The solar resource remains extremely underutilised in a synthetic fashion. With increasing clean water demands and decreasing clean water sources, solar desalination becomes all the more relevant. Direct absorption solar collectors offer improved efficiency over traditional surface absorbing collectors because they have fewer heat resistance steps and have the ability to utilise higher radiation fluxes. Carbon black- based nanofluids, with concentrations below 0.1%, were compared with each other and with the base fluid of salt water in a concentrated solar power scenario. A 1 m2 concentrating unit using a two-axis tracking system with two mirrors and a 1 m2 Fresnel lens was used to concentrate solar radiation on a 10 cm2 direct absorption solar collector flow cell. An optimum concentration of 0.001 vol % carbon black was found to show a 94 % increase in heating rate compared to that of salt water. This was accomplished with a collector efficiency of 59 %, 28 % higher than that of salt water. The overall efficiency of the system was 28 %. This low efficiency can be attributed to the high optical losses (50 % − 70 %) present in the concentrating unit.