scholarly journals A Study of the Simulation and Analysis of the Flow Field of Natural Convection for a Container House

2020 ◽  
Vol 12 (23) ◽  
pp. 9845
Author(s):  
Hsin-Hung Lin ◽  
Jui-Hung Cheng
Keyword(s):  
Wind Speed ◽  
Solar Radiation ◽  
Flow Field ◽  
Thermal Comfort ◽  
Natural Ventilation ◽  
Air Flow ◽  
Flow Mode ◽  
Inlet Temperature ◽  
Radiation Heat ◽  
Research Results

Natural disasters, such as earthquakes, windstorms, and tsunamis, can occur all over the world, and disasters caused by human factors, such as civil wars, are also a source of major disturbance. The temporary rehousing of the population is a major problem when disasters occur. The installation of the combination house is time consuming, and tents cannot be used in the event of strong rain and wind; therefore, the container house is the most effective way of solving the rehousing problem. Natural ventilation is the main factor affecting the indoor air quality, thermal comfort, and health inside a container house, and solar radiation heat can also affect temperature changes inside. The air flow field inside a dwelling is very complex, and its flow mode is affected by inlet wind speed, inlet temperature, solar radiation heat, and the size of doors and windows, etc. In this paper, the influence of natural ventilation on the ventilation inside container houses is analyzed. Assuming that there is complex fluid motion in the activity space of the container house, it is not easy to use conventional methods to predict the flow rate. Based on the correlation analysis motion between the corresponding internal flow rates, the calculation and application method of flow is simplified from the results of the wind speed coefficient obtained previously. In addition, an analysis of flow characteristics in the container house is made; simulation analysis in the container house is made by carrying out the numerical analysis of several factors, including velocity field and temperature field. The variation state of the temperature of the environment and a numerical variation of the three-dimensional space are obtained by numerical calculation; the standard k-ε turbulence model is adopted to describe the turbulence phenomena of the fluid, and the mathematical model matched by B-spline surface is used for data analysis through the surface algorithm in order to deal with complex simulation data. The research results show that, regarding the influence of natural ventilation on container houses, the ideal relative position of openings includes the combination of asymmetric windows, followed by the central positioning of the door. The four-opening configurations, where better natural ventilation performance can be achieved, are located at different diagonal positions. The average flow velocity vector form, velocity amplitude, radiation temperature distribution, and the effect of the air volume coefficient of temperature change are analyzed. The research results show that the design of container houses can meet the requirements of air flow, such as the energy consumed by the thermal comfort space. Measurements taken over time and algorithms can also check the residents’ indoor natural ventilation and provide health care by the use of various sensors.

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>

scholarly journals Air Flow Regimes and Thermal Comfort in Vehicle Cabin Considering Solar Radiation

2017 ◽  
Vol 04 (04) ◽  
Author(s):  
Ibrahim Reda ◽  
Essam E Khalil ◽  
Taher M Aboudeif ◽  
Ahmed El Degwy
Keyword(s):  
Solar Radiation ◽  
Thermal Comfort ◽  
Air Flow ◽  
Flow Regimes ◽  
Vehicle Cabin

Simulation of Indoor Air Flow Fields in Buildings With Large Interior Spaces With Stratified Air Conditioning and Perforated Side Wall Diffusers

2010 ◽  
Author(s):  
Bing Wei ◽  
Li Zhang
Keyword(s):  
Energy Consumption ◽  
Flow Field ◽  
Energy Conservation ◽  
Indoor Air ◽  
Air Conditioning ◽  
Air Flow ◽  
Side Wall ◽  
Flow Fields ◽  
Flow Mode ◽  
Indoor Air Flow

The energy consumption of AC (air conditioning) systems in large buildings is normally higher than the energy consumption in smaller buildings, and its indoor air flow field is also more complex than that in small building. To study the air flow mode and the indoor air flow fields in large spaces is of great significance to the energy conservation of AC systems and thermal comfort of the occupants. This paper presents an example using a large building that uses stratified air conditioning delivered through the linear slot sidewall diffusers and perforated sidewall diffusers. Using CFD simulation methods, three air flow field situations were simulated: (1) total air volume supplied from linear slot diffusers located in the middle of a side wall, (2) 50% flow through the linear slot diffusers the remainder supplied through the perforated sidewall diffusers, (3) 30% of the volume supplied with linear slot diffusers, 70% supplied through the perforated sidewall diffusers. The simulated results show that the third airflow mode is the optimal one for the three modes, which is good for achieving energy conservation and a comfortable building thermal environment in buildings with large spacial areas.

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.

Enhancement of Gravity Ventilation in Buildings

2017 ◽  
Author(s):  
Magdalena Nakielska ◽  
Krzysztof Pawłowski
Keyword(s):  
Natural Ventilation ◽  
Air Flow ◽  
Electrical Energy ◽  
Climatic Conditions ◽  
Demand Systems ◽  
Solar Chimney ◽  
Correct Operation ◽  
Research Results ◽  
Heat Demand ◽  
Flow Through

Nowadays, people are looking for solutions related to ventilation, cooling or heat demand systems, which would be energy efficient and, at the same time, would not cause the degradation of the surrounding environment. As far as ventilation is concerned, an good solution is a natural ventilation, which improves thermal comfort rooms without increasing the consumption of electrical energy in the building. In order to improve the mode of action of the natural ventilation in the building, one can mount various elements supporting the air flow. One of them is a solar chimney. In order to check the correct operation of a gravity ventilation installation in Poland’s climatic conditions, the measurements was carried out on a test stand on the 3.1 building of UTP University of Science and Technology in Bydgoszcz. The received results show the intensification of the air flow through the room the value between 50% and 150%, depending on a measuring hour (Chen et al. 2003). These research results were compared with the research results received before the installation of the solar chimney on the ducts of the gravity ventilation.

Numerical Analysis of Construction Ventilation of Long Railway Tunnel in Plateau Area

2011 ◽  
Vol 243-249 ◽  
pp. 3489-3492
Author(s):  
Bao Long Lin ◽  
Xiao Yun Jia
Keyword(s):  
Finite Element ◽  
Numerical Analysis ◽  
Wind Speed ◽  
Flow Field ◽  
Air Flow ◽  
Railway Tunnel ◽  
Finite Element Software ◽  
Plateau Area ◽  
The Future ◽  
The Face

Based on the conditions of Guanjiao tunnel, numerical analysis of air flow field is carried out by the finite element software—CFD in this paper. The results show that when the wind speed is 11m/s, the outlet to the face is less than 50m was better; if the speed is 8m/s ~ 4m/s, the distance is less than 40m better. Under the same conditions, the face wind speed of 40m is larger than of 30m. The faster of the speed, the greater of the attenuation along the way. The best distance from duct to the face is suggested according to different wind speed, which can provide a reference for the construction ventilation of the similar projects in the future.

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.

scholarly journals PENGARUH TATA RUANG PADA PENGHAWAAN ALAMI RUMAH VERNAKULAR MELAYU PONTIANAK

2019 ◽  
Vol 6 (1) ◽  
pp. 53
Author(s):  
Tri Wibowo Caesariadi
Keyword(s):  
New York ◽  
Wind Speed ◽  
Thermal Comfort ◽  
Earthquake Engineering ◽  
Natural Ventilation ◽  
Building Materials ◽  
Spatial Arrangement ◽  
Spatial Layout ◽  
Indoor Space ◽  
Vernacular House

Arsitektur vernakular adalah arsitektur yang memiliki respon yang baik terhadap iklim setempat. Hal ini juga berpengaruh terhadap kenyamanan termal dalam bangunan. Sebagai kota yang memiliki iklim tropis lembab, kenyamanan termal bangunan di Kota Pontianak banyak ditentukan oleh pergerakan angin yang terjadi di dalam bangunan. Adaptasi terhadap iklim pada rumah vernakular melayu Pontianak tidak hanya pada penggunaan elemen bangunan seperti bukaan dan bahan bangunan, juga pada tata ruang yang khas, di antaranya terdapat teras, ruang tengah serta pelataran belakang yang memisahkan rumah induk dengan rumah anak. Tujuan penelitian adalah melihat apakah tata ruang ini berpengaruh terhadap penghawaan alami di ruang dalam. Penelitian dilakukan dengan pengukuran di lapangan terhadap variabel kenyamanan termal, terutama temperatur dan kelajuan angin. Kemudian hasil pengukuran dianalisis secara deskriptif kuantitatif dan dilihat hubungan antara variabel dengan tata ruang, yaitu bagaimana temperatur dan kelajuan angin yang berbeda terjadi di setiap ruang, sehingga dapat ditarik kesimpulan. Hasil penelitian menunjukkan bahwa tata ruang di rumah vernakular melayu Pontianak, yaitu hadirnya teras dan pelataran belakang turut berperan dalam penghawaan alami yang terjadi di ruang dalam. Teras berperan dalam menurunkan temperatur luar yang masuk ke dalam bangunan (30,74 °C di ruang luar, lalu 29,84 °C di teras depan, dan 29,09 °C di ruang dalam). Pelataran belakang serta tata ruang dalam memberikan pergerakan angin yang lebih baik, ditunjukkan dengan selisih yang kecil antara kelajuan angin di ruang dalam dengan ruang luar pada rumah dengan pelataran belakang (0,51 m/s) dibandingkan dengan rumah tanpa pelataran belakang (0,77 m/s).Kata-kata Kunci: penghawaan alami, vernakular, tata ruangEFFECT OF SPACE LAYOUT TO NATURAL VENTILATION IN MELAYU PONTIANAK VERNACULAR HOUSEVernacular architecture is architecture that has good response to local climate. This also affects the thermal comfort in the building. As a city that has a humid tropical climate, the thermal comfort of buildings in Kota Pontianak is largely determined by the movement of the wind that occurs inside the building. Adaptation to climate in Pontianak's melayu vernacular house is not only on the use of building elements such as openings and building materials, but also on the typical spatial layout, including a terrace, a central room and a back veranda that separates the main house from the secondary house. The aim of the study was to see whether this spatial arrangement has an effect on natural ventilation in the indoor space. The study was conducted with measurements of thermal comfort variables, especially temperature and wind speed. Then the measurement results were analyzed descriptively quantitatively and viewed the relationship between variables and spatial arrangement – i.e. how the temperatures and wind speed differ in each rooms – so that conclusions could be drawn. The results showed that the layout in Pontianak's melayu vernacular house, namely the presence of terraces and back veranda, played a role in the natural ventilation that occurred in the indoor space. The terrace plays a role in reducing the outside temperature that enters the building (30.74 °C in the outdoor, then 29.84 °C on the front terrace, and 29.09 °C in the indoor). Back veranda and spatial layout provide better wind movement, indicated by small difference between the speed of wind in the indoor and the outdoor space of the house with back veranda (0.51 m/s) compared to the house without back veranda (0.77 m/s).Keywords: natural ventilation, vernacular, spatial layoutREFERENCESBoutet, Terry S. (1987) Controlling Air Movement: A Manual for Architects and Builders. New York: McGraw-Hill Book Company.Caesariadi, Tri Wibowo; Kalsum, Emilya (2011) Climatic Responsive Space in Melayu Pontianak House: A Preliminary Study. The CIB Inter-national Conference: Enhancing the Locality in Architecture, Housing and Urban Environment. January 22, 2011. Yogyakarta.Engin, N.; Vural, N.; Vural, S.; Sumerkan, M.R. (2005) “Climatic Effect in the Formation of Vernacular Houses in the Eastern Black Sea Region”. Building and Environment, Vol. 42. www. sciencedirect.comGutierrez, Jorge (2004) “Notes On the Seismic Adequacy of Vernacular Buildings”. Paper No. 5011. 13th World Conference on Earthquake Engineering. Vancouver.Koenigsberger, O.H.; Ingersoll, T.G.; Mayhew, Alan; Szokolay, S.V., (1973) Manual of Tropical Housing and Building, Part One: Climatic Design, London: Longman Group Limited.Lechner, Norbert (2001) Heating, Cooling, Lighting: Design Methods for Architects. New York: John Wiley & Sons, Inc.Lippsmeier, Georg (1997) Bangunan Tropis. Jakarta: Erlangga.Sozen, Mujgan S.; Gedik, Gulay Z. (2006) “Evaluation of Traditional Architecture in Terms of Building Physics : Old Diyarbakir Houses”. Build and Environment, Vol. 42. www.elsevier.com.Szokolay, Steven V. (2008) Introduction to Archi-tectural Science: The Basis of Sustainable Design, 2nd ed.. Oxford: Architectural Press Elsevier.

Influence of Main Stage Air Splits on the Ignition Performance of TeLESS-II Combustor

2017 ◽  
Author(s):  
Xiaotong Mi ◽  
Chi Zhang ◽  
Bo Wang ◽  
Yuzhen Lin
Keyword(s):  
Flow Field ◽  
Air Flow ◽  
Pollutant Emissions ◽  
Recirculation Region ◽  
Stable Operation ◽  
Inlet Temperature ◽  
Main Stage ◽  
Fuel Distribution ◽  
Baseline Case ◽  
The Impact

The centrally staged layout is preferred in the advanced aero-engine combustor to achieve low pollutant emissions as well as stable operation in lean premixed prevaporized combustion. However, because the high-speed main stage airflow prevents the pilot fuel droplets arriving at igniter tip and has a strong convection effect on the initial flame kernel, the application of centrally staged combustor is restricted by its poor ignition and lean blow-out performance. In the centrally staged combustor, the main stage and pilot stage have strong coupled influences on the flow field and fuel distribution. The aim of this paper is to research the impact of the main stage air split on the ignition performance for the baseline case and the comparison case of the main swirler in the TeLESS-II combustor. The main stage air flow rate of the comparison case is about 8 percent less than that of the baseline case. The results of the ignition test at room inlet temperature and pressure indicate that the ignition performance of the comparison case is significantly better than that of the baseline case. The results of the lean blow-out tests show that the main stage air splits do not make the lean blow-out performance worse. To achieve a better understanding of the test results, PLIF technology and CFD analysis were used to measure the fuel distribution and non-reacting flow field. The PLIF and CFD results demonstrate that the most of the fuel spray disperse outward into the main stage cold airflow in the baseline case so that the pilot flame is hard to be established, which leads to poor ignition performance. On the other hand, in the comparison case, the most of the fuel is confined in the recirculation region, which gives a better ignition performance. Compared with the baseline case, the main stage airflow velocity decays faster in the comparison case. It changes the direction of the instantaneous velocity in the spark vicinity, which makes it more likely for the ignition kernel to be captured by the recirculation stream in the comparison case. Therefore, the different fuel distribution and flow field characteristics cause the ignition performance improvement in the comparison case. The improvement is due to the different main stage air flow rates, which is the consequence of the main stage air split.

scholarly journals Analysis of the influence of selected factors on natural greenhouse ventilation

2018 ◽  
Vol 49 ◽  
pp. 00036
Author(s):  
Sławomir Grabarczyk
Keyword(s):  
Wind Speed ◽  
Natural Ventilation ◽  
Air Flow ◽  
Leeward Side ◽  
Air Exchange Rate ◽  
Solar Radiation Intensity ◽  
Thermal Screen ◽  
Flow Through ◽  
American Society ◽  
Air Exchange

In greenhouses, in order to maintain proper indoor air temperature, during the period of high values of solar radiation intensity, shading treatments using thermal screens and ventilation are applied. The research was carried out in a mono-span greenhouse in order to determine the effectiveness of natural ventilation. The object of analysis is a greenhouse with a thermal screen installed inside. The tests were carried out during the summer days. The effect of the research was to determine the ventilation air flow through the vents of the greenhouse on the basis of measurements and calculation analyzes. The dependence of the air flow on the windward and leeward side was determined from the wind speed and the temperature difference between the indoor and outdoor air. On the basis of calculations made from observation during shading of the cultivated area and with open ventilators, the coefficients of air exchange per unit floor area of the greenhouse were determined. It was established that at a wind speed exceeding 0.8 m/s, the air exchange rate in the tested greenhouse exceeds the value recommended by the American Society of Agricultural Engineers of 0.04 m3/(s.m2).

Sign in / Sign up

Export Citation Format

Share Document