scholarly journals EXAMINATION OF BUOYANCY DRIVEN VENTILATION DESIGN USING THE CHARACTERISTICS OF OPENING RATIO OF NATURAL VENTILATION OPENING

2021 ◽  
Vol 86 (784) ◽  
pp. 608-618
Author(s):  
Kei SHIMONOSONO ◽  
Kimiko KOHRI ◽  
Hisaya ISHINO
Keyword(s):  
Natural Ventilation ◽  
Opening Ratio

scholarly journals Development of a model for single-sided, wind-driven natural ventilation in buildings

2017 ◽  
Vol 38 (4) ◽  
pp. 381-399 ◽  
Author(s):  
Junli Zhou ◽  
Cheng Ye ◽  
Yan Hu ◽  
Hassan Hemida ◽  
Guoqiang Zhang ◽  
...  
Keyword(s):  
Flow Rate ◽  
Natural Ventilation ◽  
Pulsating Flow ◽  
Wind Pressure ◽  
Mean Flow ◽  
Total Flow ◽  
Total Flow Rate ◽  
Small Opening ◽  
Opening Ratio ◽  
Large Opening

Natural ventilation is a simple and energy-efficient method to adjust the indoor environment. This study aims to develop a model for predicting the total flow rate of single-sided natural ventilation. It is motivated by the fact that the wind-driven ventilation itself is commonly considered to consist two components – a mean component and a fluctuating component. Pulsating flow rate, mean and broadband ventilation rate are discussed and considered in the model due to fluctuating wind velocity driven by the fluctuating pressures and unsteady flows around the opening. The new model shows that the total flow rate is majorly caused by pulsating flow when the area of opening is small, but it is mainly caused by mean flow in the case of large opening. Opening ratio can be taken as a boundary to distinguish the small opening area and the larger one from the case analyses in this study. Reynolds Averaged Navier-Stoke model, large eddy simulation, and other correlations are utilized to validate the developed model. The results of current method agree reasonably well with those of transient simulation. Finally, a simplified version of the model is developed which is useful for predicting the total flow rate of natural ventilation in buildings. Practical application: The model can be applied to predict the total flow rate of single-sided natural ventilation in buildings due to wind pressure. The model shows that the total flow rate is majorly caused by the pulsating flow when the area of opening is small, but it is mainly caused by the mean flow in the case of large opening. An opening ratio of 3% can be taken as a boundary to distinguish the small opening area and the large one from the cases analysed in this study.

Investigation of the natural ventilation of wind catchers with different geometries in arid region houses

2020 ◽  
Vol 14 (3) ◽  
pp. 7109-7124
Author(s):  
Nasreddine Sakhri ◽  
Younes Menni ◽  
Houari Ameur ◽  
Ali J. Chamkha ◽  
Noureddine Kaid ◽  
...  
Keyword(s):  
Arid Region ◽  
Natural Ventilation ◽  
Reduction Rate ◽  
Internal Flow ◽  
Climatic Conditions ◽  
Maximum Pressure ◽  
Ventilation Technique ◽  
Window Position ◽  
The One ◽  
Flow Velocities

The wind catcher or wind tower is a natural ventilation technique that has been employed in the Middle East region and still until nowadays. The present paper aims to study the effect of the one-sided position of a wind catcher device against the ventilated space or building geometry and its natural ventilation performance. Four models based on the traditional design of a one-sided wind catcher are studied and compared. The study is achieved under the climatic conditions of the South-west of Algeria (arid region). The obtained results showed that the front and Takhtabush’s models were able to create the maximum pressure difference (ΔP) between the windward and leeward of the tower-house system. Internal airflow velocities increased with the increase of wind speed in all studied models. For example, at Vwind = 2 m/s, the internal flow velocities were 1.7, 1.8, 1.3, and 2.5 m/s for model 1, 2, 3, and 4, respectively. However, at Vwind = 6 m/s, the internal flow velocities were 5.6, 5.5, 2.5, and 7 m/s for model 1, 2, 3, and 4, respectively. The higher internal airflow velocities are given by Takhtabush, traditional, front and middle tower models, respectively, with a reduction rate between the tower outlet and occupied space by 72, 42, 36, and 33% for the middle tower, Takhtabush, traditional tower, and the front model tower, respectively. This reduction is due to the due to internal flow resistance. The third part of the study investigates the effect of window (exist opening) position on the opposite wall. The upper, middle and lower window positions are studied and compared. The air stagnation or recirculation zone inside the ventilated space reduced from 55% with the lower window to 46% for the middle window and reached 35% for the upper window position. The Front and Takhtabush models for the one-sided wind catcher with an upper window position are highly recommended for the wind-driven natural ventilation in residential houses that are located in arid regions.

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 The Effect Of Outside Corridor’s Orientation to Interior Thermal Condition at Lawang Sewu Semarang.

2018 ◽  
Vol 73 ◽  
pp. 01011
Author(s):  
Benediktus Yosef Arya Wastunimpuna ◽  
Wahyu Setia Budi ◽  
Erni Setyowati
Keyword(s):  
Heat Stress ◽  
Relative Humidity ◽  
Thermal Condition ◽  
Natural Ventilation ◽  
Thermal Conditions ◽  
Standard Theory ◽  
Hot Wire ◽  
Air Movement ◽  
Dutch Colonial

The outside corridor of Dutch Colonial Building in Indonesia was made to make the temperature of the room more comfortable. Lawang Sewu Building in Semarang is one example of a building that has an outside corridor along the building and until now still use natural ventilation. This study focuses on finding out whether there is a difference on the thermal conditions of each room’s orientation, so after that we know the effect of orientation of the outdoor corridor to the temperature of the interior. In this study the experiment based on measurement using Heat Stress WBGT Meter for Wet Bulb Temperature, Dry Bulb Temperature, Relative Humidity, and KW0600653 Hot Wire Anemometer for the air movement. The data will be analysed using thermal standard theory to find out which point has the most comfortable thermal conditions.. At the end of this study will be found the effect of corridor’s orientation to thermal condition of the interior in Lawang Sewu Semarang.

scholarly journals Experimental Data and Simulations of Performance and Thermal Comfort in a Typical Mediterranean House

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3311
Author(s):  
Víctor Pérez-Andreu ◽  
Carolina Aparicio-Fernández ◽  
José-Luis Vivancos ◽  
Javier Cárcel-Carrasco
Keyword(s):  
Energy Efficiency ◽  
Thermal Comfort ◽  
Energy Demand ◽  
Natural Ventilation ◽  
Thermal Characterization ◽  
Energy Performance ◽  
Building Stock ◽  
Energy Demands ◽  
Dwelling House ◽  
Account Standard

The number of buildings renovated following the introduction of European energy-efficiency policy represents a small number of buildings in Spain. So, the main Spanish building stock needs an urgent energy renovation. Using passive strategies is essential, and thermal characterization and predictive tests of the energy-efficiency improvements achieving acceptable levels of comfort for their users are urgently necessary. This study analyzes the energy performance and thermal comfort of the users in a typical Mediterranean dwelling house. A transient simulation has been used to acquire the scope of Spanish standards for its energy rehabilitation, taking into account standard comfort conditions. The work is based on thermal monitoring of the building and a numerical validated model developed in TRNSYS. Energy demands for different models have been calculated considering different passive constructive measures combined with real wind site conditions and the behavior of users related to natural ventilation. This methodology has given us the necessary information to decide the best solution in relation to energy demand and facility of implementation. The thermal comfort for different models is not directly related to energy demand and has allowed checking when and where the measures need to be done.

Sign in / Sign up

Export Citation Format

Share Document