Adaptive Thermal Comfort Model Research Articles

Exploring the natural ventilation potential of urban climate for high-rise buildings across different climatic zones

The natural cooling capacity of the environment can effectively reduce the building energy consumption by natural ventilation (NV). For architects, developing NV strategies requires a comprehensive understanding of the distribution characteristics of urban meteorology. This study investigates the vertical characteristics of urban local-scale meteorological parameters across climatic zones. It aims to assess the climatic potential for NV of outdoor air in high-rise buildings. Firstly, using Weather Research and Forecasting (WRF) model coupled with Local Climate Zone (LCZ) data and sounding data, the vertical distribution of meteorological parameters are explored in typical urban areas across different climatic zones. Then, based on an adaptive thermal comfort model, the climatic potential is assessed for NV in high-rise buildings via the indicator of annual natural ventilation hour (NVH). Finally, the characteristics of urban meteorology is further is analyzed in terms of its impact on the natural ventilation potential (NVP) in each climatic zone. Results indicate that air temperature decreases with height from 0 to 500 m, with more pronounced temperature gradients in compact building areas. Near the ground level, Kunming (Temperate Zone) has the most NVH, reaching 4,840 h annually. However, when building height exceeds 100 m, Guangzhou (Hot Summer and Warm Winter, HSWW) becomes more suitable for NV. In cold regions, low temperatures limit NVP during winter, while high humidity constrains it in Temperate and HSWW zones. Overall, the annual NVP in high-rise building areas exceeds that of low-rise building areas. These distribution characteristics of NVP are anticipated to promote the utilization of natural resources for sustainable urban development.

Towards developing a model of adaptive acoustic comfort in the built environment: A thematic analysis from an expert focus group

The adaptive capacities of building occupants have so far been primarily investigated in relation to the thermal climate through the adaptive thermal comfort model. However, the concept of adaptation extends beyond thermal conditions and is relevant to other sensory modalities, such as acoustics. This is significant for both human health and well-being, as well as environmental considerations. The latter aspect is linked to potential variations in acoustic sensitivities between naturally ventilated and mechanically ventilated buildings, which, if identified and acknowledged, could lead to a greater applicability of passive ventilation strategies through tailored acoustic criteria. Drawing from thematic analysis of discussions held in a focus group comprising 8 experts in acoustics, soundscape, and adaptive thermal comfort, this study aims to 1) delineate the underlying assumptions of acoustic adaptation in built environments, and 2) establish a research agenda towards developing a framework for adaptive acoustic comfort. The identified themes include: the definition of adaptive acoustic comfort, potentially contributing acoustic and non-acoustic factors, differences and similarities with the adaptive thermal comfort model, and the methodology for collecting data. In terms of results, 1) adaptive acoustic comfort would be based on potential modifying effects of recent past acoustic exposure and other environmental factors (including multi-domain effects), contextual, and personal factors on people's acoustic expectations and preferences. 2) To test this concept, the very first step will have to be the construction of a comprehensive global acoustic comfort database.

Effects of an extreme heat event on indoor conditions of social heritage housing in Mediterranean climate

Social heritage housing in Mediterranean historic cities is particularly vulnerable to climate change hazards as protection policies lead to its exclusion from energy retrofitting programmes, leaving their residents - at higher risk of fuel poverty and the heat-island effect – defenceless. Increasingly frequent heatwaves can potentially produce “overheating” in these buildings, a thermal state that impedes people's comfort with harmful consequences to their health. Other indoor air quality factors, like humidity and CO₂ levels, also affect residents' health. The objective of this research is to evaluate the actual indoor environmental quality of three occupied dwellings in social buildings of high heritage value located in two historic cities in Andalusia (Spain) during the extreme heat events that occurred in 2022. A monitoring campaign was conducted and the data collected over the summer was analysed and evaluated using existing metrics. Our results show that the CO2 concentration rates generally remained below the upper limit of 1000 ppm in all cases, probably due to the high air infiltration rates measured (5.83 h−1, 4.39 h−1 and 14.65 h−1). On the contrary, the relative humidity rates were outside the acceptable range (45–60 %) for 90 % of the occupied hours in all cases. In the warmest city, overheating was continuous and severe in all rooms, according to the metric adopted (CIBSE standards TM52 and TM59 under the adaptive thermal comfort model). The situation was particularly critical in the free-running bedroom, but the overheating index values in the living rooms, where air conditioning was installed and used about 50 % of the occupied time, also deviated significantly from the acceptable limits.

Energy Efficiency Assessment of Existing Rural Houses in Nantong Based on Human Thermal Comfort

Current research on rural houses in China mainly focuses on improving energy efficiency, with relatively few studies addressing energy-saving measures and enhancing thermal comfort for residents. Therefore, this paper focuses on existing rural houses in Nantong City, Jiangsu Province, as the research object. Through on-site measurements and questionnaire surveys, it was found that the average indoor temperature of rural houses is 28.5 °C in summer and below 10 °C in winter, failing to meet the comfort needs of the villagers. To further study human thermal comfort, a linear regression method was used to establish an indoor Mean Thermal Sensation (MTS) model for Nantong’s rural houses. The neutral temperature in summer was found to be 26.46 °C, and an adaptive thermal comfort model for rural residents in the Nantong area was established. Through single-factor simulation and orthogonal experiments, the optimal comprehensive energy-saving renovation scheme was proposed. Finally, a typical rural house in Zhangzhuang Village was used as a case for building renovation practice. After the renovation, the number of thermal comfort hours increased by 145 h per year, the thermal comfort compliance rate reached 47.07%, and the overall energy-saving rate was 57.41%.

Research on Virtual Energy Storage Scheduling Strategy for Air Conditioning Based on Adaptive Thermal Comfort Model

Research on Virtual Energy Storage Scheduling Strategy for Air Conditioning Based on Adaptive Thermal Comfort Model

Using setpoint temperatures based on adaptive thermal comfort models: The case of an Australian model considering climate change

It has recently become clear that using adaptive thermal comfort models to determine setpoint temperatures is a successful energy-saving method. Global models like ASHRAE 55 and EN16798-1 have been used in recent experiments using adaptive setpoint temperatures. This work, however, has taken a different route by concentrating on a region-specific Australian adaptive comfort model. The goal is to compare the energy implications of the use of setpoint temperatures based on the Australian local comfort model compared to the worldwide adaptive ASHRAE 55 model to highlight the significance of choosing the most fitting comfort model for making accurate predictions. All of Australia's climate zones are taken into account, as well as mixed-mode building operation scenarios, current and future scenarios, namely the years 2050 and 2100 for Representative Concentration Pathways (RCP) 2.6, 4.5, and 8.5. It has been found that the Australian-model-based adaptive setpoint temperatures taking into account mixed-mode significantly lowers energy demand when compared to the ASHRAE 55 adaptive model (average energy-saving value of 63 %). Considering climate change, the Australian model has an average energy demand of 13–26 kW h/m2·year, and an average increase of 1–13 kW h/m2·year. In the case of ASHRAE 55 model, energy demand decreases in future scenarios and average values range between 3 and 11 kW h/m2·year. Therefore, setting setpoint temperatures in accordance with the Australian regional adaptive comfort model is a very efficient method for energy conservation. These differences raise awareness on the importance of the selection of the appropriate adaptive thermal comfort model.

Passive cooling and thermal comfort performance of Passive Downdraught Evaporative Cooling (PDEC) towers in a Saudi library: An on-site study

In the hot arid climate of Saudi Arabia, where air conditioning, primarily fueled by fossil fuels, accounts for a significant portion of energy consumption, the implementation of Passive Downdraught Evaporative Cooling (PDEC) towers presents a sustainable solution. This study conducts an extensive evaluation of PDEC towers in a public library, focusing on their effectiveness in reducing reliance on conventional cooling and enhancing thermal comfort. Through detailed field measurements, the study examines the influence of wind speed on the towers' cooling performance, correlating it with internal environmental conditions. The research extends to a comparative analysis of two prominent thermal comfort models: the Predicted Mean Vote (PMV) and the Adaptive Thermal Comfort (ATC) model. Findings indicate a notable interaction between wind speed and indoor air temperature, where increased wind speeds correspond to higher indoor temperatures. Despite this, the PDEC towers demonstrate a significant reduction in temperature, maintaining cooling effectiveness between 70 % and 75 %. The comparative study of thermal comfort models reveals that the ATC model provides a more relevant assessment of comfort levels in naturally ventilated spaces, with 71 % of the recorded temperatures falling within the comfortable range during the monitoring period. The research highlights the PDEC tower's potential in delivering effective passive cooling, adaptable to wind speed changes, and contributing to a sustainable and energy-efficient building environment in hot arid climates.

Seasonal field study on thermal comfort in university classrooms in Mediterranean climate

The assessment of indoor environmental conditions of educational buildings is not only essential to ensure the correct performance of heating, cooling and ventilation systems but it is also fundamental to guarantee a suitable environment. This study aims to analyse the thermal comfort of students in teaching–learning spaces in university buildings with natural ventilation. A field measurement campaign and a questionnaire survey were carried out from September 2021 to June 2022 in educational buildings in southern Spain. The collected data were analysed and the neutral temperature in each season was obtained, based on the thermal sensation votes of 1966. The neutral temperatures found in this study were 23.5°C, 23.1°C, 23.3°C and 23.9°C, for autumn, winter, spring and summer, respectively. The ranges obtained for 90% acceptability in the winter season (21.1°C–25.1°C) provided lower temperature limits than the ranges obtained in the summer months (22.6°C–25.3°C). The highest values for clothing insulation were found in the autumn (0.90 clo) and winter (0.75 clo) seasons, compared to the spring (0.5 clo) and summer (0.4 clo) seasons. An adaptive thermal comfort model was applied. These findings could be used to improve thermal comfort and to optimise energy consumption according to the students’ actual thermal perception.

Deriving thermal sensitivity across educational stages: Evidence-based definition of Griffiths' coefficient

Thermal sensitivity directly impacts occupants' comfort by influencing neutral temperatures and comfort models. The Griffiths method, commonly used to derive thermal sensitivity, often assumes a constant value of 0.5°C-1 for calculating occupants' neutral temperatures. However, it is important to note that thermal sensitivity can vary depending on factors such as building type, climatic conditions, operation mode (i.e., natural ventilation, mechanical ventilation, or mixed mode), and occupants' age. This study aims to define whether age-dependent differences in thermal sensitivity exist in schools, achieved through the formulation of specific Griffiths coefficients for each educational stage. A field study was conducted in naturally ventilated classrooms within the same climate zone, collecting 1548 subjective responses and objective measurements from students across different educational stages. The results demonstrate that the thermal sensitivity in schools is lower than the commonly assumed values, especially in primary schools (0.085°C-1), and it increases with students' age. This variation is reflected in the corresponding neutral temperatures, which also increase with age. Using a constant Griffiths coefficient can lead to significant estimation errors in neutral temperature, potentially up to 1 °C, impacting both comfort and energy consumption. This study emphasizes that there are different thermal comfort expectations related to students’ age. To improve the reliability of adaptive thermal comfort models and ensure accurate neutral temperatures estimations, it is essential for future research to consider the students' age when evaluating the thermal sensitivity.

Exploring thermal comfort in rural houses of Chhattisgarh state, India: A comprehensive survey and adaptive model analysis

Thermal comfort studies in India are very much at an emerging stage. According to Indian codes, in the summer, the comfortable temperature range for residential buildings is 23–26 °C. The recommended Indian residential comfort range does not consider the impact of India’s enormous cultural and geographical heterogeneity. Additionally, there seems to be very little effort to conduct a thermal comfort field survey in India’s rural regions. In recent years, houses in rural India have been converted from kutcha (mud houses) to pucca (concrete houses). This work is aimed at proposing an adaptive thermal comfort model for the premonsoon season in the rural area of Raipur, Chhattisgarh, India. The model was achieved using a field study survey conducted in 80 rural area houses in the months of June and July. Regression analysis, the Griffiths method, and the Fanger method have been adopted to analyze thermal comfort. Based on the regression analysis, the comfort band (voting −1 to +1) is established in the range of 28.39 °C to 32.31 °C, with 30.30 °C as the neutral temperature. The study has been carried out to assess the influence of gender, age, controls, and fan usage on thermal comfort perception in rural households.

Improved grey principal component analysis neural network based adaptive thermal comfort model: Application in the enclosed cabin with microclimatic conditions

Predicting the thermal comfort of operators in enclosed cabins under extreme operational conditions is crucial for the enhanced and optimal design of cabin air circulation systems. In this study, an improved supervised machine learning algorithm, namely a Grey Principal Component Analysis (G-PCA) was proposed to evaluate the operators’ thermal comfort. The comprehensive dataset was first attained and constructed from the proposed 32 indicators, which recorded each tested object’s EEG and physiological features, core body temperature, skin temperature, and subjective assessments. The accuracy of the proposed model was demonstrated by comparing it with the results predicted via existing indicator sets (PMV and 7-point skin temperature) and modelling algorithms (BP and PCA BP). The results showed that the prediction accuracy of the PMV model, 7-point skin temperature, the 32 indicators were found to be 79.4%, 82.8%, 96.1%, utilising the G-PCA WNN algorithm, and the prediction accuracy of BP, PCA BP, G-PCA WNN is 82.3%, 89.9%, 96.1%, based on the 32 indicators. A conclusion could be drawn that the proposed 32 indicators can incorporate a more comprehensive range of thermal comfort information, and the improved G-PCA WNN thermal comfort prediction model achieved the best prediction performance among the compared algorithms and models.

An investigation of indoor thermal environments and thermal comfort in naturally ventilated educational buildings

Indoor thermal conditions are essential in educational buildings. The health and well-being of students can be affected by a poor thermal environment, which also has a clear impact on building energy consumption. In this context, the indoor thermal environment in naturally ventilated university classrooms is explored in this study during a complete academic year. A monitoring campaign and a questionnaire survey were conducted simultaneously in higher education buildings in Spain. A total of 2115 sets of data were collected. Thermal sensation prediction indices (predicted mean vote, extended predicted mean vote and adaptive predicted mean vote) were applied to evaluate student’s thermal perception and their prediction accuracy was assessed. Additionally, two machine-learning models, based on Artificial neural network (ANN) and random forest (RF) algorithms, were formulated to predict occupants’ thermal sensation. The obtained results evidenced that the proposed ANN and RF models outperform traditional indices. Finally, it is also proposed an adaptive thermal comfort model. The results obtained suggest that students have a greater adaptive capacity to changes in environmental conditions than suggested by the ASHRAE-55 adaptive model and that they preferred an environment with lower temperatures than those suggested by the EN-16798 adaptive model.

A systematic approach for assessing buildings with natural materials in the Mediterranean climate

Natural building materials, including bioaggregates and biocomposites, have been making a comeback in recent years, in an attempt to minimize the Embodied and Operational Energy and Carbon (EE, OE, EC, OC) related to construction. This paper presents monitoring results of three buildings (two residential and one educational) built with such materials in the Mediterranean climate of western Crete. Temperature and relative humidity monitoring results show a very stable indoor environment behavior even when the buildings were unoccupied, thus not appropriately operated. Additional measurements undertaken and presented here include CO2 concentration in the occupied residential building with a combustion heater; and blow-door tests to better understand infiltration issues related with such construction. Results analysis shows that such materials are appropriate alternatives, definitely in bioclimatic building design for the specific climate. Indoor conditions analyzed vis-à-vis the adaptive thermal comfort model are shown to be within the thermal comfort zone, almost for all climatic conditions.

Thermal comfort in Indian naturally ventilated buildings: A comprehensive review

A significant amount of global energy is expended to meet the cooling requirements in buildings. There has been a huge shift from naturally ventilated buildings to air-conditioning with an annual shift of 15.75% considering an overall increase in extreme heat incidences in cities during summer. Studies show that reducing cooling energy consumption significantly is possible by applying passive approaches in buildings. In this study, thermal comfort in naturally ventilated buildings on a global scale, with a specific emphasis on India, has been examined through a review of existing studies. Bibliometric analysis, followed by comparative analysis, is used to identify and evaluate research on methods for assessing thermal comfort and developing adaptive models for occupants in diverse buildings and climates. It is observed that Griffith’s method is popularly used along with PMV-PPD to obtain thermal comfort interpretations in Indian naturally ventilated buildings. Moreover, the major contributors to thermal comfort studies are Europe and Southeast Asia. Further, Indian subcontinent has a wider comfort range than what international field studies have suggested. While the residents of naturally ventilated buildings in cold climates have a comfort range of 12.5–32 °C, for composite climates, the range is 15.3–33.8 °C, and for hot and humid climates, the range is 18.4–33.5 °C. Additionally, the variation in the thermal comfort range is also significantly influenced by local cultural factors. Therefore, a customized thermal comfort model that should not only reflect the unique climatic conditions but also include cultural factors of the Indian subcontinent can ensure that building occupants are provided with a comfortable and healthy indoor environment.

Calculating Comfort Indexes and Applying Comfort Models to Predict Thermal Sensation Vote in Sports Centres

Predicting the indoor thermal comfort of people while doing sports might pose challenges, as the combination of high metabolic rate, increased humidity of the space due to physical exercise, and the alternate of more and less intense tasks influence perception. This paper is aimed at comparing environmental data (temperature and relative humidity) and calculating comfort indexes (heat index) and two comfort models (Fanger’s predicted mean value and the adaptive thermal comfort model) with people’s perceptions of the environment. Indoor environmental data for the analysis were collected by monitoring several rooms in eight sports centres in a Mediterranean climate. The thermal sensation votes (TSVs) of the occupants were obtained through an online survey. A detailed explanation of the methodology of the monitoring, creation, and management of the survey and the tools used to analyse the data is provided. Results compare the relation between the TSV and the parameters or indexes calculated. Fanger’s predicted mean vote (PMV) model is not able to correctly predict people’s sensations, neither for low nor for high metabolic rates. Finally, the neutral temperature of the adaptive model for the studied conditions is calculated. Among the studied parameters and indices, temperature exhibits the strongest correlation with the thermal sensation of the occupants. However, occupants did not report a significant sensation regarding humidity in accordance with the objective conditions of the rooms. The heat index also did not show any significant correlation with the TSV. Nevertheless, across a wide range of conditions, including variations in metabolic activities, temperature, and relative humidity, the percentage of thermal dissatisfaction (indicated by “very hot” responses) remains consistently high. Notably, the temperature at which a peak in neutral sensation can be achieved is less than 21° for low metabolic rate activities.

PENILAIAN JEJAK KARBON DAN KESELESAAN TERMAL DI BENGKEL WELDING DAN KONKRIT

Abstract: Global warming is the phenomenon of global temperature increase from year to year due to the greenhouse effect. Currently, carbon dioxide concentrations are estimated to be most dominant in the atmosphere. Therefore, this carbon footprint study will be conducted in the institutional area to determine the actual amount of CO2 present in Politeknik Kuching Sarawak institution. Research on ways to reduce carbon dioxide emissions will also be conducted indirectly. The objective of the study was to analyze carbon dioxide footprints in skill institutions that emit large amounts of gas emissions. Adaptive thermal comfort model is methods can be identified from previous readings to record or analyze data by using Air Quality Detector, Lux Meter and Anemometer. While to refer and compare the data obtained, we refer to the existing standards that are ASHRAE 55 standards and CIBSE Guide A. The result found is carbon footprint in concrete and welding laboratory in Politeknik Kuching Sarawak institution is still in the safe range but measures or proposals to reduce carbon emissions need to be initiated to maintain safety in terms of ventilation and environment in the institution.

Exploring the natural ventilation potential for supertall buildings considering vertical meteorology: A case study in Harbin, China

The natural ventilation strategy is gaining increasing attention from architects due to its advantages in reducing energy consumption and maintaining a healthy indoor environment. For supertall buildings, the vertical variation in outdoor meteorology has inspired us to explore the energy-saving potential by adopting natural ventilation strategy. This study investigates the impact of vertical variation in urban meteorology on the natural ventilation potential (NVP) of supertall buildings based on numerical simulation and field observation. Firstly, the Weather Research and Forecasting (WRF) model is used to simulate the urban meteorology of the study region by integrating the local climate zone (LCZ) map. Next, meteorological data from sounding experiments by unmanned aerial vehicle (UAV) and monitoring stations are used to validate the simulated result, and thereby to explore the vertical meteorology in urban area. Finally, the vertical NVP in supertall buildings is quantitatively assessed considering the impact of LCZ in urban areas based on thermal comfort models. The findings reveal that atmospheric temperature decreases approximately linearly with increasing altitude, with a maximum temperature gradient of up to −0.82 °C/100 m. Static models underestimated the annual natural ventilation hours (NVHs) by at least 348 h compared to the adaptive thermal comfort model. Compared to low-density building regions, the higher NVP is indicated in high-density building regions. This study aims to illustrate the importance of considering the vertical variations of urban meteorology, and is expected to assist architects and policy makers in quantifying the energy saving potential of natural ventilation in supertalls.

Holistic analysis to reduce energy poverty in social dwellings in southern Spain considering envelope, systems, operational pattern, and income levels

Energy renovations carried out in energy poor households should consider a holistic view in the short-, mid- and long-term, especially in warm areas such as Andalusia, in the south of Spain. This study addresses the existing knowledge gap on technological and economic interactions in the energy poverty of family units in warm areas of Spain. To do this, the study performs a parametric analysis. In this parametric analysis, a dataset of 36,230,400 instances was developed considering envelope, HVAC systems, an operational pattern (based on static and adaptive thermal comfort models), and family units’ income levels. Likewise, the energy poverty ratio was compared based on the high share of energy expenditure in income (2 M). The results showed that improving envelope and establishing adaptive operational patterns did not effectively reduce energy poverty cases in low-income families in the south of Spain. However, these strategies were appropriate in family units with greater incomes to remove energy poverty cases, regardless of the low reduction in energy consumption by improving the envelope. This study is a starting point to combine social aids, energy improvements and rational energy use through adaptive operational patterns.

Assessment of the energy implications adopting adaptive thermal comfort models during the cooling season: A case study for Mediterranean nursing homes

Assessment of the energy implications adopting adaptive thermal comfort models during the cooling season: A case study for Mediterranean nursing homes

Enhancement of Indoor Thermal Comfort Using Alternative Building Materials and Construction Technology in Low Income Housing - A Case of Trivandrum, Kerala

In India, rapid urbanisation followed by increased demand for housing has led to higher energy consumption in the building sector and a larger percentage of which is contributed by the housing sector. And the population using affordable housing is higher compared to other developed countries (MOUHA, 2013). The occupants tend to achieve the desired level of thermal comfort by personal adjustments and mechanical means. Using energy intensive methods for comfort is not feasible for a country, like India, with a low energy economy. This study analyses the indoor thermal comfort in low income housing with respect to the building materials and construction technology used. Two typologies of housing were studied which includes a row housing constructed using conventional materials, with hollow brick cement plastered walls and RCC roof slabs, and a vertical stacking multi dwelling constructed using Laurie Baker’s alternative construction technology, with rat-trap bond brick walls and filler slabs. The study explored the current scenario of housing based on a thermal comfort field study using questionnaire survey and onsite measurements (following ASHRAE class II protocol) which was then simulated using Design Builder software changing the wall material used to understand the improvement in indoor thermal comfort. An adaptive thermal comfort model and neutral temperature was generated for both types of housing which was then compared with IMAC Model ranges. The adaptive comfort ranges obtained for both housing were too warm than the acceptable ranges and the PMV values in row housing are hot, while that in vertical stacking is slightly warm to warm. The neutral temperature obtained in vertical stacking housing (28 deg C) is within the acceptable range, whereas that of row housing (28.8 deg C) is greater than the upper limit range of neutral temperature under the IMAC model. The results showed that building material with good thermal performance can cause a significant reduction in indoor temperatures thus improving indoor thermal comfort. Thus indoor thermal comfort in low income housing can be improved by using alternative construction technology, without compromising cost-effectiveness and affordability, and thus contributing to energy efficiency.