Experimental study of a nanofluid-based indirect solar cooker: Energy and exergy analyses

In this study, the effects of using different heat transfer fluids on the energy and exergy efficiencies of a new indirect solar cooker are experimentally investigated. The studied heat transfer fluids are thermal oil and three thermal oil-based nanofluids including SiO2-oil, TiO2-oil, and SiC-oil with 0.5 wt%. In this research, the performance of the solar collector and cooking unit, as the two main sections of the indirect solar cooker, is also evaluated from the energy and exergy viewpoints. Based on the results, using the nanofluids in the indirect solar cooker improves the energy and exergy outputs as well as the energy and exergy efficiencies compared to those of the system with thermal oil. Moreover, among the studied cases, the solar cooker with SiC-oil nanofluid has a superior performance. The results reveal that using SiC-oil nanofluid instead of thermal oil in the indirect solar cooker decreases the time taken to boil 2 L of water about 17 min (23.29%). The use of SiO2-oil, TiO2-oil, and SiC-oil nanofluids in the system enhances the overall energy efficiency of the solar cooker by 1.17, 3.54, and 4.27% points compared to that of thermal oil, respectively.