Pub Date : 2023-01-02DOI: 10.1080/14733315.2022.2161142
Y. Yau, Y. Chuah, K. Chuah, U. Rajput, H. J. Liew
Abstract This article presents a study conducted to test the design guidelines of stratum ventilation (SV) for the conditions set in the tropics (Malaysia). Three different ventilation strategies and six different cases for SV were designed and examined by varying the layout of the return outlets and the air change per hour values. The ventilation strategy with a return outlet at the same level on opposite wall was found better than others. The simulation results of the medium-size room show that the thermal comfort is only favourable up to the centre region. Locations near the diffusers were noticed too cold and locations far away were too warm. In addition, the air flow pattern shows that the room has a high PPD due to quasi-stagnant zones that exist between the air jets from the diffusers. A similar condition does not exist in the small-size room, which was found under the acceptable range of PPD index (0%–25%). The ventilation strategy-1 (VS-1) is found with a greater energy saving with EUC 1.45 for the small room and 1.50 for the medium room compared to the other two ventilation strategies. The SV design guidelines are found adequate for the need of thermal comfort.
{"title":"The preliminary evaluation of design guidelines of stratum ventilation in a large tropical lecture hall","authors":"Y. Yau, Y. Chuah, K. Chuah, U. Rajput, H. J. Liew","doi":"10.1080/14733315.2022.2161142","DOIUrl":"https://doi.org/10.1080/14733315.2022.2161142","url":null,"abstract":"Abstract This article presents a study conducted to test the design guidelines of stratum ventilation (SV) for the conditions set in the tropics (Malaysia). Three different ventilation strategies and six different cases for SV were designed and examined by varying the layout of the return outlets and the air change per hour values. The ventilation strategy with a return outlet at the same level on opposite wall was found better than others. The simulation results of the medium-size room show that the thermal comfort is only favourable up to the centre region. Locations near the diffusers were noticed too cold and locations far away were too warm. In addition, the air flow pattern shows that the room has a high PPD due to quasi-stagnant zones that exist between the air jets from the diffusers. A similar condition does not exist in the small-size room, which was found under the acceptable range of PPD index (0%–25%). The ventilation strategy-1 (VS-1) is found with a greater energy saving with EUC 1.45 for the small room and 1.50 for the medium room compared to the other two ventilation strategies. The SV design guidelines are found adequate for the need of thermal comfort.","PeriodicalId":55613,"journal":{"name":"International Journal of Ventilation","volume":"29 1","pages":"77 - 99"},"PeriodicalIF":1.5,"publicationDate":"2023-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72975369","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 : 2022-11-15DOI: 10.1080/14733315.2022.2143062
Shahrzad Marashian, S. Sadrizadeh, O. Abouali
Abstract The airflow and micro-particle dispersion in a 3-D ventilated scaled room has been simulated numerically. The flow field was studied by the Eulerian method using a Reynolds Averaged Navier-Stokes model, and we used the Lagrangian approach to solve the equations of particle motion. The purpose is to evaluate and compare various discrete random walk methods (DRW) and continuous random walk methods (CRW) to evaluate particle concentration distribution in indoor environments. The isotropic DRW method’s performance has been compared with models in which anisotropy of turbulence is applied, including CRW and modified DRW models based on near-wall direct numerical simulation results, near-wall kinetic energy, and the helicity of the flow. The results reveal that the isotropic DRW method can predict particle concentration in the indoor environment, and using a modified DRW model is not necessary. HIGHLIGHTS We have examined the performance of the isotropic DRW stochastic model in predicting the concentration of suspended micro-particles in a ventilated room. Three modifications of isotropic DRW models, based on near-wall DNS Particle concentration results of modified DRW models based on helicity, have also been investigated. The modified DRW model, based on near-wall DNS results and the CRW model, does not have a good performance for concentration prediction in a ventilated room. The modified DRW model based on helicity and near-wall kinetic energy has good agreement with experimental data.
{"title":"Modeling particle distribution in a ventilated room with modified discrete random walk methods","authors":"Shahrzad Marashian, S. Sadrizadeh, O. Abouali","doi":"10.1080/14733315.2022.2143062","DOIUrl":"https://doi.org/10.1080/14733315.2022.2143062","url":null,"abstract":"Abstract The airflow and micro-particle dispersion in a 3-D ventilated scaled room has been simulated numerically. The flow field was studied by the Eulerian method using a Reynolds Averaged Navier-Stokes model, and we used the Lagrangian approach to solve the equations of particle motion. The purpose is to evaluate and compare various discrete random walk methods (DRW) and continuous random walk methods (CRW) to evaluate particle concentration distribution in indoor environments. The isotropic DRW method’s performance has been compared with models in which anisotropy of turbulence is applied, including CRW and modified DRW models based on near-wall direct numerical simulation results, near-wall kinetic energy, and the helicity of the flow. The results reveal that the isotropic DRW method can predict particle concentration in the indoor environment, and using a modified DRW model is not necessary. HIGHLIGHTS We have examined the performance of the isotropic DRW stochastic model in predicting the concentration of suspended micro-particles in a ventilated room. Three modifications of isotropic DRW models, based on near-wall DNS Particle concentration results of modified DRW models based on helicity, have also been investigated. The modified DRW model, based on near-wall DNS results and the CRW model, does not have a good performance for concentration prediction in a ventilated room. The modified DRW model based on helicity and near-wall kinetic energy has good agreement with experimental data.","PeriodicalId":55613,"journal":{"name":"International Journal of Ventilation","volume":"75 1","pages":"289 - 306"},"PeriodicalIF":1.5,"publicationDate":"2022-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86650948","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 : 2022-07-24DOI: 10.1080/14733315.2022.2103230
C. Su, ChiaYuan Shih, ShiuanCheng Wang, Ming E. Tsai
Abstract Some countries have enacted the full-scale hot smoke test standards to verify the effectiveness of smoke extraction systems. Unfortunately, the judgment of most performed tests is based on vision and lacks scientific value. It is important to establish a scientific and quantifiable measurement system for visibility judgment in a large space. This paper analyzed the visibility values obtained through the light attenuation in a full-scale hot smoke test site. The quadratic regression relationships between the gray scale values and the attenuation ratios were derived. The visibility of the test site can be also obtained by grayscale analysis of recorded images. A qualified emergency direction light was used as a light source, and a closed-circuit television and a portable camera were adopted for image recording. These images were converted into grayscale pictures to obtain the gray scale values at the center of the bright spot. By comparing with the light attenuation ratio of the quantifiable measurement equipment in front of the light source, the results showed excellent relevance and demonstrated the applicability of the captured images.
{"title":"Visibility analysis by light attenuation ratio recorded with portable camera at the full-scale hot smoke test site","authors":"C. Su, ChiaYuan Shih, ShiuanCheng Wang, Ming E. Tsai","doi":"10.1080/14733315.2022.2103230","DOIUrl":"https://doi.org/10.1080/14733315.2022.2103230","url":null,"abstract":"Abstract Some countries have enacted the full-scale hot smoke test standards to verify the effectiveness of smoke extraction systems. Unfortunately, the judgment of most performed tests is based on vision and lacks scientific value. It is important to establish a scientific and quantifiable measurement system for visibility judgment in a large space. This paper analyzed the visibility values obtained through the light attenuation in a full-scale hot smoke test site. The quadratic regression relationships between the gray scale values and the attenuation ratios were derived. The visibility of the test site can be also obtained by grayscale analysis of recorded images. A qualified emergency direction light was used as a light source, and a closed-circuit television and a portable camera were adopted for image recording. These images were converted into grayscale pictures to obtain the gray scale values at the center of the bright spot. By comparing with the light attenuation ratio of the quantifiable measurement equipment in front of the light source, the results showed excellent relevance and demonstrated the applicability of the captured images.","PeriodicalId":55613,"journal":{"name":"International Journal of Ventilation","volume":"60 1","pages":"273 - 288"},"PeriodicalIF":1.5,"publicationDate":"2022-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90704984","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 : 2022-05-23DOI: 10.1080/14733315.2022.2077523
Haiqing Hao, Shuguang Jiang, Kai Wang, Yuchen Zhang, Zhengyan Wu
Abstract The sensitivity analysis is an important analysis method to realize the intelligent control of branch air volume for the mine ventilation network. Aiming at the current situation that the ventilation on-demand (VOD) regulation cannot meet the large demand for air volume in specific air consumption branches in mine, this paper proposed a multi-branch wind resistance joint regulation method based on sensitivity analysis of the ventilation network. Based on the sensitivity theory, the concept of sensitivity change rate was proposed to quantitatively analyze the change law of the sensitivity of branch air volume to multi-branch air resistance, and the calculation formula of the sensitivity change rate matrix was obtained. The Lagrangian interpolation method is used to further optimize the relationship between air volume sensitivity and wind resistance. By using the loop air volume method to calculate and analyze a large number of ventilation networks, the adjustable range of wind resistance was determined and the air volume dispatching calculation model for multi-branch was established, which can more efficiently, accurately, and reliably adjust the branch air volume. This theory was applied to the optimal selection of regulating branch set and stability analysis of branch air volume. Finally, the rationality of this theory is verified through case analysis. In addition, this theory can also be applied to the preparation of emergency plans and the rapid prediction of the changing trend of the branch air volume during the disaster period.
{"title":"Multi-branch joint adjustment method of mine ventilation based on sensitivity","authors":"Haiqing Hao, Shuguang Jiang, Kai Wang, Yuchen Zhang, Zhengyan Wu","doi":"10.1080/14733315.2022.2077523","DOIUrl":"https://doi.org/10.1080/14733315.2022.2077523","url":null,"abstract":"Abstract The sensitivity analysis is an important analysis method to realize the intelligent control of branch air volume for the mine ventilation network. Aiming at the current situation that the ventilation on-demand (VOD) regulation cannot meet the large demand for air volume in specific air consumption branches in mine, this paper proposed a multi-branch wind resistance joint regulation method based on sensitivity analysis of the ventilation network. Based on the sensitivity theory, the concept of sensitivity change rate was proposed to quantitatively analyze the change law of the sensitivity of branch air volume to multi-branch air resistance, and the calculation formula of the sensitivity change rate matrix was obtained. The Lagrangian interpolation method is used to further optimize the relationship between air volume sensitivity and wind resistance. By using the loop air volume method to calculate and analyze a large number of ventilation networks, the adjustable range of wind resistance was determined and the air volume dispatching calculation model for multi-branch was established, which can more efficiently, accurately, and reliably adjust the branch air volume. This theory was applied to the optimal selection of regulating branch set and stability analysis of branch air volume. Finally, the rationality of this theory is verified through case analysis. In addition, this theory can also be applied to the preparation of emergency plans and the rapid prediction of the changing trend of the branch air volume during the disaster period.","PeriodicalId":55613,"journal":{"name":"International Journal of Ventilation","volume":"6 1","pages":"207 - 224"},"PeriodicalIF":1.5,"publicationDate":"2022-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80506977","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 : 2022-05-16DOI: 10.1080/14733315.2022.2073324
P. Balthazar, N. Yusoff, M. A. Ismail
Abstract In dry climates, evaporative cooling techniques are frequently used in place of air-conditioners to increase energy efficiency and reduce installation costs. An evaporative nozzle is a type of evaporative cooling technique. Evaporative nozzle spraying is a technique that is used in a variety of applications, including cooling and humidification. The performance of evaporative spray nozzles with a number ranging from 2 to 8 nozzles has been examined in terms of nozzle combinations, orientations (horizontal and vertical), and Reynolds numbers ranging from 13000 to 83000. In general, the results show that relative humidity is inversely proportional to the Reynolds number. Furthermore, the nozzle numbers are proportional to the relative humidity. As the number of nozzles in a vertical arrangement increases from 2 to 8, the relative humidity rises to 90%. For 8 spray nozzles, the vertical arrangement produces 7.4% higher outlet relative humidity than the horizontal arrangement. The current investigation’s highest relative humidity is 90%, which occurs for 8 nozzles in the vertical direction at Reynolds number 13300. Moreover, the horizontal and vertical correlations were developed to predict the outlet relative humidity with respect to the nozzle orientation.
{"title":"Study on orientation and number of water spray nozzles for scientific experimental application","authors":"P. Balthazar, N. Yusoff, M. A. Ismail","doi":"10.1080/14733315.2022.2073324","DOIUrl":"https://doi.org/10.1080/14733315.2022.2073324","url":null,"abstract":"Abstract In dry climates, evaporative cooling techniques are frequently used in place of air-conditioners to increase energy efficiency and reduce installation costs. An evaporative nozzle is a type of evaporative cooling technique. Evaporative nozzle spraying is a technique that is used in a variety of applications, including cooling and humidification. The performance of evaporative spray nozzles with a number ranging from 2 to 8 nozzles has been examined in terms of nozzle combinations, orientations (horizontal and vertical), and Reynolds numbers ranging from 13000 to 83000. In general, the results show that relative humidity is inversely proportional to the Reynolds number. Furthermore, the nozzle numbers are proportional to the relative humidity. As the number of nozzles in a vertical arrangement increases from 2 to 8, the relative humidity rises to 90%. For 8 spray nozzles, the vertical arrangement produces 7.4% higher outlet relative humidity than the horizontal arrangement. The current investigation’s highest relative humidity is 90%, which occurs for 8 nozzles in the vertical direction at Reynolds number 13300. Moreover, the horizontal and vertical correlations were developed to predict the outlet relative humidity with respect to the nozzle orientation.","PeriodicalId":55613,"journal":{"name":"International Journal of Ventilation","volume":"250 1","pages":"193 - 206"},"PeriodicalIF":1.5,"publicationDate":"2022-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77482512","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 : 2022-05-05DOI: 10.1080/14733315.2022.2064962
R. Traversari, R. Bezemer, S. V. van Heumen, K. Kompatscher, M. Hinkema, I. Eekhout
Abstract Social distancing measures to lower the risk of SARS-CoV-2 transmission limit seating capacity in and constrain restaurants’ ability to operate in an economically sustainable way. Experiments have been conducted in a real-size mock-up of a restaurant, using different table setting and configurations of the ventilation system. The study has analysed the effects on total exposure to aerosols in different settings compared with social distancing. Ventilation rate is the most decisive factor for the total exposure. The particle removal rate is directly proportional to the ventilation rate, while total exposure decreases with higher ventilation rates. At low ventilation rate, setups with protective screens perform comparably or somewhat superior to the social distancing configuration, but effect size is much smaller than for ventilation rate and results are not always significant. Air supply system type does not have significant effect on either total exposure or exposure duration.
{"title":"Effect of different setups, protective screens and air supply systems on the exposure to aerosols in a mock-up restaurant","authors":"R. Traversari, R. Bezemer, S. V. van Heumen, K. Kompatscher, M. Hinkema, I. Eekhout","doi":"10.1080/14733315.2022.2064962","DOIUrl":"https://doi.org/10.1080/14733315.2022.2064962","url":null,"abstract":"Abstract Social distancing measures to lower the risk of SARS-CoV-2 transmission limit seating capacity in and constrain restaurants’ ability to operate in an economically sustainable way. Experiments have been conducted in a real-size mock-up of a restaurant, using different table setting and configurations of the ventilation system. The study has analysed the effects on total exposure to aerosols in different settings compared with social distancing. Ventilation rate is the most decisive factor for the total exposure. The particle removal rate is directly proportional to the ventilation rate, while total exposure decreases with higher ventilation rates. At low ventilation rate, setups with protective screens perform comparably or somewhat superior to the social distancing configuration, but effect size is much smaller than for ventilation rate and results are not always significant. Air supply system type does not have significant effect on either total exposure or exposure duration.","PeriodicalId":55613,"journal":{"name":"International Journal of Ventilation","volume":"34 1","pages":"245 - 256"},"PeriodicalIF":1.5,"publicationDate":"2022-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83646364","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 : 2022-04-26DOI: 10.1080/14733315.2022.2068250
M. Salari, F. Tabatabaei, Reza Fouladi-Fard, A. Mohammadbeigi, A. Nadali, M. Fahiminia, M. Fiore
Abstract Sick building syndrome (SBS) is an outcome of poor indoor air quality (IAQ) that can affect human health and performance. Heating system (HS) types are a factor of indoor air emission. The present study was conducted to evaluate the effect of the HS on IAQ and SBS in residential buildings. The air pollutant levels were monitored in the heating-season and non-heating-season. The SBS questionnaire was completed for each non-smoking people (22-50 years). People with respiratory diseases such as asthma and bronchitis were excluded. Results implied that pollutants concentrations and SBS symptoms were strongly influenced by HS type (P- value < 0.05). Tiredness, dry-throat, and dry-eyes were the commonest reported SBS symptoms. The open-fireplace users had more complain about dry throat (33%) and tiredness (33%) compared to other symptoms. The maximum prevalence of SBS symptoms observed for the use of the open-fireplace, gas-heater, and water circulating system was 40, 27, and 10%, respectively. In 33% of the study population, these symptoms are alleviated when individuals left the buildings. Nausea was the only reported symptom in the homes with the water circulating system. The findings of the present study provide helpful data that can be considered to develop a strategy for increasing public health.
{"title":"Influence of heating systems on indoor air quality and sick building syndrome (a case study in Qom, Iran)","authors":"M. Salari, F. Tabatabaei, Reza Fouladi-Fard, A. Mohammadbeigi, A. Nadali, M. Fahiminia, M. Fiore","doi":"10.1080/14733315.2022.2068250","DOIUrl":"https://doi.org/10.1080/14733315.2022.2068250","url":null,"abstract":"Abstract Sick building syndrome (SBS) is an outcome of poor indoor air quality (IAQ) that can affect human health and performance. Heating system (HS) types are a factor of indoor air emission. The present study was conducted to evaluate the effect of the HS on IAQ and SBS in residential buildings. The air pollutant levels were monitored in the heating-season and non-heating-season. The SBS questionnaire was completed for each non-smoking people (22-50 years). People with respiratory diseases such as asthma and bronchitis were excluded. Results implied that pollutants concentrations and SBS symptoms were strongly influenced by HS type (P- value < 0.05). Tiredness, dry-throat, and dry-eyes were the commonest reported SBS symptoms. The open-fireplace users had more complain about dry throat (33%) and tiredness (33%) compared to other symptoms. The maximum prevalence of SBS symptoms observed for the use of the open-fireplace, gas-heater, and water circulating system was 40, 27, and 10%, respectively. In 33% of the study population, these symptoms are alleviated when individuals left the buildings. Nausea was the only reported symptom in the homes with the water circulating system. The findings of the present study provide helpful data that can be considered to develop a strategy for increasing public health.","PeriodicalId":55613,"journal":{"name":"International Journal of Ventilation","volume":"95 1","pages":"257 - 272"},"PeriodicalIF":1.5,"publicationDate":"2022-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86046571","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 : 2022-04-23DOI: 10.1080/14733315.2022.2064042
Junliang Cao, Xuejiao Peng, Xiaoxin Man, Yue Li, Jing Liu
Abstract This paper investigates the wind pressure distribution of a thousand-meter scale megatall building through a wind tunnel test. One key challenge is that the power-law wind profiles are not applicable due to the height limitation. Therefore, a mesoscale meteorological model WRFv3.4 (Weather Research & Forecasting Model) was used to explore the wind profile covering the height of the thousand-meter scale megatall building. Then the wind profile was reproduced in the wind tunnel representing the actual vertical distribution of wind speed by a passive simulation method, and thereby the wind pressure test was conducted in the wind tunnel. Moreover, to investigate the effect of the inlet wind profile on the wind pressure, a wind tunnel test using the power-law wind profile was carried out for comparison as well. It was revealed that the wind pressure distribution was greatly influenced by the inlet wind profile, which should be investigated with accuracy in the wind tunnel.
摘要:本文通过风洞试验研究了某千米尺度巨型高层建筑的风压分布。一个关键的挑战是幂律风廓线由于高度的限制而不适用。因此，采用中尺度气象模式WRFv3.4 (Weather Research & Forecasting model)对覆盖千米尺度超大高层建筑高度的风廓线进行研究。然后用被动模拟的方法在风洞中再现代表实际风速垂直分布的风廓线，从而在风洞中进行风压试验。此外，为了研究入口风廓线对风压的影响，采用幂律风廓线进行了风洞试验进行比较。结果表明，进口风廓线对风压分布的影响较大，需要在风洞中进行精确的研究。
{"title":"Measurements on the surface wind pressure characteristics of a thousand-meter scale megatall building by wind tunnel test","authors":"Junliang Cao, Xuejiao Peng, Xiaoxin Man, Yue Li, Jing Liu","doi":"10.1080/14733315.2022.2064042","DOIUrl":"https://doi.org/10.1080/14733315.2022.2064042","url":null,"abstract":"Abstract This paper investigates the wind pressure distribution of a thousand-meter scale megatall building through a wind tunnel test. One key challenge is that the power-law wind profiles are not applicable due to the height limitation. Therefore, a mesoscale meteorological model WRFv3.4 (Weather Research & Forecasting Model) was used to explore the wind profile covering the height of the thousand-meter scale megatall building. Then the wind profile was reproduced in the wind tunnel representing the actual vertical distribution of wind speed by a passive simulation method, and thereby the wind pressure test was conducted in the wind tunnel. Moreover, to investigate the effect of the inlet wind profile on the wind pressure, a wind tunnel test using the power-law wind profile was carried out for comparison as well. It was revealed that the wind pressure distribution was greatly influenced by the inlet wind profile, which should be investigated with accuracy in the wind tunnel.","PeriodicalId":55613,"journal":{"name":"International Journal of Ventilation","volume":"20 1","pages":"168 - 192"},"PeriodicalIF":1.5,"publicationDate":"2022-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79579862","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 : 2022-02-06DOI: 10.1080/14733315.2022.2036477
D. Prakash
Abstract Residential buildings in the street canyon are highly suffering from reduced natural ventilation since the surrounding buildings completely mask the window and door openings. For such buildings, ventilation through the roof is an excellent method, and the buildings with courtyard space are believed to provide good ventilation and comfort. However, proper designing of courtyard buildings is highly essential, and for that, a complete airflow study in and around the courtyard building is required. Hence, in this research work, a low-rise residential courtyard building is considered, and the influence of courtyard space shape factor and roof topology on the ventilation performance of courtyard buildings is studied. The airflow study is made with the aid of the computational fluid dynamics (CFD) technique. Grid sensitivity analysis, validation of CFD results with wind tunnel experiments, and repeatability error analysis on wind tunnel test rig are also conducted to ensure the reliability of CFD simulation results. From this analysis, the courtyard with a wider space entraps more air from the atmosphere, and the building with low height offers uniform airflow in the courtyard space. Roof topology significantly influences the airflow around the building. Among the analyzed roof shape, pitched roof shape seems to perform relatively better and enhance the indoor air velocity by 42% with reference to the building without courtyard space. Also, the thermal comfort index for the building with courtyard space is 1.16 whereas for a building without a courtyard is 2.42 on a 3 scale. The percentage dissatisfaction index (PPD) is 52.9% lesser in the building with courtyard space.
{"title":"Ventilation performance analysis on low-rise courtyard building for various courtyard shape factors and roof topology","authors":"D. Prakash","doi":"10.1080/14733315.2022.2036477","DOIUrl":"https://doi.org/10.1080/14733315.2022.2036477","url":null,"abstract":"Abstract Residential buildings in the street canyon are highly suffering from reduced natural ventilation since the surrounding buildings completely mask the window and door openings. For such buildings, ventilation through the roof is an excellent method, and the buildings with courtyard space are believed to provide good ventilation and comfort. However, proper designing of courtyard buildings is highly essential, and for that, a complete airflow study in and around the courtyard building is required. Hence, in this research work, a low-rise residential courtyard building is considered, and the influence of courtyard space shape factor and roof topology on the ventilation performance of courtyard buildings is studied. The airflow study is made with the aid of the computational fluid dynamics (CFD) technique. Grid sensitivity analysis, validation of CFD results with wind tunnel experiments, and repeatability error analysis on wind tunnel test rig are also conducted to ensure the reliability of CFD simulation results. From this analysis, the courtyard with a wider space entraps more air from the atmosphere, and the building with low height offers uniform airflow in the courtyard space. Roof topology significantly influences the airflow around the building. Among the analyzed roof shape, pitched roof shape seems to perform relatively better and enhance the indoor air velocity by 42% with reference to the building without courtyard space. Also, the thermal comfort index for the building with courtyard space is 1.16 whereas for a building without a courtyard is 2.42 on a 3 scale. The percentage dissatisfaction index (PPD) is 52.9% lesser in the building with courtyard space.","PeriodicalId":55613,"journal":{"name":"International Journal of Ventilation","volume":"182 1","pages":"56 - 76"},"PeriodicalIF":1.5,"publicationDate":"2022-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76014435","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 : 2021-12-08DOI: 10.1080/14733315.2020.1778884
A. Janssens, Maria Kapsalaki
In the past 40 years, since the first oil crisis in the seventies, energy and climate goals have been shaping many countries’ policy and legislative agendas. The building sector plays a crucial role in achieving these goals, considering the energy use attributed to buildings and its huge potential for improved energy performance. Whereas in the past most of the focus was on reducing the energy consumption, it is now clear that better performing buildings must ensure an acceptable Indoor Environmental Quality (IEQ), by providing higher Indoor Air Quality (IAQ) and comfort levels for their occupants. Building ventilation entails both challenges and opportunities to achieve this goal. Since 1980, the annual conference of the Air Infiltration and Ventilation Centre AIVC has been the meeting point for presenting and discussing major research results and developments regarding infiltration and ventilation in buildings. In 2019 the AIVC completed its 40th year of existence and the conference organisers thought that it would be good to pay attention to the evolution during these 40 years. This is the context which defined the core theme of the joint 40th AIVC, 8th TightVent and 6th Venticool Conference, organised in Ghent, Belgium: ‘From energy crisis to sustainable indoor climate – 40 years of AIVC’. Over 120 contributions were presented at the conference after a call for abstracts on aspects of smart ventilation in relation to indoor air quality and health, building and ductwork airtightness, and ventilative and resilient cooling. There were two separate calls for abstracts and papers depending on whether the authors were interested in the peer review of their papers or not. This special issue of the International Journal of Ventilation presents a selection of the peer reviewed conference papers addressing issues raised by the conference topics. The analysis of infiltration related energy use is the subject of a Spanish study (Poza-Casado et al.). The study aims to assess the energy impact of uncontrolled airflows through the envelope in residential buildings in Spain. For this purpose, airtightness results of more than 400 blower door tests have been analyzed, showing great potential for energy saving in the country through better air tightness. However, in projects where airtightness requirements are imposed, testing procedures to measure air infiltration should allow to obtain reliable test results in an affordable way. Three other papers are dealing with these issues. A new test device for building air tightness is introduced and validated by a Dutch research team (Lanooy et al.), using the buildings ventilation system for pressurisation, to allow for a cheaper and faster test procedure. Prignon et al. contribute to the quantification of uncertainty in pressure and air flow rate measurements in fan pressurisation tests, by analyzing the uncertainty in zero-flow pressure approximations due to short-term fluctuation of wind speed and direction during
自上世纪70年代第一次石油危机以来，在过去的40年里，能源和气候目标一直影响着许多国家的政策和立法议程。考虑到建筑的能源使用及其改善能源性能的巨大潜力，建筑部门在实现这些目标方面发挥着至关重要的作用。而在过去，大部分的重点是减少能源消耗，现在很明显，性能更好的建筑必须确保一个可接受的室内环境质量(IEQ)，通过提供更高的室内空气质量(IAQ)和舒适度的居住者。为了实现这一目标，建筑通风带来了挑战和机遇。自1980年以来，空气渗透与通风中心(AIVC)的年度会议一直是介绍和讨论建筑物渗透与通风方面的主要研究成果和发展的会议点。2019年，AIVC完成了它的第40个年头，会议组织者认为关注这40年的发展是件好事。这就是在比利时根特举办的第40届AIVC、第8届TightVent和第6届Venticool会议的核心主题:“从能源危机到可持续室内气候——AIVC的40年”。在会议上发表了120多篇关于智能通风与室内空气质量和健康、建筑和管道系统气密性以及通风和弹性冷却相关方面的摘要。根据作者是否对其论文的同行评议感兴趣，有两种不同的摘要和论文征集。本期《国际通风杂志》特刊精选了同行评议的会议论文，讨论了会议主题提出的问题。渗透相关的能源利用分析是西班牙一项研究的主题(Poza-Casado等人)。该研究旨在评估通过西班牙住宅建筑围护结构的不受控制的气流对能源的影响。为此，对400多个风机门试验的气密性结果进行了分析，显示出通过更好的气密性在国内节能的巨大潜力。然而，在有气密性要求的项目中，测量空气渗透的测试程序应该允许以负担得起的方式获得可靠的测试结果。另外三篇论文也在讨论这些问题。荷兰研究小组(Lanooy et al.)介绍并验证了一种新的建筑物气密性测试设备，该设备使用建筑物通风系统进行加压，从而实现了更便宜、更快速的测试过程。Prignon等人通过分析测试过程中由于风速和风向的短期波动而导致的零流压力近似的不确定性，对风机增压试验中压力和空气流速测量的不确定性进行了量化。进一步，一篇论文由
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