Pub Date : 2023-09-26DOI: 10.1177/01436244231205363
Małgorzata Kacprzak, Magdalena Stolarska, Piotr Lis
The fungal communities inhabiting apartments in multifamily buildings ( N = 33 apartments) with natural ventilation were determined during seasonal variation in the south part of Poland (Silesia region). It was found that the average level of CO 2 concentration usually not exceeded 1000 ppm. The minimal value was noted in November – 402 ppm, however the maximal concentration was equal 6156 ppm and obtained in June. The average fungal colony forming units (CFU/m 3 ) was calculated as follows: 1.06 × 10 2 (February), 1.17 × 10 2 (June) and 2.98 × 10 2 (November). The most frequently occurred species/genera: yeast and yeast-like fungi, Aspergillus niger, Penicillium spp., Cladosporium cladosporioides, Rhodotorula rubra; Culvaraia lunata, Dematiaceae family, Ulocladium consortiale, Verticillium spp.; Fusarium spp., Alternaria alternata; Oidiodendron griseum. The cluster analysis showed no mutual similarity between communities of air fungi isolated from bathrooms of all studied apartments as well as between communities isolated from other indoor spaces (rooms, kitchens, halls). This suggests that natural ventilation has no (or minimal effect) on the propagation of fungal spores between apartments. Statistically significant positive correlation between the concentration of fungi in the air and external humidity, carbon dioxide levels (February, November), and external temperature (November) were found. This study provides that natural ventilation has no effect on the spread of fungal spores inside the building and are not contributed to increase of fungal airborne health risk transmission. It also shows evidence of seasonal changes in carbon dioxide in multi-family homes with natural ventilation. This may give input to establish CO 2 benchmark data in such type of buildings.
{"title":"Culturable airborne fungi communities in naturally ventilated indoor spaces of old residential buildings in Poland","authors":"Małgorzata Kacprzak, Magdalena Stolarska, Piotr Lis","doi":"10.1177/01436244231205363","DOIUrl":"https://doi.org/10.1177/01436244231205363","url":null,"abstract":"The fungal communities inhabiting apartments in multifamily buildings ( N = 33 apartments) with natural ventilation were determined during seasonal variation in the south part of Poland (Silesia region). It was found that the average level of CO 2 concentration usually not exceeded 1000 ppm. The minimal value was noted in November – 402 ppm, however the maximal concentration was equal 6156 ppm and obtained in June. The average fungal colony forming units (CFU/m 3 ) was calculated as follows: 1.06 × 10 2 (February), 1.17 × 10 2 (June) and 2.98 × 10 2 (November). The most frequently occurred species/genera: yeast and yeast-like fungi, Aspergillus niger, Penicillium spp., Cladosporium cladosporioides, Rhodotorula rubra; Culvaraia lunata, Dematiaceae family, Ulocladium consortiale, Verticillium spp.; Fusarium spp., Alternaria alternata; Oidiodendron griseum. The cluster analysis showed no mutual similarity between communities of air fungi isolated from bathrooms of all studied apartments as well as between communities isolated from other indoor spaces (rooms, kitchens, halls). This suggests that natural ventilation has no (or minimal effect) on the propagation of fungal spores between apartments. Statistically significant positive correlation between the concentration of fungi in the air and external humidity, carbon dioxide levels (February, November), and external temperature (November) were found. This study provides that natural ventilation has no effect on the spread of fungal spores inside the building and are not contributed to increase of fungal airborne health risk transmission. It also shows evidence of seasonal changes in carbon dioxide in multi-family homes with natural ventilation. This may give input to establish CO 2 benchmark data in such type of buildings.","PeriodicalId":272488,"journal":{"name":"Building Services Engineering Research and Technology","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134885565","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-20DOI: 10.1177/01436244231203193
Petros Ampatzidis, Emily Bowyer, David Coley, Victoria Stephenson
Decarbonising the built environment is at the heart of many nations' route to net zero. This leads to policies that target specific technologies. Within such policies, there is a natural instinct to combine the need to reduce carbon emissions with solving other issues, such as fuel poverty. Here, we examine for the first time if, from a carbon perspective, this is optimal. By assembling energy performance certificates and household economic deprivation data, we use fuzzy matching techniques to produce a single statistically robust dataset of 44,300 households. Then, through secondary data analysis, we closely examine the carbon impact and cost of energy retrofits. Overall, upgrading to band C is the most viable strategy. However, the results demonstrate that households belonging to the least deprived 20% present more than double the carbon saving potential compared to those in the most deprived 20% (2.7 and 1.2tCO 2 /yr, respectively), and offer the best return in CO 2 savings on money spent. This highlights the need for retrofitting policy to be cognisant of both building stock and deprivation and the disproportionate role in climate change played by the more affluent. The results offer important new insights for governments and suggest a rethinking of retrofit initiatives. Practical Application: This study is the first to employ such data to identify retrofit strategies for governments and offers three key practical applications. (i) It shows how by combining such data one can start to develop policy that is tuned to the demographics and stock, and that by disaggregating the data a lot can be learnt prior to the development of local or national policy. (ii) It clearly puts to bed the idea that attacking fuel poverty is the most effective way towards carbon reductions. (iii) It suggests a new way of thinking about targeted interventions that optimise carbon reduction in a cost-effective way.
{"title":"Decarbonising at scale: Extracting strategic thinking from EPC and deprivation data","authors":"Petros Ampatzidis, Emily Bowyer, David Coley, Victoria Stephenson","doi":"10.1177/01436244231203193","DOIUrl":"https://doi.org/10.1177/01436244231203193","url":null,"abstract":"Decarbonising the built environment is at the heart of many nations' route to net zero. This leads to policies that target specific technologies. Within such policies, there is a natural instinct to combine the need to reduce carbon emissions with solving other issues, such as fuel poverty. Here, we examine for the first time if, from a carbon perspective, this is optimal. By assembling energy performance certificates and household economic deprivation data, we use fuzzy matching techniques to produce a single statistically robust dataset of 44,300 households. Then, through secondary data analysis, we closely examine the carbon impact and cost of energy retrofits. Overall, upgrading to band C is the most viable strategy. However, the results demonstrate that households belonging to the least deprived 20% present more than double the carbon saving potential compared to those in the most deprived 20% (2.7 and 1.2tCO 2 /yr, respectively), and offer the best return in CO 2 savings on money spent. This highlights the need for retrofitting policy to be cognisant of both building stock and deprivation and the disproportionate role in climate change played by the more affluent. The results offer important new insights for governments and suggest a rethinking of retrofit initiatives. Practical Application: This study is the first to employ such data to identify retrofit strategies for governments and offers three key practical applications. (i) It shows how by combining such data one can start to develop policy that is tuned to the demographics and stock, and that by disaggregating the data a lot can be learnt prior to the development of local or national policy. (ii) It clearly puts to bed the idea that attacking fuel poverty is the most effective way towards carbon reductions. (iii) It suggests a new way of thinking about targeted interventions that optimise carbon reduction in a cost-effective way.","PeriodicalId":272488,"journal":{"name":"Building Services Engineering Research and Technology","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136308867","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-07DOI: 10.1177/01436244231200631
Kai Li, Yan Zhou, Difang Wei, Xiaoyu Jin
The purpose of this paper is to investigate the optimal air gap thickness of PV wall in different modes (unclosed, partially-enclosed, enclosed). Based on the heat transfer models and evaluation indexes of PV wall, the electrical and thermal performances are analyzed with experimental method and COMSOL software. The experimental results show that 100 mm thickness can be selected as the optimum size for air gap. The computed results show that PV wall with a 50 mm thickness fully enclosed air gap is the best, with a daily total energy savings of 328.06 Wh/m2, but it is not obvious compared with 100 mm. Therefore, the optimal scheme in winter is to use the 50∼100 mm thickness fully enclosed air gap. The exterior surface temperature of 50 mm and 100 mm enclosed air gap are significantly higher than the bare wall. They can increase equivalent thermal resistances by 0.41 and 0.51 m2·K/W, respectively. Furthermore, the reasons for the total energy savings decreasing with the increase enclosed air gap thickness are discussed. The results of this research can provide some guidance for the application of PV walls in similar climate regions and promote the development of building integrated photovoltaics.
{"title":"An investigation of the electrical and thermal performances of the photovoltaic wall with different air gap thicknesses and modes in winter","authors":"Kai Li, Yan Zhou, Difang Wei, Xiaoyu Jin","doi":"10.1177/01436244231200631","DOIUrl":"https://doi.org/10.1177/01436244231200631","url":null,"abstract":"The purpose of this paper is to investigate the optimal air gap thickness of PV wall in different modes (unclosed, partially-enclosed, enclosed). Based on the heat transfer models and evaluation indexes of PV wall, the electrical and thermal performances are analyzed with experimental method and COMSOL software. The experimental results show that 100 mm thickness can be selected as the optimum size for air gap. The computed results show that PV wall with a 50 mm thickness fully enclosed air gap is the best, with a daily total energy savings of 328.06 Wh/m2, but it is not obvious compared with 100 mm. Therefore, the optimal scheme in winter is to use the 50∼100 mm thickness fully enclosed air gap. The exterior surface temperature of 50 mm and 100 mm enclosed air gap are significantly higher than the bare wall. They can increase equivalent thermal resistances by 0.41 and 0.51 m2·K/W, respectively. Furthermore, the reasons for the total energy savings decreasing with the increase enclosed air gap thickness are discussed. The results of this research can provide some guidance for the application of PV walls in similar climate regions and promote the development of building integrated photovoltaics.","PeriodicalId":272488,"journal":{"name":"Building Services Engineering Research and Technology","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130077922","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-25DOI: 10.1177/01436244231194281
The thermal comfort prediction model assesses indoor climate, which has a signi fi cant impact on building energy consumption and thus its sustainability. The use of a good prediction model is critical to the success of building design. This paper develops a thermal comfort prediction model that can not only accurately predict thermal comfort of building occupant but also be used to design sustainable buildings.
{"title":"Practical applications","authors":"","doi":"10.1177/01436244231194281","DOIUrl":"https://doi.org/10.1177/01436244231194281","url":null,"abstract":"The thermal comfort prediction model assesses indoor climate, which has a signi fi cant impact on building energy consumption and thus its sustainability. The use of a good prediction model is critical to the success of building design. This paper develops a thermal comfort prediction model that can not only accurately predict thermal comfort of building occupant but also be used to design sustainable buildings.","PeriodicalId":272488,"journal":{"name":"Building Services Engineering Research and Technology","volume":"164 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134930972","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-28DOI: 10.1177/01436244231186902
Tiezhu Sun, Huan Sun, Yi Chen, Xiang Huang, Junjie Chu
Data-driven artificial neural networks (ANN) based on data drivers with their powerful self-learning capability and high adaptability are gaining increasing attention for the application in modeling indirect evaporative coolers (IEC). However, most ANN models of IEC in existing studies are either limited to a specific climate region or conventional IEC configurations. In this paper, a multi-region back-propagation (BP) neural network model for predicting the performance of advanced dew-point IECs is developed. Operational data for ANN model development were collected through field measurements in IEC projects in three typical climate zone cities in China (Dunhuang, Yulin, and Fuzhou), covering arid, moderately wet, and humid regions. A comparative study of three single-region neural network models was conducted in terms of both convergence characteristics and statistical performance metrics. Each model contains two input variables (inlet air temperature, inlet air humidity) and one output variable (wet-bulb efficiency). The results show that the model fits best in Yulin, followed by Dunhuang and Fuzhou, with total correlation coefficients of 0.9918, 0.9477, and 0.8946, respectively. The predicted values of wet-bulb efficiency are in good agreement with the actual operating data, and the deviation of almost all predicted values is within ±10%. The application values of IEC ANN models are as follows. First, the IEC-ANN model can predict IEC performance adaptively based on dynamic operational data. Therefore, it can provide the best operating strategy and design parameters for different situations. In addition, it can provide a fast response to guide the system operation when auxiliary control is required. Most importantly, this new approach requires only a limited number of tests rather than exhaustive experimental studies or dealing with complex mathematical models, and future manufacturers can use neural network technology to evaluate the performance of dew-point indirect evaporative coolers, thus saving engineering budget and time.
{"title":"Development of artificial neural network models for indirect evaporative coolers in multi-climate regions based on field measurement","authors":"Tiezhu Sun, Huan Sun, Yi Chen, Xiang Huang, Junjie Chu","doi":"10.1177/01436244231186902","DOIUrl":"https://doi.org/10.1177/01436244231186902","url":null,"abstract":"Data-driven artificial neural networks (ANN) based on data drivers with their powerful self-learning capability and high adaptability are gaining increasing attention for the application in modeling indirect evaporative coolers (IEC). However, most ANN models of IEC in existing studies are either limited to a specific climate region or conventional IEC configurations. In this paper, a multi-region back-propagation (BP) neural network model for predicting the performance of advanced dew-point IECs is developed. Operational data for ANN model development were collected through field measurements in IEC projects in three typical climate zone cities in China (Dunhuang, Yulin, and Fuzhou), covering arid, moderately wet, and humid regions. A comparative study of three single-region neural network models was conducted in terms of both convergence characteristics and statistical performance metrics. Each model contains two input variables (inlet air temperature, inlet air humidity) and one output variable (wet-bulb efficiency). The results show that the model fits best in Yulin, followed by Dunhuang and Fuzhou, with total correlation coefficients of 0.9918, 0.9477, and 0.8946, respectively. The predicted values of wet-bulb efficiency are in good agreement with the actual operating data, and the deviation of almost all predicted values is within ±10%. The application values of IEC ANN models are as follows. First, the IEC-ANN model can predict IEC performance adaptively based on dynamic operational data. Therefore, it can provide the best operating strategy and design parameters for different situations. In addition, it can provide a fast response to guide the system operation when auxiliary control is required. Most importantly, this new approach requires only a limited number of tests rather than exhaustive experimental studies or dealing with complex mathematical models, and future manufacturers can use neural network technology to evaluate the performance of dew-point indirect evaporative coolers, thus saving engineering budget and time.","PeriodicalId":272488,"journal":{"name":"Building Services Engineering Research and Technology","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130253156","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2006-08-01DOI: 10.1191/0143624406bse163oa
D. Mumovic, I. Ridley, T. Oreszczyn, M. Davies
Accurate assessment of both surface and interstitial condensation risk is important not only to reduce the damaging effect of moisture within the structure of buildings, but also to provide a healthy environment free from mould growth. The current British Standard (BS EN ISO 13788: 2002) contains an assessment procedure based on the assumption of a steady-state heat flow through the building envelope, neglecting the transient nature of the problem. This paper compares and evaluates numerical results of the condensation risk calculation under both steady-state and transient conditions using the existing numerical codes. Significant differences are apparent between the predictions of the simple (steady-state) and complex (transient) methods for all construction details modelled. Practical application : The current British Standard (BS EN ISO 13788: 2002) gives calculation methods for determining the internal surface temperature of a building component or building element below which mould growth is likely, given the internal temperature and relative humidity–the method can also be used to assess the risk of other surface condensation problems. The calculation methods in the Standard are steady-state. The paper concludes that for cases where the steady-state method predicts that surface RH values will remain below the key value of 80%, a transient method can predict surface RH values to be above 80% for several hours. The practical implications of this work then are that transient calculation methods may be necessary under certain circumstances. This is particularly relevant given that the issue of a time period of a few hours is now more pertinent as it relates to a new transient performance standard in the new draft Approved Document F (Building Regulations–England and Wales).
准确评估表面和间隙冷凝风险不仅对减少建筑物结构内湿气的破坏性影响很重要，而且对提供一个没有霉菌生长的健康环境也很重要。现行的英国标准(BS EN ISO 13788: 2002)包含了一个基于假设通过建筑围护结构的稳态热流的评估程序，忽略了问题的瞬态性质。本文对现有数值规范在稳态和瞬态条件下的凝结危险计算结果进行了比较和评价。简单(稳态)和复杂(瞬态)方法对所有建筑细节建模的预测之间存在明显差异。实际应用:现行的英国标准(BS EN ISO 13788: 2002)给出了在给定内部温度和相对湿度的情况下，确定建筑构件或建筑构件的内部表面温度的计算方法，该方法也可用于评估其他表面冷凝问题的风险。标准中的计算方法是稳态的。本文得出结论，对于稳态法预测地表RH值将保持在80%以下的关键值的情况，瞬态法可以预测地表RH值在数小时内保持在80%以上。这项工作的实际意义是，在某些情况下，瞬态计算方法可能是必要的。考虑到几个小时的时间段问题现在更加相关，因为它涉及到新的批准文件草案F(建筑法规-英格兰和威尔士)中的新的暂态性能标准，这一点尤其相关。
{"title":"Condensation risk: comparison of steady-state and transient methods","authors":"D. Mumovic, I. Ridley, T. Oreszczyn, M. Davies","doi":"10.1191/0143624406bse163oa","DOIUrl":"https://doi.org/10.1191/0143624406bse163oa","url":null,"abstract":"Accurate assessment of both surface and interstitial condensation risk is important not only to reduce the damaging effect of moisture within the structure of buildings, but also to provide a healthy environment free from mould growth. The current British Standard (BS EN ISO 13788: 2002) contains an assessment procedure based on the assumption of a steady-state heat flow through the building envelope, neglecting the transient nature of the problem. This paper compares and evaluates numerical results of the condensation risk calculation under both steady-state and transient conditions using the existing numerical codes. Significant differences are apparent between the predictions of the simple (steady-state) and complex (transient) methods for all construction details modelled. Practical application : The current British Standard (BS EN ISO 13788: 2002) gives calculation methods for determining the internal surface temperature of a building component or building element below which mould growth is likely, given the internal temperature and relative humidity–the method can also be used to assess the risk of other surface condensation problems. The calculation methods in the Standard are steady-state. The paper concludes that for cases where the steady-state method predicts that surface RH values will remain below the key value of 80%, a transient method can predict surface RH values to be above 80% for several hours. The practical implications of this work then are that transient calculation methods may be necessary under certain circumstances. This is particularly relevant given that the issue of a time period of a few hours is now more pertinent as it relates to a new transient performance standard in the new draft Approved Document F (Building Regulations–England and Wales).","PeriodicalId":272488,"journal":{"name":"Building Services Engineering Research and Technology","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130003366","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2006-08-01DOI: 10.1191/0143624406bse161oa
S. Rees, H. R. Thomas, Z. Zhou
A three-dimensional numerical simulation of transient heat transfer behaviour measured during a full-scale experiment is presented. The experimental data, provided by others, was measured at a purpose built, full-scale test-house, over a 5-year period. The paper addresses some of the practical problems associated with undertaking multi-dimensional simulations, even when the problem is reasonably well defined. Comparisons are made between numerical results and measured data over an annual cycle. Good correlation of results has been achieved. Phase lag of ground temperature variations was also accurately represented in the simulation. The need to pre-condition the simulation to arrive at realistic initial conditions is shown to be necessary in this class of problem. Practical application: At the design stage a predictive assessment of building energy consumption and dissipation is clearly of value. However, the accuracy of any simulation fundamentally depends on the precision with which relevant factors are included. Above-ground insulation of buildings has steadily improved and as a consequence thermal losses due to earth-contact have become proportionally more important. Within this context, this paper aims to provide a case study for validation of models against full-scale field-measured data. The work will also contribute to innovative design that may utilize the thermal mass of foundation materials to achieve the required thermal performance.
{"title":"A numerical and experimental investigation of three-dimensional ground heat transfer","authors":"S. Rees, H. R. Thomas, Z. Zhou","doi":"10.1191/0143624406bse161oa","DOIUrl":"https://doi.org/10.1191/0143624406bse161oa","url":null,"abstract":"A three-dimensional numerical simulation of transient heat transfer behaviour measured during a full-scale experiment is presented. The experimental data, provided by others, was measured at a purpose built, full-scale test-house, over a 5-year period. The paper addresses some of the practical problems associated with undertaking multi-dimensional simulations, even when the problem is reasonably well defined. Comparisons are made between numerical results and measured data over an annual cycle. Good correlation of results has been achieved. Phase lag of ground temperature variations was also accurately represented in the simulation. The need to pre-condition the simulation to arrive at realistic initial conditions is shown to be necessary in this class of problem. Practical application: At the design stage a predictive assessment of building energy consumption and dissipation is clearly of value. However, the accuracy of any simulation fundamentally depends on the precision with which relevant factors are included. Above-ground insulation of buildings has steadily improved and as a consequence thermal losses due to earth-contact have become proportionally more important. Within this context, this paper aims to provide a case study for validation of models against full-scale field-measured data. The work will also contribute to innovative design that may utilize the thermal mass of foundation materials to achieve the required thermal performance.","PeriodicalId":272488,"journal":{"name":"Building Services Engineering Research and Technology","volume":"44 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124396102","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2006-08-01DOI: 10.1191/0143624406bse159oa
A. Elmualim
This paper discusses experimental and theoretical investigations and Computational Fluid Dynamics (CFD) modelling considerations to evaluate the performance of a square section wind catcher system connected to the top of a test room for the purpose of natural ventilation. The magnitude and distribution of pressure coefficients (Cp) around a wind catcher and the air flow into the test room were analysed. The modelling results indicated that air was supplied into the test room through the wind catcher's quadrants with positive external pressure coefficients and extracted out of the test room through quadrants with negative pressure coefficients. The air flow achieved through the wind catcher depends on the speed and direction of the wind. The results obtained using the explicit and AIDA implicit calculation procedures and CFX code correlate relatively well with the experimental results at lower wind speeds and with wind incidents at an angle of 08. Variation in the Cp and air flow results were observed particularly with a wind direction of 458. The explicit and implicit calculation procedures were found to be quick and easy to use in obtaining results whereas the wind tunnel tests were more expensive in terms of effort, cost and time. CFD codes are developing rapidly and are widely available especially with the decreasing prices of computer hardware. However, results obtained using CFD codes must be considered with care, particularly in the absence of empirical data. Practical application: There exist various modelling techniques for the investigation of the performance of natural systems such as wind catchers. These modelling techniques include simple calculation procedures, wind tunnel testing, salt bath, Computational Fluid Dynamics (CFD) and real building performance (POE studies). The calculation procedural models are simple to use, however, due to their simplicity they do not provide a full picture of the performance of the natural ventilation system and air movement inside rooms. Other models such as wind tunnels and CFD are more comprehensive but expensive and time consuming to use. Various commercial CFD models are available in the market today and not many of them are specifically designed for modelling of natural ventilation. Results obtained using CFD models should be considered with care specially in the absence of empirical data and if the results were obtained by novice users. Wind catchers are innovative techniques for the application of natural ventilation in buildings in temperate climates such as that of the UK. Their performance greatly depends on wind conditions. However, they should be designed as an integral part of the overall design of the HVAC system in a hybrid or mixed mode operation. The natural ventilation system of wind catchers should be exploited whenever possible, particularly in the hot summer months to reduce the energy and environmental cost of full operation of an air-conditioning system.
{"title":"Dynamic modelling of a wind catcher/tower turret for natural ventilation","authors":"A. Elmualim","doi":"10.1191/0143624406bse159oa","DOIUrl":"https://doi.org/10.1191/0143624406bse159oa","url":null,"abstract":"This paper discusses experimental and theoretical investigations and Computational Fluid Dynamics (CFD) modelling considerations to evaluate the performance of a square section wind catcher system connected to the top of a test room for the purpose of natural ventilation. The magnitude and distribution of pressure coefficients (Cp) around a wind catcher and the air flow into the test room were analysed. The modelling results indicated that air was supplied into the test room through the wind catcher's quadrants with positive external pressure coefficients and extracted out of the test room through quadrants with negative pressure coefficients. The air flow achieved through the wind catcher depends on the speed and direction of the wind. The results obtained using the explicit and AIDA implicit calculation procedures and CFX code correlate relatively well with the experimental results at lower wind speeds and with wind incidents at an angle of 08. Variation in the Cp and air flow results were observed particularly with a wind direction of 458. The explicit and implicit calculation procedures were found to be quick and easy to use in obtaining results whereas the wind tunnel tests were more expensive in terms of effort, cost and time. CFD codes are developing rapidly and are widely available especially with the decreasing prices of computer hardware. However, results obtained using CFD codes must be considered with care, particularly in the absence of empirical data. Practical application: There exist various modelling techniques for the investigation of the performance of natural systems such as wind catchers. These modelling techniques include simple calculation procedures, wind tunnel testing, salt bath, Computational Fluid Dynamics (CFD) and real building performance (POE studies). The calculation procedural models are simple to use, however, due to their simplicity they do not provide a full picture of the performance of the natural ventilation system and air movement inside rooms. Other models such as wind tunnels and CFD are more comprehensive but expensive and time consuming to use. Various commercial CFD models are available in the market today and not many of them are specifically designed for modelling of natural ventilation. Results obtained using CFD models should be considered with care specially in the absence of empirical data and if the results were obtained by novice users. Wind catchers are innovative techniques for the application of natural ventilation in buildings in temperate climates such as that of the UK. Their performance greatly depends on wind conditions. However, they should be designed as an integral part of the overall design of the HVAC system in a hybrid or mixed mode operation. The natural ventilation system of wind catchers should be exploited whenever possible, particularly in the hot summer months to reduce the energy and environmental cost of full operation of an air-conditioning system.","PeriodicalId":272488,"journal":{"name":"Building Services Engineering Research and Technology","volume":"2015 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125704888","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2006-08-01DOI: 10.1191/0143624406bse160oa
F. Yik, J. Lai, K. Chan, E. Yiu
It is envisaged that more and more specialist works will be employed in modern buildings for enhancing performance and sustainability. Subcontracting is an economical way of procuring specialist works for modern buildings but it may also give rise to various kinds of problems. Such problems may originate from the characteristics of the specialist works and from subcontracting as a procurement method. In the paper, the key characteristics of specialist works are identified and their implications are analysed. Through discussing how new technologies penetrate the market, the pricing strategies that vendors of new technologies may adopt together with their implications are unveiled. The problems with procuring specialist works through subcontracting are then reviewed, and the issues that building developers should take note of in deciding to equip a building with a specialist work and in procurement and management of the specialist subcontract are highlighted and discussed. Practical application: By providing an in-depth exposition on subcontracting within the construction industry, the paper can act as a source of information and guide for those initiating and managing projects that involve substantial amounts of subcontracting, especially to project clients when they procure specialist works through subcontracting. The potential problems discussed include not only those that may arise during the construction stage, readers’ attention is also drawn to the impacts on operation and maintenance and the aftermarket monopoly power of vendors of proprietary products and services.
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Pub Date : 2006-08-01DOI: 10.1191/0143624406bse157tn
Mcibse Mhkie
This study examined the acceptable noise level in an office environment by interviewing 422 occupants about the aural environment being perceived in 61 air-conditioned offices in Hong Kong. The survey samples covered different types of building and prevalent mechanical air supply system. In particular, the measured equivalent continuous noise level Leq in the offices was chosen as an indicator and correlated with the subjective responses from occupants on a visual analogue assessment scale and a dichotomous assessment scale. The results showed that this acceptability was significantly influenced by the office noise level and it would be correlated with a logistic regression model. A satisfaction criterion of the noise level could be evaluated from the frequency distribution of the occupants’ response at certain Leq. In addition, the proposed satisfaction criterion of aural comfort in current design practice was confirmed by the survey samples: an indoor environment with an equivalent continuous noise level Leq of 57.5 dBA would be adopted as a design criterion for some offices. Practical application: The neutral criterion for aural comfort indicated by the equivalent continuous noise level Leq in air-conditioned offices was determined within the range of 45-70 dBA and the ‘optimum’ noise level La/57.5 dBA to be maintained in an office was determined from the survey. This study provides a template for applying a statistical frequency analysis and logistic regression model to examine the ‘optimum’ criteria for aural environment indicated by equivalent continuous noise level Leq in air-conditioned offices elsewhere.
{"title":"A method of assessing the acceptability of noise levels in air-conditioned offices","authors":"Mcibse Mhkie","doi":"10.1191/0143624406bse157tn","DOIUrl":"https://doi.org/10.1191/0143624406bse157tn","url":null,"abstract":"This study examined the acceptable noise level in an office environment by interviewing 422 occupants about the aural environment being perceived in 61 air-conditioned offices in Hong Kong. The survey samples covered different types of building and prevalent mechanical air supply system. In particular, the measured equivalent continuous noise level Leq in the offices was chosen as an indicator and correlated with the subjective responses from occupants on a visual analogue assessment scale and a dichotomous assessment scale. The results showed that this acceptability was significantly influenced by the office noise level and it would be correlated with a logistic regression model. A satisfaction criterion of the noise level could be evaluated from the frequency distribution of the occupants’ response at certain Leq. In addition, the proposed satisfaction criterion of aural comfort in current design practice was confirmed by the survey samples: an indoor environment with an equivalent continuous noise level Leq of 57.5 dBA would be adopted as a design criterion for some offices. Practical application: The neutral criterion for aural comfort indicated by the equivalent continuous noise level Leq in air-conditioned offices was determined within the range of 45-70 dBA and the ‘optimum’ noise level La/57.5 dBA to be maintained in an office was determined from the survey. This study provides a template for applying a statistical frequency analysis and logistic regression model to examine the ‘optimum’ criteria for aural environment indicated by equivalent continuous noise level Leq in air-conditioned offices elsewhere.","PeriodicalId":272488,"journal":{"name":"Building Services Engineering Research and Technology","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127704531","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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