Mixed-mode Office Buildings Research Articles

Balcony design recommendations to enhance daylight, thermal and energy performance of mixed-mode office buildings

The use of balconies in hot climates holds the potential to block direct solar radiation thus reducing energy consumption for cooling and enhancing visual comfort. However, balconies may also diminish daylight availability within the room, thereby affecting occupants’ satisfaction and wellbeing. This study aimed to provide balcony design recommendations through a parametric analysis of various combinations of balcony design parameters (balcony depth, width, location on the façade, and parapet type), along with key building design parameters (façade orientation, floor level, and glazed door width), considering a multi-domain objectives assessment. The results demonstrate that balcony design can effectively enhance visual comfort, thermal performance, and energy efficiency while ensuring optimal daylight availability in office rooms located in subtropical climates. Recommendations for balcony design were tailored to each façade orientation and thoughtfully combined with the glazed door width. One optimal combination, featuring a 3-meter-wide glazed door and a 2-meter-deep balcony, proved beneficial for all façade orientations across all floor levels. However, the choice of parapet type should align with the balcony’s location, which is directly correlated with the room’s depth. The insights gained from this study offer valuable information for building designers, highlighting that balconies should not be designed solely as decorative façade elements or spaces for building services. Furthermore, the cross-analysis method developed in this study can be applied by researchers and designers to their own case studies.

Balcony design to improve natural ventilation and energy performance in high-rise mixed-mode office buildings

Balconies have the potential to promote airflow and regulate solar heat gain, which can reduce energy usage for cooling in buildings. However, designing these elements can be challenging due to complex trade-offs for natural ventilation and energy performance, highlighting the need for advanced simulation tools to guide balcony design decisions. This study aims to evaluate the impacts of balcony design on natural ventilation and thermal and energy performance in high-rise mixed-mode office buildings in São Paulo, Brazil. To this end, an integrated method that involves computational fluid dynamics (CFD) and building performance simulations (BPS) is developed to identify optimal solutions. Through this method, the performance of 40 balcony designs is studied, comprising diverse alternatives for three balcony design parameters (width, depth, and location on the façade). Furthermore, the research is performed considering the balcony effects on two façade orientations (north and south), two wind incidences (windward and leeward), and three floor levels (upper, medium, and lower floors). Results are analysed through a sensitivity analysis, percentage of change and cross-analysis. The findings indicate that narrow and shallow balconies (2 m × 0.5 m) are the best design option for the south façade; they enhance natural ventilation and reduce energy consumption for cooling across all floor levels and balcony locations. Conversely, for the north, sun-facing façade, it is recommended to use wide and deep balconies (5 m × 2 m) to reduce solar gains and associated energy consumption for cooling, despite potential limitations in natural ventilation.

Occupant’s Thermal Perception in Mixed-mode Office Buildings of the Tropical Climate

Thermal comfort and energy consumption in office buildings is a global critical concern. This study investigated this challenge in the Faculty of Environmental Technology, Abubakar Tafawa Balewa University, Bauchi-Nigeria. Through a field survey and physical environment measurements. The study explored occupant perceptions of thermal comfort and satisfaction. It evaluated the thermal comfort and satisfaction of occupants in a mixed-mode office building, focusing on potential discrepancies between perceived comfort and internationally recommended standards. Despite air temperatures falling outside the PMV model's comfort range, high thermal comfort, and satisfaction levels were reported by the respondents. These findings align with other studies in Nigeria, suggesting adaptation and acclimatization to local conditions. The study further examined the relationship between thermal comfort and occupant satisfaction. The result revealed a moderate positive association, suggesting increased thermal comfort leads to higher satisfaction among occupants. While thermal comfort explained 25% of the variance in satisfaction scores. Finally, the study suggests the localization of comfort standards, improved mixed-mode system performance, and encouraging evidence-based design interventions that will ultimately benefit both occupants and the environment.

Predicting the clothing insulation through machine learning algorithms: A comparative analysis and a practical approach

Since indoor clothing insulation is a key element in thermal comfort models, the aim of the present study is proposing an approach for predicting it, which could assist the occupants of a building in terms of recommendations regarding their ensemble. For that, a systematic analysis of input variables is exposed, and 13 regression and 12 classification machine learning algorithms were developed and compared. The results are based on data from 3352 questionnaires and 21 input variables from a field study in mixed-mode office buildings in Spain. Outdoor temperature at 6 a.m., indoor air temperature, indoor relative humidity, comfort temperature and gender were the most relevant features for predicting clothing insulation. When comparing machine learning algorithms, decision tree-based algorithms with Boosting techniques achieved the best performance. The proposed model provides an efficient method for forecasting the clothing insulation level and its application would entail optimising thermal comfort and energy efficiency.

Machine learning-based approach to predict thermal comfort in mixed-mode buildings: Incorporating adaptive behaviors

Mixed-mode (MM) buildings are designed to provide mechanical air conditioning and natural passive cooling as regulated by occupants. This would enable the potential of shifting the narrow comfort range in HVAC (heating, ventilation and air conditioning) buildings to a wider range similar to NV (naturally ventilated) buildings. Recent studies have provided evidence of higher degrees of thermal adaptation among occupants in MM buildings. However, limited attention has been given to understanding the linkages between these expanded ranges and the specific adaptive behaviors or contextual factors that influence them. This paper aims to investigate the influence of occupants’ adaptive behaviors on thermal comfort in MM buildings. A one-year field study in two MM office buildings with 5096 valid questionnaires was conducted in Chongqing, China, under hot summer and cold winter climatic characteristics by developing machine learning algorithms compared with classic thermal comfort models. Results show that incorporating adaptive behaviors as input variables enhances the performance of machine learning algorithms, leading to improved overall model performance, while the classic thermal comfort index PMV (predictive mean vote) presents the limited accuracy but the best recall in most cases. This paper also demonstrates that some energy-inefficient thermal adaptations were found in MM buildings during the HVAC mode, such as using air conditioning in mild spring and autumn, and frequent window openings during cooling periods of summer. It is therefore valuable for future research to further focus on how MM buildings both incorporate positive features and reduce negative features during the HVAC and NV modes.

A field study on thermal acceptability and energy consumption of mixed-mode offices building located in the hot-dry climate of Burkina Faso

To ensure thermal comfort in hot dry climates such as the climate of Burkina Faso, occupants of buildings often rely on air conditioning systems. Defining the appropriate conditions for thermal comfort is crucial to reduce energy consumption. This paper presents the findings of a field study that aimed to assess acceptable temperatures for thermal comfort and analyze the energy consumption related to the use of air conditioning systems in a mixed-mode office building. Surveys were also conducted to gather occupants’ feedback on thermal comfort. The results of the study revealed that the average air temperature was 27.1 °C with standard deviation of 1.7 °C. Fifty-four offices were investigated and all 93 occupants to the survey consider their thermal environment comfortable. The study also identified neutral air temperature and operative temperature which are between 26.2 °C and 26.5 °C, and 26.3 °C and 26.5 °C, respectively. The results show a non-significant gap between the neutral temperature of male and female subjects. It was observed that the energy consumption for comfort is linked to the neutral temperature. These findings can serve as a starting point for establishing thermal comfort parameters for mixed-mode office buildings in Sudano-Sahelian climates having a particular socio-cultural context.

Thermal sensitivity and adaptive comfort in mixed-mode office buildings in humid subtropical climate

ABSTRACT This study evaluates thermal sensitivity, expectations, and adaptability in mixed-mode ventilated buildings by subjective and objective assessments. A field study of simultaneous measurements of physical environmental parameters and right-here-right-now surveys was conducted in three office buildings from summer to winter in humid subtropical climates. The study confirmed previous findings that thermal adaptability and preferences changes as the ventilation system switches between natural ventilation (NV) and air-conditioning (AC). Occupants in this study showed more sensitivity to temperature changes than previously reported by ASHRAE Standards, yet thermal sensitivity was the same under different modes of operation. The neutral temperature was 0.5 oC higher than the predicted neutral temperature by ASHRAE 55 under both modes of operation. Thermal expectations were 1.5 oC warmer than the neutral temperature estimated by ASHRAE 55 when the building was operated by AC, while thermal expectations were almost the same as predicted by ASHRAE 55 under NV mode. Thermal comfort range was 0.75 oC wider than those predicted by ASHRAE 55 under NV operation, and the same as ASHRAE 55 under AC operation. The findings of this research provide a better understanding of mixed-mode building operations and perspectives from occupants, important for building designers and building operation managers.

Study on adaptive model and behavioural adaptation for thermal comfort of Japanese office buildings

This study focuses on the behavioural aspects of the occupants in Japanese office buildings. The behavioural adaptations such as window opening, heating/cooling use, clothing adjustments are important contributor factors for the adaptive thermal comfort. Therefore, understanding the behavioural aspects of the office workers can lead to have the guidelines to explain the mechanism of the adaptive model. The main aim of this study is to identify the differences in behavioural adaptation of the occupants in Japanese office buildings. Environmental parameters such as air temperature, relative humidity, and so on were measured in five mixed-mode office buildings located in Aichi prefecture were analysed for 15 months’ survey with 35 occupants. Thermal comfort survey together with the occupants’ behavioural survey were conducted in these office buildings. An adaptive relationship can be derived to estimate the indoor comfort temperature estimated by Griffiths method from the prevailing outdoor temperature. The results suggest that the proportion of heating and cooling use is related to the outdoor air temperature. The proportion of clothing adjustment is different for the different modes and are correlated to the outdoor air temperature. The acknowledge of the adaptive thermal comfort and the occupant behaviour of the selected buildings will be fruitful in designing the building with maximum thermal comfort in the future.

Operational energy and embodied impacts of retrofitting the window frames of mixed-mode office buildings

Design decisions normally consider the building's operational phase as the main criterion to reduce energy expenses in a building. In less efficient buildings, reducing the operational energy becomes the most important aspect to address in the design, construction and operational phases, for it represents the highest life cycle energy flow. However, energy-efficient solutions often reduce operational energy demand by increasing the building's embodied energy and greenhouse gas emissions, which have been overlooked in energy performance analyses. This work aims at investigating the operational energy and the consequent embodied impacts resulting from the retrofit of the window frame of mixed-mode office buildings located in a hot climate, with a focus on reducing the cooling energy demand. The method consists of an experimental study based on a case study, in which the EnergyPlus and the SimaPro software tools are used to evaluate the operational energy and the environmental impacts. Results showed that reducing the WWR and increasing the window opening factor conveyed operational energy savings but in some retrofit scenarios tested, these retrofit measures were counterproductive from the CED and GWP perspective. The main scientific contribution of this work is understanding the importance of the building analysis from a life-cycle approach. The results obtained can assist companies and designers to make their decisions from a broader environmental perspective.

Stochastic models for window opening and air-conditioning usage in mixed-mode offices for a humid subtropical climate in Brazil

The way buildings are operated highly influences energy consumption, and occupants play a significant role in it. However, challenges related to the prediction of occupants’ behavior decrease the potential to accurately predict a building’s energy consumption. Such inaccuracy presents one reason for the gap between measured and simulated energy data. In an effort to bridge this gap, this work aims at creating statistical models to predict occupant behavior, in relation to window and air conditioning operation in mixed-mode office buildings in a humid subtropical climate. The statistical behavioral models developed were based on data collected in an 18-month monitoring campaign conducted in São Carlos, Brazil. Two types of statistical methods were applied: generalized linear mixed and Markov chain models. Model results showed high probabilities of status change in both controls upon arrival and departure. Indoor temperature approximately at 24 °C and outdoor temperature around 23 °C show the lowest probability of either control being activated. In addition, the behavioral patterns presented by the models show an alternating use of the controls, indicating a conscious use of the available equipment.

INVESTIGATION OF THE THERMAL COMFORT AND PRODUCTIVITY IN JAPANESE MIXED-MODE OFFICE BUILDINGS

This study investigates the overall comfort and productivity of Japanese office workers in mixed-mode office buildings. The indoor thermal environment is adjusted using the air-conditioning in Japanese office buildings to maintain thermal comfort and productivity. Thus, it is necessary to research thermal comfort and productivity to understand how occupants prepare themselves to be at a comfortable temperature and perform their daily tasks under mixed-mode (MM) and free-running (FR) modes. Environmental parameters such as air temperature, relative humidity, and so on were measured in 17 Japanese office buildings with the help of digital instruments, and thermal comfort transverse surveys were conducted for two years in Tokyo, Yokohama, and Odawara of Japan. The data were collected every once a month for a day visiting each building with the measurement instruments, together with the questionnaires. Almost 3000 votes were collected. This paper evaluates the overall comfort discussions followed by how the occupant could achieve their productivity. The occupants were found to be thermally comfortable and productive in the office. The most suitable comfortable temperature range for MM mode was found to be 22–26 °C and 23–25 °C for FR mode. The workers' productivity range is defined by the globe temperature range of 21–27 °C for MM and 20–27 °C for FR mode. The findings should be useful to suggest that whenever new office buildings are designed, these factors always need to be taken into consideration.

Decision-making pathways to daylight efficiency for office buildings with balconies in the tropics

Daylight in the indoor environment is directly influenced by the building surroundings, envelope and its shading devices, such as balconies. Despite their potential in contributing to increase shaded periods and, at the same time, act as a daylight distribution system, balconies are not designed to their full potential when used in office buildings and the literature lack studies that investigate the effect of balconies on their luminous performance. This study aims to explore this niche: the integration of balconies to the design of office buildings in the tropics, in order to improve their daylight performance. The research method was based on a parametric design approach in combination with daylight simulations, while combining a systematic analysis with a data mining algorithm. The study revealed successful combinations of building design parameters as well as important cut-off points for design decision-making to achieve daylight efficiency in typical mixed-mode office buildings in the city of São Paulo , Brazil. Results provided multiple design routes to achieve successful performance targets showing that, if properly dimensioned, balconies could be an efficient shading device and daylight diffuser. As a key contribution, successful combinations of design parameters that allow deeper balconies to yield better Useful Daylight Illuminance levels were identified. Further details about when balconies stop influencing daylight performance results as well as when an increase in balcony depth becomes beneficial to performance were reported in attempt to develop design guidelines for the early design stages for office buildings in São Paulo. • Analysis of the role of balconies to improve daylight in office buildings. • Decision-making pathways to improve daylight whilst reducing cooling demand. • Cut-off points for design decision-making to achieve daylight efficiency.

Occupant behaviour in mixed-mode office buildings in a subtropical climate: Beyond typical models of adaptive actions

Recent years have seen considerable interest amongst building professionals and researchers in describing occupant behaviour. This has led to the development of models of adaptive behaviour to improve the accuracy and realism of building energy and indoor environment simulations. The objective of this study was to go beyond the typical behaviour models for building simulation and suggest models for other adaptive actions, such as changing clothes or ingestion of hot or cold beverages. The scope of the study is mixed-mode buildings, which alternate the air-conditioning operation and the opening of windows according to outdoor conditions and occupant preferences. A field study on occupant thermal comfort and behaviour in office buildings was performed in a subtropical climate in Brazil. Simple and multiple logistic models and mixed effects logistic models of adaptive actions were used to analyse key variables based on the results of the field campaign. Occupant clothing behaviour was affected by thermal sensation, clothing insulation and indoor operative temperature. The action of drinking a hot beverage was affected by occupant thermal sensation and the indoor operative temperature, while the cold drink intake was linked to both indoor and outdoor thermal conditions. Our analysis of windows and air-conditioning operation may be used by researchers and practitioners as input for simulations of mixed-mode offices, which can improve energy use predictions.

Assessing energy saving potentials of office buildings based on adaptive thermal comfort using a tracking-based method

Occupants’ thermal comfort and their adaptation behaviors are essential aspects of building design and energy operation. There is a growing need to better understand the impact of seasonal variation on occupants’ dynamic thermal comfort which provides evidence for building energy flexible design and management. The aim of this study is to investigate the interaction between occupants’ thermal sensation and adaptive behavior in office buildings. Such understanding can provide detailed adaptation rules of human behavior in dynamic office buildings and quantify energy demands. In this study, a framework of a tracking method is proposed, which combines data collection (continuous monitoring of environmental parameters and daily questionnaire surveys), time boundary division and data analysis. Using the tracking method, field surveys were carried out in three mixed-mode office buildings in Chongqing, China. The time-series data was analyzed based on the indoor operative temperature under free-running conditions and five seasonal periods are classified i.e. Latter Spring (LS), Early Cooling period (EC), Middle Cooling period (MC), Latter Cooling period (LC) and Early Autumn (EA). Results show that for the same outdoor temperatures in different seasons, occupants’ clothing insulation varied, indicating that the occupants were more sensitive to environmental changes in EA than in LS, as well as in EC than in LC. The study that flexible energy operation based on the thermal comfort demand can achieve energy savings compared with fixed temperature.

Energy performance of mixed-mode office buildings: Assessing typical construction design practices

Studies have demonstrated the energy savings potential of mixed-mode ventilated office buildings. Yet, it is important to widen the knowledge about how those buildings have been designed and built in practice, and which design parameters have greater influence on its energy performance. The aim of this paper was to evaluate how building envelope design parameters influence the energy performance of cellular mixed-mode office buildings, in order to identify key design variables. The analysis presents a comparison among literature research studies and typical construction practices from a sample of buildings located in the city of Sao Paulo, Brazil. According to a base case model, established based on the real buildings sample, three sensitivity analysis techniques were performed to obtain relative parameter sensitivity to thermal loads: OFAT, Morris and Monte Carlo. Results showed the importance of the window opening effective area and the reduced impact of the window-to-wall ratio on the energy performance of mixed-mode office buildings. By applying a multivariate regression model, it showed significant in predicting 78.1% of the variance in annual thermal loads. The accurate determination of annual thermal loads into mixed-mode office buildings can be used to optimize the envelope characteristics based on a combination of input data and the building geometry. Findings from this study could also be applied to other locations, provided that similar climatic environment and urban context are taken into account.

Mixed-mode office buildings: energy savings and illuminance levels in a high-altitude tropical climate

Edifícios de modo misto (MM), os quais usam ventilação natural e resfriamento mecânico para proporcionar conforto térmico e economia de energia, tem um grande potencial em climas onde o uso da ventilação natural é favorável (ex. Brasil). Nesses edifícios, as janelas operáveis são fontes tanto de ventilação natural quanto iluminação e ganhos internos, e suas características podem influenciar no consumo de energia. Este trabalho tem como objetivo avaliar o desempenho energético e luminoso de edifícios de modo-misto com janelas operáveis em um clima tropical de altitude no Brasil. Considerando variações nos parâmetros do envelope (percentual de abertura na fachada e orientação solar), o desempenho é avaliado em relação à economia de energia, tempo de uso do ar condicionado, período de utilização da ventilação natural e o balanço entre a demanda de energia e os níveis de iluminância. O método é composto por simulações computacionais nos programas Daysim e EnergyPlus. Os resultados mostraram que a estratégia de modo-misto tem um grande potencial para reduzir o consumo do ar condicionado. As grandes reduções ocorreram nos maiores PAFs, atingindo 39,4% de economia de energia (fachada norte, PAF = 80%). Apesar disso, enquanto o maior PAF forneceu maior disponibilidade de ventilação natural, aumentou o desconforto devido a elevadas iluminâncias, atingindo cerca de 90% da área do escritório. Portanto, quando o modo misto foi usado, os casos com melhor equilíbrio entre níveis adequados de iluminância e baixo consumo de energia foram a fachada sul com todos os PAFs e as fachadas leste e oeste com PAF de 30%. É importante ressaltar que a adoção destas soluções depende dos requisitos de projeto do edifício.

Towards the quantification of energy demand and consumption through the adaptive comfort approach in mixed mode office buildings considering climate change

Heating, Ventilating and Air Conditioning (HVAC) systems represent one of the highest energy consumptions for office buildings. They are traditionally based on fixed setpoint temperatures during working hours and disregard outdoor conditions. The use of natural ventilation coupled with HVAC systems is frequently proposed when considering the global tendency towards reducing energy consumption in buildings. Buildings working under mixed mode instead of full air-conditioned mode, are a climate adaption development and usually lead to a decrease in energy consumption. However, there is no consensus on comfort thresholds and it is difficult to predict energy demand and consumption when considering global warming. This research focuses on quantifying the application of an adaptive comfort control mode in mixed mode office buildings. It consists of using daily setpoint temperatures based on the adaptive thermal comfort approach, in both present and future scenarios. The results show a 74.6% reduction in energy demand and a 59.7% drop in energy consumption when the adaptive comfort control implemented model (ACCIM) is applied in the current scenario. Results also establish that the ACCIM is more resilient to climate change, despite the fact that an increase in energy demand and consumption can be expected. The reduction of the energy demand ranges, with respect to the baseline model, from 31.0% currently to 39.1% in 2080, while energy consumption changes from 40.2% to 62.0% in 2080.

Influence of building design and control parameters on the potential of mixed-mode buildings in India

The potential of mixed-mode office buildings with varying design and control parameters is examined by using an uncertainty analysis in the three climate zones of India. The analysis is in terms of cooling energy consumption, thermal comfort conditions, and natural ventilation hours. Furthermore, influential parameters are identified using sensitivity analysis. In this study, opening the windows enables natural ventilation. Night-time ventilation through the windows is not enabled because these are mostly closed at night. A maximum natural ventilation of 10% of the total building occupancy hours are observed in warm and humid, and hot and dry climates; however, they are slightly higher in the composite climate. A further increase in the number of natural ventilation hours leads to an increase in the occupancy hours outside the Indian Model for Adaptive Comfort model for mixed-mode buildings with at least 90% of occupants are satisfied. There are no occupancy hours outside of 80% of occupants are satisfied. The choice of thermal comfort band is crucial for determining the potential of mixed-mode buildings. The cooling setpoint temperature, building size, window solar heat gain coefficient, and surface properties of exterior surfaces are identified as the more influential parameters than the thermophysical properties of building envelope constructions. Although the building envelope which is in compliance with the Energy Efficient Building Code of India increases energy efficiency during air-conditioning periods, whether it reduces natural ventilation hours, because of overheating during such period remains to be determined.

Associations of occupant demographics, thermal history and obesity variables with their thermal comfort in air-conditioned and mixed-mode ventilation office buildings

Building occupants' perception of thermal comfort can be influenced by a number of contextual factors, such as their demographic and anthropometric characteristics, behavioural patterns and cultural aspects. The objective of this work is to investigate the relationship between various contextual factors and the perception of thermal comfort in workplaces, by examining the gap between the current thermal comfort criteria and the actual requirements observed for different groups of occupants. The classic thermal comfort field research design i.e. simultaneous measurements of physical environmental parameters and questionnaire surveys, was implemented for two years in both centralised HVAC and mixed-mode office buildings located in Southern Brazil. Over 7500 questionnaires were completed by occupants of the buildings. Key variables including the participants' gender, age, body mass index, prior exposure to air-conditioning and building ventilation type were investigated in order to identify their association with thermal discomfort in the office workplace. Our results suggest that males, overweight occupants and those who are more frequently exposed to air-conditioning are more likely to express thermal discomfort due to feeling ‘warm’, compared to females, non-overweight occupants and those who were exposed to air-conditioning less frequently. In comparison, females, non-overweight occupants, air-conditioning light users, and occupants of centralised HVAC buildings were more likely to declare ‘cold’ discomfort. We also investigated how those variables were related to the width of thermal comfort zone. The analysis indicates that different groups of occupants require different comfort zones, suggesting that group differences should be considered when designing/operating spaces for diverse groups of occupants.

Field study of mixed-mode office buildings in Southern Brazil using an adaptive thermal comfort framework

Studies about thermal comfort in mixed-mode buildings have been performed in order to better understand this type of building and its influence on occupants’ thermal perception. However, there is still no consensus amongst researchers regarding whether mixed-mode buildings should be evaluated separating each mode of operation (natural ventilation or air-conditioning) and whether adaptive thermal comfort theory applies to both modes of operation. Does the mode of operation of a mixed-mode building, ceteris paribus, influence occupant thermal comfort perception? Trying to answer such questions, field studies on thermal comfort were conducted in three mixed-mode office buildings in the city of Florianópolis (a temperate and humid climate), Southern Brazil. Buildings were equipped with mechanical cooling systems and operable windows, both controlled by occupants. Thermal comfort questionnaires were collected at the same time and location that environmental variables were measured by microclimate instruments. Almost 5500 questionnaires were answered by occupants of the three buildings in both modes of operation over the four seasons. Analysis of the results indicated that occupants’ thermal perception was influenced by the mode of operation. Adaptive thermal comfort models were developed for natural ventilation and air-conditioning mode of mixed-mode buildings. This work found no evidence to support a single adaptive model for mixed-mode buildings. During natural ventilation mode, occupants adapted to indoor temperature fluctuations as predicted by the adaptive thermal comfort theory. On the other hand, during air-conditioning operation a weak adaptive relation (indoor comfort temperature vs. outdoor climate) was observed – a range of about 4°C of indoor temperature fluctuation may be used for the operation of the air-conditioning system without compromising thermal comfort, which could help saving energy. This work is a first step towards building an adaptive model of thermal comfort for Brazilian subtropical climate.