Optimization of nanofluid volumetric receivers for solar thermal energy conversion

► Experimental and modeling study of nanofluids as volumetric receivers for CSP. ► Experiments with carbon-coated nanoparticles in Therminol® VP-1 agree with model. ► Receiver efficiency increases with increasing receiver height and concentration. ► Optimum optical thickness (1.7) of nanofluid is tuned by adjusting particle loading. ► Well-suited for beam-down CSP; idealized receiver-side efficiencies exceed 35%.