# Analysis of Climate-Oriented Researches in Building
## 3 Results and Discussion
### Results of Cluster Analysis
#### 3.2.5 Cluster 5--Indoor Thermal Comfort  
The fifth cluster is composed of 17 papers on indoor thermal comfort, which generally deal with the concept of the adaptive thermal comfort model and its evolution over time, the conventional thermal comfort model and the potential for energy savings in the application of thermal comfort models in buildings. All studies of this cluster are presented in Table S3. The adaptive thermal comfort (ATC) model for naturally ventilated buildings, developed by [PERSON] and [PERSON], as an alternative to the conventional model of thermal comfort [64], with all the limits of its application, the energy saving potential and the problems of its development [55], was adopted as an amendment to the ASHRAE 55 Standard and then went through different stages of evolution from its conceptual formation to its application in buildings to minimise energy consumption. First, it was found that the ATC model has a clear dependence on local climatic conditions and the thermal preferences of the population in different regions of the world. Generally, the ATC model is more applicable to regions of the world with a warm climate [118, 119, 120]. These studies showed that the effect of indoor air speeds on thermal comfort in buildings with natural ventilation requires detailed research for different climate zones [119, 120]. The application of the ATC model in colder climate conditions was also considered with estimates of potential energy savings [121]. It has been shown that the ATC model can only be used in the summer period to natural ventilated office space under Dutch climatic conditions, with a cooling energy saving potential of up to 10%. [122]. For conference and exhibition building in Beijing, a hybrid HVAC system operated with natural ventilation cooling and with the application of a high standard level of the ATC model can be used between 63% and 66% of the hours in July and August, and that can help to reduce energy consumption [121]. This cluster presents studies not only on the ATC model, but also on the conventional model of thermal comfort. Thus, in 2008, although the author accepts the best applicability of the ATC model for naturally ventilated buildings, [PERSON] conducted a review on the predicted mean vote (PMV) model of thermal comfort created by [PERSON], demonstrating its strengths and weaknesses. Possible methods of optimisation and improvement of the PMV model were also analysed [60]. Later, the authors of a study carried out in Hong Kongconcluded on the importance of taking into account air velocity for thermal comfort in an air-conditioned office building and recommended the use of air-conditioning systems with individual control for this type of building [123]. The existence of two models of thermal comfort, of course, leads to the development of research in terms of comparing them with each other. For example, in India, for residential buildings, it was concluded that the ATC model is more suitable for reflecting the thermal preferences of the population than the PMV model [124]. A good comparative study of the two models was published in 2013 on field studies in thermal comfort research, presenting all research according to the four Koppen climate zones. The authors concluded that the conditioned spaces have narrower comfort zones compared to free-running buildings. In all climate zones, the most popular adaptation methods are related to the modification of air movement and clothing of the building occupants [125]. Additionally, there were still attempts to develop a single ATC model for air-conditioned and natural ventilated office buildings [126]. Most of the above studies focus on office and residential buildings. However, on the other hand, school buildings also receive significant attention from thermal comfort researchers. The interest in studying thermal comfort in schools is because children spend most of their time there, and their academic performance and emotional health depend on thermal comfort.