Research on the Effect of Natural Ventilation on Buses in Summer Based on CFD Numerical Simulation Method

2011 ◽  
Vol 361-363 ◽  
pp. 1056-1060 ◽  
Author(s):  
Bao Lin ◽  
Xue Ting Wang ◽  
Xiao Hu
Keyword(s):  
Numerical Simulation ◽  
Thermal Comfort ◽  
Natural Ventilation ◽  
Thermal Environment ◽  
Air Flow ◽  
Cost Effective ◽  
Simulation Method ◽  
Computational Domain ◽  
Cfd Numerical Simulation ◽  
Different Parts

Because of the relatively narrow space and high density distribution of the passengers, the bus interior environment deteriorates in summer. Natural ventilating introduces a fresh natural freeze, provides the bus interior with appropriate distribution of air supply temperature and velocity field. Making good use of natural ventilation is an operating strategy ideal for improving passengers’ satisfaction, which is considered as an environmental friendly and cost effective approach. Based on CFD numerical simulation, with a whole-domain approach, this paper predicts air flow and thermal comfort in naturally ventilated bus. The outside and inside airflow is modelled simultaneously and within the same computational domain. The thermal environment in different parts of the bus interior is compared. Different vehicle velocities and conditions of windows are taken into account, analysis are made regarding to the effect of both of them on the interior thermal comfort. The result shows, air disturbance at the bus rear parts are intenser than the other parts with better thermal satisfaction; the quality of air flow in different parts makes the temperature difference in bus achieve as high as 3°C; the use of roof openings distributes the temperature more evenly.

URBAN FACADE GEOMETRY ON OUTDOOR COMFORT CONDITIONS: A REVIEW

2020 ◽  
Vol 4 (1) ◽  
pp. 45
Author(s):  
Elahe Mirabi ◽  
Nasrollahi Nazanin
Keyword(s):  
Thermal Comfort ◽  
Urban Areas ◽  
Natural Ventilation ◽  
Flow Behavior ◽  
Air Flow ◽  
Urban Geometry ◽  
Wide Range ◽  
Low Energy Buildings ◽  
Outdoor Comfort ◽  
Solar Access

<p>Designing urban facades is considered as a major factor influencing issues<br />such as natural ventilation of buildings and urban areas, radiations in the<br />urban canyon for designing low-energy buildings, cooling demand for<br />buildings in urban area, and thermal comfort in urban streets. However, so<br />far, most studies on urban topics have been focused on flat facades<br />without details of urban layouts. Hence, the effect of urban facades with<br />details such as the balcony and corbelling on thermal comfort conditions<br />and air flow behavior are discussed in this literature review. <strong>Aim</strong>: This<br />study was carried out to investigate the effective factors of urban facades,<br />including the effects of building configuration, geometry and urban<br />canyon’s orientation. <strong>Methodology and Results</strong>: According to the results,<br />the air flow behavior is affected by a wide range of factors such as wind<br />conditions, urban geometry and wind direction. Urban façade geometry<br />can change outdoor air flow pattern, thermal comfort and solar access.<br /><strong>Conclusion, significance and impact study</strong>: In particular, the geometry of<br />the facade, such as indentation and protrusion, has a significant effect on<br />the air flow and thermal behavior in urban facades and can enhance<br />outdoor comfort conditions. Also, Alternation in façade geometry can<br />affect pedestrians' comfort and buildings energy demands.</p>

The Simulation of Natural Ventilation of Buildings With Different Location of Windows/Openings

2015 ◽  
Author(s):  
A. Idris ◽  
B. P. Huynh ◽  
Z. Abdullah
Keyword(s):  
Air Quality ◽  
Flow Pattern ◽  
Turbulence Model ◽  
Natural Ventilation ◽  
Air Flow ◽  
Building Design ◽  
Building Envelope ◽  
Navier Stokes ◽  
Computational Domain ◽  
Numerical Predictions

Ventilation is a process of changing air in an enclosed space. Air should continuously be withdrawn and replaced by fresh air from a clean external source to maintain internal good air quality, which may referred to air quality within and around the building structures. In natural ventilation the air flow is due through cracks in the building envelope or purposely installed openings. Its can save significant amount of fossil fuel based energy by reducing the needs for mechanical ventilation and air conditioning. Numerical predictions of air velocities and the flow patterns inside the building are determined. To achieve optimum efficiency of natural ventilation, the building design should start from the climatic conditions and orography of the construction to ensure the building permeability to the outside airflow to absorb heat from indoors to reduce temperatures. Effective ventilation in a building will affects the occupant health and productivity. In this work, computational simulation is performed on a real-sized box-room with dimensions 5 m × 5 m × 5 m. Single-sided ventilation is considered whereby openings are located only on the same wall. Two opening of the total area 4 m2 are differently arranged, resulting in 16 configurations to be investigated. A logarithmic wind profile upwind of the building is employed. A commercial Computational Fluid Dynamics (CFD) software package CFD-ACE of ESI group is used. A Reynolds Average Navier Stokes (RANS) turbulence model & LES turbulence model are used to predict the air’s flow rate and air flow pattern. The governing equations for large eddy motion were obtained by filtering the Navier-Stokes and continuity equations. The computational domain was constructed had a height of 4H, width of 9H and length of 13H (H=5m), sufficiently large to avoid disturbance of air flow around the building. From the overall results, the lowest and the highest ventilation rates were obtained with windward opening and leeward opening respectively. The location and arrangement of opening affects ventilation and air flow pattern.

BIOCLIMATIC OPTIMIZATION: SKYLIGHT GROUND FLOOR NEW BUILDING, UDLA PARK TORRE II

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Mauro Cepeda ◽  
Santiago Morales F. ◽  
Viviana Cabrera
Keyword(s):  
Energy Efficiency ◽  
Thermal Comfort ◽  
Natural Ventilation ◽  
Air Flow ◽  
Internal Flow ◽  
Effective Area ◽  
Academic Environment ◽  
Minimum Area ◽  
Ground Floor ◽  
Beneficial Effects

When high thermal comfort and energy efficiency are provided in an academic environment many beneficial effects on student’s comfort, performance, productivity, and health are shown. The research provides a parametric airflow evaluation of a skylight in a ground floor of new educational building assuming a variation of 4 stages with eight scenarios for the admissions office. By means of the bioclimatic analysis, Predicted Mean Vote (PMV) and Predicted Percentage of Dissatisfied (PPD) indices, the best internal airflow performance for the study area applying natural ventilation is achieved with the air flow optimization. A minimum area of 1.79 m has been established for extraction and movement of the internal flow, both with the natural extraction louvers system measuring 12 inches by 60 inches and the 18 inches by 60 inches, they work properly. However, the 18 inches by 60 inches system has better effectiveness as it has fewer louver units to be placed, is more homogeneous, avoids turbulence and provides better air extraction. In addition, by having fewer louver units distributed along the length of the skylight, it will allow the operation to be more controlled during the operation of the building. The use of 8 louvers of those proportions, with an individual effective area of 0.23 m and a total of 1.84 m was recommended in accordance with the results obtained.

Climatic Strategies of Indoor Thermal Environment for Residential Buildings in Yangtze River Region, China

2011 ◽  
Vol 20 (1) ◽  
pp. 101-111 ◽  
Author(s):  
Baizhan Li ◽  
Wei Yu ◽  
Meng Liu ◽  
Nan Li
Keyword(s):  
Energy Efficiency ◽  
Thermal Comfort ◽  
Yangtze River ◽  
Air Conditioning ◽  
Natural Ventilation ◽  
Thermal Environment ◽  
Residential Buildings ◽  
Design Strategies ◽  
River Region ◽  
Climatic Adaptability

Yangtze River Valley is situated within the Hot Summer and Cold Winter zone, and residents in this region of China would require HVAC system to alleviate thermal comfort conditions, although this is tempered by the Design Code (DBJ50-071-2007) for energy efficiency. A 1-year survey of about 200 residential homes was carried out in eight cities covering the breadth of the region. The acceptable temperature range for the residents in this area was 16.3—28.1°C and the thermal neutral temperature was found to be 27.6°C in summers and 17.5°C in winters. People in different area can vary in their adaptability and comfortableness. Therefore, there is a need to investigate the national comfort parameter introduced in the Code for Design of Heating and Ventilation and Air Conditioning (GB50019-2003). The results found that if air-conditioning system was set to 27.5°C instead of 26°C as required by GBJ19-87: Design Standard of Heating and Ventilation and Air Conditioning, a 16.5% saving of energy consumption could be achieved. The findings demonstrated the role of natural ventilation in the expansion of the thermal comfort zone for the residents, especially during the summer seasons. A climatic adaptability model has been established by this study to contribute to the passive climatic design strategies for a better economic and energy efficiency of buildings.

Design and Aerodynamic Characteristics Study of a Spherical Aircraft

2013 ◽  
Vol 662 ◽  
pp. 612-615
Author(s):  
Peng Li ◽  
Yan Heng Zhang ◽  
Han Xu Sun ◽  
Hao Pan
Keyword(s):  
Numerical Simulation ◽  
Simulation Method ◽  
Aerodynamic Characteristics ◽  
Aircraft Structure ◽  
Research Results ◽  
Aerodynamic Model ◽  
Numerical Simulation Method ◽  
Cfd Numerical Simulation

In order to achieve the goals of small aircraft’s taking off and landing in any posture and the protection of propeller, a new single-propeller spherical aircraft structure was proposed, which had the capacity of flying in the air and walking on the ground simultaneously. An aerodynamic model of the aircraft was built. The aerodynamic characteristics of the spherical aircraft, including the lift and the anti-torque and the generated torque of the flow deflectors under the propeller’s down airflow, are studied in depth by means of CFD numerical simulation method. A reasonable design and installation program is proposed according to the research results.

Indoor Thermal Environment Simulation of Xi'an Residential Building in Summer

2012 ◽  
Vol 512-515 ◽  
pp. 2882-2886
Author(s):  
Shi Jie Wu ◽  
Zeng Feng Yan
Keyword(s):  
Thermal Comfort ◽  
Natural Ventilation ◽  
Thermal Environment ◽  
Residential Building ◽  
Indoor Thermal Environment ◽  
Indoor Thermal Comfort ◽  
Energy Plus ◽  
Environment Simulation ◽  
Indoor Air Flow ◽  
Night Ventilation

Natural ventilation is an important role to improve the residential building indoor thermal environment in summer. This paper use Energy Plus to simulate indoor thermal environment and use CFD to simulate indoor air flow for Xi’an residential building, analysis the influence that different ventilation mode for indoor thermal environment factors. Then with the simulated result of PMV-PPD value to estimate indoor thermal comfort. Proved night ventilation is necessary in residential building in Xi’an and effectiveness to improve indoor thermal comfort.

scholarly journals Evaluation of Thermal Comfort in the Traditional Bourgeoisie Houses in Beirut

2020 ◽  
Vol 3 (1) ◽  
pp. p1
Author(s):  
Jad Hammoud ◽  
Elise Abi Rached
Keyword(s):  
Thermal Comfort ◽  
Natural Ventilation ◽  
Heat Waves ◽  
Thermal Environment ◽  
Thermal Sensation ◽  
Residential Buildings ◽  
Ventilation System ◽  
Electricity Consumption ◽  
Comfort Level ◽  
Climate Zones

The increasing of energy demands has considerably increased the requirements for new and traditional buildings in different climate zones. Unprecedented heat waves have increased climate temperature, in particular, in moderate climate zones such as Lebanon. In Beirut, only the residential sector consumes 50% of total electricity consumption. HVAC (Heating, Ventilation and Air conditioning) systems are used to reach acceptable thermal comfort levels in the new residential buildings. In case of the traditional bourgeoisie houses in Beirut, there are no discussions about the use of HVAC systems to achieve the required thermal comfort level. Thus, to reach an acceptable thermal comfort level, these houses which already contain natural ventilation system shall adapt the modern thermal comfort requirements and thermal comfort strategies and technologies where their architectural features and existing materials condition the available solutions. In order to identify the best options within the possible intervention lines (envelopes, passive strategies, equipment, renewable energy systems), it is necessary to perceive the real performance of this type of houses. In this context, the article presents the results of the study of thermal performance and comfort in a three case studies located in Beirut. Detailed field data records collected are analyzed, with a view to identify the indoor thermal environment with respect to outdoor thermal environment in different seasons. Monitoring also included measurement of hygrothermal parameters and surveys of occupant thermal sensation.

scholarly journals Assessment of indoor thermal environment of Aceh house based on WBGT index

2021 ◽  
Vol 881 (1) ◽  
pp. 012023
Author(s):  
Muslimsyah ◽  
A Munir ◽  
Y Away ◽  
Abdullah ◽  
K Huda ◽  
...  
Keyword(s):  
Thermal Comfort ◽  
Natural Ventilation ◽  
Thermal Environment ◽  
Ventilation System ◽  
Vernacular Architecture ◽  
Maximum Temperature ◽  
Cooling Process ◽  
Temperature Index ◽  
Indoor Thermal Environment ◽  
Temperature Ranges

Abstract Thermal comfort is one of the standard assessments of building thermal environment. Air movement is an important parameter for in a naturally ventilated to achieve thermal comfort by accelerating the evaporative cooling process on the human body. Aceh House has a standard of thermal comfort with a vernacular architecture with a natural ventilation system. This vernacular architectural building has a fairly high harmonization of the environment because it has undergone a process of adaptation. In this study, observations were made at the Original House (OH), the Adaptive Reuse House (ARH), and the Aceh Modified House (AMH). By using the method of assessing changes in environmental comfort, using Wet Bulb Temperature Index (WBGT) method, the minimum and maximum temperature ranges are 25°C and 30°C. In the WBGT thermal rating, AMH has the higher thermal and is followed by ARH and OH respectively. Thus, OH has lower thermal compared to other Aceh houses.

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