Thermal Comfort Conditions Research Articles

Effects and Interactions of Incubation Time and Preplacement Holding Time on Mortality at Placement, Yolk Sac Utilization, Early Feeding Behavior and Broiler Live Performance.

The effects and interactions of incubation time and chick preplacement holding time on mortality at placement, utilization of yolk sac, crop filling rate, early feeding-drinking behavior, and broiler live performance were investigated. Ross 308 broiler hatching eggs from a 39-week-old flock were set in two identical setters in a commercial hatchery, with the setting time 12 h earlier in one machine. At the end of incubation, chicks were removed from the hatchers at the same time. Thus, the incubation times were either 504 h (normal incubation time (NIT) treatment) or 516 h (longer incubation time (LIT) treatment). After the pull time, chicks from each incubation time group were subjected to either 6, 24, 48, 60, or 72 h preplacement holding times. At placement, chicks were given access to feed and water. In total, 19,200 chicks were randomly assigned to a total of 10 subtreatment groups (2 incubation times × 5 preplacement holding times). Therefore, a total of 1920 chicks were used in each subtreatment group for the grow-out period in a commercial broiler house. For the first week of the experiment, 160 randomly selected as-hatched (not sexed) chicks were placed in 12 replicate floor pens (120 total pens). From the second week of age onward, chicks from two pens were combined into six replicate pens, with 320 chicks per replicate (60 total pens). An interaction was found between incubation time and preplacement holding time for residual yolk sac (RYS) weight (g, %) (p < 0.001). RYS weight was greater at pull time and at 6 and 24 h of preplacement holding in the NIT treatment compared to the LIT treatment, while differences were no longer evident at 48-72 h. The lowest percentage of chicks with full crops and eating activity was observed in the shortest preplacement holding time (6 h) group at 3 h after placement. As expected, the initial BW at placement clearly decreased with increasing duration after the pull time (p < 0.05), with the highest and lowest weights found in the 6 and 72 h holding time treatments, respectively. This BW difference was still evident at 35 d after placement and chicks held for the longest period after the pull time (72 h) showed the lowest BW (p < 0.001). However, there was no significant difference between the 6 and 60 h preplacement holding times. Mortality during the first 7 d after placement increased only when the preplacement holding time was extended to 72 h (p = 0.031). Similarly to the 7 d results, chicks held for 72 h exhibited higher 0-35 day mortality compared to those held for 6 or 24 h (p = 0.028). Neither BW nor mortality was affected by incubation time treatment at 35 d after placement (p > 0.05). It can be concluded that there were no significant differences in average BW and mortality, up to and including a 60 h holding time under thermal comfort conditions, but a 72 h preplacement holding time resulted in final BW and mortality being negatively affected. In addition, LIT tended to have a beneficial effect on BW and mortality compared to NIT when the preplacement holding time was shorter (6-24 h) but had a negative effect for extended holding times (48-72 h).

Research on indoor thermal comfort of expressway service building based on SPMV

According to the characteristics of “temporary stay” and “streamlined” passenger flow in expressway service buildings, this article uses the “streamlined thermal comfort” index to characterize the indoor thermal comfort condition of the buildings,to create an overall comfortable space based on the “streamline trajectory”.The article proposes to divide comprehensive thermal comfort into “regional static thermal comfort” and “inter-zone dynamic thermal comfort”, revise the existing PMV(Predicted Mean Vote) index, and integrate the characteristics of the two types of indicators to form a comprehensive thermal comfort evaluation index based on “passenger trajectory”. The main work of this article includes: Firstly, using the temperature frequency method, a regression curve fitting between actual thermal sensation and indoor operative temperature is conducted to obtain the acceptable thresholds of MTS(Median Thermal Sensation), PMV neutral temperature, and actual temperature, forming a streamlined static thermal comfort index. The metabolic rate M value is segmented according to a 6-minute stabilization time to form a streamlined dynamic thermal comfort index; Introduce the factor of regional residence time τ to form a comprehensive thermal comfort index for streamlining. Secondly, an empirical analysis was conducted on the revised indicators, and the measured TSV(Thermal Sensation Vote) = -1, 0, 1 curves under different operating conditions in summer and winter were fitted with the SPMV(Streamline-Predicted Mean Vote) curve, revealing that the error in each functional area was within 10 %. The analysis results show that the modified index SPMV has greatly improved its consistency with the measured thermal sensation TSV, and can be used to evaluate the indoor thermal comfort of expressway service buildings in cold regions.The research results have high practical value for creating comfortable indoor environments in different indoor spaces of transportation commercial complexes, and have universal significance for creating streamlined indoor dynamic comfortable environments in urban commercial complexes.

A satellite-based approach for thermal comfort simulation: A case study in the GBA

With global warming, the issue of urban surface overheating has emerged as one of the most urgent concerns for modern cities worldwide. However, the simulation of thermal comfort with high spatiotemporal resolution remains a challenge. In this study, an approach is presented to integrate several global meteorological raster data for the production of high spatial and temporal resolution thermal comfort raster datasets. Our approach produced a dataset in the Guangdong-Hong Kong-Macao Greater Bay Area (GBA) covering 98.30% of diurnal moments in 5 years, and the spatial coverage of the region exceeded 87%. The assessment results showed that from 2002 to 2020, mean universal thermal climate index (UTCI) slightly increases from 16.0 to 20.6 °C to 17.3–26.2 °C, dominated by no heat stress (9.0 °C–26.0 °C). The low-value center of UTCI locates in the north GBA, around Zhaoqing and northern Guangzhou, while the high-value center moved westward from Huizhou to Foshan, Dongguan, and the south of Guangzhou. Over the past 18 years, the heat stress has become larger in the spatial extent and more prolonged. The heat island effect has intensified over the past 18 years, resulting in a coexistence of the positive heat island intensity and the negative heat island intensity. The result investigates urban thermal comfort conditions for urban thermal environment management and provides a spatial reference for human-centered urban planning.

Study on Microclimate and Thermal Comfort in Small Urban Green Spaces in Tokyo, Japan—A Case Study of Chuo Ward

Small urban green spaces are abundant in densely populated urban areas, but little is known about their impact on the urban heat island effect and thermal comfort. Therefore, this study selected as research sites four small urban green spaces in a typical high-density built-up area, Chuo Ward in Tokyo, Japan. The ENVI-met software 5.1.1 simulation method was used to analyze these sites’ microclimate and thermal comfort conditions. The following are the results: (1) Small urban green spaces significantly reduce urban air temperatures, particularly during hot weather, with temperature reductions ranging from 2.40 °C to 2.67 °C, consistently lower than the highest temperatures in Tokyo’s Chuo Ward, mainly between 1:00 and 2:00 p.m. (2) Thermal comfort analysis indicates that small urban green spaces can significantly improve urban thermal comfort during the day, particularly around noon, by reducing one or two thermal comfort levels compared to typical urban street blocks. However, these differences gradually diminish throughout the evening and night, and thermal comfort inside and outside green spaces becomes more uniform. (3) Green space size is not the only factor influencing thermal comfort; the layout of plants within the green space and the layout of the surrounding buildings also have an impact. Despite their small size, even small green spaces can significantly enhance comfort. This study highlights the need to promote urban sustainability through the extensive integration of small green spaces in dense urban environments. Small green spaces can serve as a high-frequency, low-cost solution for environmental sustainability by addressing the increasingly severe urban heat island effect as well as environmental challenges that in the urbanization process.

Deep learning and thermographic imaging method for thermal comfort prediction in different genders

With the rising demand for electrification and intelligent functions in automobiles, the interest in passenger-centric air conditioning thermal management systems has swiftly increased. However, predicting personalized passenger comfort and applicability continues to pose challenges. The main challenge is how to use valid data to accurately predict the individual needs and preferences of different passengers. In this paper, we developed a deep learning model for a passenger-centric air conditioning system using ResNet50 (a deep residual network architecture consisting of 50 neural network layers). A spatial attention model was also incorporated (Attention-ResNet50) to enhance thermal comfort prediction accuracy. Experiments were conducted to collect basic image data under various thermal comfort and environmental conditions. Infrared images were gathered and classified into cold, comfortable, and warm categories for training, validation, and testing. The accuracy of thermal comfort prediction on testing sets is approximately 5 % higher when incorporating the spatial attention mechanism module compared to the standard ResNet50 model. Thermal comfort tests and predictions were also conducted for different genders. The female thermal comfort prediction model demonstrated significantly higher accuracy levels, nearing 100 % in situations characterized by cold or warm scenarios. The higher accuracy of female comfort prediction results, verifying that female facial features are more sensitive to temperature variation in their surroundings.

Thermal Stress and Impact on Health in Workers of Refrigeration

Objective: The objective of this research was to determine the thermal stress conditions generated by low temperatures in the refrigerated warehouses of a plant in Venezuela; it was carried out between 2022 and 2023.Methods: it was carried out within the positivist paradigm, quantitative approach, under a field study, observational design, descriptive level and cross-sectional. The population was made up of 13 workers who worked the day shift, being the census sample. Environmental parameters such as temperature, humidity and air speed were measured in different areas, using calibrated instruments. With the data obtained, the localized cooling index was calculated and the metabolic load was evaluated by observing the tasks, as well as the thermal insulation of the workers' clothing.Results: the sample studied had an average age of over 50 years and a work experience of over 8 years; 35 % of the sample reported a cardiovascular history. Most of the jobs had thermal comfort conditions according to the WCI; 15.38 % of the workers felt cold; where a potential risk was identified in one of the workplaces due to excessive air speed and in another due to insufficient thermal insulation of clothing.Conclusion: Therefore, it was concluded that it is necessary to complement the evaluation with medical checks for workers, due to the possible impact of prolonged exposure to cold on their health.

Experiments and CFD simulation of an air-conditioned tractor cabin for thermal comfort of tractor operators in Pakistan

Tractors are manufactured without air-conditioned cabins in Pakistan. This leads to thermal discomfort for tractor operators working under direct solar exposure. Therefore, this study aimed to design and install an air-conditioned cabin on a tractor. Experiments were undertaken to evaluate the installed cabin performance under two scenarios i.e., conventional (S–I) and enhanced (S-II) air distribution. Computational fluid dynamics (CFD) simulations were used to analyze airflow and calculate thermal comfort indices. The results showed that the air-conditioned cabin attained optimum thermal conditions under the enhanced air distribution scenario (S-II). In this scenario, the inside cabin temperature was an average of 27.4 °C, compared with 30.4 °C in S–I. The relative humidity remained similar in both scenarios, around 53 %. The temperature difference between the cabin and the ambient environment was 11.09 °C in S-II, aligning with the thermal comfort conditions outlined in ISO 14269–2. Furthermore, the CFD simulations showed a predicted mean vote (PMV) index of 0.61 and the percentage people dissatisfied (PPD) index of 26.5 %. These results also confirm the provision of optimum thermal conditions for operator inside the cabin. The simulations also demonstrated good agreement with experimental data, with a small difference in air temperature (2 °C) and relative humidity (5.8 %). In the light of these findings, this study recommends installation of air-conditioned cabin on tractors with enhanced air distribution (S-II) in Pakistan to improve thermal comfort of operators.

SOCIALIZATION OF THERMAL COMFORT STANDARDS AT SMKN 4 SOUTH TANGERANG

Vocational High School (SMK) is a formal education unit that provides education that prepares students to work in specific fields. Students can continue their vocational education after completing their education at the junior high school level. SMK Negeri 4 South Tangerang is one of the 4th Vocational High Schools in the City of South Tangerang, specializing in Building Modeling and Information Design, Health Services, Animation, and Visual Communication Design. SMKN 4 South Tangerang is located on Jalan Sumatra-Tidore, Jombang Village, Ciputat District, South Tangerang City, Banten Province, with a land area of 4,562 m2. Currently, SMK Negeri 4 South Tangerang uses a natural air circulation system with openings in each class; then, each class uses a fan for artificial air circulation. There are four types of building comfort: thermal comfort, space comfort, and audio comfort. Space comfort is related to the comfort of movement space and relationships between spaces. Meanwhile, thermal comfort is an essential part of building comfort because room temperature influences the feeling of comfort. This is because every human being has sensors on their skin that work when there are hot or cold temperatures. Thermal comfort conditions that comply with standards will help the teaching and learning process be streamlined at SMK Negeri 4 South Tangerang. So that SMK Negeri 4 South Tangerang has thermal comfort that meets standards, Budi Luhur University organizes Community Service activities to socialize the achievement of thermal comfort at SMK Negeri 4 South Tangerang. The method of implementing activities uses the concept of Problem Solving. At the same time, the Problem-Solving concept uses input stages, problem-solving processes, and output. The aim of socializing the achievement of thermal comfort is so that the management of SMK Negeri 4 South Tangerang knows how to achieve thermal comfort standards so that students at the School are comfortable when carrying out the teaching process.

Optimizing thermal comfort in physical exercise spaces: A study of spatial and thermal factors

Fitness centers have become famous for maintaining a healthy lifestyle. They require different thermal comfort conditions and higher fresh air supply rates than other indoor spaces. However, even well-designed centers may cause discomfort due to factors such as design decisions, ventilation, overheating, and overcrowding. The standards for fitness centers do not consider these specific requirements sufficiently, so this study focuses on understanding the thermal comfort requirements during physical exercise and evaluating spatial and thermal factors affecting the thermal environment around the body. The study investigated the ceiling height, lateral and frontal distances between machines, and vent locations as spatial factors and inlet temperature and air velocity as thermal factors. A thirty-minute moderate-intensity constant work rate exercise test was conducted in a controlled climatic chamber using a cycle ergometer with six healthy male participants. The experiment conditions were simulated in CFD software using the collected data. Once a validated simulation model was provided, computational models for different environmental and spatial scenarios for the five-person cycling class were generated. Using Taguchi L9 (34) orthogonal arrays method, nine spatial scenarios were simulated with three different thermal operations each. Optimal factor levels were determined by using thermal comfort conditions (based on predicted mean vote) around the body’s thermal plume. The results showed that a ceiling height of 5 m, lateral and frontal distances of 1 m and 0.5 m between machines, and Type 2 (two inlets mounted on the ceiling) ventilation strategy were optimal for achieving better thermal comfort values in a thermal condition of 18 °C and 0.2 m·s−1. The study found that increasing the ceiling height and using cross-positioned vents that project air vertically from the ceiling improved the comfort conditions significantly. It is expected that these criteria, which were determined, compared with the standards and detailed, will contribute to the production processes of comfortable exercise spaces.

A simulation-based evaluation of using PCMs in buildings for energy efficiency under different climate conditions

Today, majority of energy consumed in buildings is used to provide thermal comfort conditions. Reducing heating and cooling loads to provide comfort conditions in buildings is possible by taking the right passive design decisions concerning the variables that affect these loads. The building envelope which seperates indoor environment from the outdoor environment and affects the development of indoor thermal comfort conditions is the most important determining factor for energy loads in buildings. In this study, after applying PCM on the building envelope and inner walls and inner floors annual heating, cooling and total energy consumptions and indoor environment comfort conditions in the zones were evaluated. The study was done for Istanbul representing temperate humid climatic zone and for Diyarbakir representing hot-dry climatic zone in the same degree-day region according to the TS825 standards. The residential building simulated for calculations is a 3 storey building with a rectangle floor plan and flat roof and the dimensions of these buildings are 10 m × 30 m × 9 m. The building comprises 9 zones and the building coverage is 300 m2. In order to reduce the difference in energy consumption and thermal comfort conditions among the zones due to their different locations, PCM was applied on inner walls and inner floors in addition to the building envelope to develop a range of alternatives. Annual energy performance evaluation and calculation of daily operative temperature values for January 21 which represents the heating period and July 21 which represents the cooling period were done by the EnergyPlus simulation tool. According to the calculations, the total energy load of the building in the A4.2 alternative where PCM was applied on the building envelope and on inner walls and inner floors was reduced by 11.96 % and 9.69 % in Istanbul and Diyarbakır respectively. With the alternatives, differences in energy consumption among the zones were reduced but not eliminated. Operative temperature values in the zones changed by 1.04 °C – 3.32 °C in Istanbul and by 0.87 °C – 1.16 °C in Diyarbakır with the PCM application contributing to the improvement of indoor comfort conditions.

Analyzing energy poverty and carbon emissions in a social housing complex due to changes in thermal standards

Energy Poverty (EP) is a problem that affects low-income families who struggle to afford maintaining comfortable thermal conditions in their homes. This issue contradicts the objectives of the United Nations Sustainable Development Goals (SDGs), particularly those related to promoting good health and well-being (SDG 3), reducing pollution (SDG 13), and eradicating poverty in all its forms (SDG 1). In this context, this study aims to examine the potential impact of changes in thermal regulations on EP and carbon emissions in a Chilean social housing complex. Unlike previous research that relies on aggregate statistical data at the national level, this study adopts a micro-scale approach, analyzing EP variables at the level of individual households. Semi-structured questionnaire surveys were conducted, and the Ten Percent Rule Index (TPRI) was used to measure EP, while energy use was assessed to estimate carbon emissions. The findings reveal that the social housing complex is experiencing EP, primarily due to factors such as unaffordability, low energy-efficient homes, lack of energy literacy, and the use of firewood as a primary energy source, resulting in a TPR of 14.5 %. However, retrofitting to meet the latest proposed thermal standards can significantly reduce EP, with up to 22 % of households moving away from EP, and lead to a substantial reduction of up to 55 % in total carbon emissions. The study highlights the effectiveness of using the TPRI to evaluate EP and provides insights to better understand how housing retrofitting programs in developing countries may promote sustainability and inclusivity while reducing EP.

A Comparative Analysis of Outdoor Thermal Comfort Indicators Applied in China and Other Countries

Outdoor thermal comfort is an important criterion for evaluating the quality of outdoor activity environments and is also a significant indicator for assessing sustainable building design. Over the past century, more than 165 indoor and outdoor thermal comfort indexes have been developed to define human thermal comfort conditions under various circumstances and to quantify indoor and outdoor thermal environmental conditions. However, in the process of outdoor thermal comfort indicators becoming widely used worldwide, it remains a pressing research issue to compare the current state of application in China and other countries, identify the key areas of application for both sides, and outline the trends in outdoor thermal comfort index application. This study analyzed 346 articles on outdoor thermal comfort indicators. Employing bibliometric methods, we outline the general landscape of outdoor thermal comfort index applications in China and other countries. Additionally, we utilize comparative analysis to uncover similarities and differences in the research focus on outdoor thermal comfort. The research findings indicate the following: (1) Compared to China, other countries started outdoor thermal comfort index application research earlier. Their papers have higher average citation counts and engage in close academic collaborations. However, the quantity of published papers is fewer than in China. (2) The top five frequently used indexes in both China and other countries are PET (including mPET), UTCI, PMV, SET* (including OUT_SET*), and THI (including DI). China tends to use PET and UTCI more frequently than other countries. (3) The potential future directions for outdoor thermal comfort index applications in both China and other countries include: “monitoring and controlling regional outdoor thermal comfort at the temporal and spatial scales”, “multi-factors coupling effects on outdoor thermal comfort”, “human health assessment and prediction based on outdoor thermal comfort”, and “utilizing computational algorithms to calculate outdoor thermal comfort”. This study can serve as a reference for researchers and designers in the industry, contributing to the creation of sustainable outdoor environments.

Design and transient analysis of renewable energy-based residential net-zero energy buildings with energy storage

In this research, by the installation of solar collectors and photovoltaic panels, a building with almost zero energy emissions is designed in TRNSYS software, and with a parameter study on a residential building located in a typical city, the optimal design conditions to provide suitable conditions for thermal comfort, and the electrical power required by the building is suggested. Also, to improve the investigated system, in addition to the two-dimensional design, the three-dimensional design of the building is examined. After the design of the building, it is observed that Bushehr is suitable for designing a building with almost zero energy emissions through the installation of solar collectors and photovoltaic panels due to having the appropriate intensity of sunlight. Also, due to the suitable radiation conditions, it is suitable to use a battery to store electrical energy, and also because the cooling load required to provide thermal comfort in the summer season is high, therefore, the use of a diesel engine is suitable for use in emergency situations. Among the different fuels for starting a diesel engine, diesel fuel has the lowest consumption, and hydrogen fuel has the highest consumption.

Impacts of energy saving measures on IEQ, task performance and COVID-19 contagion risk in public buildings: analysis of a case-study in Bozen-Bolzano, Italy

The recent 2022 energy crisis has pushed several Italian public administrations to adopt solutions to reduce energy demand for space heating in public buildings. Reduction of HVAC system operation time, decrease of heating setpoint and changes to ventilation schedules are some examples of typically implemented measures. However, some of them are in direct competition with those adopted so far to limit the risk of COVID-19 contagion, such as higher ventilation rates. Furthermore, limited operation time and lower setpoints can lead to suboptimal thermal comfort conditions for workers in public buildings, with subsequent decrease of their task performances. In this framework, to assess the global efficacy of the most recent energy saving policies in public buildings, this research focuses not only on the quantification of energy savings but also on the analysis of increased COVID-19 contagion risk, as well as performance loss due to suboptimal building operation conditions. To investigate the impact of new building operation policies for energy savings, an intermediate storey of a public office building in Bolzano, Italy, was selected as a case-study.

Extensive green roofs thermal effect and energy saving indoor by cooling

This work analyzes the thermal effect of extensive green roofs (EGR), in different climatic conditions of eight cities in Mexico. A house is simulated and temperature, comfort sensation and air conditioning energy consumption are analyzed. The results show that the extensive green roof helps to decrease the maximum interior temperature, especially in the rooms located on the upper floor, where greater energy saving for air conditioning (cooling) is also observed. In all the cases studied, EGRs contribute to achieve thermal comfort conditions; in fact, their implementation under some climatic conditions avoids the use of air conditioning.

A feasibility study on using fNIRS brain signals to recognize personal thermal sensation and thermal comfort conditions.

Many studies have shown some relationships between thermal perception (including thermal sensation and thermal comfort) and human physiological parameters, such as brain signals. However, further research is still needed on how these parameters can help recognize the state of a human's personal thermal perception. This study aims to investigate the potential of using fNIRS brain signals to evaluate and predict personal thermal perception and cognitive performance in a steady-state temperature. The present study investigated changes in the fNIRS signal during ambient temperature manipulation. Thirty healthy young individuals were selected as the subjects, and they were exposed to two steady temperatures of 28.8 and 19 °C. After acclimatizing to either temperature, the oxy/deoxy-hemoglobin changes of the prefrontal cortex (PFC) were measured in both rest and cognitive task states using 16-channel fNIRS. Results showed that exposure to different temperatures was significantly associated with the brain signals recorded during the task state. Many significant correlations were discovered between fNIRS signals and thermal perceptionindices. Furthermore, subjects' performance changes led to changes in the fNIRS signals. Logistic regression showed that fNIRS can determine whether a person is thermally comfortable or uncomfortable.

Analysis of the Influence of Chilled Water Temperature Setpoint on Thermal Comfort and Energy Consumption

This study experimentally analysed the influence of chilled water temperature setpoints on thermal comfort conditions and energy consumption of an office building. Three chilled water temperature setpoints (10 °C, 12.5 °C, and 14 °C) were studied. The indoor environment variables (temperature and relative humidity) which are considered indicators of thermal comfort were recorded with data loggers for three consecutive days for each chilled water temperature setpoint (CWTS). Similarly, energy consumption was used as a metric to determine the system’s efficiency. The predicted percentage of dissatisfied (PPD) and predicted mean vote (PMV) indicators were computed and analysed using the Thermal Comfort/ASHRAE 55-2020 modelling tool from the centre for the built environment (CBE). Additionally, computational fluid dynamics (CFD) modelling and analysis were performed using ANSYS Fluent to study the indoor environment conditions of the office at the different chilled water temperature setpoints. A comparison between the calculated, measured, and predicted satisfaction of occupants was done. The results obtained when varying the chilled water temperature setpoints reveal that increasing the chilled water temperature setpoint (by 12%) reduces energy consumption per hour by 2% without compromising thermal comfort. The study demonstrated that the CWTS could be reset between 14 and 15 °C to reduce energy consumption and maintain thermal comfort. Moreover, the CFD model can be used to compare the indoor environmental characteristics of chiller systems.

Enhancing Sustainability in Building Design: Hybrid Approaches for Evaluating the Impact of Building Orientation on Thermal Comfort in Semi-Arid Climates

The evaluation of human thermal comfort inside buildings plays a pivotal role in reducing energy consumption and enhancing sustainability in the built environment. The estimation of thermal comfort is based on objective (physical factors) and subjective (psychological factors) aspects. This study aimed to find a hybrid way to evaluate more accurate thermal comfort in the buildings as per their orientations. This study assessed the effect of building orientation on thermal comfort conditions in row houses in semi-arid climates, based on a synthesis of the predictive mean vote (PMV) model and the thermal sensation vote (TSV). For this purpose, row houses were selected in the region of this study. This study concluded that the PMV model calculates a lower thermal comfort level than the TSV method, and that the thermal comfort demand within the houses was higher than ASHRAE Standard 55. The occupants inside the houses had a lower thermal tolerance. This implied that the residents of these buildings can consume more energy during the summer, typically the harshest season. This study presented new mathematical models for occupants’ thermal comfort evaluation in the study region, depending on the building’s orientation. In both models, for assessing thermal performance during both the summer and winter seasons, east-facing buildings consistently ranked as the second-best orientation. This suggested that, overall, east-facing buildings can be considered the best choice throughout the entire year in terms of thermal comfort. This study suggested a novel indicator to evaluate the optimum building orientation in the study area in terms of thermal performance.

A comparative study of the whole life carbon of a radiant system and an all-air system in a non-residential building

There is an urgent need to reduce carbon emissions from the building sector. This study focused on the whole life carbon of a building’s heating, ventilation, and air conditioning system. A methodology to compare the whole life carbon of different HVAC systems was proposed and used in a case study with boundary conditions in Denmark. All-air system and radiant systems were compared, as they have different working principles and the potential for differences in both their embodied and operational carbon. The radiant system was a Thermally Active Building System (TABS), and the all-air system was a packaged variable-air-volume system with reheat. The building model was based on the medium-sized office of prototype buildings developed by the U.S. Department of Energy. Life cycle stages of the building were classified based on EN15978:2011. Two models, one for dynamic building simulation and the other for measuring the mass of materials (e.g., concrete), were adopted in a novel approach. The operational carbon of the HVAC systems was calculated under very similar indoor thermal comfort conditions. The whole life carbon was 10.1 kgCO2-eq/m2/year and 9.0 kgCO2-eq/m2/year for the all-air system and TABS, respectively. Compared to the all-air system, TABS reduced annual total primary energy use by 34% and whole life carbon by 11%. If dynamic carbon intensity of the grid were to be implemented, further reduction of carbon emission is expected with TABS, owing to its flexibility in operation with the activated thermal mass.

Study of occupant behaviour to improve thermal comfort conditions by arranging furniture in student hostel rooms

Research on thermal comfort has revealed various adaptive behaviours in a hostel room, such as changing clothing, use of windows, doors, and ceiling fans. Hostel rooms are used for various activities and are typically furnished with a wardrobe, bed, study table, and chair. Recent studies indicate that ceiling fan fixed at the centre of the room may not provide adequate air velocity for different activities occurring in different parts of a room. Although students generally arrange furniture based on their preferences and room geometry, the influence of fan-induced air on furniture layout to improve thermal comfort is yet to be established. In this context, this study investigates spatial adaptation and identifies the factors affecting furniture layout preferences in hostel rooms. In a yearlong study, patterns of furniture layout were observed in twenty-one naturally ventilated hostel buildings to find their relationship with environmental and non-environmental factors. A total of 1665 observation data was collected from single, double, and triple occupancy rooms. Influence of various factors on arranging the furniture was identified through a questionnaire survey. Throughout the survey, outdoor temperature varied between 23 and 41 °C and outdoor relative humidity varied between 32.3 % and 97.5 %. The spatial arrangement of furniture was evaluated against fan location. Results indicate that fan location and indoor temperature significantly influence the furniture arrangement. A logistic regression equation was developed to evaluate the trigger temperature when students began moving furniture towards ceiling fan. In a single occupancy room, above 34.2 °C, the probability of moving the bed towards the fan was found to be maximum. In single and double occupancy rooms, students move the bed near the ceiling fan predominantly during night-time to get sufficient air movement. A cautious design of furniture layout and adding a personalised fan for various activities may improve the thermal comfort in hostel rooms.