Conference Paper

Indoor airflow behavior and thermal comfort in a courtyard house in warm humid tropics

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Abstract

This paper assesses the effects of indoor airflow behavior modifying the indoor air temperature on thermal comfort conditions in a residential tropical courtyard building where courtyard maintains direct contacts with outdoor environment through openings found in the envelope. Results taken from a field investigation and a computer simulation reveal that given the ambient climatic conditions particular indoor airflow behaviors are sufficient to lower the indoor air temperatures below the ambient level in the courtyard as well as in surrounding internal spaces. Thus, thermal comfort condition not correlated to the number of openings but to the distribution pattern and volumetric rate of indoor airflow in enhancing heat exchange between wall surfaces and air. The optimum range of ambient wind direction, which required for optimum distribution and volumetric flow of indoor air, was found within a range of 30-60 degrees to the longitudinal axis of the courtyard and building.

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... One of the main factors affecting design solutions is Climate Condition when it comes to constructing new buildings, as well as the building's location and function. The hot arid climate of the Middle East was one of the driving forces in adopting courtyards into traditional architecture [17]. Courtyards can temper the indoor environment by improving the natural ventilation and level of humidity, especially with the hot and humid weather coupled with the high temperature in the UAE. ...
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Courtyards are traditionally associated with the Middle East countries, where climate and culture have given shape to a particular type of traditional architecture. The study evaluates the environmental and social impacts of courtyards in an educational building integrated with occupant’s interaction behavior. The case study of the University of Sharjah includes eight different courtyards unoccupied for many years, in different locations around the building with various proportions; the objectives were to examine and evaluate the impact of redesigning the interior spaces of the courtyards in terms of environmental and social aspects. The inductive and experimental approach were adopted in this research, where two surveys were conducted for the occupants, before and after the design applications. In addition to the use of eco-tech software for simulation. In conclusion, the results of surveys and interviews clarified the problem and offered some recommendations and simulation analysis provided recommendations and guidelines for designers.
... Tablada, Blocken, et al, 2005 [20] Bittencourt & Peixoto, 2001 [21] Rajapaksha, Nagai, et al, 2002 [22] Soflaei, Shokouhian, et al, 2016 [23] Mousli & Semprini, 2016 [24] The impact of courtyard geometry and openings design on natural ventilation. ...
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For hot regions, studies have been advocating re-adopting the courtyard pattern for its thermal advantages. Aiming at developing thermally comfortable courtyards, studies have been exploring the impact of courtyards geometry on their shading and natural ventilation, which are the two environmental principles of courtyards. However, there is a lack of studies on the impact of manipulating courtyards geometry on the thermal sensation of occupants. This research investigates the impact of changing the courtyard geometry and the resulted shading on Mean Radiant Temperature (MRT) and Globe temperature (Tg). The latter represents the thermal perception of occupants and the former is the main effective factor on the thermal sensation of people in outdoor and semi-outdoor spaces. The research carried out simulation experiments to test 360 different courtyard configurations. The simulation experiments included using Envi-met and IES-VE simulation tools. The former was used to determine MRT and Tg, and the latter to determine shading levels. Baghdad was selected to represent an example of a hot city in which summer air temperature reaches around 50 °C. The results show that the difference in shading that results from changing the courtyard geometry can lead to a difference in MRT and Tg of up to 15°C.
... Tablada, Blocken, et al, 2005 [20] Bittencourt & Peixoto, 2001 [21] Rajapaksha, Nagai, et al, 2002 [22] Soflaei, Shokouhian, et al, 2016 [23] Mousli & Semprini, 2016 [24] The impact of courtyard geometry and openings design on natural ventilation. ...
Conference Paper
Full-text available
For hot regions, studies have been advocating re-adopting the courtyard pattern for its thermal advantages. Aiming at developing thermally comfortable courtyards, studies have been exploring the impact of courtyards geometry on their shading and natural ventilation, which are the two environmental principles of courtyards. However, there is a lack of studies on the impact of manipulating courtyards geometry on the thermal sensation of occupants. This research investigates the impact of changing the courtyard geometry and the resulted shading on Mean Radiant Temperature (MRT) and Globe temperature (Tg). The latter represents the thermal perception of occupants and the former is the main effective factor on the thermal sensation of people in outdoor and semi-outdoor spaces. The research carried out simulation experiments to test 360 different courtyard configurations. The simulation experiments included using Envi-met and IES-VE simulation tools. The former was used to determine MRT and Tg, and the latter to determine shading levels. Baghdad was selected to represent an example of a hot city in which summer air temperature reaches around 50 °C. The results show that the difference in shading that results from changing the courtyard geometry can lead to a difference in MRT and Tg of up to 15°C.
... In addition, the external wind incidence within 30-60 degrees from the longitudinal axis promotes optimum indoor thermal conditions. More details are published elsewhere [2]. ...
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This paper explore the effects of indoor airflow behaviour in modifying the indoor thermal conditions in a courtyard residence found in the tropics. The design theme is centred towards an exploitation of architectural concepts and principles of the traditional courtyard built forms of the country as a source of deriving passive design strategies. Field investigation reveals a significant correlation between wall temperature and indoor air temperature. Airflow behaviors are sufficient to modify indoor thermal conditions to achieve comfortable environments. Furthermore, computational analysis discloses that a relatively better indoor thermal modification is seen when the courtyard acts as an air funnel discharging indoor air into the sky, than the courtyard acts as a suction zone inducing air from its sky opening during daytime hours. Consequently promotes nocturnal ventilation.
... Contrary, the best thermal conditions with comfortable (PMV * vote of 0.2) indoor environment were found in case 2. More details are published elsewhere [10]. However, the real problem occurs when the relative humidity moves to higher levels during the early nighttime where indoor air temperatures remain around 28-29°C. ...
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Reports on an experimental investigation into the ventilation performance of courtyard and atrium buildings for cooling purposes. Model tests of these structures were carried out in a wind tunnel. Ventilation was assessed from actual air flow rates measured by means of orifice plates inserted in the models. The effect of courtyard geometry and orientation to the wind were examined together with possibilities of inducing higher ventilation rates by roofing the courtyard and exploiting the pressure field over the roof. The study highlighted the importance of orientation of the building to the oncoming wind and the potential and limitations of some ventilation strategies that could be used in atrium structures. (J.M.M.)
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This paper investigates the effects of airflow patterns and airflow rates on thermal behavior of a ventilated courtyard building in a warm humid climate. With some airflow patterns indoor air temperature can be brought to a level below the ambient, while with others the indoor air temperature may be higher than the ambient. The integration of a courtyard in the building design can optimize indoor airflow and is of significant importance with regard to the indoor thermal environment provided the courtyard maintains correct contacts with the outdoor environment. The current paper explores airflow patterns and airflow rates in a modern tropical courtyard house in respect to corresponding indoor thermal modifications. A thermal investigation was carried out on the site by manually changing the composition of airflow inlets (openings) found in the building envelope. From the results it is observed that the different airflow patterns affected different thermal environments and sometimes a cool condition within the courtyard and in the surrounding indoor spaces. Relatively low indoor air temperature was observed with a particular air movement pattern created through the openings found on a longitudinal horizontal axis through the courtyard. The temperature was below the ambient by 1.3 degree C with an airflow range of 1.5 to 2.0 air changes h-1.
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This paper assesses the applicability of some architectural design elements to provide comfort ventilation in humid tropical regions: size and location of windows, building eaves and roof shapes for a single unit house. Most window and roof configurations are sufficent to produce only a slightly more comfortable level although they can certainly increase the indoor air velocity. The improvement of indoor air velocity can minimize the physiological effect of the high humidity. Among the tested models, the room with a high gable roof combining with eaves improves significantly the indoor air velocity. Cet expose evalue l'applicabilite de certains elements de configuration visant a assurer une ventilation de confort daus les regions tropicales humides: dimensions et emplacement des fenetres, formes d'avant-toit et de toiture pour une maison individuelle. La plupart des configurations de fenetre et de toiture suffisent seulement a fournir un minime supplement de confort, bien qu'elles puissent effectivement ameliorer la circulation interieure de l'air. Une amelioration de circulation interieure de l'air peut attenuer les effets physiologiques d'une forte humidite. Parmi les modeles essayes, le local comportant une toiture a pignon eleve associee a des avant-toits offre une nette amelioration de circulation interieure de l'air.
Airflow patterns at courtyards
  • S Alvarez
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Alvarez S, Sanchez F and Molina JL. 1998, Airflow patterns at courtyards, Proc. of the 14 th International Conference on Passive and Low Energy Architecture -PLEA '98, pp. 218-223. Lisbon, Portugal.
Turbulence and draft: the turbulence of airflow has a significant impact on the sensation of draft
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