Analysis of the Perceived Thermal Comfort in a Portuguese Secondary School: Methodology and Results

Abstract

This paper presents a methodology to assess the thermal environment in non-university classrooms, using the example of the results obtained from a multipurpose classroom of a Portuguese secondary school during a week of November. According to the defined protocol, both hygrothermal parameter values and thermal assessments were obtained and used for the calculation of both static and adaptive thermal comfort indicators, including Matias' Portuguese adaptive comfort indicator. Occupants perceived a neutral thermal environment (Thermal Sensation Vote, TSV, of-0.03), while their thermal preference was a warmer environment (Thermal Preference Vote, TPV, of +0.64). Female occupants tended to demand a warmer environment during this study, despite their thermal perception was similar to male occupants. Predicted Mean Vote (PMV) was lower than TSV in 0.35 points, so it underestimates occupants' real thermal perception. When occupants' acceptance vote are compared with Adaptive indicators, Matias' obtains similar acceptance values (80 %) than the occupants' assessments (85 %), while ASHRAE indicator shows lower values (27 %). In conclusion, the exposed methodology allows to characterise the thermal comfort level of Iberian non-university classrooms, so further investigation is required.

Thermal Comfort Evaluation Using Linear Discriminant Analysis (LDA) and Artificial Neural Networks (ANNs)

“…Similar thermal acceptability (above 85%) by people of different nationalities participating in the study was also obtained by the authors of the study in Japan [16]. In Portugal, thermal comfort was accepted by over 85% of respondents [18]. The same results were obtained from studies in Spain [19] and India [17].…”

“…Man has a great ability to adapt to existing conditions. The authors from Portugal concluded that if gender is added as an analysis factor, it can be seen that TSV does not shown significant differences between male and female respondents [18].…”

“…The most frequently analyzed is the indoor air temperature [15][16][17]. There are also authors who prefer calculations of thermal comfort indicators, i.e., PMV, PPD, PET, SET [18][19][20][21]. It is a more technical method and less associated with people's subjective feelings.…”

Indoor Comfort and Symptomatology in Non-University Educational Buildings: Occupants’ Perception

“…The measurement campaign was developed in the selected classrooms according a data collection protocol [16,17,60] in which physical parameters relating to hygrothermal comfort, CO2 concentration, and illuminance were obtained in a spatial matrix [61] previously and throughout the survey distribution period (30 min, twice per day), taking the average of the values obtained, both outdoor and indoor, as can be seen in Figure 3 and Table 2: During the measurements both the initial state and the operation of doors, windows, solar devices, heating systems, and electric lighting, as well as changes in the occupants' distribution, were collected. Performance and uncertainty of measurement instrumental are described in Table 3:…”

“…The survey was designed to collect information and votes from occupants in order to comprehensively assess the environment in conjunction with the measurement of the physical parameters. The survey design was based on the experience of previous research [16,17,60,61,65] with the aim to collect data with an objective approach. The completion of the survey took around 20 minutes per classroom, being distributed during the measurement campaigns, and were performed twice per day both in a winter and a midseason day.…”