Aperture design is very important in the design process of rainwear,as garment aperture is one of the main pathways for air exchange between clothing microclimate and the environment.The purpose of this study was to i...Aperture design is very important in the design process of rainwear,as garment aperture is one of the main pathways for air exchange between clothing microclimate and the environment.The purpose of this study was to investigate the effects of aperture design on whole and local ventilations of rainwear.Ventilation was measured by a tester developed based on the steady-state method.A rainwear suit with top and bottom was chosen as the basic ensemble.Apertures were added at the arm,chest,back and knee separately.Local ventilation of the arm,chest,back and whole ventilation of the top and bottom in different walking and wind conditions were measured.Local and whole ventilations at five aperture conditions for the top and four for the bottom were studied.The results indicated that local ventilation value of the chest was the biggest and the arm was the smallest.Whole ventilation of the suit was the biggest when walking at 5.6 km/h,with all the designed apertures opened.Local ventilation value was bigger when opening arm aperture than that of opening chest or back aperture.The bottom ventilation was the highest when both front and back apertures were opened.展开更多
Based on the current indoor natural ventilation and lighting in the space of traditional residential buildings,this paper starts from the passive-design optimization of the spatial natural ventilation and lighting,and...Based on the current indoor natural ventilation and lighting in the space of traditional residential buildings,this paper starts from the passive-design optimization of the spatial natural ventilation and lighting,and makes quantitative evaluation on the quality of current interior natural ventilation and lighting for two typical residential buildings by three indexes,including wind speed,static wind area ratio and satisfaction ratio about minimum lighting coefficient. Based on that, this paper conducts the passive design optimization, and establishes the quantitative association and reevaluation among the passive reformation design, natural ventilation,and lighting environmental quality,proposing the general strategy for the existing residential buildings to respond to the passive reformation design of the natural ventilation and lighting. The special reconstruction of core functionary space of integration of "the living room + dining room + partial space"is researched,and the redesign for the optimization and replacement of both indoor and outdoor enclosure parts is explored,which is expected to provide practical exploration on the strategies for passive construction of spatial natural environmental quality within a large number of highly-energy-consumed residential buildings in China,as well as the green design of residential buildings.展开更多
Given the perennial incidence of thermal discomfort, health issues, as well as energy costs associated with naturally ventilated classrooms in Yola, the study aimed at enhancing the effectiveness of classroom designs ...Given the perennial incidence of thermal discomfort, health issues, as well as energy costs associated with naturally ventilated classrooms in Yola, the study aimed at enhancing the effectiveness of classroom designs for natural ventilation comfort by examining the effects of six architectural design variables—size and position of openings, form of buildings, orientation of buildings, site planning, topography, and physical features, on the ventilation coefficients of 61 classrooms selected from nine stratified clusters in Yola, Adamawa State, Nigeria. Data were analyzed using percentages, ratios, means as well as standard deviation, and then sorted in groups using tables. The study revealed that the form and orientation of the classroom-buildings, as well as topography, site planning and other physical features, have no significant effect on ventilation coefficient. In addition, a new mean ventilation coefficient was obtained in ten classrooms against an earlier claim that ventilation coefficient cannot exceed a fixed average regardless of the ratio of wall opening to floor area.展开更多
This study applied the numerical simulator tool FDS （fire dynamics simulator）, Version 5.53, and focused on the simulation of the natural smoke flow ventilation design system, an innovative ventilation design using ...This study applied the numerical simulator tool FDS （fire dynamics simulator）, Version 5.53, and focused on the simulation of the natural smoke flow ventilation design system, an innovative ventilation design using the parallel processing technology MPI （message passing interface）. The design was then compared with the exhaust efficiency of a typical natural smoke vent. The natural smoke flow ventilation design system was located at the top of the factory, where smoke streams effectively converged. Therefore, the source of fire was designed to be 2 MW, which has a better exhaust efficiency than typical natural smoke vent with same area. The simulation discovered that the exhaust efficiency of the natural smoke ventilation design systems is higher than that of typical natural smoke vent with 2 times the opening area and that was not affected by external wind speed, Instead, external wind speed can help to enhance the exhaust efficiency. Smoke exhaust of typical natural smoke vents was affected by external wind speed, even leading them to become air inlets which would disturb the flow of air indoors, leading to smoke accumulation within the factory.展开更多
With a sustained period of economic growth, rapidly growing populations and with more diversified economies Africa need sustainable development; hence the greater need for massive investments in energy. Sub-Saharan co...With a sustained period of economic growth, rapidly growing populations and with more diversified economies Africa need sustainable development; hence the greater need for massive investments in energy. Sub-Saharan countries such as Djibouti have the potential and ability to harness their natural ventilation as a passive cooling system for designing new houses. The rapid expansion of the Djibouti city is affecting negatively the environment and the safety and comfort of its inhabitants. Proper atmospheric urban planning and management are key to making cities environmentally friendly and sustainable. Based on energy consumption, climate conditions in Djibouti and numerical analysis using Computational Fluid Dynamics （CFD）, it is apparent that the natural ventilation creates a thermally comfortable indoor environment in buildings during the cool season of the year. Measured wind data from two measurement systems are presented and discussed. Statistical analyses, wind rose, Weibull distribution were carried out to understand the natural ventilation characteristic, which is used for evolving the basic criteria for economic viability of building in the semi-arid climate of Djibouti. The study found that it is possible to benefit from natural ventilation in buildings during the cool season of the year.展开更多
With the development of society, people put forward higher and higher requirements for the comfort of living environment. However, in real life, there are many defects in the design of heating, ventilation and air con...With the development of society, people put forward higher and higher requirements for the comfort of living environment. However, in real life, there are many defects in the design of heating, ventilation and air conditioning, which seriously affect peoples daily life. Therefore, the design and installation of HVAC must strictly abide by the relevant design specifications and engineering quality approval standards, and adopt safe and scientific technical methods and applicable and effective installation techniques to debug the project by item. The installation unit and the final system must be verified through a series of trial runs to ensure the safety of the system, ensure the rationality of heating, and ensure that the engineering entity meets the expected functions and requirements of users.展开更多
Ventilation system analysis for underground mines has remained mostly unchanged since the Atkinson method was made popular by Mc Elroy in 1935. Data available to ventilation technicians and engineers is typically limi...Ventilation system analysis for underground mines has remained mostly unchanged since the Atkinson method was made popular by Mc Elroy in 1935. Data available to ventilation technicians and engineers is typically limited to the quantity of air moving through any given heading. Because computer-aided modelling, simulation, and ventilation system design tools have improved, it is now important to ensure that developed models have the most accurate information possible. This paper presents a new technique for estimating underground drift friction factors that works by processing 3 D point cloud data obtained by using a mobile Li DAR. Presented are field results that compare the proposed approach with previously published algorithms, as well as with manually acquired measurements.展开更多
PCM windows are regarded as promising translucent building envelopes due to their ability to store solar heat and enhance thermal comfort.However,limitations in thermal insulation,phase transition rate,and climate ada...PCM windows are regarded as promising translucent building envelopes due to their ability to store solar heat and enhance thermal comfort.However,limitations in thermal insulation,phase transition rate,and climate adaptability hinder their further development.Hence,a novel triple-glazed window integrated with nano-enhanced PCM,reversible design and ventilation(NPRVTW)is proposed,while its dynamic photothermal transfer model is developed.Based on simulation results for the application in Guilin and Daqing,China,the thermal comfort and energy efficiency of NPRVTW are evaluated across different seasons and climates.The multi-technology coupling mechanisms are also discussed through comparisons with four other window configurations.The influences of physical properties,phase change temperature,and thickness of NPCM,as well as ventilation volume and strategy,are analyzed.The results show that adding nanoparticles to paraffin enhances solar absorption and accelerates phase change.Exhaust air in summer aids in heat removal and PCM solidification,while intake air in winter utilizes solar energy to preheat fresh air and heat the space.The reversible design regulates the direction of discharged heat to meet seasonal thermal demands.It can be concluded that NPRVTW exhibits excellent climate adaptability.In Guilin,the energy-saving rates in summer and winter are 41.84%and 55.62%,respectively,with NPCM4,phase change temperature of 27–29℃,a thickness of 20 mm,and a ventilation rate of 0.5 m/s recommended.展开更多
Understanding the fundamcntal relationship betwecn gas dilution rate of a cigarette and key cigarette design parameters is important in the overall control of smoke yield.In this work,an equation was derived to expres...Understanding the fundamcntal relationship betwecn gas dilution rate of a cigarette and key cigarette design parameters is important in the overall control of smoke yield.In this work,an equation was derived to express the total gas dilution with the cigarette rod length,cigarette paper air permeability,and the filter ventilation level.The relationship was validated using experimental results.The accuracy of the developed model was dependent on the regression method used,i.e.,linear or a nonlinear.The expression provides a quantitative description of the interactions between filter ventilation level,cigarette length,cigarette circumference and cigarette paper air permeability and the total air dilution at the cigarette's mouth end.展开更多
Background: Little is known about the intention formation process regarding the use of tracheostomy and invasive ventilation (TIV) in amyotrophic lateral sclerosis (ALS) patients in the course of disease progression. ...Background: Little is known about the intention formation process regarding the use of tracheostomy and invasive ventilation (TIV) in amyotrophic lateral sclerosis (ALS) patients in the course of disease progression. Objective: To clarify the intention formation process in the use of TIV in ALS patients for the purpose of providing decision-making support. Methods: We conducted a follow-up study of 14 patients using semi-structured interviews, participant observation, and medical records review. Results: The patients’ various intentions regarding the use of TIV were formed as their symptoms progressed (e.g., declining motor, swallowing, and respiratory functions). Other factors influencing their decision were their considerations, such as their ability to communicate after receiving TIV treatment, the degree of support they would receive from professionals after TIV treatment, palliative care for physical distress, value of life after TIV treatment, and to what degree they would be a burden on their families. Conclusion: Patients’ intentions regarding the use of TIV were diverse and changeable. The decision of whether or not to use TIV was made out of conviction as well as considering individual experiences of symptom progression and quality of life after TIV use.展开更多
An experimental investigation of passive cooling buildings has been carried out for a typical summer days extended from July to December of Baghdad in Iraq. Six independent chambers were designed and constructed for d...An experimental investigation of passive cooling buildings has been carried out for a typical summer days extended from July to December of Baghdad in Iraq. Six independent chambers were designed and constructed for different roof constructions. Night ventilation has been applied to study the possibility of reducing air temperature in buildings by testing different air changes per hour extended from 5 to 30. Measurements outside chambers including air temperature; relative humidity and solar radiation were achieved, while surface temperature and air temperature inside the chambers were recorded. The results show that the air temperature can be decreased with a range from 3 ℃ to 6 ℃ when using 50 mm polystyrene. This decrease can further be lowered by 2 ℃ to 4 ℃ if night ventilation of change per hours in buildings is allowed. The reduction in air temperature can be reduced to 5 ℃ by combination of external night ventilation and white paint.展开更多
基金National Natural Science Foundation of China(No.51506076)China’s Post-Doctoral Science Fund(No.2016M591763)Fundamental Research Funds for the Central Universities,China(Nos.JUSRP 51735b,2232017D3-19)
文摘Aperture design is very important in the design process of rainwear,as garment aperture is one of the main pathways for air exchange between clothing microclimate and the environment.The purpose of this study was to investigate the effects of aperture design on whole and local ventilations of rainwear.Ventilation was measured by a tester developed based on the steady-state method.A rainwear suit with top and bottom was chosen as the basic ensemble.Apertures were added at the arm,chest,back and knee separately.Local ventilation of the arm,chest,back and whole ventilation of the top and bottom in different walking and wind conditions were measured.Local and whole ventilations at five aperture conditions for the top and four for the bottom were studied.The results indicated that local ventilation value of the chest was the biggest and the arm was the smallest.Whole ventilation of the suit was the biggest when walking at 5.6 km/h,with all the designed apertures opened.Local ventilation value was bigger when opening arm aperture than that of opening chest or back aperture.The bottom ventilation was the highest when both front and back apertures were opened.
基金Sponsored by the Key Project of National Natural Science Foundation of China (Grant No.51138004)the South China Key Laboratory Fund (Grant No.20121458321)the Architect Design on Energy-saving Residence in Shanghai (Grant No.08-2A-0183-zong)
文摘Based on the current indoor natural ventilation and lighting in the space of traditional residential buildings,this paper starts from the passive-design optimization of the spatial natural ventilation and lighting,and makes quantitative evaluation on the quality of current interior natural ventilation and lighting for two typical residential buildings by three indexes,including wind speed,static wind area ratio and satisfaction ratio about minimum lighting coefficient. Based on that, this paper conducts the passive design optimization, and establishes the quantitative association and reevaluation among the passive reformation design, natural ventilation,and lighting environmental quality,proposing the general strategy for the existing residential buildings to respond to the passive reformation design of the natural ventilation and lighting. The special reconstruction of core functionary space of integration of "the living room + dining room + partial space"is researched,and the redesign for the optimization and replacement of both indoor and outdoor enclosure parts is explored,which is expected to provide practical exploration on the strategies for passive construction of spatial natural environmental quality within a large number of highly-energy-consumed residential buildings in China,as well as the green design of residential buildings.
文摘Given the perennial incidence of thermal discomfort, health issues, as well as energy costs associated with naturally ventilated classrooms in Yola, the study aimed at enhancing the effectiveness of classroom designs for natural ventilation comfort by examining the effects of six architectural design variables—size and position of openings, form of buildings, orientation of buildings, site planning, topography, and physical features, on the ventilation coefficients of 61 classrooms selected from nine stratified clusters in Yola, Adamawa State, Nigeria. Data were analyzed using percentages, ratios, means as well as standard deviation, and then sorted in groups using tables. The study revealed that the form and orientation of the classroom-buildings, as well as topography, site planning and other physical features, have no significant effect on ventilation coefficient. In addition, a new mean ventilation coefficient was obtained in ten classrooms against an earlier claim that ventilation coefficient cannot exceed a fixed average regardless of the ratio of wall opening to floor area.
文摘This study applied the numerical simulator tool FDS （fire dynamics simulator）, Version 5.53, and focused on the simulation of the natural smoke flow ventilation design system, an innovative ventilation design using the parallel processing technology MPI （message passing interface）. The design was then compared with the exhaust efficiency of a typical natural smoke vent. The natural smoke flow ventilation design system was located at the top of the factory, where smoke streams effectively converged. Therefore, the source of fire was designed to be 2 MW, which has a better exhaust efficiency than typical natural smoke vent with same area. The simulation discovered that the exhaust efficiency of the natural smoke ventilation design systems is higher than that of typical natural smoke vent with 2 times the opening area and that was not affected by external wind speed, Instead, external wind speed can help to enhance the exhaust efficiency. Smoke exhaust of typical natural smoke vents was affected by external wind speed, even leading them to become air inlets which would disturb the flow of air indoors, leading to smoke accumulation within the factory.
文摘With a sustained period of economic growth, rapidly growing populations and with more diversified economies Africa need sustainable development; hence the greater need for massive investments in energy. Sub-Saharan countries such as Djibouti have the potential and ability to harness their natural ventilation as a passive cooling system for designing new houses. The rapid expansion of the Djibouti city is affecting negatively the environment and the safety and comfort of its inhabitants. Proper atmospheric urban planning and management are key to making cities environmentally friendly and sustainable. Based on energy consumption, climate conditions in Djibouti and numerical analysis using Computational Fluid Dynamics （CFD）, it is apparent that the natural ventilation creates a thermally comfortable indoor environment in buildings during the cool season of the year. Measured wind data from two measurement systems are presented and discussed. Statistical analyses, wind rose, Weibull distribution were carried out to understand the natural ventilation characteristic, which is used for evolving the basic criteria for economic viability of building in the semi-arid climate of Djibouti. The study found that it is possible to benefit from natural ventilation in buildings during the cool season of the year.
文摘With the development of society, people put forward higher and higher requirements for the comfort of living environment. However, in real life, there are many defects in the design of heating, ventilation and air conditioning, which seriously affect peoples daily life. Therefore, the design and installation of HVAC must strictly abide by the relevant design specifications and engineering quality approval standards, and adopt safe and scientific technical methods and applicable and effective installation techniques to debug the project by item. The installation unit and the final system must be verified through a series of trial runs to ensure the safety of the system, ensure the rationality of heating, and ensure that the engineering entity meets the expected functions and requirements of users.
基金supported by the Natural Sciences and Engineering Research Council of Canada (NSERC) under grant CRDPJ 44580412Barrick Gold Corporation and Peck Tech Consulting Ltd
文摘Ventilation system analysis for underground mines has remained mostly unchanged since the Atkinson method was made popular by Mc Elroy in 1935. Data available to ventilation technicians and engineers is typically limited to the quantity of air moving through any given heading. Because computer-aided modelling, simulation, and ventilation system design tools have improved, it is now important to ensure that developed models have the most accurate information possible. This paper presents a new technique for estimating underground drift friction factors that works by processing 3 D point cloud data obtained by using a mobile Li DAR. Presented are field results that compare the proposed approach with previously published algorithms, as well as with manually acquired measurements.
基金supported by the Natural Science Foundation of Guangxi Province No.2024GXNSFAA010421the National Science Foundation of China No.52368009 and No.52078110.
文摘PCM windows are regarded as promising translucent building envelopes due to their ability to store solar heat and enhance thermal comfort.However,limitations in thermal insulation,phase transition rate,and climate adaptability hinder their further development.Hence,a novel triple-glazed window integrated with nano-enhanced PCM,reversible design and ventilation(NPRVTW)is proposed,while its dynamic photothermal transfer model is developed.Based on simulation results for the application in Guilin and Daqing,China,the thermal comfort and energy efficiency of NPRVTW are evaluated across different seasons and climates.The multi-technology coupling mechanisms are also discussed through comparisons with four other window configurations.The influences of physical properties,phase change temperature,and thickness of NPCM,as well as ventilation volume and strategy,are analyzed.The results show that adding nanoparticles to paraffin enhances solar absorption and accelerates phase change.Exhaust air in summer aids in heat removal and PCM solidification,while intake air in winter utilizes solar energy to preheat fresh air and heat the space.The reversible design regulates the direction of discharged heat to meet seasonal thermal demands.It can be concluded that NPRVTW exhibits excellent climate adaptability.In Guilin,the energy-saving rates in summer and winter are 41.84%and 55.62%,respectively,with NPCM4,phase change temperature of 27–29℃,a thickness of 20 mm,and a ventilation rate of 0.5 m/s recommended.
文摘Understanding the fundamcntal relationship betwecn gas dilution rate of a cigarette and key cigarette design parameters is important in the overall control of smoke yield.In this work,an equation was derived to express the total gas dilution with the cigarette rod length,cigarette paper air permeability,and the filter ventilation level.The relationship was validated using experimental results.The accuracy of the developed model was dependent on the regression method used,i.e.,linear or a nonlinear.The expression provides a quantitative description of the interactions between filter ventilation level,cigarette length,cigarette circumference and cigarette paper air permeability and the total air dilution at the cigarette's mouth end.
文摘Background: Little is known about the intention formation process regarding the use of tracheostomy and invasive ventilation (TIV) in amyotrophic lateral sclerosis (ALS) patients in the course of disease progression. Objective: To clarify the intention formation process in the use of TIV in ALS patients for the purpose of providing decision-making support. Methods: We conducted a follow-up study of 14 patients using semi-structured interviews, participant observation, and medical records review. Results: The patients’ various intentions regarding the use of TIV were formed as their symptoms progressed (e.g., declining motor, swallowing, and respiratory functions). Other factors influencing their decision were their considerations, such as their ability to communicate after receiving TIV treatment, the degree of support they would receive from professionals after TIV treatment, palliative care for physical distress, value of life after TIV treatment, and to what degree they would be a burden on their families. Conclusion: Patients’ intentions regarding the use of TIV were diverse and changeable. The decision of whether or not to use TIV was made out of conviction as well as considering individual experiences of symptom progression and quality of life after TIV use.
文摘An experimental investigation of passive cooling buildings has been carried out for a typical summer days extended from July to December of Baghdad in Iraq. Six independent chambers were designed and constructed for different roof constructions. Night ventilation has been applied to study the possibility of reducing air temperature in buildings by testing different air changes per hour extended from 5 to 30. Measurements outside chambers including air temperature; relative humidity and solar radiation were achieved, while surface temperature and air temperature inside the chambers were recorded. The results show that the air temperature can be decreased with a range from 3 ℃ to 6 ℃ when using 50 mm polystyrene. This decrease can further be lowered by 2 ℃ to 4 ℃ if night ventilation of change per hours in buildings is allowed. The reduction in air temperature can be reduced to 5 ℃ by combination of external night ventilation and white paint.
