver in which a heat transfer fluid (HTF) gains the solar heat. PTCs can be integrated with refrigeration systems, power plants, and industrial processes. Different HTFs depending on the working temperature and application are used in PTCs, in which nanofluids are considered as an engineered HTF for enhanced performance. Nanofluids generally can be made by mixing nanoparticles with conventional fluids such as water or thermal oils to achieve improved thermophysical specifications like a higher thermal conductivity and absorption of the PTCs are introduced. Finally, challenges and future perspectives of nanofluid-enhanced PTCs are presented.