AA, Combined Paper on Sustainable Cooling Strategy UEA,,Jan 2008

Challenging the Supremacy of Airconditioning

Re-conceiving the Built Environments of the Gulf Region

Simos YannasDirector, Environment & Energy Studies Programme, Architectural Association School of Architecture, London

IntroductionThe absolute dependence on mechanical air conditioning

that characterises contemporary buildings in the UAE is a major issue that is both poorly understood and potentially intractable. While the more extreme periods of high ambient air temperatures and humidity that characterise the climates of the region may be alleviated by the use of air conditioning, there is no technical justification for the whole year to be treated the same way other than the climatic inadequacy of buildings now being built here. Nor is there any scientific or physiological evidence for the common practice of maintaining constant indoor temperatures at the kind of levels commonly provided in winter to heated buildings in cold climates. On the contrary, there is widely accepted empirical research and physiological justification for abandoning such practice so that both residents and visitors can respond to daily and seasonal variations of the outdoor climate through natural adaptive processes of the human body. Currently, the temperature difference between the airconditioned spaces inside buildings and the streets and urban spaces outside frequently rises above 20 degrees centigrade, high enough for a thermal shock when entering or exiting airconditioned buildings and motor cars. Heat discharges from airconditioning equipment, and from the power stations that produce the electricity used to drive building appliances, lead to urban warming. In Dubai this is bound to keep increasing at a fast rate owing to the intense building activity leading to additional heat discharges from airconditioning plant. One effect of urban warming is to drive cooling loads for buildings higher, calling for larger airconditioning plant and/or more energy to operate it. Another is the deterioration of environmental conditions outdoors, undermining the usability of outdoor spaces, a serious blow to the essence of any city. At the rate at which building activity is now taking place in the UAE, a complete abandonment of the outdoor environment for a network of enclosed, airconditioned malls is probably only a matter of time. Were this to happen it could mean the return of the outdoor urban environment to a far worse desert than the one from which it was won. This could severely erode the value of property and businesses housed here. To prevent such fate and contribute to the use and enjoyment of the city it is essential to narrow the temperature differences between indoor and outdoor spaces. This will require, first, the acceptance of adaptive standards of thermal comfort

as now commonly understood by the international scientific and engineering communities; second, a better understanding of the technical aspects of building design for these climates; third, an equally improved approach to the microclimatic design of outdoor spaces.

In view of the absence of any environmentally appropriate, contemporary built precedents, a major research effort will be required to underpin the formulation of guidelines and regulations to help redirect building design and the retrofitting of existing buildings toward climatically adaptive and environmentally sustainable models. Given that it has taken over thirty years of funded scientific research and applications in Europe and North America to make a significant, though as yet far from sufficient or satisfactory, difference in the environmental performance of buildings, the effort required will be substantial. However, the likely cost of any such research is insignificant compared to the saving in capital and running costs it can help achieve. Challenging as the technical research might be in order to bridge the present knowledge gap as quickly as possible, it cannot even start without a change in the cultural perception of the role of mechanical AC. The current dependence on mechanical AC must be challenged, its operational characteristics ought to be rethought and the environmental attributes and expectations from the buildings being built in the Region should be reconceived.

Our Masters Programme in Sustainable Environmental Design at the Architectural Association School of Architecture in London is committed to exploring architectural solutions that can achieve thermal and visual comfort at near zero carbon emission for most new buildings in most climatic regions. In response to Nader Ardalan’s call for an environmental agenda for the Gulf Region we undertook a series of studies that combined reviews of historic precedents with parametric studies using computer simulation models and fieldwork involving short-term measurements in the warmest period of the year. These are summarized in the next section of this article. The studies led to the formulation of some preliminary guidelines that were tested on a variety of building programmes. The projects developed for these programmes are illustrated in the final section of the article.

PrecedentsCourtyard Tradition in Islamic Architecture

The courtyard form has a long tradition in Islamic architecture. Study of some of the palace complexes surviving in Spain has provided insights on how the courtyard and the shaded porticos that surrounded them helped modulate indoor environmental conditions under the very intense summer conditions experienced in the south of the country. Measurements taken recently in the 14th century Palace of the Lions, Fig. 4 a-b, a residential complex of the Alhambra in Granada show the role of the courtyard and its porticos as transitional spaces mitigating the effects of the outdoor temperature and intense summer

Fig. 4 The Palace of the Lions, Alhambra, Granada, Spain. (a) View of the courtyard (b) Section showing solar control provided by the porticos at midday on solstices and equinox (c) Temperature measurements over a four-day period in summer showing modulating effects of courtyard, porticos and the building’s thermal inertia.

sunshine. The graph, Fig. 4c, shows outdoor, courtyard and indoor temperatures measured over four consecutive days. With the outdoor air reaching peaks of 31-35C those in the courtyard are lower at 27-30C and are further reduced indoors by the thermal inertia of the building. The daily range of 18-25C and average of 22C achieved indoors is quite remarkable and is achieved despite the fact that the courtyard is now operating without the lavish vegetation that used to populate it and which has been recently removed to protect the building’s foundations from moisture (Jiménez Alcalá 2002).

Fig. 4a Fig. 4b

Fig. 4c

42 43Architecture & Art Architecture & Art

A series of short-term measurements of temperature and relative humidity were undertaken in outdoor and semi-outdoor spaces in areas of Dubai during July 2007 in the hottest period of the year (Thapar 2007). The measurements were taken in Bastakia and Deira and in outdoor locations near the water and the city’s new developments. These were then compared with readings taken on the roof of a three-storey building of the Youth Hostel Association (YHA) that was selected as representing a reference urban temperature unaffected by built form, vegetation or water. At each location measurements were supplemented with a thermal comfort survey among passers-by or subjects

Fig. 5 Measurements in Bastakia (a) Graph comparing temperature measurements taken in courtyard, adjoining street and reference urban location; (b) courtyard ; (c) street; (d) location of reference temperature datalogger on roof of YHA building.

found sitting there. The results show considerable but systematic differences between the “dry” inland reference location and the wetter locations of the old town and the waterside new developments. These provide some useful insights on improving microclimatic conditions in this city.

Dating from the 1890’s the Bastakia quarters in Dubai comprise some sixty buildings that form a dense urban tissue around narrow winding streets. Measurements were taken in the courtyard of a restored house and in nearby streets and compared with readings from the YHA, Fig.5ad.

Courtyard House and Transitional Structures in old Dubai

The courtyard with a height to width ratio of 1.8:1, Fig. 5b, recorded the lowest temperature by 1-3K from the street of 2:1 height to width ratio, Fig. 5c, and by as much as 4-6K from the YHA readings. However, on the day of the measurements this advantage was counteracted by higher measured relative humidity in the area of the Bastakia owing to Northerly winds blowing from the creek.

In Deira, a densely built shopping district developed in the 1960’s, the measurements were taken in the Gold Souk, in a street parallel to the souk, and near the water along the creek. The graph, Fig. 6a, shows that although not protected from the sun the area near the water Fig. 6b registered the lowest and most stable temperatures during the hottest part of the day presumably owing to the stabilizing influence of the water mass and the effect of evaporation. The Gold Souk, Fig. 6c, which is well protected from the sun, achieves a lower temperature than the parallel street, Fig. 6d, which though narrow

is exposed to the sun for part of the day. The difference reaches some 1.5K during the peak midday sunshine period falling to nil at the end of the day as both spaces cool toward the ambient air temperature after sunset. Exposure to the sun in the open street leads to surface temperature that are higher than the air temperature thus having a negative effect on pedestrian comfort. On the day of the measurements the mean radiant temperature in the open street was estimated to be higher by over 5K at 2pm. On the other hand, being protected from the sun throughout the day, the building surfaces surrounding the souk would remain close to air temperature. The importance of this was confirmed by the comfort survey which voted the souk area as comfortable whereas the open street was found to be uncomfortable. This (10 July 2007) was a hot day with a peak temperature that rose above 45C at the YHA. This makes the reduction of 7-10K achieved by the fieldwork spots in Deira particularly notable.

Fig. 6 Measurements in Deira(a) Graph comparing temperature measurements taken in Gold souk, adjoining street and near the water, (b) water’s edge (c) Gold souk (d) street parallel to souk.

The dense organic forms and shaded transitional spaces of Deira and the Bastakia provide some clear microclimatic benefits that derive from the resulting solar protection and thermal inertia. Jointly these attributes lead to both lower and more stable temperatures than those resulting in less dense areas with higher exposure to solar radiation.

However, a densely built form can also prevent air flow and reduce air velocity which can be problematic at times. Near the sea the courtyard form needs to be more adaptable so as to open to cool breezes, but protect from warmer air at times.

Fig. 5a

Fig. 5b Fig. 5c Fig. 5d

Fig. 6a

Fig. 6b Fig. 6c Fig. 6d


Dubai Marina and Greens Today

Readings taken in the area of the Dubai Marina and the Greens residential area were lower than the YHA reference temperatures by up to 7K around midday, Fig. 7 a-c. These effects diminish after sunset. The Marina area is influenced by the proximity of the water and the winds blowing from the Gulf, while Greens displays the effect of vegetation and shading trees. However, again humidity levels near the sea were significantly higher. This is significant as the comfort survey identified high humidity as a major discomfort factor that undermined the effect of lower air temperatures.

Fig. 7 Measurements in Dubai Marina and Greens(a) Marina (b) Green (c) Graph comparing temperature measurements taken in Dubai Marina and Greens with reference urban location.

Overall the comfort survey confirmed people’s high adaptive potential with temperatures close to 40C reported as comfortable by subjects in the shade and exposed to air flow. Wind velocities of 2.0m/s were reported as desirable at these temperatures. As in all hot climates urban activity in Dubai avoids the hottest part of the day. Markets in Deira open at 6am and are deserted at midday. Evenings are the most popular time to enjoy outdoor activity.

TABLE 1. Monthly Weather Data for Abu Dhabi City

Source: Meteonorm Nomenclature

Tair Mean daily air temperature (dry-bulb), oCTa min Mean daily minimum temperature, oCTa max Mean daily maximum temperature, oCTwet Mean daily wet-bulb temperature, oCGGhor Global (direct & diffuse) solar radiation on the horizontal, kWh/m² mean daily totalGDhor Direct radiation on the horizontal,kWh/m² mean daily totalWind Wind speed, m/s WD Predominant wind direction (North=0)

Fig. 1 Hourly values of direct and diffuse solar radiation on the horizontal and hourly mean, maximum and minimum values of dry-bulb temperature for each month plotted against the calculated adaptive comfort range. Background colour identifies mild, warm and hot periods of the year. (Source: Weather data generated with Meteonorm plotted with Square One Weather Tool).

Parametric Studies Climate Analysis for Sustainable Environmental Design Weather data for Abu Dhabi City (24.28oN 54.25oE)

and Dubai (25.14oN 55.17oE) were obtained using the Meteonorm global meteorological database (Meteotest 2004). The data files representing ten-year average data for the two cities are almost identical. A summary of mean daily values of the main parameters is given in Table 1.

The monthly variations of the outdoor dry-bulb temperature show that the annual cycle can be divided into three distinct periods, Figs 1-2: a four-month period of mild weather (December to March inclusive) characterized by daily mean temperatures of 20-23oC; a warm period (November and April) with mean temperatures of 25-26oC, and a hot period (May-October inclusive) with mean temperatures of 29-34oC.

The diurnal temperature range of 10-12K involves night-time ambient air temperatures that are low enough for convective cooling of building structures for most of the year. However, the useful cooling potential available from this source is being eroded by the urban warming caused resulting from the heat discharges from airconditioning appliances on buildings and motor cars.

Winds average 4.0-4.5 m/s throughout the year the strongest coming from the direction of the Gulf on most months except for the hottest months (July-September inclusive) when the predominant direction is recorded as South.

Thermal comfort criteria as defined by the international standard ISO 7730 and the ASHRAE Standard 55-92 can be satisfied at air and mean radiant temperatures in the range of 19-30oC (Yannas 2007). Temperatures above 30oC are also commonly tolerated in hot climates when air movement is available. Air velocities of up to 1.0m/s are generally acceptable indoors whereas outdoors in the city air velocities of up to 2.0m/s will help extend the comfort range further provided subjects are protected from direct solar radiation. Such wider range is consistent with fieldwork undertaken to assess adaptive practices in hot climates (Auliciems and Szokolay 1997; Humphreys, Nicol and Raja 2007) and a comfort survey undertaken last summer (Thapar 2007). With these considerations thermal comfort can be achieved by natural means in this climate for much of the year.

Sunshine is strong throughout the year with an annual average of 8 hours of bright sunshine per day, rising to some 10 hours per day in the hot period. Clearly, solar protection of occupied spaces is essential outdoors as well as indoors throughout the year. The incident solar radiation is high all year varying in the range of 3.7-7.0 kWh/m2 on unobstructed horizontal surfaces. Roofs, streets, pavements and other exposed manmade surfaces will get extremely hot affecting outdoor comfort as well as building cooling loads unless specially treated.

For solar energy applications the prospects are extremely good for all types of applications both thermal and electric; sun-tracking appliances can intercept as much as 6.5-8.5 kWh per m2 collector area daily throughout the year.

Fig. 7a Fig. 7b

Fig. 7c


Relative humidity mean daily values of 50-65% conceal fairly high levels of absolute humidity that rise to 15-25 g/kg during the hot period. However, with the exception of three months when the wet-bulb temperature is too high, the temperature difference between dry-bulb and wet-bulb (wet-bulb depression) reaches regular peaks of 10-15K during daytime indicating useful potential for evaporative cooling if needed.

Calculated hourly sky temperature depressions which provide a measure of radiative cooling to the night sky are in the range of 10-12K in the hot period indicating a useful potential at night time.

The sky luminance is high throughout the year in the range 15,000-70,000 lx during work hours in the mild period to 50,000-100,000 lx in the hot period about half is diffuse illuminance from the sky vault. Under these conditions 1-2% of the outdoor illuminance is sufficient to meet required illumination levels for any indoor activities. These fractions can be achieved in buildings with very modest areas of glazing. Highly glazed facades risk serious problems of glare as well as excessive cooling loads and overheating.

Fig. 2 Sunpath diagram for 24N with mild, warm and hot periods of the year marked. Effective shading is required on all orientations all-year round.

Fig.3 Hourly dry-bulb, wet-bulb and sky temperatures at the beginning of the hot period (May) and surface temperature on horizontal plane exposed to sun in Abu Dhabi.

Figure 3 shows the hourly patterns of the dry-bulb, wet- bulb and sky temperatures on a typical day at the beginning of the hot period in May. The sky temperature depression (dry-bulb minus sky temperature) is of 10-13K. This gives a measure of the cooling potential by longwave radiation to the sky. Although this appears to be as high during daytime as at night, during the day the outgoing longwave radiation is overtaken by the incoming longwave and shortwave radiation from the sun and sky. At night-time, however, the net outgoing longwave radiation is sufficiently high to lower temperatures of surfaces exposed to the sky below that of the ambient air temperature. This is shown on the graph by a reference surface temperature (yellow line) calculated for a horizontal surface with a solar reflectance typical of urban surfaces and with unobstructed view of the Sun and sky. In this case this can be seen to be of the order of 2K relative to the air temperature. During daytime exposure to solar radiation raises the temperature of such surface well above that of the ambient air making it contribute to the urban heat island effect. The temperature elevation would be much higher on darker surfaces such as asphalt. The graph also indicates the potential for direct evaporative cooling which with a wet-bulb depression varying in the range of 5-15K is quite substantial during daytime at this time. This is progressively reduced in the summer becoming unavailable in the form of direct evaporativecooling toward the middle of the hot period.

Fig. 8 Simulation results showing effect on wind velocity of variations in the orientation and geometry of courtyard openings.

Urban Form

A number of courtyard variants based on the forms encountered in old Dubai were modelled using the ENVI-met three-dimensional microclimate model for simulating microclimatic interactions in an urban environment. Coutyard height-to-width ratios H/W of between 1.5:1 and 2:1 were considered as providing reasonable shading as well as potential for holding cooler air during daytime,Figs 8 and 9.

The simulation studies investigated the effect of openings in the courtyard blocks to improve ventilation conditions. Openings perpendicular to the main streets helped increase air flow. Moreover:

Broader N-S streets (i.e in the direction of the predominant wind) and narrower E-W streets provide deeper penetration of wind as well as reduced incident solar radiation

Wind speeds are highest where the wind enters the urban blocks; these areas are good for public functions that require good airflow.

Chamfering of the edges of blocks helps improve ventilation and wind speeds especially in streets perpendicular to the main wind direction.

Fig. 9 Simulation results showing effect on wind velocity and absolute humidity of variations in courtyard openings.

Staggering of blocks leads to improved air flow Removing parts of the lower two floors of the courtyard

blocks improves wind penetration inside the fabric as well as creating covered double height urban spaces at road intersections; these provide transitional spaces that have better wind access as well as being shaded.


Building Design

Hourly cooling loads and indoor resultant temperatures were calculated for a number of building variants using climatic data for Abu Dhabi and Dubai with the Tas dynamic thermal simulation model (EDSL 2006). The building specification assumed for these simulation studies was of compact square plan with good access to daylight. This was tested for both office and residential occupancy with an average rate of internal heat gain of 15 Watts per square metre floor area. The following building parameters were varied as part of parametric studies:

Window Areas were varied from a minimum required for daylighting to fully glazed elevations.

Window Orientations: windows were assumed to be equally distributed between two orientations, either North-South or East-West

Glazing Type: clear single glazing, clear double glazing, coated double glazing

Solar Control: none, maximum (no direct radiation at any time)

Opening area for convective cooling was assumed to vary in the range 10-50% of occupied floor and to

Fig. 10 Simulated annual cooling energy demand showing effect of applying passive design measures (all runs with a fixed cooling setpoint of 29C; see text for effect of different cooling setpoints on cooling energy demand).

be activated when the outdoor air temperature provided potential for free cooling

Thermal Transmittances of opaque elements were considered within the range 0.25-1.0 W/m2K for external walls and roofs

Cooling setpoints: 22 oC and 29oC

For a base case with a cooling setpoint of 22 oC and unprotected windows of a surface area equivalent to 50% of the building’s floor area, the cooling energy requirement was calculated at 230 kWh/m2 building floor area. When the main building parameters were optimized this dropped to 96 kWh/m2 for the same cooling setpoint and window to floor ratio, and to 70 kWh/m2 when window areas were reduced to a lower window-to-floor ratio of 10-25%. Finally, adopting a cooling setpoint of 29oC as suggested by the adaptive comfort algorithms eliminated the need for airconditioning for a total of at least six months in the year leading to a total cooling energy demand of only 25 kWh/m2, an overall saving of some 90 percent compared to the base case, Fig. 10.

Our studies of architectural precedents, field measurements, computer modelling and current building activity in Dubai and Abu Dhabi have highlighted four critical concepts which are central to any consideration of sustainable environmental design for the region. These are:

Transition: in the UAE climates all movements between indoors and outdoors, and pedestrian activity within and between parts of the city, require solar protection almost permanently in conjunction with variable control of air flow, air temperature and humidity; these attributes should be provided by specially designed structures providing users the space and time in which to adapt from one environmental condition to another.

Permeability: this refers to the permanent and/or variable extent to which air and moisture should be allowed to flow through building envelopes and the urban tissue.

Separation: this refers more generally than the above to the permanent and/or variable environmental coupling or decoupling (zoning) of indoor or outdoor spaces

Identity: materiality, provenance, expression, relevance (architectural, environmental, sociocultural).

The application of these four concepts is illustrated in the projects that follow. The following are specific design considerations and guidelines derived from this research:

the adaptive basis of human thermal comfort must be acknowIedged from the outset; there can be no possible claim to sustainable environmental design based on conventional airconditioning settings and schedules.

the creation of transitional structures between spaces at largely different environmental conditions is the most fundamental architectural objective in this climate; it is aimed at protecting from thermal shock as well as reducing cooling loads and improving pedestrian thermal comfort.

Heat generating appliances for use in buildings should be identified by source, magnitude and hours of operation and their thermal effects decoupled from occupied spaces where feasible.

Glazing should be sized in the first instance to provide

adequate daylighting for the building programme being considered; owing to high sky illuminance in this climate this will lead to very modest glazing areas thus reducing cooling loads and the thermal and visual discomfort caused by commonly oversized windows.

Solar protection is required for all glazed elements on all orientations in this climate; this requires specification of fixed and/or movable external shading elements on elevations. Aiming to control solar gain solely through glazing transmittance is insufficient in this climate and some of the tinted and reflective glazings that have been used on recent buildings in the region will tend to worsen thermal and lighting problems.

Glazing that is protected at all times from direct solar radiation, and thus receiving solely diffuse radiation from the sky for daylighting, is not sensitive to orientation as the amounts of diffuse radiation do not vary much with orientation.

Provisions should be made for natural ventilation by controllable means independent of window opening that could be also operable for night-time convective cooling; the apertures provided for these purposes should not be glazed.

In the mild and warm periods of the year between November and April, effective solar control in conjunction with night-time free cooling by natural ventilation is sufficient to maintain indoor temperatures within the adaptive comfort zone.

Radiative and evaporative cooling techniques are complementary and are applicable in the warm and hot periods of the year helping to restore comfort.

Ceiling fans can help extend the upper limits of the adaptive comfort range in the hot period.

When no combination of the above is sufficient to provide comfort during occupancy, the spaces to be mechanically air conditioned should be zoned so that energy use can be minimised; moreover, the principles of transition should be respected so as to prevent thermal and visual discomfort when transiting between inside and outside.

Architectural Design Strategies for Sustainability


Projects The first set of projects undertaken in 2007 by the

student group on our Masters programme in Sustainable Environmental Design focused on transitional structures. These included canopies, walkways, pavilions, bus shelters and sheltered markets. Designs for several such structures were put forward by the student teams. Dynamic attributes that would allow such structures to respond to daily and seasonal variations in environmental conditions and to occupant requirements were identified. Features singled out by the project teams in the course of this first stage were then drawn together into a test design that involved all of the teams working as a single design/build group.

Fig. 11 c Erecting the structure on the AUS campus, February 2007.

In the course of an intensive one-week period the group finalised the design and fabricated the test structure at the AA School’s Hooke Park laboratories in Dorset, Fig. 11 a-b. The components of the structure were then flown to the UAE and the structure was assembled for testing on the campus of the American University of Sharjah in February 2007, Fig. 11c. This provided some useful insights on the solar control attributes and operability of the structure by its users. However, the weather conditions were too mild at the time to test the structure’s resistance to heat and ability to cool at night.

Fig. 11 a Test structure designed by Masters group in January 2007

Fig. 11 b Building of test structure at AA School’s Hooke Park facility in February 2007


Fig. 12a Proposal to leave Lulu island as a public resource for the city offering a variety of recreational activities.

Fig. 12b Proposed mixed-use development on floating platforms between Abu Dhabi city centre and Lulu.

Fig. 12c Axonometric views of scheme

Fig. 12e Axonometric views showing green areas and built zones and land uses of proposed development

Fig. 12d Axonometric views of scheme

Fig. 12f Axonometric views showing green areas and built zones and land uses of proposed development

The second set of projects was inspired by Al Lulu Island, an uninhabited, manmade islet off the coast of Abu Dhabi. On a study trip to the UAE in February 2007, our group visited the island and studied the latest proposals for its development. Back in London a number of projects were developed by the student teams, some within the developer’s masterplan and others as alternatives to that masterplan. Some of the resulting schemes are illustrated here. All of the project teams shared the knowledge acquired from climate analysis, parametric studies using dynamic thermal simulation and the design concepts and architectural strategies developed from these studies and summarised in previous sections of this article.

The scheme by Surane Gunasekara and Yuan-Chun Lan, Fig. 12 a-j, proposes to leave the island as a public resort for the city, confining its proposals for new, mixed-use development to floating platforms that form bridges with the city of Abu Dhabi. The scheme’s building proposals illustrate a stepped reduction in built density, starting with taller buildings on the city centre side of the bridges and tending to low-rise development on the island side of the platforms. Strong environmental considerations characterise the building design, Fig. 12 g-j, that provides clear design applications of the concepts of transition, permeability, separation and identity, introduced above.


Fig. 12g across dwelling unit showing openable components in open and closed positions.

Fig. 12h Axonometric view of Southern elevation showing double-layered screen in position providing shading via horizontal overhangs and vertical elements, and air flow through permeable second screen layer.

Fig. 12i View from inside.

Fig. 12j Different degrees of permeability and separation provided by the buildings’ external skin in response to daily and seasonal cycles (left, southern elevation; right northern elevation).

The proposal for an arena on Lulu Island by Krista Raines, Fig. 13 a-c, follows from her masterplan with Annisa Julison to develop the island as an Olympic Sports Complex. Multilayered solar protection and good air flow potential were the key considerations for the design and were based on mapping of the daily and seasonal schedules of the sporting activities.

Fig. 13a Proposal to develop Lulu Island as a sports complex.


Fig. 13b - c Axonometric views of proposed arena.

The multipurpose stadium proposal by Natalia Kokosalaki, Fig. 14 a-f, provides generic solutions applicable in hot climates with spectator areas that are open to air flow, but well protected from the sun and served with natural cooling from retractable passive downdraught evaporative cooling towers (Kokosalaki 2007).

Fig. 14a Axonometric of stadium identifying the geometry of roof components optimised for shading the spectator areas

Fig. 14b Percentage shading achieved by the roof components at different times.

Fig. 14c Air flow simulation showing effect of different wind speeds and roof canopies

Fig. 14d Day and night views of stadium showing roof shading and cooling devices

Fig. 14e Plan of stadium showing occupancy strategy with openings for airflow through spectator tiers.

Fig. 14f Section.

Fig. 13b


Figs. 15 a-b Masterplan proposal for Lulu Island.

The scheme by Yasamin Arbabi, is for a high-density, low-rise residential cluster based on a masterplan for the island developed with Harsh Thapar as an alternative to that of the developers, Fig. 15 a-b. The proposals make extensive use of private and public transitional spaces that help ensure solar protection and good airflow through the cluster, as well as radiative cooling techniques for the individual dwelling units Fig. 15 c-h.

Figs. 15d - c plan, section and axonometric vies of low-rise residential cluster.

Fig. 15f-c Section through dwelling unit showing cross ventilation paths

Fig. 15e - c plan, section and axonometric vies of low-rise residential cluster.


Fig. 16c

The following proposals are for schemes that can easily fit within the developer’s current masterplan. The scheme by Kanika Agarwal and Vidhi Gupta, Fig. 16, is for a holiday resort on the Gulf side of the island. This emphasises the use of semi-open, transitional spaces and experiments with the air permeability of building structures and with proposals for roof cooling techniques. Fig. 16a Site Location

Fig. 16b

Fig. 16d

Figs. 16a-b-c-d Proposal for a holiday resort on the north-west coast of Lulu island.

The scheme by Tiffany Broyles and Anya Thomas proposes the development of second homes along a beach boardwalk that includes provision of transitional spaces for public use, Fig. 17 a-b. The boardwalk structure provides a continuous shaded path with the dwelling units opening from or closing into the structure as required by the owners, Fig. 17 c. The sea side elevation of the units is conceived as an adjustable grid that can provide variable air and light permeability over daily and seasonal cycles controllable by occupants or automatically, Fig. 17 d-e.

Fig. 17b public spaces along boardwalk

Fig. 17c Dwelling units along boardwalk

Figs. 17d-e-f Seaside elevation of unit and detail conceived as a grid of adjustable opening and permeability for daylight and air flow.

Fig. 17a Boardwalk along Lulu coast

Fig. 17d


The office design by Annie Diana Babu, Figs. 18 a-d, provides a compact shaded envelope facing North and South with daylit interior and good airflow potential for passive night-time cooling.

Fig. 18a sections showing transitional space on the south side of building and openings for daylighting and fresh air supply at centre of plan

Fig. 18c

Figs. 18c-d Southern elevation and views into transitional space

Acknowledgments

The following Masters students of the 2006-07 academic year collaborated on projects described here: Kanika Agarwal, Yasamin Arbabi, Annie Diana Babu, Tiffany Broyles, Matthew Frankel, Surane Gunasekara, Vidhi Gupta, Annisa Julison, Min-Hui Lai, Yuan-Chun Lan, Farah Naz, Krista Raines, Sachin Rastogi, Harsh Thapar, Anya Thomas, Lydia Yiannoulopoulou. The measurements at the Palace of the Lions in Alhambra were carried out by Benito Jiménez Alcalá as part of fieldwork for his PhD research completed under my supervision at the AA School in 2002. The measurements in Dubai and microclimatic simulations using the ENVI-met software were performed by Harsh Thapar as part of the research for his MSc Dissertation Project completed in September 2007. The stadium proposals by Natalia Kokosalaki form part of her MArch Dissertation Project completed in February 2007.

I would like to thank Prof. George Katodrytis and the American University of Sharjah for hosting our group and allowing us to assemble and test the structure on the AUS campus; Dr Senthil Nathan and the Abu Dhabi Colleges for their hospitality in Abu Dhabi; Robert Hudson of Mouchel Parkman for guiding our visit to Lulu Island; Nader Ardalan for sponsoring the projects described in this paper as part of his Gulf Research Project initiative;

References

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my colleagues Werner Gaiser, Klaus Bode, Gustavo Brunelli and Raul Moura for their contributions to the year’s teaching.

MSc / MArch Sustainable Environmental Design, Architectural Association School of Architecture

The main research object of the Master’s Programme in Sustainable Environmental Design is the relationship between architectural form, materiality and environmental performance, and how this should evolve in response to climate change and newly emerging programmatic requirements in urban environments. The taught programme is in two stages. In the first stage (October-April) team projects act as vehicles for exploring the principles and tools of sustainable design introduced in lectures and software workshops. Project teams combine MSc and MArch candidates. In the second stage MSc and MArch candidates work separately on individual dissertation projects. MSc dissertation projects combine design research with case-study work related to candidates’ backgrounds. MArch dissertation projects extend into a design application with Phase 1 completed within the current academic year and Phase 2 continuing into the following Autumn Term.

www.aaschool.ac.uk/ee


Documents

AA, Combined Paper on Sustainable Cooling Strategy UEA,,Jan 2008