Determination of thermal comfort and discomfort intervals for open spaces in Maringá city, Paraná State, Brazil, using PET index

Abstract

Prediction models of thermal comfort in open spaces are considered a fundamental tool in neighborhood planning, as well as in open space design within urban areas. However, most of these indices were developed for cold climates. For this reason, conducting a preliminary analysis is necessary to ensure that they are suitable for a location presenting a different, warmer climate. The objective of this work is to analyze the real thermal sensation in the city of Maringá, Paraná State, Brazil, based on PET (thermal comfort index). For this, we collected information on climate, users and subjective variables at seven locations spread throughout the downtown area. The analysis allowed for the proposal of new intervals of thermal stress levels for Maringá. The index presented a low percentage of correct answers and correlation with the votes of real sensation, for this reason, calibration was required. The proposed range of thermal comfort and thermal stress for Maringá City is: cold thermal stress, Ta ≤ 19.5°C; thermal comfort, 19.5°C < Ta < 30°C and hot thermal stress, Ta ≥ 30°C. This proposal reached 67% of percentage of correct answers and 0.29 of correlation with the response of real thermal sensation. This result is compatible with other works conducted in Brazil and its use is acceptable as a predictor of real thermal sensation in the city of Maringá, PR.