Dispersing trace amounts of nanoparticles into common base fluids has a significant impact on the optical as well as thermo physical properties of base fluid. This characteristic can be used to effectively capture and transport solar radiation. Enhancement of the solar irradiance absorption capacity leads to a higher heat transfer resulting in more efficient heat transfer as shown in figure 2.
The efficiency of a solar thermal system is reliant on several energy conversion steps, which are in turn governed by the effectiveness of the heat transfer processes. While higher conversion efficiency of solar to thermal energy is possible, the key components that need to be improved are the solar collector. An ideal solar collector will absorb the concentrated solar radiation, convert that incident solar radiation into heat and transfer the heat to the heat transfer fluid. Higher the heat transfer to fluid, higher is the outlet temperature and higher temp lead to improved conversion efficiency in the power cycle.
nanoparticles have several orders of magnitude higher heat transfer coefficient when transferring heat immediately to the surrounding fluid. This is simply due to the small size of nanoparticle.