1 Introduction

Recent decades have witnessed growing public concern surrounding sustainable development requirements worldwide. Much debate has focused on resolving the social and environmental problems associated with rapid urbanization. In particular, the development of sustainable neighborhoods has increasingly attracted interest [1]. Taking steps to protect the environment by managing CO2 emissions is a global trend in multiple domains, including transportation and mobility and the built environment [2]. Residential neighbourhoods and districts in the kingdom of Saudi Arabia suffer from a lack of an integrated approach to environmental, economic values, which leads to issues such as; a low standard of life quality, inadequate environmental protection and ineffective transportation [3]. At the nearby level endures districts in Middle easterner and other Arabian countries numerous of the natural issues, on numerous levels begin to deplete energy generation from fossil and water demand and expanding squander extent of vitality without the good thing about them which highlights negative slant towards the exhaustion of natural assets [4].

Sustainable low energy villages and neighborhoods that exploit renewable resources are expected to play a significant role in reducing energy demand henceforth, by improving sustainability standards in areas with high levels of access to renewable energy resources, such as solar and wind energy [5]. The Al-Baha region is characterized by a combination of coastal, mountainous and flat topography, with good access to renewable resources. The region has many villages distributed across it, due to its social composition.

It is essential to ensure any new construction meets sustainability criteria, with designers expected to focus on strategies to minimize energy consumption and demand. This can achieved by starting at the level of local residential units, moving up to the level of neighborhoods and/or villages. Hence, any new village should be developed reflecting concerns over both the health of its inhabitants and the natural environment [6]. Designing a sustainable village for the future requires multiple facets be considered to ensure a cutting-edge and sustainable design [7]. Therefore designers need to emphasize a clean and healthy environment, prioritizing future sustainability. Application of macro and micro energy generation in remote villages is important, as many remote villages currently have limited access to electricity. To fulfil environmental objectives, new villages should be designed with essential services, powered by renewable energy, ideally generated locally. Using local renewable resources and local construction materials and educating people about sustainability and environmental responsibility to support a healthy life style is crucial [8]. Designing sustainable villages and neighborhoods by implementing sustainability criteria is the aim of this research. It seeks to provide an ideal model, that can be used to demonstrate how a sustainable village can be managed socially and environmentally. The village design will focus on residential units that fulfil environmental architectural requirements, implement renewable energy sources and provide vital infrastructure and services as well as open spaces. The sustainable village will reduce biologically and socially toxic challenges, enrich and promote prosocial behavior and encourage psychological acceptance. This study is arranged into six main sections: (i) introduction which highlight the gab, statement of problem; (ii) the used methodology in the study; (iii) site selection analysis which present used site in study; (iv) the final design and analysis with application the roles strategies; (v) discussion in term of importance and benefits; and (vi) conclusion and recommendations.

2 Methodology and design principals

The methodology involved designing sustainable homes in a sustainable neighborhood based on providing local residents with renewable energy (solar radiation and wind energy). Five roles were established for the village and serve as the basis of the design methods employed (see Fig. 1). Hence the study will focus in the following objectives;

  • Objective one: designing sustainable village in the main gate of Al-Baha region.

  • Objective two: application the five roles strategies in sustainable village prototype.

  • Objective three: discussing the importance and benefit to addressing urban sustainable roles in future villages and neighborhood.

Fig. 1
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Sustainable design strategies

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2.1 Applied architectural design strategies

The architectural design strategies focus on residential units, which will be designed to align with international environmental standards, while also meeting local environmental and cultural requirements. Six main methods were adopted as illustrated in Table 1 below.

Table 1 Architectural design approach
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The design of the residential units is the key factor affecting energy demand in neighborhoods [9]. Architectural design plays a significant role in energy demand, as well as in how environmental design is embedded into designes [10, 11]. In the proposed design, many strategies are suggested to minimize energy consumption and demand. Firstly reducing the unit area allocated based on an average number of occupants, considering the area occupied by typical houses in Saudi Arabia. The allocated area will provide all facilities and meet the household’s needs while keeping energy demand to a minimum. Secondly, using a sloping shaped roof will help to limit exposure to direct solar radiation and minimize energy demand. To further assist with cooling, the roof will be covered by grass to insulate the building against the sun’s heat, while also facilitating rain water harvesting and the use of photovoltaic panels [12, 13]. Thirdly, the units throughout the neighborhood should minimize winnows and glazed areas, maintaining efficient natural ventilation and lighting [14]. This will help reduce heat transfer through glazed areas. As Saudi Arabia is characterized as having a hot arid climate, the building envelope efficiency should be classified as low heat transference (U-Value). Fourthly, exploiting the basement as a usable floor area plays a significant role in energy saving [15]. As mentioned in many studies, ground heat exchange can provide natural ventilation while conserving as much energy as possible [16, 17] as noted here. Fifthly, using a rectangular shaped design for the unit will make it possible to avoid a south facing orientation and direct solar heat through building shape [18, 19]. Finally, creating semi-detached or terraced units will improve efficiency in the area, and play a significant role in energy saving [20, 21].

2.2 Alternative energy strategies

Exploiting natural energy resources is critical to meet regulatory objectives to provide a sustainable and clean environment. Therefore, macro energy generation and micro energy generation methods were proposed. For strategies supporting on-site renewable energy harvesting see Table 2 below.

Table 2 Strategies for gathering on-site renewable energy
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Due to the high availability of solar radiation in the southern region of Saudi Arabia [22, 23], exploitation of this natural resource can achieve a clean environment and minimize CO2 emissions. Photovoltaic (PV) devices will be located on top of all service buildings (e.g., schools, health centers, security station sport centers and other services facilities). The energy generated from solar radiation will be exploited to operate these services, with additional support from energy generated by harvesting wind power. Solar street-lights are also being proposed to operate public lighting throughout the whole neighborhood, with backup systems fueled by wind energy. Thus, to harvest wind energy, it is proposed to locate five wind turbines close to the neighborhood. Residential units will also include PV panels located in car parks and on roofs to harvest solar radiation, covering most of occupants’ needs, although it is anticipated additional power will be needed from supply companies.

2.3 Construction materials

To minimize energy use during the construction process, local materials will be used to avoid the extra energy expenditure associated with off-site manufacture and transportation [24, 25]. This can be achieved by manufacturing building elements from locally sourced raw materials. The manufactured materials can be designed to include greater insulation and low thermal transience. Furthermore, designing a building envelope that will slow heat transmission to achieve thermal comfort was a key aim of this project. An efficient building envelope plays a significant role in energy saving [26, 27] in both hot and cold climates. Table 3 below presents the strategies employed when designing the building envelope within the neighborhood, to apply it in all residential units and facilities.

Table 3 Construction materials
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Calculation of the u-value will help to evaluate the efficiency of the building fabric, by determining thermal resistance [28, 29]. Therefore, a calculation of the thermal transference of the building’s envelope was made using the equation below:

$${\text{u-value}}=\frac{1}{R-Value}; \quad {\text{R-value}}=\frac{Thickness (m)}{Conductivity}$$

In addition, external windows were designed using efficient double glazing to reduce heat transference through windows while also providing natural ventilation and sun light [30,31,32].

2.4 Rainwater harvesting and grey water recycling

Many methodologies have been proposed to increase the water supply to residential buildings. One is to engage in rainwater harvesting [33] and greywater recycling. This strategy is important to consider in low energy housing and villages designed around sustainability principals [34, 35]. It is proposed that this project allocate catchment areas for rainwater to be managed and consumed for external purposes, based on the amount of rainwater that can be potentially harvested [36]. Hence, Table 4 presents the rainwater strategies applied.

Table 4 Water management approach
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The calculation for rain water harvesting is dependent on the total catchment area, where the below equation determines potential annual rain water harvesting;

$${\text{Rain water harvesting}}=({\text{cachment area}}^{2}) \times {\text{(Annual rainfall)}} \times (0.9)$$

The roof areas of all residential units should be exploited as catchment areas for rain water. The water harvested will be saved in a specific water tank at each property to exploit this as an alternative water source for outdoor use. This water can be used for external irrigation of private gardens, washing and other uses after filtering. In addition, pathways and public car parks can be used for rain water harvesting and water collected in central water tanks across the village. This water will be used to irrigate public parks and gardens, which may cover over 70% of the land areas of the village. Decentralized urban water recycling systems offer an additional way to collect water for cities. They can help take some of the pressure off the reliance on water supplies from big companies [37]. For private residential units, a greywater recycling system will be introduced with recycled water reused for outdoor purposes.

2.5 Waste disposal recycling and management

One sustainability principle relates to how to integrate waste disposal and consume and manage recyclable waste. When we fail to handle refuse properly, it can contaminate the environment, making people sick [38]. This research offers a framework for waste management and disposal as detailed in Table 5 below.

Table 5 Waste disposal management approach
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It is essential to separate household waste, identifying recyclable products, such as cans, tins, papers and others. This approach will support steps towards a cleaner environment. Therefore, allocating colored bins to separate waste in both private units and public locations is important, to achieve efficient waste disposal. Furthermore, central bins can be located around the village to allow waste disposal companies to effectively manage waste removal. Waste will be delivered separately to landfill sites located at least 5 km away from the village. These landfills will handle solid waste in a manner that is environmentally and economically sustainable [39, 40].

3 Environmental site description and analysis

The site is located a few miles from downtown Al Aqiq, and more than 30 miles from both Al-Baha city and Baljurashi city. It was chosen due to its geographical characteristics, and its location close to Al-Baha airport. The Hijaz region experiences damp air fronts that move in from the surrounding plain giving rise to mists and fog. In addition, the range of weather includes thunderstorms, chilly temperatures, and heavy rainfall, with spring and summer months witness moderate temperatures. Figure 2 shows the national scale which reflect the location of Al-Baha region while Fig. 3 shows Al-Aqiq Governorate.

Fig. 2
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National scale and Al-Baha region (source: [41])

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Fig. 3
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Al-Aqiq Governorate (source: google earth)

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Meanwhile, the commercial sector has a different environment to the Hijaz region. It has moderate winters, and pleasant spring temperatures across the undulating coastal plains. Generally speaking, the Al-Baha region has a dry climate that is warm in summer and relatively cold in winter (Al-Baha municipality website, n.d.). The atmospheric pressure is between 602 and 607, typical temperatures range from highs of 23 to a low of 12, and the average annual rainfall in the Hijaz area varies from 229 to 581 mm, and from 100 to 250 mm in the Tihama sector (Al-Baha municipality website, n.d.). The site was selected taking into account the suitability of the area, its location and the possibility of constructing an environmentally sustainable village meeting the five criteria chosen (see Fig. 4).

Fig. 4
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Site and characteristics (source: google earth)

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The environmental analysis covers the availability of on-site renewable energy, annual rainfall, wind, hours of sunlight and traffic survey. Figure 4 details the site boundary and environmental survey, and Table 6 illustrates the climatic conditions in Al-Baha.

Table 6 Weather  and topographical profile “chemical properties of groundwater for Al-Baha region”
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4 Urban environmental design prototype and analysis

The design covers 4,945,000 m2 and includes the majority of urban facilities and services expected, such as schools, shops, health centers, and open spaces. The aim of the design is to incorporate sustainable strategies to minimize energy demand immediately, starting from the construction of the first residential units. The design contains more than 6150 residential units, and includes private and semi-private open spaces and public open spaces. Furthermore, the design covers schools provision at all levels for both genders, as well as multiple health centers and services. In addition, a private college is proposed to boost the local economy and promote the development. Figure 5 below presents the final land use design plan for the village.

Fig. 5
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Environmental design layout

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How to plan and design new elements in the city context to improve energy performance and sustainability is the main goal of the study. To analyze complexity, various urban morphological factors were studied, impacting the energy consumption of the entire city [43]. Public Places Urban Spaces provides an in-depth overview of the principles, theory and practices of urban planning, both for newcomers and those who need a clear and systematic guide [44]. The final design of the village has been revised by five experts by providing their comments in application sustainable criteria and exploiting local alternative energy in the line of social needs. Some of the applied methods can be reflected in the design such as; cluster design, open spaces and floor area ration (FAR) but some are described such as the import of construction materials from surrounded mountains and allocated energy stations in macro scale to support the village infrastructure. It is evident that the design concept started with the cluster, and includes many housing and private gardens for each unit. The facilities and services are located in central parks to minimize walking distance for residents and three main central parks.

4.1 Residential and cluster design features

Cluster’s design includes the location of the building within its site as well as group of buildings within the cluster to involve its own facility and open space. According to Neufert architecture standards, the Fig. 6 below shows the buildings group “cluster design” sample and its criteria while Fig. 7 presents the unit location within the site.

Fig. 6
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Cluster design samples (source: Neufert-4th-edition [45])

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Fig. 7
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House location in site (source: Neufert-4th-edition [45])

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Each cluster comprises 16 properties, each with privacy and a rear courtyard. Car parks have private entrances within a small area of the building to minimize construction area and use space efficiently. Each house will have its own on-site renewable energy technology to exploit solar radiation and generate electricity. Figure 8 shows the cluster design and description (Table 7).

Fig. 8
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Cluster design and description

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Table 7 (Land use details) details the areas considered by designers when allocating renewable energy strategies
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Each unit area has been designed to keep the indoor area as small as possible, to minimize energy consumption. In addition, the attic roof has been designed as sloping to support rain water harvesting, support the addition of on-site renewable energy collection, and to protect upper floor rooms from the external hot and arid climate by providing an attic space for use as storage and insulation. Figure 4 shows the unit prototype and cluster design. To ensure double-glazed windows perform optimally it is important to enclose the right amount of air between the panes. To achieve this we employed the degree-days method to determine how much air is needed [46]. Windows are responsible for about 60% of energy loss from buildings. Therefore, monitoring window efficiency is important in informing a building’s energy requirements [47]. In the literature, U-value assessments of windows are usually conducted by implementing theoretical and numerical methods [47]. The double-glazed windows proposed are a vertical rectangular shape that minimizes the glazed area to avoiding solar heating while also providing vital natural ventilation for the dwelling. The residential unit area is about 250 m2 with an extra 100 m2 area for the rear private garden and a private allocated car park. Some social challenges may arise when minimizing the area of residential units but in an environmental design, sustainability is the chief concern. Architecturally, the residential units have a high efficiency building envelope including efficiently designed glazing. External windows are rectangular shape with a total area 1.5 m2 allocated to windows in the property. This will provide necessary sunlight and natural ventilation, while keeping insulation as efficient as possible. Details of the building envelope are provided in Table 8 below.

Table 8 Building envelope description
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4.2 Application of on-site renewable energy and rain water harvesting

Today, it is widely recognized internationally that the construction sector is one of the main energy consumers. Therefore, interventions in this sector have huge potential to reduce energy consumption and greenhouse gas emissions [48]. Exploiting solar radiation is important in this project, due to availability of natural resources for use as alternative energy. The energy generation from solar radiation has been suggested to using photovoltaic (PV) systems that can generate energy inform of electricity from solar radiation. the amount of this converted energy is vary depending climatic conditions and availability of solar radiation during the year. The average energy generation from solar radiation to energy inform of electricity should exceed 7% of total annual available solar radiation [49, 50]. Hence, the proposed design includes a rooftop solar powered panel system, comprising PV panels covering 20 m2 for each dwelling. The panels will convert the solar heat to energy in the form of electricity to support the majority of household needs, with any remaining energy requirements met by the Saudi electricity company. Power generation will be between 3000 to 7000 kWh annually, as the solar radiation in the southern region is about 2100 kWh/m2. The quantity of energy needed to power buildings will be estimated using software simulation tools.

In hot arid countries, interest in rainwater harvesting systems has surged recently due to severe droughts, worries about the impact on the built environment of stormwater runoff, and growing water demand [51]. One significant result is that local legislation and economic restrictions have had a major impact on the level of rain water harvesting system adoption and the chosen technology. Additionally, despite the fact that design guidelines have been established by many nations, suggestions are still sometimes arranged solely with the aim of water conservation, without taking the possible advantages associated with the numerous functions of rain water harvesting into consideration [52]. In addition, rainwater is typically viewed as a risk rather than as a positive resource when it comes to local water sources [53]. However, a rainwater harvesting system will be implemented for each dwelling taking into account the total roof area of each building, as determined by a simple equation. Rainwater harvesting is one of energy use approach where this been aimed in the study. Rain water harvesting also still depending on annual rainfall in Al-Baha and allocated area of rainwater harvesting (catchment area). The method used is annual rainwater harvesting in the allocated area (– 10%). The average annual rainfall in Al-Baha is 150–200 mm according to [54, 55]. Hence, the annual anticipated rainwater harvesting yield for each dwelling is up to13,500 l, calculated as below:

$${\text{Rain water harvesting}}=({\text{cachment area}}^{2})\times ({\text{annual rainfall}}) \times (0.9)$$
$${\text{Rain water harvesting}}=(75 {\text{m}}^{2})\times (200) \times (0.9)$$

Based on this calculation above, a storage tank for rain water will be included with each unit. The harvested water can be used for purposes such as land irrigation, car washing and other outdoor uses.

5 Discussion

Energy conservation is a key component of environmental protection measures. It can be achieved through the efficient design of the built environment from the urban scale to the architectural unit scale. Efficient design includes an urban design with open spaces that encourage walking rather than using vehicles. Many benefits can be attained by applying sustainability principles when developing the Saudi built environment envelope, as discussed below.

5.1 Exploiting alternative resources

Urban designers of villages should seek to address social needs, environmental requirements, topography and on-site renewable resources. This will afford residents access to a healthy environment that is also commensurate with their social needs. The design applied means vehicles need not be used within the village setting, as the entire village has pathways linking key facilities to all residential units. Furthermore, natural resources have been employed to limit CO2 emissions; i.e., wind energy generation and solar radiation.

According to Peters (2017), environmentally responsible building design will ensure a clean and healthy environment [56]. It important to highlight that, by minimizing the detrimental effects on buildings and to the environment, sustainable design aims to improve the environmental quality of interior spaces [57]. Internationally, designers, developers and decision makers need to consider sustainability when making plans to expand the built environment. This includes reducing the energy demand of buildings through architectural design, building envelope design and exploitation of local renewable resources.

At the planning stages, the environmental design started by determining the specifications for residential units and continued up to the level of the urban design for the entire village. The sloping roof strategy is one of the most significant factors applied in the design, due to the need to integrate a low energy design and on-site renewable energy, as well as rain water harvesting. Furthermore, the open space factor is vital for ensuring natural ventilation and social integration through access to social activities for residents [58, 59]. The final village design considers energy resources, water management and waste disposal management, so as to meet environmental requirements [60] while fulfilling energy demands.

5.2 Economic considerations

The major focus of the research is on environmental friendliness, and the cost of housing stock in light of the changing lived environment. It shows the organization-economic mechanism that informs sustainable development of the dwelling [61]. Hence, improvements to quality of life require sustainable economic improvements [62]. The urban design of the village plays a significant role in economic aspect of Saudi Arabia. Typically, houses are operated annually and rely on burning fossil fuels, which results in high demand in terms of costs to provide energy in form of electricity [63]. It is well known that high levels of energy are consumed by the residential sector. Thus, the energetic causal connections between vitality utilization, vitality cost and financial action in Saudi Arabia necessitates a request side approach [64]. On this basis, developers and consumers should take into account the need to minimize energy demand and favor clean renewable resources.

The sustainability concept has been adopted and acknowledged within the building industry worldwide. However, the significance of social factors have received relatively less consideration [65]. It is essential to issue a sustainable evaluation and develop assessment tools to determine and manage environmental projects in Saudi Arabia. This will make it possible to achieve sustainable development in the residential building industry [66]. A feasible evaluation device can then be created to meet the neighborhood’s needs from a social and financial perspective [66, 67]. Current residential buildings can be further developed to minimize energy demand in a way that is sustainable within the local economy. Meanwhile, establishing construction and building materials production firms locally will provide jobs for residents, in a manner that is compatible with Saudi Arabia’s Vision 2030 plan.

5.3 Environmental protection

The transition to low CO2 thermal energy systems requires the provision of concrete information to support both public and private sector decision-making that is future-oriented and optimal in the context of system dependencies [68]. Analysis of ecosystem services can provide quantitative targets for urban ecological revitalization, as determined by the site-specific ecology and climate in urban regions. This is important because the majority of urban ecosystems are currently experiencing significant negative environmental impacts. If cities can provide ecosystem services, then the pressure on surrounding ecosystems can be reduced [69]. Pollution also represents a significant threat to the ecosystem [70, 71]. The Al-Baha region has many forests, which shelter a unique varieties of medicinal plants. These forests are also home to a wide variety of wildlife that needs to being protected to maintain the ecosystem in Al-Baha. Urban sprawl will impact the ecosystem, and higher CO2 emissions will affect natural plants and wildlife, creating an imbalance in the ecosystem. This will encourage developers to protect forests and construct future buildings in terms of low energy design. In addition, wastewater arising due to the higher number of residential units could disturb the ecosystem. Wastewater from farms, residential housing as well as agro-industrial processing can compromise the integrity of the natural environmental. For environmental protection purposes it is crucial to limit energy consumption when treating wastewater [72].

5.4 Future work: validation

Based on the final design and analysis; the benefits of the sustainable low energy village need to be discussed locally and globally in terms of environmental, social and economic aspects. Hence, this prototype can be applied in future neighborhoods in the built environment in Saudi Arabia, playing a key role in energy saving, and the development of a healthy environment. Computer simulations should be conducted to examine annual energy consumption where energy is being consumed as well as the annual energy generation via PV panels, and annual CO2 emission rates.

6 Conclusion and recommendations

The study focus is on designing a prototype sustainable low energy village in south western Saudi Arabia, which is characterized by a mountainous topography and a wealth of renewable energy resources. The village design integrates architectural design strategies that are compatible with environmental requirements, and PV panels for each property, with wind energy generation via wind turbines around the village. Furthermore, renewable energy generation has been calculated according the availability of solar radiation and areas where PV panels can be used. Meanwhile, rainwater harvesting and greywater recycling systems strategies have been applied for all residential units, and in some public areas of the village, with annual rainwater harvested based on annual rainfall in the Al-Baha region. Waste management and disposal are taken into account as the design included colored bins for solid recyclable waste and implementation of landfill within five km of from the village. The study concludes with the following recommendations;

  1. 1.

    Design future neighborhoods with sustainable requirements and low energy design.

  2. 2.

    Exploit local natural resources during future building projects, and make it compulsory for all residences to have PV panels.

  3. 3.

    Minimize residential unit area as far as possible while meeting occupants daily requirements.

  4. 4.

    Increase the number of public open spaces within neighborhoods as much as possible, for social and environmental purposes.

  5. 5.

    Establish an environmental method scheme to evaluate village design and with particular emphasis on environmental requirements.

  6. 6.

    Research how best to meet zero-carbon energy demand in the Saudi built environment architecturally and socially and integrate renewable energy generation.

  7. 7.

    Design and construct low energy villages by every city in Saudi Arabia to provide a healthy environment and build public awareness of the importance of low energy villages.

  8. 8.

    Support construction materials factories to avoid the need to import materials to minimize energy expenditure.

  9. 9.

    Use local materials in the built environment to protect the local urban and architectural identity of Saudi Arabia.