## 1 Introduction  
Latent heat thermal energy storage (TES) using phase change materials (PCM) is an effective way of storing thermal energy because of its high energy storage density and the nearly isothermal melting and solidification processes at the phase change transition temperature of the PCM [1]. Many PCMs have been proposed in the literature for different temperature ranges, being the phase change temperature and phase change enthalpy, the main parameters provided by the authors [1; 2; 3]. However, the PCM should fulfill several other requirements besides the two mentioned above. [PERSON] et al. [4] summarized the main requirements for selecting proper TES materials and systems by classifying them into chemical, kinetic, physical, thermal, economic, environmental, and technological. Therefore, the selection procedure of a PCM becomes a crucial step for an optimum operation of the thermal process and the latent heat TES system. The critical parameters and necessary requirements for a specific process are not always easy to identify and are often in conflict with each other. Latent heat TES systems working under partial load operating conditions as a consequence of the thermal processes with whom they are coupled (such as the ones shown in Table 1), are one of the specific cases which require a proper PCM selection. Partial load operating conditions refer to the charging and discharging processes where the PCM is not fully loaded. These conditions can be either an intrinsic characteristic of thermal processes, which may not have a continuous energy supply, such as solar thermal or industrial waste heat recovery processes, or can be used as a TES storage management tool to adapt current TES systems to the demand of the final user. Therefore, the selected PCM needs to undergo several charging and discharging processes, meaning that the selected PCM should have an acceptable cycling and thermal stability. Some authors did an attempt to study different critical parameters besides the phase change temperatures and enthalpies, and performed a more detailed characterization of different PCM in this temperature range [5; 6; 7; 8]. [PERSON] et al. [5] studied the feasibility of storing latent heat with liquid crystals by performing different techniques such as polarized light microscopy, differential scanning calorimetry (DSC), thermogravmetry analysis (TGA), and rheological measurements. They found that these materials showed promising results despite the fact that further investigations were required. [PERSON] et al. [6] carried out a characterization of five pure sugar alcohols and three eutectic blends, evaluating their key thermal and physical properties, providing empirical equations, and comparing the values to those of most currently used PCM within the temperature range between 70 and 180 \({}^{\circ}\)C. Results showed the potential of sugar alcohols if issues such as thermal stability, thermal endurance and crystallization kinetics are solved. [PERSON] et al. [7] performed a PCM selection within the temperature range of 120-150 \({}^{\circ}\)C. They identified eleven candidates and studied their thermal behaviour by performing TGA and DSC analysis, before and after five cycles, coupled with a quadrupole mass spectrometer. They concluded that only few organic materials presented suitable properties to be applied in this temperature range but emphasised the importance of the measurement conditions on the results. Moreover, they suggested that further investigations concerning long-term stability should be done. [PERSON] et al. [8] proposed a new methodology for PCM selection based on the health hazard and both the cycling and thermal stability properties. They added the health hazard analysis to evaluate the impact of PCM not only on humans but also for the facilities design and maintenance, and the thermal and cycling stability to evaluate the durability of the PCM for a certain industrial application.