Building and Environment最新文献

英文中文

Mixing characteristics and co-flow behavior in interactive cascade ventilation: An experimental approach

IF 7.1 1区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Building and Environment

Pub Date : 2025-02-01 DOI: 10.1016/j.buildenv.2024.112360

Han Li , Ruoyi Liu , Xiangfei Kong , Leilei Wang , Jinchao Li , Man Fan

Achieving optimal indoor air quality that is both healthy and comfortable remains a persistent pursuit. Interactive cascade ventilation (ICV) has demonstrated remarkable performance, harnessing a temperature gradient to reverse the direction of buoyancy flux. The aim of this study is to investigate the mixing characteristics and co-flow behavior of ICV. Experiments, informed by Abramovich's theory and the principles of similarity, are conducted using a scaled-down experimental setup. The research results indicate that varying the temperature difference between the upper and lower jets from 2 °C to 7 °C significantly influences the deflection angle. Notably, the lower jet exhibits a more pronounced decrease of 52 %, suggesting that the warmer lower jets effectively uplift the cooler upper jets. It can counteract their descent, optimizing the use of cool air in occupied spaces. Additionally, analysis of different velocity ratios reveals a reduction in the deflection angle from 12.69° to 5.57° as the velocity ratio increases from 0.5 to 0.81. A modified jet equation has been derived, which delineates the central path of the jet trajectory. The insights obtained from this research serve to bolster the theoretical framework for optimizing critical supply air parameters within the ICV system, thereby significantly enhancing its ventilation performance. These findings elucidate the underlying mechanisms of ICV, leading to a more profound understanding of its operational dynamics.

{"title":"Mixing characteristics and co-flow behavior in interactive cascade ventilation: An experimental approach","authors":"Han Li , Ruoyi Liu , Xiangfei Kong , Leilei Wang , Jinchao Li , Man Fan","doi":"10.1016/j.buildenv.2024.112360","DOIUrl":"10.1016/j.buildenv.2024.112360","url":null,"abstract":"<div><div>Achieving optimal indoor air quality that is both healthy and comfortable remains a persistent pursuit. Interactive cascade ventilation (ICV) has demonstrated remarkable performance, harnessing a temperature gradient to reverse the direction of buoyancy flux. The aim of this study is to investigate the mixing characteristics and co-flow behavior of ICV. Experiments, informed by Abramovich's theory and the principles of similarity, are conducted using a scaled-down experimental setup. The research results indicate that varying the temperature difference between the upper and lower jets from 2 °C to 7 °C significantly influences the deflection angle. Notably, the lower jet exhibits a more pronounced decrease of 52 %, suggesting that the warmer lower jets effectively uplift the cooler upper jets. It can counteract their descent, optimizing the use of cool air in occupied spaces. Additionally, analysis of different velocity ratios reveals a reduction in the deflection angle from 12.69° to 5.57° as the velocity ratio increases from 0.5 to 0.81. A modified jet equation has been derived, which delineates the central path of the jet trajectory. The insights obtained from this research serve to bolster the theoretical framework for optimizing critical supply air parameters within the ICV system, thereby significantly enhancing its ventilation performance. These findings elucidate the underlying mechanisms of ICV, leading to a more profound understanding of its operational dynamics.</div></div>","PeriodicalId":9273,"journal":{"name":"Building and Environment","volume":"269 ","pages":"Article 112360"},"PeriodicalIF":7.1,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143164326","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Assessing ventilation performance in schools using continuous CO2 monitoring: Insights from renovation projects

IF 7.1 1区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Building and Environment

Pub Date : 2025-02-01 DOI: 10.1016/j.buildenv.2024.112406

Samy Clinchard , Ulla Haverinen-Shaughnessy , Richard Shaughnessy

Well-functioning ventilation is critical for healthy indoor environments. In this study, carbon dioxide (CO₂) was continuously measured to assess ventilation performance before and after a major renovation campaign involving 48 school buildings. A novel method was developed to identify build-up and decay periods from the data. Two metrics were then investigated: air change rates (ACRs), which were calculated using build-up and decay periods, and daily maximum concentrations (DMCs) of CO₂ measured during school days. Multiple paired samples t-tests revealed statistically significant changes following the renovations: an increase of ACRs and a decrease of DMCs. This study highlights the feasibility, benefits, and scalability of continuously measuring CO₂ to investigate ventilation performance in schools.

引用次数: 0

Impact of unit type and configuration on indoor natural ventilation performance of high-rise, high-density residential buildings in Hong Kong

IF 7.1 1区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Building and Environment

Pub Date : 2025-02-01 DOI: 10.1016/j.buildenv.2024.112444

Pingying Lin , Hao Qin , Sunnie Sing Yeung Lau , Qin Wei

Indoor natural ventilation of residential buildings is challenging in High-rise high-density urban environment. By analyzing 659 residential floor plans built in Hong Kong over the past 10 years, a trend of bigger floor plan with multiple units and preference of view over ventilation as design principle were identified. Furthermore, 16 typical unit types located in various positions within the plan were analyzed for their ventilation performance using coupled CFD simulation technology. The results helped identify four unit types with good natural ventilation performance and three floor plans that provide effective indoor natural ventilation for different site conditions. The paper also highlighted several design guidelines to enhance indoor ventilation, such as the importance of placing openings on different façades or surface levels to create a pressure difference, achieving a balanced distribution of inlet and outlet areas, and positioning rooms within the wind path between inlets and outlets. These strategies contribute to improved indoor air quality and ventilation efficiency in high-density urban environments.

{"title":"Impact of unit type and configuration on indoor natural ventilation performance of high-rise, high-density residential buildings in Hong Kong","authors":"Pingying Lin , Hao Qin , Sunnie Sing Yeung Lau , Qin Wei","doi":"10.1016/j.buildenv.2024.112444","DOIUrl":"10.1016/j.buildenv.2024.112444","url":null,"abstract":"<div><div>Indoor natural ventilation of residential buildings is challenging in High-rise high-density urban environment. By analyzing 659 residential floor plans built in Hong Kong over the past 10 years, a trend of bigger floor plan with multiple units and preference of view over ventilation as design principle were identified. Furthermore, 16 typical unit types located in various positions within the plan were analyzed for their ventilation performance using coupled CFD simulation technology. The results helped identify four unit types with good natural ventilation performance and three floor plans that provide effective indoor natural ventilation for different site conditions. The paper also highlighted several design guidelines to enhance indoor ventilation, such as the importance of placing openings on different façades or surface levels to create a pressure difference, achieving a balanced distribution of inlet and outlet areas, and positioning rooms within the wind path between inlets and outlets. These strategies contribute to improved indoor air quality and ventilation efficiency in high-density urban environments.</div></div>","PeriodicalId":9273,"journal":{"name":"Building and Environment","volume":"269 ","pages":"Article 112444"},"PeriodicalIF":7.1,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143164515","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Integration of phase-change materials in heat recovery ventilator systems for enhanced thermal performance: Based on in-situ experiments

IF 7.1 1区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Building and Environment

Pub Date : 2025-02-01 DOI: 10.1016/j.buildenv.2024.112452

Yongjun Choi, Jihee Nam, Sungwoong Yang, Sumin Kim

The building sector is responsible for approximately 23 % of global energy consumption and 37 % of worldwide carbon emissions, as reported by the International Energy Agency and the United Nations Environment Programme. In Korea, extreme seasonal temperature fluctuations necessitate enhanced building systems to achieve efficient heat exchange. This study investigates the performance improvement of heat recovery ventilator (HRV) systems through the integration of phase-change materials (PCM), which significantly increase heat exchange efficiency and reduce external air loads by storing and releasing latent heat during phase-change. In-situ experiments were conducted to enhance building energy efficiency by incorporating PCM into ana HRV system. This system was designed not only as part of the heating, ventilation, and air conditioning infrastructure but also to directly moderate outdoor air temperatures—lowering them during hot summer months and raising them during cold winter months. This approach facilitates heat exchange at reduced temperature differentials, improving the efficiency of replacing polluted indoor air with fresh outdoor air, thereby delivering comfortable, conditioned supply air. The in-situ experiments were conducted to evaluate the performance of PCM-enhanced HRV systems under extreme seasonal conditions. Results indicated that during summer, the integration of PCM reduced temperatures by up to 9.52 K and increased sensible heat exchange efficiency by approximately 50 % under peak conditions. In winter, the system achieved temperature increases of up to 9.41 K, along with a 4 % improvement in heat exchange efficiency. These findings suggest that PCM-integrated HRV systems represent a promising advancement for enhancing energy-efficient building management.

{"title":"Integration of phase-change materials in heat recovery ventilator systems for enhanced thermal performance: Based on in-situ experiments","authors":"Yongjun Choi, Jihee Nam, Sungwoong Yang, Sumin Kim","doi":"10.1016/j.buildenv.2024.112452","DOIUrl":"10.1016/j.buildenv.2024.112452","url":null,"abstract":"<div><div>The building sector is responsible for approximately 23 % of global energy consumption and 37 % of worldwide carbon emissions, as reported by the International Energy Agency and the United Nations Environment Programme. In Korea, extreme seasonal temperature fluctuations necessitate enhanced building systems to achieve efficient heat exchange. This study investigates the performance improvement of heat recovery ventilator (HRV) systems through the integration of phase-change materials (PCM), which significantly increase heat exchange efficiency and reduce external air loads by storing and releasing latent heat during phase-change. <em>In-situ</em> experiments were conducted to enhance building energy efficiency by incorporating PCM into ana HRV system. This system was designed not only as part of the heating, ventilation, and air conditioning infrastructure but also to directly moderate outdoor air temperatures—lowering them during hot summer months and raising them during cold winter months. This approach facilitates heat exchange at reduced temperature differentials, improving the efficiency of replacing polluted indoor air with fresh outdoor air, thereby delivering comfortable, conditioned supply air. The <em>in-situ</em> experiments were conducted to evaluate the performance of PCM-enhanced HRV systems under extreme seasonal conditions. Results indicated that during summer, the integration of PCM reduced temperatures by up to 9.52 K and increased sensible heat exchange efficiency by approximately 50 % under peak conditions. In winter, the system achieved temperature increases of up to 9.41 K, along with a 4 % improvement in heat exchange efficiency. These findings suggest that PCM-integrated HRV systems represent a promising advancement for enhancing energy-efficient building management.</div></div>","PeriodicalId":9273,"journal":{"name":"Building and Environment","volume":"269 ","pages":"Article 112452"},"PeriodicalIF":7.1,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143164529","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

No “true” greenery: Deciphering the bias of satellite and street view imagery in urban greenery measurement

IF 7.1 1区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Building and Environment

Pub Date : 2025-02-01 DOI: 10.1016/j.buildenv.2024.112395

Yingjing Huang , Rohit Priyadarshi Sanatani , Chang Liu , Yuhao Kang , Fan Zhang , Yu Liu , Fabio Duarte , Carlo Ratti

Urban greenery is a crucial element in building sustainable cities and communities. Despite the widespread use of satellite and street view imagery in monitoring urban greenery, there are significant discrepancies and biases in their measurement across different urban contexts. Currently, no literature systematically evaluates these biases on a global scale. This study utilizes the Normalized Difference Vegetation Index (NDVI) from satellite imagery and the Green View Index (GVI) from street view imagery to measure urban greenery in ten cities worldwide. By analyzing the distribution and visual differences of these indices, the study identifies eight factors causing measurement biases: distance-perspective limitation, single-profile constraint, access limitation, temporal data discrepancy, proximity amplification, vegetative wall effect, multi-layer greenery concealment, and noise. Moreover, a machine learning model is trained to estimate the bias risks of urban greenery measurement in urban areas. We find that bias in most cities primarily stem from an underestimation of GVI. Dubai and Seoul present fewer areas with overall bias risk, while Amsterdam, Johannesburg and Singapore present more such areas. Our findings provide a comprehensive understanding of the differences between the metrics and offer insights for urban green space management. They emphasize the importance of carefully selecting and integrating these measurements for specific urban tasks, as there is no “true” greenery.

{"title":"No “true” greenery: Deciphering the bias of satellite and street view imagery in urban greenery measurement","authors":"Yingjing Huang , Rohit Priyadarshi Sanatani , Chang Liu , Yuhao Kang , Fan Zhang , Yu Liu , Fabio Duarte , Carlo Ratti","doi":"10.1016/j.buildenv.2024.112395","DOIUrl":"10.1016/j.buildenv.2024.112395","url":null,"abstract":"<div><div>Urban greenery is a crucial element in building sustainable cities and communities. Despite the widespread use of satellite and street view imagery in monitoring urban greenery, there are significant discrepancies and biases in their measurement across different urban contexts. Currently, no literature systematically evaluates these biases on a global scale. This study utilizes the Normalized Difference Vegetation Index (NDVI) from satellite imagery and the Green View Index (GVI) from street view imagery to measure urban greenery in ten cities worldwide. By analyzing the distribution and visual differences of these indices, the study identifies eight factors causing measurement biases: distance-perspective limitation, single-profile constraint, access limitation, temporal data discrepancy, proximity amplification, vegetative wall effect, multi-layer greenery concealment, and noise. Moreover, a machine learning model is trained to estimate the bias risks of urban greenery measurement in urban areas. We find that bias in most cities primarily stem from an underestimation of GVI. Dubai and Seoul present fewer areas with overall bias risk, while Amsterdam, Johannesburg and Singapore present more such areas. Our findings provide a comprehensive understanding of the differences between the metrics and offer insights for urban green space management. They emphasize the importance of carefully selecting and integrating these measurements for specific urban tasks, as there is no “true” greenery.</div></div>","PeriodicalId":9273,"journal":{"name":"Building and Environment","volume":"269 ","pages":"Article 112395"},"PeriodicalIF":7.1,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143163364","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Experimental study on particle deposition behavior in air supply ducts of a high-speed train

IF 7.1 1区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Building and Environment

Pub Date : 2025-02-01 DOI: 10.1016/j.buildenv.2024.112494

Fan Wu , Chao Yu , Jianci Yu , Shuaixiong Zhou , Zhiqiang Fan , Renze Xu

The deposition of particles within high-speed trains’ air supply ducts can significantly affect air supply quality, energy efficiency, and the respiratory health of passengers. To study particulate deposition characteristics in such ventilation ducts, an experimental setup replicating a high-speed train air supply duct was constructed. The effects of airflow rate, absolute humidity, particle size, and concentration were quantitatively analyzed. Results indicate that the duct's structure heavily influences deposition patterns, with particles mainly depositing in the main duct and static pressure chamber, while minimal deposition occurs in bent regions. At an airflow rate of 1200 m³/h, the deposition flux shows limited dependence on particle size, but this dependence becomes significant at 1800 m³/h. Increasing particle concentration leads to varying increases in deposition flux across duct surfaces, with bent regions showing a greater sensitivity to concentration changes. High absolute humidity encourages the deposition of smaller particles but has little impact on larger particles. These findings offer valuable insights into the mechanisms of dust accumulation in train air conditioning systems.

{"title":"Experimental study on particle deposition behavior in air supply ducts of a high-speed train","authors":"Fan Wu , Chao Yu , Jianci Yu , Shuaixiong Zhou , Zhiqiang Fan , Renze Xu","doi":"10.1016/j.buildenv.2024.112494","DOIUrl":"10.1016/j.buildenv.2024.112494","url":null,"abstract":"<div><div>The deposition of particles within high-speed trains’ air supply ducts can significantly affect air supply quality, energy efficiency, and the respiratory health of passengers. To study particulate deposition characteristics in such ventilation ducts, an experimental setup replicating a high-speed train air supply duct was constructed. The effects of airflow rate, absolute humidity, particle size, and concentration were quantitatively analyzed. Results indicate that the duct's structure heavily influences deposition patterns, with particles mainly depositing in the main duct and static pressure chamber, while minimal deposition occurs in bent regions. At an airflow rate of 1200 m³/h, the deposition flux shows limited dependence on particle size, but this dependence becomes significant at 1800 m³/h. Increasing particle concentration leads to varying increases in deposition flux across duct surfaces, with bent regions showing a greater sensitivity to concentration changes. High absolute humidity encourages the deposition of smaller particles but has little impact on larger particles. These findings offer valuable insights into the mechanisms of dust accumulation in train air conditioning systems.</div></div>","PeriodicalId":9273,"journal":{"name":"Building and Environment","volume":"269 ","pages":"Article 112494"},"PeriodicalIF":7.1,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143164092","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Using PeopleHour for occupant-centric office building performance assessment

IF 7.1 1区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Building and Environment

Pub Date : 2025-02-01 DOI: 10.1016/j.buildenv.2024.112366

Gulai Shen , John J. Gilbert IV , Ali Mehmani

Measuring and benchmarking office building performance is crucial for enhancing energy efficiency, reducing environmental impact, and improving occupant productivity. Traditional Energy Use Intensity (EUI) metrics and benchmarking methods developed based on them have limitations in accounting for factors like occupancy, can hardly be explainable, and lack evolution with the advent of more real-time data. This paper introduces a set of metrics for building performance based on PeopleHour, which incorporates both the number and duration of occupancy to provide a more occupant-centric perspective on office building performance. By adjusting EUI and other related metrics to reflect building performance normalized by occupancy, we offer a more accurate measure of office building efficiency. Using sample office building data from Nantum OS, we demonstrate how PeopleHour-adjusted metrics reveal insights that traditional methods may overlook, particularly during significant occupancy changes before and after the COVID-19 pandemic. This approach emphasizes the importance of occupancy-driven operations especially as the shift of work mode and office building uses after the pandemic. It suggests that PeopleHour can enhance energy benchmarking practices, leading to more informed decisions for improving building performance across various sectors.

{"title":"Using PeopleHour for occupant-centric office building performance assessment","authors":"Gulai Shen , John J. Gilbert IV , Ali Mehmani","doi":"10.1016/j.buildenv.2024.112366","DOIUrl":"10.1016/j.buildenv.2024.112366","url":null,"abstract":"<div><div>Measuring and benchmarking office building performance is crucial for enhancing energy efficiency, reducing environmental impact, and improving occupant productivity. Traditional Energy Use Intensity (EUI) metrics and benchmarking methods developed based on them have limitations in accounting for factors like occupancy, can hardly be explainable, and lack evolution with the advent of more real-time data. This paper introduces a set of metrics for building performance based on PeopleHour, which incorporates both the number and duration of occupancy to provide a more occupant-centric perspective on office building performance. By adjusting EUI and other related metrics to reflect building performance normalized by occupancy, we offer a more accurate measure of office building efficiency. Using sample office building data from Nantum OS, we demonstrate how PeopleHour-adjusted metrics reveal insights that traditional methods may overlook, particularly during significant occupancy changes before and after the COVID-19 pandemic. This approach emphasizes the importance of occupancy-driven operations especially as the shift of work mode and office building uses after the pandemic. It suggests that PeopleHour can enhance energy benchmarking practices, leading to more informed decisions for improving building performance across various sectors.</div></div>","PeriodicalId":9273,"journal":{"name":"Building and Environment","volume":"269 ","pages":"Article 112366"},"PeriodicalIF":7.1,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143164094","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Mitigating impacts of hot weather on outdoor workers by attaching phase change materials based on body mapping of physiology

IF 7.1 1区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Building and Environment

Pub Date : 2025-02-01 DOI: 10.1016/j.buildenv.2024.112393

Shuting Gu , Zhen Yang , Hongyu Chen , Wenwei Ma , Hongyi Gao , Ying Zhang , Jingxian Xu

To effectively mitigate impacts of hot weather on outdoor workers and improve their thermal comfort and work efficiency, a novel cooling vest (CV) with phase change material (PCM) was developed. The originality of this CV lies in the distribution of PCM packages which are totally based on body mapping of thermal sensation and perspiration. Human tests were performed in a climate chamber simulating hot outdoor environment (35 °C, 55 %RH) to evaluate thermal and movement comfort of workers wearing this CV. The results showed that skin temperature (T_sk) of each localized area was significantly (p < 0.05) reduced by 3.90–9.00 °C compared to that without CV. Besides, a great advancement compared to previous research is the cooling effect could last for the entire 2 h. Subjective thermal sensation was improved from hot (+3) to slightly warm (+1). Pearson correlation analysis revealed T_sk of back and scapula had the strongest correlation (p < 0.01, r > 0.8) with local and overall thermal sensation vote (TSV), indicating cooling these two body parts would achieve a more certain decreased TSV compared to cooling other body parts. Meanwhile, the self-perceived level of fatigue by subjects was lowered because of the improved thermal comfort. This newly developed CV managed to effectively improve both the thermal comfort and work efficiency of outdoor workers without adding extra load. This study provides new technology with physiological and ergonomic basis for creating thermally comfortable near-body environment for workers who have to be exposed to hot environment.

{"title":"Mitigating impacts of hot weather on outdoor workers by attaching phase change materials based on body mapping of physiology","authors":"Shuting Gu , Zhen Yang , Hongyu Chen , Wenwei Ma , Hongyi Gao , Ying Zhang , Jingxian Xu","doi":"10.1016/j.buildenv.2024.112393","DOIUrl":"10.1016/j.buildenv.2024.112393","url":null,"abstract":"<div><div>To effectively mitigate impacts of hot weather on outdoor workers and improve their thermal comfort and work efficiency, a novel cooling vest (CV) with phase change material (PCM) was developed. The originality of this CV lies in the distribution of PCM packages which are totally based on body mapping of thermal sensation and perspiration. Human tests were performed in a climate chamber simulating hot outdoor environment (35 °C, 55 %RH) to evaluate thermal and movement comfort of workers wearing this CV. The results showed that skin temperature (<em>T</em><sub>sk</sub>) of each localized area was significantly (<em>p <</em> 0.05) reduced by 3.90–9.00 °C compared to that without CV. Besides, a great advancement compared to previous research is the cooling effect could last for the entire 2 h. Subjective thermal sensation was improved from hot (+3) to slightly warm (+1). Pearson correlation analysis revealed <em>T</em><sub>sk</sub> of back and scapula had the strongest correlation (<em>p <</em> 0.01, <em>r ></em> 0.8) with local and overall thermal sensation vote (TSV), indicating cooling these two body parts would achieve a more certain decreased TSV compared to cooling other body parts. Meanwhile, the self-perceived level of fatigue by subjects was lowered because of the improved thermal comfort. This newly developed CV managed to effectively improve both the thermal comfort and work efficiency of outdoor workers without adding extra load. This study provides new technology with physiological and ergonomic basis for creating thermally comfortable near-body environment for workers who have to be exposed to hot environment.</div></div>","PeriodicalId":9273,"journal":{"name":"Building and Environment","volume":"269 ","pages":"Article 112393"},"PeriodicalIF":7.1,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143164256","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Implications of the spatiotemporal distribution of CO2 on indoor air quality: A field study with reduced-order modeling

IF 7.1 1区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Building and Environment

Pub Date : 2025-02-01 DOI: 10.1016/j.buildenv.2024.112451

Vamsi Bankapalli , Narsing K. Jha , Jay Dhariwal , Saran Raj K , Seshan Srirangarajan

We conducted a field study to monitor CO₂ concentrations spatiotemporally in a lecture theatre, to explore its implications for Indoor Air Quality (IAQ), particularly in relation to airborne pathogen transmission. It is widely recognized that ensuring adequate ventilation in buildings can reduce the probability of airborne transmission, with indoor CO₂ levels serving as a valuable indicator of ventilation effectiveness. While the temporal evolution of CO₂ concentrations has been well-documented in the literature, to the best of our knowledge, the spatiotemporal distribution remains less understood, especially in large spaces (>10 m) that are poorly ventilated (air change rates below approximately 1.0 h⁻¹) and air-conditioned buildings. Hence, we analyzed spatiotemporal CO₂ variations across four cases with different occupancy levels and seating arrangements using field study data. Our data reveal how factors such as number of people and their seating configurations, asymmetrical airflow vents in a tiered seating-designed room, and buoyancy-driven ventilation flow through an open doorway influenced spatiotemporal CO₂ variations for a given room geometry of our testbed. Moreover, we developed a spatiotemporal reduced-order model that can simulate the spatiotemporal distribution of pathogen quanta using real-world data of CO₂ concentrations. This derived model presented a linear relationship between CO₂ concentrations and pathogen dispersion. Moreover, we explore the IAQ-energy trade-off by using airborne infection probability as a proxy for health outcomes and sensible ventilation load as a proxy for energy demand. Based on this analysis, we propose design guidelines that aim to balance IAQ with energy.

{"title":"Implications of the spatiotemporal distribution of CO2 on indoor air quality: A field study with reduced-order modeling","authors":"Vamsi Bankapalli , Narsing K. Jha , Jay Dhariwal , Saran Raj K , Seshan Srirangarajan","doi":"10.1016/j.buildenv.2024.112451","DOIUrl":"10.1016/j.buildenv.2024.112451","url":null,"abstract":"<div><div>We conducted a field study to monitor CO₂ concentrations spatiotemporally in a lecture theatre, to explore its implications for Indoor Air Quality (IAQ), particularly in relation to airborne pathogen transmission. It is widely recognized that ensuring adequate ventilation in buildings can reduce the probability of airborne transmission, with indoor CO₂ levels serving as a valuable indicator of ventilation effectiveness. While the temporal evolution of CO₂ concentrations has been well-documented in the literature, to the best of our knowledge, the spatiotemporal distribution remains less understood, especially in large spaces (>10 m) that are poorly ventilated (air change rates below approximately 1.0 h⁻¹) and air-conditioned buildings. Hence, we analyzed spatiotemporal CO₂ variations across four cases with different occupancy levels and seating arrangements using field study data. Our data reveal how factors such as number of people and their seating configurations, asymmetrical airflow vents in a tiered seating-designed room, and buoyancy-driven ventilation flow through an open doorway influenced spatiotemporal CO₂ variations for a given room geometry of our testbed. Moreover, we developed a spatiotemporal reduced-order model that can simulate the spatiotemporal distribution of pathogen quanta using real-world data of CO<sub>2</sub> concentrations. This derived model presented a linear relationship between CO₂ concentrations and pathogen dispersion. Moreover, we explore the IAQ-energy trade-off by using airborne infection probability as a proxy for health outcomes and sensible ventilation load as a proxy for energy demand. Based on this analysis, we propose design guidelines that aim to balance IAQ with energy.</div></div>","PeriodicalId":9273,"journal":{"name":"Building and Environment","volume":"269 ","pages":"Article 112451"},"PeriodicalIF":7.1,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143164524","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Comparing RANS- and LES-based statistical methods for determining low-occurrence strong wind speeds in an actual urban area

IF 7.1 1区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Building and Environment

Pub Date : 2025-02-01 DOI: 10.1016/j.buildenv.2024.112464

Wei Wang , Tingjun Yang , Yezhan Li , Naoki Ikegaya

The low-occurrence strong wind speed (LOSWS) is a crucial factor in the urban wind environment. While several studies have estimated LOSWS based on high-order moments in statistical modelling, methods using commonly analyzed statistics in numerical simulations are more convenient but have not been thoroughly evaluated for urban cases. In this study, two statistical methods, KB method, which uses mean velocity components and turbulent kinetic energy, and Beta method, which additionally includes the integral time scale, were applied to estimate LOSWS using statistics from the Reynolds-averaged Navier–Stokes (RANS) simulations of an actual urban case. The accuracy of LOSWS estimation was also evaluated using statistics from large-eddy simulation (LES) to quantify potential error sources in the estimates derived from RANS statistics. Using LES statistics, both KB and Beta methods showed relative errors within ±10 % for LOSWSs at a 10 % exceedance probability and within ±25 % at 1 % and 0.1 % exceedance probabilities at most points. Although estimations based on RANS statistics showed larger deviations than those based on LES statistics, these two methods can still provide valuable a priori estimations, with most scatter points distributed along the 1:1 line, indicating acceptable agreement between the estimated and actual values. The main source of error for the two methods with RANS statistics is the numerical accuracy of turbulent kinetic energy. However, the significantly lower computational cost of RANS makes these estimations valuable for practical applications. The findings of this study provide valuable insights for estimating LOSWS using low-order statistics from LES or RANS simulations.

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