## 4 Conclusions  
In conclusion, fatty esters from methanol and 1-decanol and fatty acids of different carbon chain length (myristic acid, palmitic acid, stearic acid, behenic acid) to be used as possible PCM were successfully synthesized through Fischer esterification with purities over 89%. While methyl esters of myristic, palmitic and stearic acid have been synthesized before and their thermal properties partially investigated, to the best of the author's knowledge, a clear lack in experimental thermal data exists in regards of methyl behenate and all decyl esters produced. The synthetic procedure was validated through comparison of properties of the self-produced methyl palmitate with the commercial homologue purchased. While simple drying with rotary evaporation was sufficient to purify the final methyl esters, all decyl esters had to be further purified through one or more consequent crystallizations in methanol. ATR-IR proved to be a valid technique for identification of residual unreacted acid or alcohol in a qualitative manner; however, it did not allow for identification of different esters. On the other hand, NMR and GC-MS analysis allowed for correct identification of structures and compound identity. Additionally, eventual residual impurities could be successfully detected and quantified through both methods. Identification of residual impurities was possible also through DSC analysis, where side peaks could be observed in case of impurities, together with lower \(\Delta\)H. The phase change temperatures of the esters ranged between 14 \({}^{\circ}\)C and 45 \({}^{\circ}\)C circa. As reported by [PERSON] et al. [PERSON] et al. (2015), PCM in the range between 5 \({}^{\circ}\)C and 40 \({}^{\circ}\)C appear to be interesting for low-medium temperature applications, such as free cooling (19-24 \({}^{\circ}\)C), evaporative and radiative cooling systems (around 18 \({}^{\circ}\)C), solar absorption chillers (29 \({}^{\circ}\)C), and passive heating and cooling of buildings (19-29 \({}^{\circ}\)C). Preliminary works conducted on such setups with different PCM (salt hydrates, paraffins) showed promising results, with high cost saving and decrease in energy consumption (25-30%). The esters produced proved to be interesting PCM candidates thanks to \(\Delta\)H over 190 J/g for 10 \({}^{\circ}\)C/min heating rates. Additionally, the DSC indicates rather moderate supercooling rates for all samples. A trend could be observed correlating both degradation temperatures and phase transition temperatures to the chemical structure of the molecules. In the first case, a higher thermal stability was observed for longer carbon chains, confirming the tendency of longer molecules to form more tightly packed structures and stronger intermolecular bonds. On 2424 the other hand, an increase in the melting temperatures with increasing carbon chain length was observed for both methyl esters and decyl esters, but with parallel trends and a higher influence from the fatty acid carbon length compared to the alcohol. This is attributed to odd-even numbered carbon chain length effect described in previous works [PERSON] et al. (2015); [PERSON] et al. (2015). Given the lack of experimental thermal data on esters, future research on different ester classes (e.g. diesters, lactones, aromatic, benzylic esters) is planned, in order to collect further information about the thermal behavior and possible trends, and to individuate the best suitable candidates to be used as PCM for different scopes and applications. All authors listed conceived and designed the project and contributed to experiments' development and in reviewing the paper; [PERSON], [PERSON], and [PERSON] acquired the funding; [PERSON] and [PERSON] performed the experiments; [PERSON], [PERSON], [PERSON] and [PERSON] analyzed the data; [PERSON] contributed reagents, materials and analysis tools; [PERSON] wrote the paper. This research was funded by Swiss National Science Foundation (SNSF, project number PZENP2_173636).