Experimental work and analysis of confined urban spaces

Coronel, Juan; Álvarez, S. López

doi:10.1016/s0038-092x(00)00096-7

Cited by 19 publications

(9 citation statements)

References 1 publication

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“…No clear correlation could be found between the aspect ratio and the air temperature. This contrasts with the higher air temperature differences reported by Coronel & Alvarez (2001) and Grundström et al (2003). Furthermore, T a as a conservative quantity reacts little to urban geometry and can therefore be used only as a secondary indicator for comfort outdoors.…”

Section: Discussioncontrasting

confidence: 71%

“…Yet air stratification may take place in the canyon volume at higher aspect ratios (Santamouris et al 1999). Coronel & Alvarez (2001) and Grundström et al (2003) reported that measured air temperatures at street level in-canyon were 8 and 10 K lower in relation to a free location in a hot summer period for streets with H/W ratios of 5 and 10, respectively. Ali-Toudert & Mayer (2005) report on a maximum difference of 3 K between wide and deep streets with H/W = 0.5 and H/W = 4, respectively, with N-S oriented streets becoming cooler than E-W streets as the aspect ratio increases.…”

Section: Outdoor Thermal Comfortmentioning

confidence: 98%

“…air temperature, humidity and wind speed (e.g. Swaid et al 1993, Coronel & Alvarez 2001, Grundström et al 2003. Though still used, this approach is unrealistic in sunlit locations because of the additional effects of solar radiation.…”

Section: Outdoor Thermal Comfortmentioning

confidence: 99%

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Outdoor thermal comfort in the old desert city of Beni-Isguen, Algeria

Ali-Toudert¹,

Djenane²,

Bensalem³

et al. 2005

Clim. Res.

145

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The present study addresses the issue of outdoor thermal comfort in a hot and dry climate in relation to urban geometry. This experimental work, conducted in an old desert city, aims to provide some quantitative knowledge on the effectiveness of traditional design forms in ensuring a comfortable thermal environment outdoors under extreme summer conditions. The study focused on the role of the geometry of urban canyons. Air temperature, air humidity and wind speed were measured during summer 2003 in various urban streets in the old Saharan city of Beni-Isguen, Algeria (32.40°N). The short-wave and long-wave radiation fluxes received by a human body from the 3D surroundings were also measured in order to allow an accurate calculation of the heat gained by a pedestrian. Bio-meteorological methodology was used and thermal comfort was expressed by means of the physiologically equivalent temperature (PET) index. The results show that the heat stress in a hot-dry climate is very high in unobstructed locations in contrast to sheltered urban sites. The vertical street profile is of prime importance in the resulting thermal sensation. Building materials were also found to play a decisive role. Deep streets together with high thermal capacity materials mitigate the heat stress in the daytime. The high and heavy walls provide more shading and more heat storage, leading to lower surfaces temperatures. Hence, a human body absorbs less short-wave radiation owing to reduced direct exposure, and also less radiant heat from the surrounding environment is absorbed by the body. In contrast, air temperature and air humidity show little dependence on the urban geometry. Therefore, these factors are less relevant indicators for outdoor thermal comfort in the summertime.

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Section: Discussioncontrasting

confidence: 71%

Section: Outdoor Thermal Comfortmentioning

confidence: 98%

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Outdoor thermal comfort in the old desert city of Beni-Isguen, Algeria

Ali-Toudert¹,

Djenane²,

Bensalem³

et al. 2005

Clim. Res.

145

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“…The microclimatic research projects indicate that thermal comfort and behavior is highly dependent on geometrical parameters such as urban canyons (Thorsson, Lindberg, Bjorklund, & Rayner, 2011) (Coronel & Alvarez, 2001) (Santamouris, Papanikolaou, Koronakis, Livada, & Asimakopoulos, 1999) (Yang, Li, & Yang, 2012) (Bourbia & Awbi, 2004a) (Herrmann & Matzarakis, 2012) (Ndetto & Matzarakis, 2013) (KaLun Lau, Lindberg, Rayner, & Thorsson, 2015). For instance, Ali-Toudert conducted research during summer of a hot and dry climate, discussing creating and expanding a microclimatic comfort zone on street level (Ali Toudert, 2005) (Ali- Toudert & Mayer, 2006) (Ali-Toudert, Djenane, Bensalem, & Mayer, 2005.…”

Section: Introductionmentioning

confidence: 99%

Numerical evaluation of thermal comfort in traditional courtyards to develop new microclimate design in a hot and dry climate

Nasrollahi

Hatami

Khastar

et al. 2017

Sustainable Cities and Society

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The growing interest in thermal comfort of outdoor environments yields in different analysis on courtyards as a common space between urban and architectural scales. However, there is a limited knowledge regarding the microclimatic behavior of such spaces. Using ENVI-met simulations, this paper aims to numerically discuss the thermal performance of different configurations of traditionally designed courtyards in Shiraz, Iran, which experiences hot summers and cold winters. The geometrical effects such as orientation and H/W (height to width ratio) of courtyards are considered as potential parameters to improve the microclimatic conditions. In this paper, PMV and UTCI are used as thermal comfort indices.The obtained results indicate mean radiant temperature and wind speed as the most effective parameters for thermal comfort of courtyards. In addition, the aforementioned geometrical parameters might not be able to solely create a desirable condition, but they could significantly improve the thermal comfort of courtyards during summer and winter. To achieve a desirable thermal comfort level, the results suggest using configurations of a high H/W rate and southward orientation in order to obtain better shading during summer as well as allowing the solar radiation in while regulating the wind speed in winter.

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“…In turn, the standard deviation can be calculated from the range of times in which 80% of the experimental measurements are found ( ∆ℎ ) according to Equation (2). Finally, the scale-factor, , can be calculated using the standard deviation value and the maximum temperature difference recorded (∆ ) according to Equation (3).…”

Section: Proposal Of Modelmentioning

confidence: 99%

Characterizing the Air Temperature Drop in Mediterranean Courtyards from Monitoring Campaigns

et al. 2017

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Highlights: Courtyards may be a good passive strategy for enhancing thermal comfort and reducing the energy demands of buildings. It is necessary to quantify the air temperature drop in the courtyards of buildings in dominant summer climates. Computational Fluid Dynamics (CFD)-based methods have the drawback of high computational cost and complexity, so their use is limited to research purposes and advanced users. This work proposes a simplified predicting method for the decrease in air temperature in Mediterranean courtyards from the results of several experimental campaigns. Three variables have been identified that characterize the decrease in the air temperature in courtyards, all of which depend mainly on the confinement factor of the courtyard. The method could be very useful for architects and designers looking for the optimal design of this kind of space in the early stage of design. Abstract:As microclimate modifiers, courtyards may be a good passive strategy for enhancing thermal comfort and reducing the energy demands of buildings. Thus, it is necessary to be able to quantify their tempering effect in dominant summer climates. This is frequently done using calculation methods based on CFD, but these have the drawback of their high computational cost and complexity, so their use is limited to advanced users with a high level of knowledge. Thus, an alternative is required based on a simplified method that can explain and predict the air temperature drop in courtyards. This would be extremely useful for professionals looking for the optimal design of this kind of space through energy assessment programs integrating these methods. This study proposes a simplified method of characterization that aims to identify the functional dependencies of the decrease in air temperatures in courtyards, and so to predict the air temperature inside them from that outside, if available. From the results of several experimental campaigns, three variables have been identified that characterize the decrease in the air temperature in courtyards, all of which depend on the confinement factor of the courtyard. Finally, the proposed predictive method was validated by means of an additional monitoring campaign. The results show a good fit of the calculated values to the measured ones, R 2 being equal to 0.98.

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Experimental work and analysis of confined urban spaces

Cited by 19 publications

References 1 publication

Outdoor thermal comfort in the old desert city of Beni-Isguen, Algeria

Outdoor thermal comfort in the old desert city of Beni-Isguen, Algeria

Numerical evaluation of thermal comfort in traditional courtyards to develop new microclimate design in a hot and dry climate

Characterizing the Air Temperature Drop in Mediterranean Courtyards from Monitoring Campaigns

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