Determining appropriate thermal comfort period based on PET and PMV using the RayMan model : a case study in the subtropical city of Sari

Given the different climate conditions worldwide, the need for climate zone-based architectural designs is evident. This need is more felt, particularly in critical thermal conditions, and is the most important challenge for an architect. One of the main sub-climates that require a special design is the humid subtropical climate in which winters are cold and rainy, and usually, the ambient temperature is lower than the comfort zone, with hot and humid summers that demand a temperature drop to achieve a comfort zone. The most fundamental problem is thus to provide cooling and heating systems in such environments. Accordingly, the present work aims at providing critical climate conditions with potential solutions. Here, Sari, with a humid subtropical climate, was selected as a case study, and its thermal conditions were investigated utilizing Physiological Equivalent Temperature (PET) and Predicted Mean Vote (PMV) indices, and the Rayman model. The results of our first study question revealed that the percentage of days with thermal comfort was 16.9%. Also, 16.3% and 17% of the days had slight and mild cold stress, respectively. Subsequently, the results from data analysis indicated that the ventilation and dehumidification cooling systems can be considered the most appropriate passive methods. In addition, the elements of the indigenous architecture including Iwan, Talaar, upstairs house, and sloping roof, which all are rooted in the vernacular architecture of the city of Sari can be introduced as the most effective architectural solutions. Our findings are of great importance for architects and designers because such findings will guide the design of complex site conditions and even the building construction by considering the thermal comfort factor.