Pub Date : 2023-12-14DOI: 10.1080/14733315.2023.2290920
Seif Mahmoud, James Bennett, Byron Jones, Mohammad Hosni
We compare two aerosol surrogate tracers in aircraft cabins for breathing and coughing sources: tracer gas collected in the ACER Boeing 767 mock-up and fluorescent particles collected in an actual ...
{"title":"A comparative analysis of potential aerosol exposure in a wide-body aircraft cabin using tracer gas and fluorescent particles","authors":"Seif Mahmoud, James Bennett, Byron Jones, Mohammad Hosni","doi":"10.1080/14733315.2023.2290920","DOIUrl":"https://doi.org/10.1080/14733315.2023.2290920","url":null,"abstract":"We compare two aerosol surrogate tracers in aircraft cabins for breathing and coughing sources: tracer gas collected in the ACER Boeing 767 mock-up and fluorescent particles collected in an actual ...","PeriodicalId":55613,"journal":{"name":"International Journal of Ventilation","volume":"96 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2023-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138691584","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-23DOI: 10.1080/14733315.2023.2282336
Zeqi Wu, Kai Wang, Huaitao Song, Kun Wang, Lin Shao
Methane draft pressure is a secondary disaster for mine ventilation following coal and gas outbursts, which poses a long-term threat to coal mining and workers’ safety. To study the law of methane ...
{"title":"A theoretical calculation method for critical air velocity to prevent methane draft pressure-caused airflow reversion based on oscillation theory","authors":"Zeqi Wu, Kai Wang, Huaitao Song, Kun Wang, Lin Shao","doi":"10.1080/14733315.2023.2282336","DOIUrl":"https://doi.org/10.1080/14733315.2023.2282336","url":null,"abstract":"Methane draft pressure is a secondary disaster for mine ventilation following coal and gas outbursts, which poses a long-term threat to coal mining and workers’ safety. To study the law of methane ...","PeriodicalId":55613,"journal":{"name":"International Journal of Ventilation","volume":"222 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2023-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138532473","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-06DOI: 10.1080/14733315.2023.2273148
Reza Rahimi, Rahim Hassanzadeh
AbstractWind-based natural cross-ventilation is defined as a process in which fresh air is injected into a building via a high-pressure windward window and exhausts into the atmosphere through a low-pressure leeward window. There are several parameters that affect the natural ventilation performance, which should be considered in detail to reach the maximum air quality inside the buildings. In the present study, the effects of horizontal and vertical louvers on the wind-driven natural cross-ventilation performance of a generic building are assessed using computational fluid dynamics. In this regard, horizontal and vertical louvers with installation louver angles of 15°, 30°, and 45° are compared with each other and corresponding non-louver cases. Computations are carried out for three different free-wind speeds of 1, 2, and 3 m/s to show the impact of the external conditions on the natural ventilation of louvered cases. The obtained results revealed that under a low free-wind speed of 1 m/s, the minimum age of air and maximum air exchange efficiency occur for vertical louvers with an installation angle of 15°, while at moderate and high free-wind speeds of 2 and 3 m/s, the horizontal louvers with an installation angle of 15° provide the best condition for a generic building. HighlightsEffects of horizontal and vertical louvers on the wind-driven cross-ventilation were studied.At a free-wind speed of 1 m/s, the minimum age of air and maximum air exchange efficiency occur for vertical louver with α = 15°.At UH = 2 and 3 m/s, horizontal louver with α = 15° provides the best condition for a generic building.Keywords: Age of airair exchange efficiencycross-ventilationnatural ventilation Data availability statementData sharing is not applicable to this article as no new data were created or analyzed in this study.Disclosure statementNo potential conflict of interest was reported by the authors.Additional informationNotes on contributorsReza RahimiReza Rahimi is a Ph.D. candidate in Mechanical Engineering at Urmia University of Technology. His research interests include heat and mass transfer and numerical simulation.Rahim HassanzadehRahim Hassanzadeh is an associate professor of Mechanical Engineering at Urmia University of Technology. Her research focuses on wind and solar energy equipment, heat exchangers, and HVAC systems.
{"title":"Impacts of horizontal and vertical louvers on the natural cross-ventilation performance of a generic building","authors":"Reza Rahimi, Rahim Hassanzadeh","doi":"10.1080/14733315.2023.2273148","DOIUrl":"https://doi.org/10.1080/14733315.2023.2273148","url":null,"abstract":"AbstractWind-based natural cross-ventilation is defined as a process in which fresh air is injected into a building via a high-pressure windward window and exhausts into the atmosphere through a low-pressure leeward window. There are several parameters that affect the natural ventilation performance, which should be considered in detail to reach the maximum air quality inside the buildings. In the present study, the effects of horizontal and vertical louvers on the wind-driven natural cross-ventilation performance of a generic building are assessed using computational fluid dynamics. In this regard, horizontal and vertical louvers with installation louver angles of 15°, 30°, and 45° are compared with each other and corresponding non-louver cases. Computations are carried out for three different free-wind speeds of 1, 2, and 3 m/s to show the impact of the external conditions on the natural ventilation of louvered cases. The obtained results revealed that under a low free-wind speed of 1 m/s, the minimum age of air and maximum air exchange efficiency occur for vertical louvers with an installation angle of 15°, while at moderate and high free-wind speeds of 2 and 3 m/s, the horizontal louvers with an installation angle of 15° provide the best condition for a generic building. HighlightsEffects of horizontal and vertical louvers on the wind-driven cross-ventilation were studied.At a free-wind speed of 1 m/s, the minimum age of air and maximum air exchange efficiency occur for vertical louver with α = 15°.At UH = 2 and 3 m/s, horizontal louver with α = 15° provides the best condition for a generic building.Keywords: Age of airair exchange efficiencycross-ventilationnatural ventilation Data availability statementData sharing is not applicable to this article as no new data were created or analyzed in this study.Disclosure statementNo potential conflict of interest was reported by the authors.Additional informationNotes on contributorsReza RahimiReza Rahimi is a Ph.D. candidate in Mechanical Engineering at Urmia University of Technology. His research interests include heat and mass transfer and numerical simulation.Rahim HassanzadehRahim Hassanzadeh is an associate professor of Mechanical Engineering at Urmia University of Technology. Her research focuses on wind and solar energy equipment, heat exchangers, and HVAC systems.","PeriodicalId":55613,"journal":{"name":"International Journal of Ventilation","volume":"2021 6","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135635479","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-10-19DOI: 10.1080/14733315.2023.2263276
Gerrid Brockmann, Anne Hartmann, Martin Kriegel
AbstractThis is a validation study for the velocity distribution in mixing ventilation. Two different supply air diffusers a slot and a swirl diffuser form two different room airflows. For the swirl diffuser two different and for the slot diffuser five different exhaust positioning are tested numerically and experimentally. A comparison of the flow structure shows good agreement between simulation and experiment for six air changes per hour, but not for the lower air change rate of 1.5 per hour. The velocity deviations between experiment and simulation are higher for the swirl diffuser. These exist partly due to the experimental methodology, but also due to an overestimation of the supply air momentum. Thus, further sensitivity investigations are carried out for the swirl diffuser. The overestimation of the supply air momentum depends mainly on a geometric model error in the computational fluid dynamics simulation. A comparison of different turbulence models confirms the advantages of the RST elliptic blending turbulence model over the k-epsilon realizable model for the swirl diffuser case.HighlightsComparison between experimental and numerical velocity determinationFull-scale experimental data with PST-technologyTwo different supply air diffusers: slot and swirlValidation of different turbulence models including RSTCosine theorem-based method for comparison of the flow characteristicKeywords: Airflow characteristicairflow structureturbulence modelscomputational fluid dynamicsexperimental fluid dynamics Disclosure statementNo potential conflict of interest was reported by the authors.Data availability statementThe data that support the findings of this study are openly available in DepositOnce of the Technische Univeristät Berlin at https://doi.org/10.14279/depositonce-18189.Notes1 Trox GmbH, LVS/125/G1/P1-RAL9005-70%.2 Trox GmbH, VDW-Q-Z-V/500x24/P1-RAL9005-70%.3 Trox GmbH, VSD35-1-AK-M-L/600x98/C1/P1-RAL9005-70%.4 The photo is taken from a nonisothermal setup. The cylindrical heat dummies are not part of the isothermal measurements.5 Developed and manufactured by the Hermann-Rietschel-Institut, Technische Universität Berlin.6 CANON EOS 5D.7 National Institutes of Health.8 Dantec Dynamics, accuracy: ±2 % for 0–1 m s−1, ±5 % for 1–5 m s−1.9 Siemens Digital Industries Software.10 The subsequent aim of the research project is to evaluate the ventilation effectiveness, therefore, the age of the air is considered as a quality characteristic in the grid independency study.11 Python Software Foundation.12 Pillow is a PIL fork by Alex Clark and Contributors.Additional informationFundingThis work was funded by the German Federal Ministry for Economic Affairs and Climate Protection (BMWK) under the IGF funding code 20440 N. The authors assume responsibility for the content of this publication.Notes on contributorsGerrid BrockmannGerrid Brockmann is an engineering scientist at the Hermann-Rietschel-Institut of the Technische Universität Berlin and is worki
摘要本文对混合通风中的速度分布进行了验证性研究。两个不同的送风扩散器(槽形扩散器和旋流扩散器)形成两个不同的房间气流。对旋流扩压器的两种不同排气位置和槽型扩压器的五种不同排气位置进行了数值和实验测试。结果表明，当换气量为每小时6次时，模拟与实验结果吻合较好，但当换气量为每小时1.5次时，模拟与实验结果不一致。旋流扩散器的实验速度与仿真速度的偏差较大。这些存在部分是由于实验方法，但也是由于对供气动量的高估。因此，对旋流扩散器进行了进一步的灵敏度研究。在计算流体力学模拟中，供气动量的过高估计主要取决于几何模型误差。通过对不同湍流模型的比较，证实了RST椭圆混合湍流模型相对于k-epsilon可实现模型在旋流扩散器情况下的优越性。重点实验与数值速度测定的比较用pst技术的全尺寸实验数据两种不同的送风扩散器:槽型和旋涡型不同湍流模型的验证包括rstcos定理的流动特性比较方法气流特性气流结构湍流模型计算流体动力学实验流体动力学披露声明作者未报告潜在的利益冲突。数据可用性声明支持本研究结果的数据可在柏林Technische的DepositOnce中公开获取，网址为https://doi.org/10.14279/depositonce-18189.Notes1 Trox GmbH, LVS/125/G1/P1-RAL9005-70%.2Trox GmbH, VDW-Q-Z-V/500x24/ p1 - ral9005 -70%Trox GmbH, VSD35-1-AK-M-L/600x98/C1/ p1 - ral9005 -70%这张照片是在非等温装置中拍摄的。圆柱形热假人不是等温测量的一部分由Hermann-Rietschel-Institut, Technische Universität Berlin.6 CANON EOS 5D.7开发和制造8 Dantec Dynamics，精度:0-1 m s - 1±2%，1 - 5 m s - 1±5%。1.9西门子数字工业软件。10研究项目的后续目标是评估通风效果，因此，空气的年龄被认为是网格独立性研究中的一个质量特征Python Software Foundation.12 Pillow是Alex Clark和contributor开发的一个PIL分支。本工作由德国联邦经济事务和气候保护部(BMWK)根据IGF资助代码20440 n资助。作者对本出版物的内容负责。作者简介:gerrid Brockmann gerrid Brockmann是柏林理工大学赫尔曼-里切尔研究所Universität的工程科学家，自2015年以来一直从事室内空气流动特性和通风效率领域的研究。他于2013年毕业于德国亚琛工业大学机械工程专业，主修热力学和能源技术。在储热和燃气轮机研究的第一步，他收集了超过12年的计算流体动力学和实验验证过程的经验。2016年至2022年，安妮·哈特曼(Anne Hartmann)是柏林工业大学赫尔曼-里切尔研究所Universität的研究员，主要研究方向是通风、室内空气卫生、空气净化、病原体的空气传播、热舒适和空调。自2020年起，她担任污染控制课题组组长，主导新冠肺炎大流行研究课题，发表多篇室内感染风险相关论文。2023年，她带着她的专业知识来到IT G建筑系统工程研究与应用研究所。Martin Kriegel于2005年在柏林Technische Universität完成了关于置换通风的实验研究和数值模拟的博士学位。之后，他在建筑能源系统工程办公室担任项目经理和副总经理。自2011年起，英博士。马丁·克里格尔(Martin Kriegel)一直是柏林工业大学Universität赫尔曼·里切尔研究所(Hermann Rietschel institute)的负责人，专注于污染控制、室内环境质量以及建筑和地区的能源系统。
{"title":"Validation of simulated velocity distribution in isothermal mixing ventilation cases with particle streak tracking","authors":"Gerrid Brockmann, Anne Hartmann, Martin Kriegel","doi":"10.1080/14733315.2023.2263276","DOIUrl":"https://doi.org/10.1080/14733315.2023.2263276","url":null,"abstract":"AbstractThis is a validation study for the velocity distribution in mixing ventilation. Two different supply air diffusers a slot and a swirl diffuser form two different room airflows. For the swirl diffuser two different and for the slot diffuser five different exhaust positioning are tested numerically and experimentally. A comparison of the flow structure shows good agreement between simulation and experiment for six air changes per hour, but not for the lower air change rate of 1.5 per hour. The velocity deviations between experiment and simulation are higher for the swirl diffuser. These exist partly due to the experimental methodology, but also due to an overestimation of the supply air momentum. Thus, further sensitivity investigations are carried out for the swirl diffuser. The overestimation of the supply air momentum depends mainly on a geometric model error in the computational fluid dynamics simulation. A comparison of different turbulence models confirms the advantages of the RST elliptic blending turbulence model over the k-epsilon realizable model for the swirl diffuser case.HighlightsComparison between experimental and numerical velocity determinationFull-scale experimental data with PST-technologyTwo different supply air diffusers: slot and swirlValidation of different turbulence models including RSTCosine theorem-based method for comparison of the flow characteristicKeywords: Airflow characteristicairflow structureturbulence modelscomputational fluid dynamicsexperimental fluid dynamics Disclosure statementNo potential conflict of interest was reported by the authors.Data availability statementThe data that support the findings of this study are openly available in DepositOnce of the Technische Univeristät Berlin at https://doi.org/10.14279/depositonce-18189.Notes1 Trox GmbH, LVS/125/G1/P1-RAL9005-70%.2 Trox GmbH, VDW-Q-Z-V/500x24/P1-RAL9005-70%.3 Trox GmbH, VSD35-1-AK-M-L/600x98/C1/P1-RAL9005-70%.4 The photo is taken from a nonisothermal setup. The cylindrical heat dummies are not part of the isothermal measurements.5 Developed and manufactured by the Hermann-Rietschel-Institut, Technische Universität Berlin.6 CANON EOS 5D.7 National Institutes of Health.8 Dantec Dynamics, accuracy: ±2 % for 0–1 m s−1, ±5 % for 1–5 m s−1.9 Siemens Digital Industries Software.10 The subsequent aim of the research project is to evaluate the ventilation effectiveness, therefore, the age of the air is considered as a quality characteristic in the grid independency study.11 Python Software Foundation.12 Pillow is a PIL fork by Alex Clark and Contributors.Additional informationFundingThis work was funded by the German Federal Ministry for Economic Affairs and Climate Protection (BMWK) under the IGF funding code 20440 N. The authors assume responsibility for the content of this publication.Notes on contributorsGerrid BrockmannGerrid Brockmann is an engineering scientist at the Hermann-Rietschel-Institut of the Technische Universität Berlin and is worki","PeriodicalId":55613,"journal":{"name":"International Journal of Ventilation","volume":"67 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135732326","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Simulation of backflow during the dynamic containment of airlocks","authors":"Brahim Mohammedi, Athmane Gheziel, Nacim Mellel, M’hamed Salhi","doi":"10.1080/14733315.2023.2260668","DOIUrl":"https://doi.org/10.1080/14733315.2023.2260668","url":null,"abstract":"","PeriodicalId":55613,"journal":{"name":"International Journal of Ventilation","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135925869","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-30DOI: 10.1080/14733315.2023.2251316
Kwan Ouyang, Tzeng-Yuan Chen, Weijun Mao
{"title":"Experimental study on air extraction performance of novel rooftop natural ventilators","authors":"Kwan Ouyang, Tzeng-Yuan Chen, Weijun Mao","doi":"10.1080/14733315.2023.2251316","DOIUrl":"https://doi.org/10.1080/14733315.2023.2251316","url":null,"abstract":"","PeriodicalId":55613,"journal":{"name":"International Journal of Ventilation","volume":"13 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2023-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75607056","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-27DOI: 10.1080/14733315.2023.2224685
A. Janssens, Maria Kapsalaki
{"title":"Guest editorial: Ventilation challenges in a changing world - Selected papers from the 42nd AIVC Conference, 5–6 October 2022","authors":"A. Janssens, Maria Kapsalaki","doi":"10.1080/14733315.2023.2224685","DOIUrl":"https://doi.org/10.1080/14733315.2023.2224685","url":null,"abstract":"","PeriodicalId":55613,"journal":{"name":"International Journal of Ventilation","volume":"4 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2023-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78361793","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-01DOI: 10.1080/14733315.2023.2218424
A. Sengupta, H. Breesch, D. Al Assaad, M. Steeman
Airtight and highly insulated buildings are subjected to overheating risks, even in moderate climates, due to unforeseeable events like frequent heatwaves and power outages. Educational buildings share a major portion of building stocks and a large percentage of the energy is expended in maintaining thermal comfort in these buildings. Overheating risks in educational buildings can lead to heat-stress and negatively impact the health conditions and also cognitive performance of the occupants. In the light of increasing severity and longevity of heat waves in future climate scenarios, and associated power outages occurring during the heatwaves, measures to reduce overheating risk while limiting the cooling energy is gaining importance. Since the performance of existing buildings are not guaranteed during events like heatwaves, power outages, it is crucial for these buildings to be resilient to overheating. (Building) resilience is a method to deal with these uncertainties and is stated as “an ability of the building to withstand disruptions; and to maintain the capacity to adapt, learn and transform.” The focus of this paper is to evaluate thermal resilience for two test lecture equipped with low-energy cooling strategies like natural night ventilation (NNV) and indirect evaporative cooling (IEC) rooms, by dynamic Building Energy Simulations (BES). To assess the thermal resilience to overheating three different heatwaves (HW) files ( intense, severe, and longest) for 3 future scenarios (1) Historical (2010-2020), (2) mid-term (2041 -2060) and (3) long-term (2081-2100) and a 24h power outage (PO)scenario was simulated. Benchmarking was done with a base case- Typical Meteorological year(TMY) with no power outage. The heatwave files were developed adopting the methodology proposed by the 'Weather Data Task Force’ of International Energy Agency Energy in Buildings and Communities Programme (IEA EBC) Annex 80 “Resilient Cooling of Buildings”. This study shows, IEC has high to moderate recovery capacity in TMY period and low recovery capacity in HW period, for a power outage of 24 h. Recovery capacity is low during HW period, especially during an intense and longer HW period when outdoor temperature influences the cooling capacity of the IEC. The results also demonstrates the impact of the thermal mass on the resilience to overheating. Passive survivability assessment indicates, the lecture room with lighter thermal mass does not violate 30℃ threshold during a power outage in TMY period and additionally,. recovers faster (11% times faster) from peak temperature compared to lecture room with heavy thermal mass. There is a steep increase in unmet degree hours (occupied hours above24℃ threshold) during HW compared to TMY period. This paper gives a directive towards assessment of resilience to overheating and also points out the gap in the existing indicators to assess the resilience.
{"title":"Evaluation of thermal resilience to overheating for an educational building in future heatwave scenarios","authors":"A. Sengupta, H. Breesch, D. Al Assaad, M. Steeman","doi":"10.1080/14733315.2023.2218424","DOIUrl":"https://doi.org/10.1080/14733315.2023.2218424","url":null,"abstract":"Airtight and highly insulated buildings are subjected to overheating risks, even in moderate climates, due to unforeseeable events like frequent heatwaves and power outages. Educational buildings share a major portion of building stocks and a large percentage of the energy is expended in maintaining thermal comfort in these buildings. Overheating risks in educational buildings can lead to heat-stress and negatively impact the health conditions and also cognitive performance of the occupants. In the light of increasing severity and longevity of heat waves in future climate scenarios, and associated power outages occurring during the heatwaves, measures to reduce overheating risk while limiting the cooling energy is gaining importance. Since the performance of existing buildings are not guaranteed during events like heatwaves, power outages, it is crucial for these buildings to be resilient to overheating. (Building) resilience is a method to deal with these uncertainties and is stated as “an ability of the building to withstand disruptions; and to maintain the capacity to adapt, learn and transform.” The focus of this paper is to evaluate thermal resilience for two test lecture equipped with low-energy cooling strategies like natural night ventilation (NNV) and indirect evaporative cooling (IEC) rooms, by dynamic Building Energy Simulations (BES). To assess the thermal resilience to overheating three different heatwaves (HW) files ( intense, severe, and longest) for 3 future scenarios (1) Historical (2010-2020), (2) mid-term (2041 -2060) and (3) long-term (2081-2100) and a 24h power outage (PO)scenario was simulated. Benchmarking was done with a base case- Typical Meteorological year(TMY) with no power outage. The heatwave files were developed adopting the methodology proposed by the 'Weather Data Task Force’ of International Energy Agency Energy in Buildings and Communities Programme (IEA EBC) Annex 80 “Resilient Cooling of Buildings”. This study shows, IEC has high to moderate recovery capacity in TMY period and low recovery capacity in HW period, for a power outage of 24 h. Recovery capacity is low during HW period, especially during an intense and longer HW period when outdoor temperature influences the cooling capacity of the IEC. The results also demonstrates the impact of the thermal mass on the resilience to overheating. Passive survivability assessment indicates, the lecture room with lighter thermal mass does not violate 30℃ threshold during a power outage in TMY period and additionally,. recovers faster (11% times faster) from peak temperature compared to lecture room with heavy thermal mass. There is a steep increase in unmet degree hours (occupied hours above24℃ threshold) during HW compared to TMY period. This paper gives a directive towards assessment of resilience to overheating and also points out the gap in the existing indicators to assess the resilience.","PeriodicalId":55613,"journal":{"name":"International Journal of Ventilation","volume":"120 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89230853","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-27DOI: 10.1080/14733315.2023.2198791
Benedikt Kölsch, J. Pernpeintner, Björn Schiricke, E. Lüpfert
Abstract Air leakage in building envelopes is responsible for a large portion of the building’s heating and cooling requirements. Therefore, fast and reliable detection of leaks is crucial for improving energy efficiency. This paper presents a new approach to determining air leakages in a building’s envelope from the outside, combining lock-in thermography and thermal excitation by a blower door system. The blower creates a periodic overpressure within the building, inducing periodic temperature variations of the surfaces near the leaks on the outside surface, the façade. With the temperature variations excited at a known frequency, Fourier transforms of the time-series of the thermal images at the excitation frequency result in amplitude and phase images highlighting the areas affected by leaks. Periodic excitation and detection by an IR camera is known as lock-in thermography and is widely used to characterise semiconductor devices and in non-destructive testing. Excitation is usually achieved by optical, electrical, or mechanical energy input. For this work, measurements of outside façades have been performed with three excitation cycles of a period of 40 s at a 75 Pa pressure difference, leading to a total measurement time of only 2 min. Measurements have been performed with air temperature differences of 5 to 7 K at highly variable conditions of irradiance, wind, and cloud cover. The measurements show higher detection quality and less impact from changing ambient conditions than the state-of-the-art differential infrared thermography measurements. With the method highlighting the variations in the amplitude image only at the excitation frequency, variations caused by environmental effects are filtered out. A temperature difference as low as a few Kelvin is therefore sufficient, and large façades can be examined from the outside. This amplitude image is already clearer than an image created with differential thermography. A further reduction of unwanted artefacts in the image is demonstrated using phase-weighing of the amplitude by scalar product.
{"title":"Air leakage detection in building façades by combining lock-in thermography with blower excitation","authors":"Benedikt Kölsch, J. Pernpeintner, Björn Schiricke, E. Lüpfert","doi":"10.1080/14733315.2023.2198791","DOIUrl":"https://doi.org/10.1080/14733315.2023.2198791","url":null,"abstract":"Abstract Air leakage in building envelopes is responsible for a large portion of the building’s heating and cooling requirements. Therefore, fast and reliable detection of leaks is crucial for improving energy efficiency. This paper presents a new approach to determining air leakages in a building’s envelope from the outside, combining lock-in thermography and thermal excitation by a blower door system. The blower creates a periodic overpressure within the building, inducing periodic temperature variations of the surfaces near the leaks on the outside surface, the façade. With the temperature variations excited at a known frequency, Fourier transforms of the time-series of the thermal images at the excitation frequency result in amplitude and phase images highlighting the areas affected by leaks. Periodic excitation and detection by an IR camera is known as lock-in thermography and is widely used to characterise semiconductor devices and in non-destructive testing. Excitation is usually achieved by optical, electrical, or mechanical energy input. For this work, measurements of outside façades have been performed with three excitation cycles of a period of 40 s at a 75 Pa pressure difference, leading to a total measurement time of only 2 min. Measurements have been performed with air temperature differences of 5 to 7 K at highly variable conditions of irradiance, wind, and cloud cover. The measurements show higher detection quality and less impact from changing ambient conditions than the state-of-the-art differential infrared thermography measurements. With the method highlighting the variations in the amplitude image only at the excitation frequency, variations caused by environmental effects are filtered out. A temperature difference as low as a few Kelvin is therefore sufficient, and large façades can be examined from the outside. This amplitude image is already clearer than an image created with differential thermography. A further reduction of unwanted artefacts in the image is demonstrated using phase-weighing of the amplitude by scalar product.","PeriodicalId":55613,"journal":{"name":"International Journal of Ventilation","volume":"16 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2023-04-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73289641","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-23DOI: 10.1080/14733315.2023.2198793
Nima Najafi Ziarani, M. Cook, Paul D. O'Sullivan
Abstract Wind-driven single-sided ventilation (SSV) is present in many existing buildings across Europe, and with new near-zero energy building (NZEB) regulations for the refurbishment of the existing building stock, its attractiveness as a noninvasive, low-energy solution is set to continue. As a strategy, however, in addition to its air change rate capacity, the distribution of fresh air is an important evaluation criterion for its performance. Airflow guiding components located in the external opening that enhance the effectiveness of the wind-driven flow in ventilating the occupied zone could improve the quality of indoor environments. To our knowledge, the literature is sparse on the practical implications for ventilation when adopting guiding components such as louvres, an increasingly popular approach. In the present study, the performance of wind-dominant SSV was simulated using RNG and RSM CFD models, with and without louvres at three building orientations, for example, windward, parallel and leeward. The purpose of this study was to investigate whether louvres installed in the opening would improve both the effective ventilation rate and the penetration depth of the flow into the indoor space. The performance of SSV was evaluated using the age of air and interpreting the secondary air circulation inside the room affected by louvres. As a result of these investigations, a newly configured airflow guiding component was designed and compared to the other cases. Results show louvres can play a crucial role in controlling the secondary air circulation inside the room, and they could either improve or worsen the performance of SSV in terms of air-exchange efficiency. It was shown that in most cases, if louvres were the cause of incremental changes in turbulent intensity within the indoor space, then they are effective as an air-exchange efficiency improvement strategy.
{"title":"The effect of airflow guiding components on effective ventilation rates in single-sided ventilation applications","authors":"Nima Najafi Ziarani, M. Cook, Paul D. O'Sullivan","doi":"10.1080/14733315.2023.2198793","DOIUrl":"https://doi.org/10.1080/14733315.2023.2198793","url":null,"abstract":"Abstract Wind-driven single-sided ventilation (SSV) is present in many existing buildings across Europe, and with new near-zero energy building (NZEB) regulations for the refurbishment of the existing building stock, its attractiveness as a noninvasive, low-energy solution is set to continue. As a strategy, however, in addition to its air change rate capacity, the distribution of fresh air is an important evaluation criterion for its performance. Airflow guiding components located in the external opening that enhance the effectiveness of the wind-driven flow in ventilating the occupied zone could improve the quality of indoor environments. To our knowledge, the literature is sparse on the practical implications for ventilation when adopting guiding components such as louvres, an increasingly popular approach. In the present study, the performance of wind-dominant SSV was simulated using RNG and RSM CFD models, with and without louvres at three building orientations, for example, windward, parallel and leeward. The purpose of this study was to investigate whether louvres installed in the opening would improve both the effective ventilation rate and the penetration depth of the flow into the indoor space. The performance of SSV was evaluated using the age of air and interpreting the secondary air circulation inside the room affected by louvres. As a result of these investigations, a newly configured airflow guiding component was designed and compared to the other cases. Results show louvres can play a crucial role in controlling the secondary air circulation inside the room, and they could either improve or worsen the performance of SSV in terms of air-exchange efficiency. It was shown that in most cases, if louvres were the cause of incremental changes in turbulent intensity within the indoor space, then they are effective as an air-exchange efficiency improvement strategy.","PeriodicalId":55613,"journal":{"name":"International Journal of Ventilation","volume":"38 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2023-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89334956","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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