Application of carbon-based nanomaterials in solar-thermal systems: An updated review

Increasing the world population makes it necessary to look for alternative and sustainable energy resources to meet the rising energy demand. In recent years, the utilization of different renewable energies has been accelerated because of the negative effects of fossil fuels and their limited resources. Among different solar energy technologies, solar liquid and air collectors are extensively utilized for providing heated water and air. Rapid development in science and technology makes it possible to improve the performance of solar collectors. Producing nanomaterials and using the obtained nano-sized particles for improving the thermophysical specifications of the working fluid or coating material can be considered for performance improvement. In the present study, applications of carbon-based nanomaterials (CBNMs) in various solar thermal systems have been reviewed comprehensively. In other words, the effects of utilizing carbon-based nanomaterials as promising material on the overall performance have been investigated. Preparation techniques and thermophysical specifications of carbon-based nanomaterials have been explained in detail. Also, utilization of carbon-based nanomaterials in seven widely utilized solar-thermal technologies and their impacts on the thermal behavior of the tested system have been concluded. This review gives a general perspective about applicability of carbon-based nanomaterials for performance enhancement in various solar-thermal systems.