# Thermal Characterization of Phase Change Materials by Differential Scanning Calorimetry: A Review
###### Abstract  
The use of phase change materials (PCMs) in thermal energy storage (TES) applications as a system that can fill the gap between the energy supply and demand has sharply increased over recent years. Due to the dependence of the storage capacity in a TES on the transition (mostly solid/liquid) of PCMs, knowing the thermal properties of PCMs is of high importance. Calorimetric methods have an inevitable role in PCMs' characterization methods. The most important properties of PCMs that lead us to integrate them in a specific application can be determined by the calorimetric method. These properties are transition temperatures, the enthalpy of transition and the heat capacity. Among the calorimetric methods, differential scanning calorimetry (DSC) is widely available and accurate results can be obtained at a reasonable cost. Furthermore, the thermal stability of PCMs can be determined after a hundred cycles of melting and solidification. The present work proposes an extensive and comprehensive review on calorimetric measurements of PCMs via the DSC method. The objective is to highlight the relevant research with a focus on DSC characterization of PCMs. This review includes studies from 1999 to 2022 and provides a summary of the methods, results and recommendations for future measurements. phase change materials (PCM); differential scanning calorimetry (DSC); thermal energy storage (TES); latent heat; heat capacity; transition temperatures +
Footnote †: journal: Applied Sciences  
conductivity and dynamic viscosity). The mentioned properties can be obtained by conventional or unconventional methods. In the current review paper, we focus on the studies on calorimetric measurement techniques for PCMs. The technical properties obtained by calorimetric methods are transition temperature, enthalpy and specific heat. A correct measurement of these parameters is one of the primary steps before considering PCMs [5] in real-life situations. Therefore, regardless of the final PCM application (for storing heat or controlling temperature), its calorimetric evaluation is required to achieve its maximum capacity [6]. Calorimetric measurements using different methods and instruments are currently conducted to evaluate the ability of a material to store and release energy as a function of temperature [6]. Differential scanning calorimetry (DSC) is a standard widely used technique to select PCMs for a particular application by evaluation of their thermal properties, including transition temperature, enthalpy and specific heat [7; 8]. DSC is also used to study the thermal stability of PCMs by monitoring their thermal performance during cycles of melting and solidification. However, there is a limitation regarding DSC technique for PCM characterization, which is the dependency of the results on the type of DSC machine and test conditions. To address this problem, different methods and standards are defined and each suggests some recommendations to produce reliable results. This study reviews the literature that establishes a method or recommends a protocol to measure PCMs' properties by DSC and discusses the limitations and advantages of each method. The focus of this review is more on DSC characterization methods of PCMs and the related challenges, rather than reporting the measurement results. The Engineering Village platform (Elsevier) provides access to all related articles from different databases such as Science Direct, Springer, etc. The main keywords to find the articles were (PCM, DSC, TES, enthalpy, melting point and heat capacity). In the references, there are articles from 1990 to 2022. However, due to the novelty of PCM thermal characterization, most articles referred to have been published within the last ten years.