Natural Ventilation Design Research Articles

Prioritizing sustainability indicators for Uganda's built environment: Expert perspectives using the Delphi technique

The growing emphasis on energy efficiency within the built environment, driven by global concerns over climate change, has resulted in notable shifts in building energy consumption patterns. Achieving reductions in building energy use and CO₂ emissions through sustainable strategies necessitates the development of country-specific policies. While numerous energy assessment tools are available internationally, they often lack contextual relevance for Uganda and many Sub-Saharan African countries.Therefore, there is a pressing need for a tool tailored to Uganda's distinct climatic conditions. This study aimed to identify key building sustainability indicators to promote energy efficiency in Ugandan buildings. Utilizing the Delphi Technique, experts from academia, construction, energy consulting, and government agencies evaluated 35 building indicators over two assessment rounds. The consensus among experts was validated using the Interrater Agreement, with a significant Kendall's W value exceeding 0.6, rising from 0.655 in the first round to 0.704 in the second. Construction consultants showed the highest W value (0.77) in the second round, followed by energy consultants (0.74), while academicians had the lowest (0.7). The Chi-square test demonstrated strong agreement in ranking indicators across 34 degrees of freedom. The most significant indicators identified include "B20 - Optimization of energy use," "B8 - Advanced design and construction technology," and "B27 - Natural ventilation design," among others. The Delphi Technique was instrumental in achieving expert consensus, while interrater agreement was used to validate and ensure the reliability of the findings. The developed framework provides critical insights for policymakers, practitioners, and researchers seeking to advance energy efficiency and sustainability within Uganda's built environment.

Indoor Environment Design and Energy Saving Analysis of Sustainable Development Integrated with Green Building

Modern architectural design has gradually distanced itself from the actual living needs of urban residents in the process of pursuing the integration of architecture and nature. To achieve the perfect combination of sustainable ecological concepts and effective energy utilization, green buildings have become an actively pursued design concept. Unlike relying solely on high-tech means, the core goal of green buildings is to build an environmentally friendly building environment by achieving sustainable and efficient utilization of energy and resources. In the design phase, green buildings should focus on functionality and economy, and be tailored to the local economic conditions, regional characteristics, natural resources, and climate conditions of the building's location to create green buildings with unique architectural and regional characteristics. This article endeavors to furnish both theoretical underpinnings and practical directives for the indoor environment design and energy conservation efforts of green buildings. By delving into the pivotal role of indoor environments as an essential architectural component, it integrates sustainable development principles with green building practices and delves into the intricate relationship between indoor environment design and energy efficiency, thus offering valuable insights and guidance for achieving sustainable and energy-efficient indoor spaces. In this process, this article examines the energy and resource utilization benefits that green building design can achieve, as well as the specific impact of indoor environment improvement on the quality of life of residents. Through an in-depth analysis of these aspects, this article aims to provide substantial contributions to achieving the sustainable development goals of green buildings. The experimental comparison results show that in terms of natural ventilation design, compared to mechanical ventilation, the proposed scheme can achieve an annual energy cost savings of 20%.

Framework for integrated multi-scale computational fluid dynamics simulations in natural ventilation design

The wind flow field constitutes an important input parameter for computational fluid dynamics (CFD) simulations that are used in architectural design for the design and analysis of natural ventilation strategies. Despite indications that the wind flow field may vary between places, CFD simulations that do not adequately account for this potential variation are still commonplace. This may significantly compromise the integrity and accuracy of the CFD simulations. This study was a two-pronged investigation with the ultimate objective of contributing towards efforts aimed at improving the accuracy of the CFD simulations. Firstly, a framework for integrated meso-scale and micro-scale CFD simulations was developed. Secondly, the newly developed framework was then implemented by deploying it to study the variation of the wind flow field between a reference meteorological station, and a selected local building site. The findings confirmed the indications that the wind flow field might vary spatially. The integrated multi-scale framework that was developed as part of the study was not only able to capture the wind flow field variation, but it also provided a way to quantify it, ultimately, leading to the generation of a more accurate wind flow field characterization representative of the local conditions. Through its ability to integrate multiple spatial scales that typically influence one another, this framework can help to enhance the accuracy and integrity of the CFD simulations that are used for natural ventilation design. Practical application: The findings from this study can be particularly useful when undertaking spatially integrated CFD simulations to design and analyse natural ventilation strategies in the building design process.

Research on natural ventilation of a community library related to epidemiological insight by using CFD simulation method

Abstract Spreading through airflow is one of the most common routes for the transmission of viruses, which may result in serious public health problems. To acquire a healthy space for the community library, designing a reasonable ventilation system is a vital measure which can reduce the risk of transmission of the virus effectively. The purpose of this research is to study natural ventilation methods in an epidemiological insight for the design of a healthy community library by using computational fluid dynamics (CFD) software SOLIDWORKS Flow Simulation. Five typical opening types of windows were selected and studied in the research on the ventilation of the yoga room of a community library, with airflow evaluated by the ACH method, so as to search for the most suitable window type to avoid airborne virus transmission. The results acquired by SOLIDWORKS simulation showed that 75%, 90%, and 100% openings corresponding to Jalousie, casement, and double casement window types respectively are optimal in community space. The natural ventilation design by proper windows can be applied in the community library and other public spaces.

Influence of deflectors on indoor airflow velocity distribution under natural ventilation conditions

Deflectors offer a cost-effective solution for enhancing airflow distribution. The purpose of this paper is to investigate the effect of the deflector on the indoor airflow velocity distribution under natural ventilation conditions. The results obtained from numerical simulations are validated through experimental measurements using a reduced-scale model. Subsequently, the validated reduced-scale numerical model was extended to full-size rooms. A full-size numerical simulation method is used to analyze the effect of no deflector, deflectors with different opening width-to-height ratios and deflectors with different opening shapes on the percentage of indoor velocity partitions under natural ventilation conditions. The findings reveal that the judicious installation of deflectors can enhance indoor airflow velocity distribution and increase the percentage of the indoor comfort zone. Deflectors with different opening width-to-height ratios exert distinct influences on indoor airflow velocity distribution. When the deflector opening width-to-height ratio is set at 7/6, the indoor comfort zone percentage reaches its maximum at 75.98%. Furthermore, the shape of the deflector’s opening significantly affects indoor airflow velocity distribution, and when the opening shape is a rhombus shape of 4.00 cm × 9.00 cm, the proportion of indoor velocity comfort zone is the largest, which is 75.56%. This study provides a reference for the design and practice of natural ventilation in buildings.

Brine-water experimental study on the natural ventilation flow rate induced by a localized buoyancy source in an inclined narrow space

Natural ventilation is an energy-saving strategy for diluting indoor contaminants. A series of brine-water experiments are conducted to investigate the mechanisms influencing the ventilation flow rate induced by stratified buoyancy-driven flows in inclined narrow spaces, such as tunnels, corridors and pathways. The results indicate that the flow stratification is determined by source location, tunnel inclination and source buoyancy flux. While Bernoulli’s theorem still can be used to estimate the ventilation flow rate, flow stratification and the buoyant layer thickness should be taken into consideration in such an inclined configuration. The flow is divided into three flow regimes in terms of the mechanisms controlling the flow rate q. A dimensionless parameter η is proposed to categorize the flow regimes. When η < 0.5, the air inflow is mainly induced by plume entrainment and q is approximately equal to that in a horizontal tunnel. When 0.5 < η < 2, q is influenced by the stratification and increases with η. When η > 2, the flow is approximately well-mixed and a constant dimensionless ventilation flow rate is obtained. Models are proposed to estimate q in different flow regimes. The study can be a reference for natural ventilation design in such configurations.

Average surface wind pressure surrounding tall buildings with cruciform shapes

Abstract Building shape affects wind pressure on building surfaces, while limited studies have examined how building shape affects the wind pressure on cruciform-shaped tall buildings. This article investigated the variation of the average wind pressure coefficient (AWPC) on cruciform-shaped tall buildings with the height–width ratio (HWR) and height–thickness ratio (HTR). The results demonstrated the occurrence of building blockage, wind separation, wind re-circulation, and wind re-attachment on building surfaces. The frontal surface of the main building was always the windward surface with positive wind pressure. At 2/3 of the building height (H), the peak AWPCs in all scenarios were ~0.70. However, in the case with an HWR of 3.66, the side surfaces of the main building and the frontal surfaces of the branch building, wind pressure was all negative. With the HWR reduction by building width increase, wind pressure on these surfaces became positive, where the AWPCs in the HWR = 1.41 case were 0.60–0.63 and 0.64–0.69 on side and frontal surface, respectively. With the HWR decrease, both positive and negative wind pressure intensified. Along the central axis (M1) in the vertical direction, wider buildings had stronger positive wind pressure on the frontal surfaces below 0.10H, while narrower buildings had stronger positive wind pressure above 0.82H. In comparison, HTR made limited differences to the wind pressure on the frontal surface. Overall, vertical results showed that scenarios with smaller HWR underwent stronger positive and negative wind pressures. On the HTR cases, wind pressure on top surfaces showed complicated results, while thicker buildings had weaker negative wind pressure on the back surface. Overall, this study is important to understand the characteristics of wind load on cruciform-shaped tall buildings and generate implications for wind resistance, natural ventilation design, and wind electricity generation over tall buildings.

The Numerical Simulation Study of Pumping Airflow Driven by Wind Pressure for Single- and Multi-Room Buildings

Pumping airflow occurs in single-sided natural ventilation buildings when the openings are located on the leeward side; the direction of airflow through the building then changes periodicity. In order to propose a calculation method of the ventilation rates for single-room buildings and analyze the pumping ventilation for multi-room buildings, the CFD method with an SST k-ω turbulence model was used to conduct numerical simulation in this study, which is verified by other experimental results. Firstly, the qualitative and quantitative characteristics of pumping ventilation were investigated for a single-room building with two openings. The results show that the steady-state method underestimates the ventilation flow rates, and the unsteady-state method captures the microstructures of the flow better. Secondly, the vortex-shedding and indoor airflow oscillation frequencies were analyzed based on transient simulation for a single-room building. It was found that both of them increase with air speed. Then, the factors affecting ventilation flow rates were analyzed. A calculation method for dimensionless ventilation rates is proposed. Finally, the pumping ventilation for a multi-room building was numerically simulated. The ventilation rate for a middle room is greater than that for a corner room, and the ventilation rate for any room in a multi-room building is greater than the single-room building given the same room size and the same incoming wind speed. The findings of this paper are helpful for the design and evaluation of natural ventilation.

Analyzing Energy Efficient Design Strategies in High-rise Buildings with Reference to HVAC System

The Global Warming, Climate Change, Energy Depletion, and Carbon emissions are the greatest risks to humanity in the 21st century. Urbanization in many ways increases the lack of energy resources and demands more construction of high-rise towers for a better standard of living. Buildings are responsible for around one-third of global greenhouse gas emissions. With the emergence of the energy crisis, the rise of environmental consciousness, energy-saving measures, and sustainable buildings became a topic of attention. Due to advancements in technology, the design of high-rise buildings has come across various changes with large glass openings, sealed windows, and deep plans which increase the dependency on air conditioning systems (HVAC) thus increasing the demand for more energy consumption inside the building due to mechanical ventilation and air conditioning. In this paper, an attempt has been made to understand the strategies used for designing energy efficient high-rise buildings that can lower the heating and cooling load and thus increase the performance of the high-rise building. The research is based on a theoretical approach and qualitative analysis which is identified from the literature review and secondary case studies, Case studies selected for the study are office high-rise buildings which are sustainable skyscrapers and have achieved lower energy consumption in heating and cooling load compared to the typical office building which shows how an increase in natural ventilation and other architectural design parameters such as building envelop, form, orientation and integration technology like Building Management System (BMS) system can make it more energy efficient high rise building.

The Predicted Performance of Natural Ventilation Strategies in Islamic Boarding School Design in Magelang

The importance issue in providing comfortable indoor air quality conflicts with the use of energy for mechanical cooling in tropics region such as Indonesia. Natural ventilation is seen as a potential to provide comfort through the change of air within the inside and outside of the space. Natural ventilation becomes a strategy to achieve building resilience towards climate change because it requires no energy consumption. Therefore, this research aims to justify the design of natural ventilation of low-income Islamic Boarding School in Magelang using steady state simulation. The results indicated that among three ventilation strategies simulated in this study, it can be concluded that stack effect is predicted to produce higher air flow rate which results to comfortable predicted observation on adaptive comfort.

Prinsip Penerapan Sistem Penghawaan dan Pencahayaan Alami pada Bangunan Rumah Susun Sewa Mabes TNI di Bekasi

The article comes from research which aims to determine the principles of applying natural ventilation and lighting to rental flats at the TNI Headquarters in Bekasi. The design of natural ventilation and lighting systems in flats is part of efforts to meet health and fitness goals for residents economically and effectively. The research method used is a survey technique by conducting observations and literature studies to obtain information regarding applications in building design. From the results of the discussion it can be stated that the principles that must be considered are building orientation, floor plan, area of ​​light openings and effective ventilation.

Influence of natural ventilation design on the dispersion of pathogen-laden droplets in a coach bus

Natural ventilation is an energy-efficient design approach to reduce infection risk (IR), but its optimized design in a coach bus environment is less studied. Based on a COVID-19 outbreak in a bus in Hunan, China, the indoor-outdoor coupled CFD modeling approach is adopted to comprehensively explore how optimized bus natural ventilation (e.g., opening/closing status of front/middle/rear windows (FW/MW/RW)) and ceiling wind catcher (WCH) affect the dispersion of pathogen-laden droplets (tracer gas, 5 μm, 50 μm) and IR. Other key influential factors including bus speed, infector's location, and ambient temperature (Tref) are also considered. Buses have unique natural ventilation airflow patterns: from bus rear to front, and air change rate per hour (ACH) increases linearly with bus speed. When driving at 60 km/h, ACH is only 6.14 h−1 and intake fractions of tracer gas (IFg) and 5 μm droplets (IFd) are up to 3372 ppm and 1394 ppm with ventilation through leakages on skylights and no windows open. When FW and RW are both open, ACH increases by 43.5 times to 267.50 h−1, and IFg and IFd drop rapidly by 1–2 orders of magnitude compared to when no windows are open. Utilizing a wind catcher and opening front windows significantly increases ACH (up to 8.8 times) and reduces IF (5–30 times) compared to only opening front windows. When the infector locates at the bus front with FW open, IFg and IFd of all passengers are <10 ppm. More droplets suspend and further spread in a higher Tref environment. It is recommended to open two pairs of windows or open front windows and utilize the wind catcher to reduce IR in coach buses.

Zero Energy Building Approach in Design of Biohydrogen Research Centre

The utilisation of natural energy not only can reduce energy consumption in buildings but also can lower carbon emissions from the use of fossil fuel energy for building services. It is believed that with appropriate design and a good attitude of building users, the role of renewable energy in reducing carbon emissions will be maximised. This study proposed the implementation of Zero Energy Buildings (ZEB) concept in the initial stage of building design by considering buildings’ form and façade design in relation to daylighting, natural ventilation and thermal design of buildings, and photovoltaic placement to save energy and to produce electrical energy in the designed building. In this study, ZEB Concept is treated as a secondary consideration in producing the architectural design for Biohydrogen Research Centre. The primary design generator is based on the philosophy of chemical bonds form representing biohydrogen chemical bonds. For a successful implementation of the ZEB concept in the Biohydrogen Research Centre design, both active and passive means are utilised in the building design. For passive means, daylighting and natural ventilation strategies were applied. While for active means, photovoltaic panels were employed as the primary electrical energy generation. Energy demand scenarios were predicted and calculated by the amount of energy used for lighting, air conditioning, and other appliances in the building. The total area needed for photovoltaic installation was obtained by balancing the energy demand prediction with the expected energy generation. The resulting design showed a promising outcome where the building is expected to achieve surplus energy with a total of 845,595.5 kWh electricity per year.

Analysis of Palu City’s Readiness Level Assessment Towards Adipura (case study: Siranindi Village)

The utilisation of natural energy not only can reduce energy consumption in buildings but also can lower carbon emissions from the use of fossil fuel energy for building services. It is believed that with appropriate design and a good attitude of building users, the role of renewable energy in reducing carbon emissions will be maximised. This study proposed the implementation of Zero Energy Buildings (ZEB) concept in the initial stage of building design by considering buildings’ form and façade design in relation to daylighting, natural ventilation and thermal design of buildings, and photovoltaic placement to save energy and to produce electrical energy in the designed building. In this study, ZEB Concept is treated as a secondary consideration in producing the architectural design for Biohydrogen Research Centre. The primary design generator is based on the philosophy of chemical bonds form representing biohydrogen chemical bonds. For a successful implementation of the ZEB concept in the Biohydrogen Research Centre design, both active and passive means are utilised in the building design. For passive means, daylighting and natural ventilation strategies were applied. While for active means, photovoltaic panels were employed as the primary electrical energy generation. Energy demand scenarios were predicted and calculated by the amount of energy used for lighting, air conditioning, and other appliances in the building. The total area needed for photovoltaic installation was obtained by balancing the energy demand prediction with the expected energy generation. The resulting design showed a promising outcome where the building is expected to achieve surplus energy with a total of 845,595.5 kWh electricity per year.

Research on the Form of Energy-saving Building under the Influence of Natural Ventilation Technology

With the development of science and technology and the progress of society, humanity is confronting a huge energy crisis. The energy consumption of buildings and the energy consumed to produce that energy have greatly changed the environment in which we live, causing serious energy and environmental consequences. Taking the natural ventilation design method as the main line and the excellent energy-saving building cases as the breakthrough point, this paper focuses on the three dimensions of building groups, building units and building components, and compares and studies the effects of various natural ventilation technologies, the shape of the building. These buildings have strong climate adaptability and climate regulation ability, which can effectively improve and create comfortable indoor microclimates, so that the buildings do not need or reduce the dependence on building equipment, so as to achieve the purpose of reducing building energy consumption.

Numerical simulation on exploring influencing factors of wind-driven natural ventilation effect in large indoor dock

The shipbuilding industry is booming and the health problems of workers caused by the harsh indoor dock environment force us to explore efficient and reasonable ventilation methods suitable for large workshops. Due to the strong specificity of large workshops, general or local ventilation methods cannot be universally applied. It has great potential and good economy to improve indoor environment by changing natural ventilation design. Computational fluid dynamics (CFD) has gradually become a powerful tool for predicting indoor and outdoor airflow organization and optimizing indoor ventilation. This paper adopts CFD to study the effect of the inflow wind speed, the position of the side wall shutters, the area ratio and form of roof ventilators on the effectiveness of natural ventilation in a large shipyard driven by wind pressure. The results show that the influence on total ventilation volume is more obvious when the intake side is shaded than the exhaust side. Different incoming wind speeds will affect the wind pressure at the ventilation position, which is the decisive external factor affecting the natural ventilation of docks. When the area ratio of roof ventilators increases to a certain extent, its continued increase has an insignificant effect on the total ventilation volume. The influence of changing the arrangement of the roof ventilator on the natural ventilation effect can be neglected when the area ratio is kept constant.

Exploring the impact of opening ratio on indoor thermal environment: A study on natural ventilation design

AbstractThe utilization of natural ventilation to reduce thermal load and enhance thermal comfort in buildings is on the rise. Furthermore, in light of the COVID‐19 impact, natural ventilation is gaining prominence as an increasingly vital technology. However, it is crucial to address potential challenges associated with natural ventilation, particularly its impact on the indoor thermal environment. This study aimed to examine and offer insights into natural ventilation design and operational strategies for office buildings. We initially summarized the criteria and effective opening area of natural ventilation openings (αAi) in Japanese naturally ventilated buildings. Among the 37 investigated office buildings, we found a positive correlation between the natural ventilation room area and the αAi. Approximately, 25 buildings maintained a ratio of αAi to the natural ventilation room area ranging from 0.1%–0.5%. Additionally, we conducted measurements of the indoor thermal environment, focusing on the opening ratio of natural ventilation openings. The difference of indoor and outdoor temperature showed a strong negative correlation with the opening ratio, while wind direction and global solar radiation exhibited significant correlations as well. These research findings provide valuable insights for future natural ventilation designs and the incorporation of opening ratio concepts into operational methods.

Field Measurements and Analysis of Indoor Environment, Occupant Satisfaction, and Sick Building Syndrome in University Buildings in Hot Summer and Cold Winter Regions in China.

Teachers and students work and study in classrooms for long durations. The indoor environment directly affects the health and satisfaction of teachers and students. To explore the performance differences between green buildings, conventional buildings, and retrofitted buildings in terms of their indoor environment, occupant satisfaction, and sick building syndrome (SBS), as well as the correlation between these different aspects, three university teaching buildings were selected in hot summer and cold winter regions in China. These included a green building (GB), a retrofitted building (RB), and a conventional building (CB). Long-term indoor environment monitoring and point-to-point measurements were conducted during the transition season and winter and the indoor environment, satisfaction, and SBS in the three buildings were compared. A sample of 399 point-to-point questionnaires was collected. A subjective-objective indoor environmental quality (IEQ) evaluation model for schools in China was established, covering satisfaction and the indoor environment. The results showed that the compliance rate of the indoor environment in the GB and RB was generally superior to that of the CB. The overall satisfaction was the highest for the GB, followed by the CB, and then the RB. The GB had the highest overall indoor environment quality score, followed by the RB and then the CB. The occurrence of SBS was lowest in the CB, followed by the GB, and then the RB. It was determined that the design of natural ventilation should be improved and that building users should be given the right to autonomous window control and temperature control. To reduce the occurrence of SBS symptoms, attention should be paid to the control of temperature and CO2 concentration. To improve learning efficiency, it suggests reducing indoor CO2 concentrations and improving desktop illuminance. This study provides a reference for improving the indoor environment and health performance of existing university teaching buildings.

Natural ventilation design for underground parking garages

Most underground parking garages use mechanical ventilation facilities to remove excessive heat and indoor contaminants and consume significant amounts of energy. Alternatively, underground garages could reduce their electricity consumption by incorporating natural ventilation into their design. However, the effectiveness of different ventilation designs for the natural ventilation of underground space needs to be quantified. This study uses wind tunnel experiments, a Large Eddy Simulation model, and a time-scale analysis to investigate the natural ventilation and the transport of carbon monoxide (CO) in underground garages without mechanical ventilation. The garage with a ramped driveway and a vertical ventilation shaft has the highest ventilation rate and fastest decay rate of CO among the cases being studied. In addition, the simulation results reveal that the windcatcher can enhance natural ventilation when the opening is normal to the wind direction. A garage with only vertical ventilation shafts has the lowest natural ventilation rate. Nonetheless, the ventilation shafts located at the diagonal corners could remove the air contaminants accumulated at the garage corners more effectively. The building above the underground garage could increase the natural ventilation rate by raising the pressure difference between the windward and leeward openings.

Development of Decision Support System (DSS) for Greenhouse Ventilation and Cooling Control

The confined heat created by the sunlight and ambient temperature is one of the obstacles to greenhouses in the tropics. A conservatory in tropical regions thus requires a proper ventilation and cooling system to provide an ideal greenhouse temperature to support crop production. The main objective of this study is to develop a Decision Support System (DSS) for optimum greenhouse ventilation and cooling control. An equation model to predict the temperature inside was developed by considering heat generation and heat loss inside the greenhouse. The accuracy of the equation model was validated with secondary data from the on-field greenhouse by statistical evaluation metrics. The statistical evaluation proved that the equation model is good with 2.11°C of Root Mean Square Error (RMSE), 6.22% of Percent BIAS (PBIAS) and 0.94 of Nash-Sutcliffe efficiency (NSE) value. A DSS using Microsoft Excel with Visual Basic for Applications (VBA) is developed based on the equation model to provide the ventilation and cooling system information. Input required for the DSS is a climatic condition, dimension and covering greenhouse material. The output of the DSS is the temperature inside the greenhouse, natural ventilation design, forced ventilation, active cooling system design using an evaporative pad and fan, and fogging system. The DSS can be used as an approach for ventilation and cooling design recommendation for the optimum temperature inside the greenhouse.