scholarly journals Heat and Air Flow Behavior of Naturally Ventilated Offices in a Mediterranean Climate

2018 ◽  
Vol 10 (9) ◽  
pp. 3284 ◽  
Author(s):  
Halil Alibaba
Keyword(s):  
Natural Ventilation ◽  
Mediterranean Climate ◽  
Flow Behavior ◽  
Annual Average ◽  
Heat Gain ◽  
Average Heat ◽  
External Wall ◽  
Window Area ◽  
Thermal Simulations ◽  
Climate Dynamic

Air changes per hour (ach) rates for windows of different sizes and opened in different ratios were studied to establish natural ventilation concepts in offices with a Mediterranean climate. Dynamic thermal simulations were carried out in EDSL Tas for whole year investigations of an office. The office lost 0.01 W of heat during the winter but gained 0.01 W of heat during the summer. Annual average heat gain was 2.4 W. The heat gain via an external opaque wall was 138.9 W during the winter and 227.3 W during the summer, with an annual average of 190.7 W. The heat gain via an external glass surface was 128.9 W during the winter and 191 W during the summer, with an annual average of 161.5 W. The office had an average of 170.0 ach during the winter and an average of 144.7 ach during the summer, with an annual average of 157.4. The maximum annual ach performance was 480.4 ach when the external wall was fully glazed and the window was fully open, and the minimum annual ach performance was 9.8 when only 10% of the external wall was glass and 20% of the window area was open.

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 Summertime Overheating Risk Assessment of a Flexible Plug-In Modular Unit in Luxembourg

2020 ◽  
Vol 12 (20) ◽  
pp. 8474
Author(s):  
Michaël Rakotonjanahary ◽  
Frank Scholzen ◽  
Daniele Waldmann
Keyword(s):  
Risk Assessment ◽  
Natural Ventilation ◽  
Systems Design ◽  
Solar Shading ◽  
Modular Units ◽  
Building Typology ◽  
Permit Application ◽  
The One ◽  
High Flexibility ◽  
Thermal Simulations

Modular buildings offer faster construction process, provide better construction quality, allow reducing construction waste and are potentially flexible. Frames of modular units can be made of metal, timber, concrete or mixed materials but lightweight structures do not always allow erecting high-rise buildings and generally present a higher risk of overheating and/or overcooling. To reconcile these pros and cons, a typology of modular building called Slab was designed by a group of architects. The building is composed on the one hand of a permanent concrete structure named shelf-structure and on the other hand of several flexible removable timber modular units, also known as modules. The shelf-structure will host the common utility rooms and will serve as docking infrastructure for the housing modules. To provide high flexibility, the Slab building was designed to adapt to any orientation and location in Luxembourg. An energy concept and a HVAC systems design has been developed for the Slab building. Furthermore, a two-fold sustainability analysis was carried out. The first part of the analysis regards the determination of the minimum required wall thicknesses of the modules in accordance with Luxembourgish regulatory requirements, although the current regulation does not yet consider the Slab building typology. The second part, which is the subject of this paper, is thermal comfort assessment, more precisely, summertime overheating risk assessment of these modules, in compliance with Luxembourgish standard. In this regard, dynamic thermal simulations have been realized on two module variants; the first fulfills the passive house requirements, and the second—the current requirements for building permit application, which in principle corresponds to low energy house requirements. Simulations showed that with adequate solar shading and reinforced natural ventilation by window opening, overheating risk could be avoided for the normal residential use scenario for both module variants.

Enhancement of natural ventilation rate and attic heat gain reduction of roof solar collector using radiant barrier

2007 ◽  
Vol 42 (6) ◽  
pp. 2218-2226 ◽  
Author(s):  
W. Puangsombut ◽  
J. Hirunlabh ◽  
J. Khedari ◽  
B. Zeghmati ◽  
M.M. Win
Keyword(s):  
Solar Collector ◽  
Natural Ventilation ◽  
Ventilation Rate ◽  
Heat Gain ◽  
Gain Reduction

A laboratory experiment on natural ventilation through a roof cavity for reduction of solar heat gain

2008 ◽  
Vol 40 (12) ◽  
pp. 2196-2206 ◽  
Author(s):  
L. Susanti ◽  
H. Homma ◽  
H. Matsumoto ◽  
Y. Suzuki ◽  
M. Shimizu
Keyword(s):  
Laboratory Experiment ◽  
Natural Ventilation ◽  
Heat Gain ◽  
Solar Heat ◽  
Solar Heat Gain

scholarly journals Window Design of Naturally Ventilated Offices in the Mediterranean Climate in Terms of CO2 and Thermal Comfort Performance

2020 ◽  
Vol 12 (2) ◽  
pp. 473 ◽  
Author(s):  
Hardi K. Abdullah ◽  
Halil Z. Alibaba
Keyword(s):  
Thermal Comfort ◽  
Natural Ventilation ◽  
Mediterranean Climate ◽  
Computational Modelling ◽  
Co2 Concentration ◽  
The North ◽  
Adaptive Thermal Comfort ◽  
Adaptive Comfort ◽  
The Mediterranean ◽  
Window Design

Natural ventilation through window openings is an inexpensive and effective solution to bring fresh air into internal spaces and improve indoor environmental conditions. This study attempts to address the “indoor air quality–thermal comfort” dilemma of naturally ventilated office buildings in the Mediterranean climate through the effective use of early window design. An experimental method of computational modelling and simulation was applied. The assessments of indoor carbon dioxide (CO2) concentration and adaptive thermal comfort were performed using the British/European standard BS EN 15251:2007. The results indicate that when windows were opened, the first-floor zones were subjected to the highest CO2 levels, especially the north-facing window in the winter and the south-facing window in the summer. For a fully glazed wall, a 10% window opening could provide all the office hours inside category I of CO2 concentration. Such an achievement requires full and quarter window openings in the cases of 10% and 25% window-to-floor ratios (WFR), respectively. The findings of the European adaptive comfort showed that less than 50% of office hours appeared in category III with cross-ventilation. The concluding remarks and recommendations are presented.

scholarly journals Natural Ventilation of Toilet Units in K–12 School Restrooms Using CFD

Energies ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4792
Author(s):  
Yi-Pin Lin
Keyword(s):  
Public Schools ◽  
Architectural Design ◽  
Natural Ventilation ◽  
Ventilation Rate ◽  
Design Parameters ◽  
Ventilation Efficiency ◽  
Computational Fluid Dynamics Cfd ◽  
Odor Pollution ◽  
Window Area ◽  
K 12

In this study, the influence of architectural design parameters (the exterior window area, the wall height at a corridor-side, and the door gap of a toilet unit) on the airflow patterns and malodorous volatile substance (acetic acid) distributions within toilet units were investigated via computational fluid dynamics (CFD), with the restrooms in K–12 public schools (kindergarten through grade 12) of Taiwan as research objects. The results show that when there is a 2 m/s north wind in winter, all the cases exceed the required 12 air changes per hour (ACH), and most are above 43.75 ACH. When there is a 0.5 m/s south wind in summer, nearly half of the cases fail to reach 12 ACH. Maintaining an adequate natural ventilation rate and an acceptable level of odor pollution through passive design and architectural design is difficult. Thinking about how to improve the ventilation efficiency of toilet units with the aid of simple, appropriate, and energy-saving mechanical ventilation approaches is necessary.

Characterisation of a multilayer external wall thermal insulation system. Application in a Mediterranean climate

2020 ◽  
Vol 30 ◽  
pp. 101265 ◽  
Author(s):  
Marco Pedroso ◽  
Inês Flores-Colen ◽  
José Dinis Silvestre ◽  
M. Glória Gomes ◽  
Luis Silva ◽  
...  
Keyword(s):  
Thermal Insulation ◽  
System Application ◽  
Mediterranean Climate ◽  
Insulation System ◽  
External Wall

Experimental Study on Discharge Coefficients of Windward Window in Buildings with Wind-Driven Cross Ventilation

2014 ◽  
Vol 1008-1009 ◽  
pp. 1061-1067
Author(s):  
Qiao Ning Wang ◽  
Yan Ling Guan ◽  
Qi Hai Liao
Keyword(s):  
Flow Rate ◽  
Natural Ventilation ◽  
Discharge Coefficient ◽  
Static Pressure ◽  
Flow Rates ◽  
Discharge Coefficients ◽  
Window Opening ◽  
Static Pressure Difference ◽  
Window Area ◽  
The Impact

Focus on the prediction of flow rates in buildings under natural ventilation, the investigation conducted a series of model rooms with cross ventilation. The impact of window-wall ratios, windows configurations as well as corresponding flow rates was investigated. The object of this investigation is to analyze characteristics of windward window opening discharge coefficient by measuring static pressure difference and the flow rate through windows. The conclusion are as follows: For large openings, the discharge coefficient of windward window opening increases as the window-wall ratio grows up; With windward window-wall ratio of 44.4% and 11.1%, the discharge coefficient of windward openings is almost irrelevant to flow rate and less affected by leeward window area; However, with windward window-wall ratio of 2.78%, the discharge coefficient increases slightly as flow rate rises, and the larger the area of leeward opening is, the smaller the discharge coefficient of windward opening becomes.

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