Studies on latent heat energy storage (LHES) materials for solar desalination application-focus on material properties, prioritization, selection and future research potential

In recent years latent heat energy storage (LHES) has received a worldwide focus in the area of solar still applications. Among various techniques available to improve the productivity of solar stills, heat storage is one of the proverbial areas in the present scenario. LHES surpasses sensible heat energy storage (SHES) in solar still applications owing to its properties like latent heat, thermal conductivity, etc. Focus has to be given in the selection of suitable LHES material since its properties are very significant during the performance and operation of solar stills. Though previous reviews on LHES in solar stills focus only on the productivity enhancement, this paper presents an up to date comprehensive review exclusively about LHES in solar stills focusing on its productivity, properties of LHES materials and the mechanisms behind the variation in properties of LHES materials. Further, in addition to this, a detailed analysis is also presented in this paper by employing analytical hierarchy process (AHP) which enable the researchers to prioritize the properties during the selection of LHES in solar still applications. Besides AHP analysis, we also evaluate the relative efficiency of the available LHES materials for solar still application by data envelopment analysis (DEA) to find the frontier LHES materials thereby suggesting the methods to augment the properties of the frontier material (identified through DEA analysis). Thus, this paper may be a reference guide in the near future for the academicians, researchers to get an overview about the various LHES materials used in solar stills and significance of their properties for improving the yield in solar still applications.