## 3 Design and Applications  
The design of the energy storage material encapsulation is one of the most important parameters that critically influence the heat transfer in charging and discharging procedures of the storage system. The study of [PERSON] et al. [4] examined the effect of the design of the PCM macro-encapsulation on the thermal behavior of a latent heat thermal energy storage systems during both the charging and discharging processes. The obtained results revealed that the design of the thermal energy unit should be performed and analyzed based on the requirements of the application due to the fact that the macro-encapsulation design has a relevant impact on the heat transfer. [PERSON] and his team [5] conducted experiments on the investigation of hydrate heat storage systems. An evaluation of the kinetic characteristics of thermal energy storage using tetrabutylammonium acrylate hydrate as PCMs was performed. It was found that either mechanical agitation or ultrasonic vibration improved the thermal energy storage kinetic characteristics because of the detachment of the hydrate adhesion on the heat exchanger, which could be a thermal resistance between the thermal energy storage medium and heat exchanger. The work of [PERSON] and his team [6] reports the methodology that applied the estimation of thermodynamic and kinetic information to the interaction of lytic polysaccharide monooxygenenses enzymes using a filamentous fungus. This class of enzymes boost the release of oxidized products from the biomass plant. Taking into account that these enzymes are redox, their exploitation was conducted through their immobilization on electrode surfaces and investigating the parameter standard electron transfer rate constant (k\({}_{0}\)) between the immobilized electrode and the enzyme. The obtained results revealed that it is feasible for the system to be rendered reversible and consequently to be used for bio-electroatalytic purposes. Additionally, [PERSON] and coworkers [7] numerically examined the thermal improvement of a latent thermal energy storage (LTES) component, including mini-channels as dry air passages. The thermal performance of the LTES in charging and discharging processes with ranging flow rates and a varying number of channels was estimated. The results revealed that the LTES-phase change power is enhanced by increasing the number of channels. On the other hand, a decrease in the storage capacity was observed. Moreover, it was noticed that at a constant air flow rate there is an increment of the mean heat transfer rate because of the influence of the heat transfer coefficient due to the increase in the heat transfer surface area of the increased number of channels. A very interesting concept developed by [PERSON] and his team [8] based on the examination of sugar alcohols as PCMs. The effect of thermal treatment on sugar alcohol erythroid thermal, chemical, and physical properties was assessed. Moreover, experiments with erythroid and its mixtures with antioxidants were performed in order to enhance its thermal stability. It was found that in the presence of air, mixtures of erythroid with antioxidant had a lower degradation rate in comparison with pure erythritol. In another study, [PERSON] et al. [9] reported that the use of a PCM layer of 20 mm can improve the thermal comfort in the vehicle, reducing the need to use the heater or the air conditioner. It was found that the PCM reduced the temperature of the air by 9 \({}^{\circ}\)C when heating and by 4 \({}^{\circ}\)C when the temperature dropped. Finally, in the review paper of [PERSON] et al. [10], the principles of latent heat thermal energy storage systems with PCMs are discussed. This paper presents the research status of the materials that can be used as PCMs, together with the most effective methods for improving their thermal performance. Moreover, several passive applications in the building sector are highlighted.