## 4 Discussion
To further interpret the results beyond the quantitative analysis, a qualitative analysis will provide more insights and recommended applications for the modules. Indeed, although a module could be suitable in one application due to its strength in a particular KPI, the same strength could be a drawback in another application. In that account, Table 3  
Figure 11: Summary of the key performance indicators of the modules. summarizes the main qualities for the three modules based on the pros and cons of each of them. For a more comprehensive interpretation of the results, one would group the pros and cons of each module as high, medium, and low according to the strength of the KPIs. For simplicity, a threshold is required to group the results; in this case, values registering less than 10% difference from the maximum are considered as high, between 10% and 25% as medium, whereas more than 25% are considered low. TES1 is suitable for applications that require a fast response in the charging and discharging processes, and a high energy level at the module at thermal equilibrium. These characteristics are suitable for energy profiles such as HP systems, especially to reduce the compressor ON/OFF time without compromising the demand side. The module registers an acceptable energy storage density (medium) and operates with high effectiveness and COP. However, this module is not recommended for an application that requires high thermal inertia during the charging and/or discharging process. TES2 has a high energy storage density and it is suitable for applications that require a fast response in the discharging process and a medium response in the charging process. It could be recommended for energy profiles such as HP systems, to increase the compressor OFF time by providing energy to the demand side. The module operates with high COP and medium effectiveness. However, the module is not recommended for applications that require high thermal inertia in the discharging process and a high energy level of the module at thermal equilibrium (in the three-fluids HEX mode). TES3 has a high energy storage density and it is suitable for applications that require high thermal inertia in both charging and discharging processes. It operates with low effectiveness (about 33%) and an acceptable COP (about 16%) lower than the maximum. The module could be recommended to applications with low availability of electricity, e.g., freezers in vans thanks to their high energy storage density. However, the module is not recommended for an application that requires a high energy level at thermal equilibrium (in the three-fluids HEX mode). Finally, one task that remains worth investigating is comparing the condition when PCM is utilized and a condition with no PCM. However, although one could be tempted to test these modules when filled with PCM and when empty, the results would not provide a meaningful information in a practical application. Therefore, a dedicated experimental design to further delve into the issue is foreseen to be developed in future studies. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Module** & **Pros** & **Cons** \\ \hline \hline \multirow{6}{*}{TES1} & High COP & \\  & High effectiveness & \\  & High amount of energy stored (SOC) & \\  & at thermal equilibrium & \\  & High charging power (fast response & \\  & to energy source) & \\  & High discharging power (fast response to energy demand) & \\ \hline \multirow{2}{*}{TES2} & High COP & \\  & High discharging power (fast response to energy demand) & Low amount of energy stored (SOC) at thermal equilibrium \\  & High energy storage density & \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Qualitative analysis of the three modules.