## 4 Discussion  
The analyses performed point out a complex frame of results, where a few trends can be deduced, in general, for PCMs while others should be referred to each specifically analyzed case.  
Firstly, one of the clearest conclusions that can be drawn is that the benefits of PCMs, integrated into the envelope's inner face, depend logarithmically on the thickness of the boards. The presented outcomes confirm that this trend is common to all analyses and does not depend on the climatic zones, building typology, or the comfort strategy adopted. Therefore, it can be stated that increasing board thickness is particularly advantageous, considering layers up to 50 mm; further increases lead to gradually lower improvements that may not be affordable. This behavior can be explained by considering the relatively low thermal conductivity of the boards (0.27 W/mK). In this case, increasing board thickness adds a further shift in the load peaks related to the thermal conduction inside the board that gradually reduces the effectiveness of the PCM.  
Referring to different building typologies, the small office model shows higher benefits than the midrise apartment model, regardless of the climatic zone, PCM thickness, and comfort strategy adopted. The main reason for this trend can be identified in the different occupancy rates (35.3 m\({}^{2}\)/person for the midrise apartment and 18.6 m\({}^{2}\)/person for the small office) and the different internal loads of equipment and lights, which are sensibly higher in the office model. Considering the case of PCM boards located on the envelope's inner face, increasing the internal loads can increase the number of melting cycles, improving energy and comfort, especially in cooling-dominated climates.  
Lastly, considering the climatic zones analyzed, it can be stated in general that the advantages of PCMs are higher in warm climates--Zones B, C, and D--with the only countertrend exception represented by the energy demand of the small office model in active strategies, where colder zones correspond to higher benefits, thanks to a constant increase in heating energy reduction.  
Beyond these general considerations on the results obtained, referring to each analyzed case, on the one hand, the small office model has shown:  
* significant overall benefits in the active approach, thanks to an important reduction of cooling demand; moreover, in colder zones, further reductions in heating consumption lead to higher benefits;
* a significant reduction of cold discomfort in hot climates in the passive approach and a slight reduction of warm discomfort in cold climates; nevertheless, few increases of warm discomfort can be found in extremely cold climates (Reykjavik).
* On the other hand, the midrise apartment model has shown:
* primarily reductions of heating demand in the active approach, with slight improvements of cooling consumption only for hot climates; considering the overall trend, the hot climates register slightly higher benefits;
* benefits in the passive approach are related mainly to warm discomfort, with higher effectiveness in intermediate climatic zones; moreover, in cold climates, reductions of cold discomfort have been registered, with a single case of increased cold discomfort in Bergen.  
Comparing these results with those reported in similar studies, the main differences obtained can be explained by the positioning of the boards and the use of different building types, occupancy, and system availability schedules that can increase or decrease PCM effectiveness. Moreover, in this case, a PCM-embedded gypsum board was considered for adaptive implementation while, in other studies, pure PCM materials were applied to the envelope. Finally, as described by this study, the different locations can significantly change the effectiveness of the implementation of this technology.