A comparative study of the effect of phase change material (paraffin wax) on volumetric and surface direct solar steam generation

Abstract

BackgroundThe rate of evaporation in direct solar steam generation can be increased by employing several techniques. One of the passive techniques that can be used for the improvement of system performance is the use of phase change materials (PCMs). MethodsAn experimental study was carried out to explore the role of PCMs in energy storage and continuous evaporation in a direct solar steam generation (SSG) system. For this purpose, volumetric and surface methods have been employed and compared in the absence and presence of PCMs. A nanofluid composed of MWCNT@GNP (a nanocomposite of graphene and multiwall carbon nanotubes) and water was used as a photoabsorber in the volumetric method, whereas poplar wood coated with MWCNT@GNP was chosen for the surface method. Significant resultsThe results indicated that paraffin wax PCMs around the bulk fluid with benefiting from excellent capability of energy storage gave a superb performance for continuance of vapor production in both methods. The PCMs have a significant impact on maintaining the evaporation rate at night. However, in the presence of PCMs, the photoabsorber in the volumetric method represented much better performance compared to the surface method.