La matriz semilla

In many parts of the world, urban development occurs over a long period, thus allowing urban policy-makers time to respond to any further changes that could induce adverse impacts on the environment and the well-being of inhabitants. In some countries, however, urbanisation is very rapid and occurs within a relatively short period of time creating a range of environmental and energy challenges. One such country is Saudi Arabia.

Driven by the massive oil revenues, Saudi Arabia was transformed into a modern developing nation during the last 80 years. In a relatively short time-span, the country has experienced several significant urban changes that have transformed the urban fabric in major cities from the vernacular urban form into a modern one, which was introduced at the beginning of the last century by the major foreign companies and planning expertise who were working in the country during that period. For instance, in 1938, the Arabian-American Oil Company (ARAMCO) established its first housing settlements for its employees, and this is considered as the origin of the contemporary built environment in Saudi Arabia according to Al-Naim (2008). These projects, however, initially followed the western style and as such were mainly imported from the United States as Al-Naim states. Following that, in 1947, the Arabian-American Oil Company established the first planned cities in the eastern province based on the western urban planning principles which follow the gridiron pattern, which was originally planned to give more priority to transportation. Later, in the early 1950s, the country experienced a massive rapid urban growth and economic development in urban areas - due to oil revenues - which took place in major cities, one of which was Riyadh City, the capital of Saudi Arabia.

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Due to the growth of an urban-based economy and the associated large local and foreign labour migrations to the Riyadh City during the early 1950s, there was an emergence to adopt a new urban design approach to accommodate the increasing demand for new residential units and the ever-increasing number of automobiles in the city. Similar to the urban development scenario previously mentioned which took place in the eastern province, the government laid out the first gridiron sub-division of the Al-Malaz residential project in the early 1950s, which signalled a departure from the traditional urban pattern of Riyadh, to accommodate the large number of employees after the transfer of the Kingdom’s government offices and the major ministries from the Western Province to the Riyadh City (Al-Hathloul 2002). The Al-Malaz residential project was constructed over an area of about 500 hectares and consisted of about 750 detached villas and three apartment buildings, as well as the necessary supporting facilities, Figure 1.2.

Figure 1.2. Master plan of the Al-Malaz residential area in 1950, source: Al-Hathloul (2002)

At the time of planning, the Al-Malaz layout followed the formal requirements on a gridiron network, that comprises a hierarchical street network ranging in width from about 55m for the highways to about 18m for the collector streets (Mubarak 2004). In addition, other regulations such as the planning and building regulations, including building setbacks, building heights, and construction materials, were also implemented in the Al-Malaz residential project. Twenty years later, the example of the gridiron planning system that was

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adopted in the Al-Malaz residential project was widely used in conjunction with the urban expansion of the Riyadh City through the city’s first and second Master Plans in 1973 and 1982, respectively (Mubarak 2004). In general, these urban Master Plans, which were prepared by foreign companies and planning expertise - namely Doxiadis International and SCET International - have produced a city-wide gridiron comprising a system of highways that circumscribe super-blocks of gridiron sub-divisions. It is important at this point to mention that, historically, the built environments in the Middle Eastern regions were traditionally managed by the residents. Thus, the urban forms, and the urban public spaces in particular, are generally shaped according to the socio-economic and cultural norms of the community involved (Akbar 1988). However, the transfer of the responsibility for managing the built environments from the residents to the central government, as it was in the case of the Riyadh City, was at the expense of many considerations, one of which was the environmental quality. In addition to the growth of urban sprawl, which is seen by many as costly and inefficient, and the associated increase of exploration of ground water that resulted from the increase growth of urban sprawl (El-Sharif 1985), the modest efforts of adopting climatic considerations and human dimension during the design process has exacerbated the severity of the microclimate conditions in such desert region. Indeed, this increases the reliance on the active cooling systems in indoor spaces to overcome such degradation in the environmental quality of outdoor spaces. A field study, by Al-Saud (2006), investigated the existence, intensity, and magnitude of the urban heat islands in the Riyadh City has showed that such climatic phenomenon does exist in the city and is more evident during the night time. This condition increases the energy demands for cooling during the summer time from the urban dwellers by 7.7% compared to that consumed in buildings located in the surrounding rural areas. Such an increase in the energy demands for cooling costs the city over US$30 million annum. Al-Saud (2006) concluded that more attention should be given to minimise the severity of urban microclimate conditions in the Riyadh City by proposing various urban design strategies including (a) maintaining low building density in order to reduce heat emissions that are usually associated with highly populated urban areas, (b) increasing the distance between high-rise buildings to accelerate the process of heat loss, (c) increasing the surface albedo for solar radiation by using lighter colours, and (d) increasing the vegetated and green cover areas in the city.

The extreme climate condition in Saudi Arabia in general, and the lack of urban design strategies that take into account the local climate conditions in such desert region has led to

the high energy consumption Ajlan et al. 2006; Al-Jazirah 2008

generated energy in Saudi Arabia is used for operating the urban buildings, and 65 % of this generated energy is consumed by active cooling systems alone. Recently, the Saudi Arabian Secretary of Energy stated that; about 8

12:00 to 17:00 is consumed in cooling loads in Saudi Arabia According to Al-Jowair (2006

considered the highest in comparison to the corresponding energy consumed per c some developed countries including Australia, the UK and the USA,

Figure 1.3. Comparison of per capita consumption of energy in Riyadh City, Australia, the UK and the USA, source: reproduced by the author from

This higher energy consumption existing problem in the city and

excessive use of energy, particularly from urban dwellers of the total energy that generated

29.6%, 4.7%, 3.8%, and 2.1% are and agricultural premises

discussion, it appears that the massive demand for energy in Riyadh City, which is consumed mainly in cooling loads and

with the severe hot microclimate conditions in the city, particularly, during the summer time where the external air temperature could reach 48°C

account the bioclimatic design principles in the adopted urban strategies in Riyadh, and the dramatic growth of urbanisation and population, have contributed in increased air temperature in the city, which is anticipated to continue to rise in the decades to come (Jentsch et al. 2010), Figure

6192 0 1000 2000 3000 4000 5000 6000 7000 Riyadh City E n e rg y c o n su m p ti o n p e r ca p it a (k W h /y e a r)

energy consumption which mainly consumed by cooling loads in buildings Jazirah 2008). According to Said et al. (2003), 65% of the total generated energy in Saudi Arabia is used for operating the urban buildings, and 65 % of this generated energy is consumed by active cooling systems alone. Recently, the Saudi Arabian Secretary of Energy stated that; about 80% of the generated energy during the time from 12:00 to 17:00 is consumed in cooling loads in Saudi Arabia (Alarabiya.net 2013

Jowair (2006), the consumption of energy per capita in Riyadh City is considered the highest in comparison to the corresponding energy consumed per c

some developed countries including Australia, the UK and the USA, Figure

. Comparison of per capita consumption of energy in Riyadh City, Australia, the UK and the USA, source: reproduced by the author from Al-Jowair (2006

consumption per capita in the Riyadh City sheds light on the size of the existing problem in the city and indicates the urgent need to adopt a strategy to reduce the

use of energy, particularly from urban dwellers. A study shows that, generated for the Riyadh City is consumed in urban dwellings

29.6%, 4.7%, 3.8%, and 2.1% are consumed in the governmental, industrial, commercial, premises, respectively (Elhadidy et al. 2000). Based on the previous discussion, it appears that the massive demand for energy in Riyadh City, which is consumed mainly in cooling loads and in particular in residential buildings, can be decisively linked with the severe hot microclimate conditions in the city, particularly, during the summer time where the external air temperature could reach 48°C (MDA 2008). The lack of taking into account the bioclimatic design principles in the adopted urban strategies in Riyadh, and the owth of urbanisation and population, have contributed in increased air temperature in the city, which is anticipated to continue to rise in the decades to come

Figure 1.4.

3250

4625

Riyadh City Australia UK

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which mainly consumed by cooling loads in buildings (Al- , 65% of the total generated energy in Saudi Arabia is used for operating the urban buildings, and 65 % of this generated energy is consumed by active cooling systems alone. Recently, the Saudi Arabian 0% of the generated energy during the time from Alarabiya.net 2013). , the consumption of energy per capita in Riyadh City is considered the highest in comparison to the corresponding energy consumed per capita in

Figure 1.3.

. Comparison of per capita consumption of energy in Riyadh City, Australia, the UK and Jowair (2006)

sheds light on the size of the the urgent need to adopt a strategy to reduce the s that, about 60.6% urban dwellings, where consumed in the governmental, industrial, commercial, . Based on the previous discussion, it appears that the massive demand for energy in Riyadh City, which is consumed in particular in residential buildings, can be decisively linked with the severe hot microclimate conditions in the city, particularly, during the summer time . The lack of taking into account the bioclimatic design principles in the adopted urban strategies in Riyadh, and the owth of urbanisation and population, have contributed in increased air temperature in the city, which is anticipated to continue to rise in the decades to come

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9 Figure 1.4. Annual means temperature and urban population growth of Riyadh city, source: appeared

first in Jentsch (2012), the figure acquired from the author by personal communication

Driven by the success of the vernacular urban forms in accommodating the socio-economic and cultural aspects of the residents, it is commonly claimed that such vernacular urban patterns are also perfectly arranged to suite local climatic conditions. However, this is has not yet been proven, and the positive climatic effects of the vernacular urban design solutions may in fact be overestimated (Givoni 1998; Ali-Toudert 2005). Moreover, the impact of transportation and new development trends in the contemporary built environment have, to some extent, limited the opportunities to apply the traditional urban design principles. In particular, those principles were applied in the traditional urban fabric of desert climate regions to accelerate the wind flow through the use of narrow winding-street, or by the use of irregular street network to enhance the shading patterns in outdoor spaces are conflicting with the modern requirements in city planning.

With respect to the previous statements, the present demand for a sustainable built environment in Riyadh City in particular, and Saudi Arabia in general, is coupled with the need to minimise the effect of the severe microclimate conditions during the summer time on users of outdoor spaces, as well as to reduce the reliance on the use of active cooling among urban dwellers. The configuration of neighbourhood, quantified by the sky view factor and street orientations, is utilised in the present study as a means of bioclimatic urban design to investigate the influence of different neighbourhoods’ configurations on the human thermal comfort in urban spaces and energy use among urban dwellers in a hot-arid region.

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