Evaluation of an Existing Validated Emirati House versus a New Parametric Design Based on the Local Social Environment through the Application of Advanced Tools

Abstract

Al Ain is the second-largest city in the Abu Dhabi Emirate, and the population of Al Ain has been growing rapidly for the last 50 years. The residential units in Al Ain are arranged using different concepts in relation to household social and economic behaviors. While Al Ain city has mostly low-rise and mid-rise residential buildings, the local population tends to live in traditional low-rise villas. The governmental statistics show a high ratio of energy consumption in the form of electricity for cooling loads, and it is estimated to increase with the rapid growth of the population. In this context, it is important to investigate different strategies to control the energy consumption of residential buildings. The purpose of this study was to assess the energy usage and demand of an existing villa in Al Ain and see how a newer design approach can help to reduce the annual energy consumption of households. The newer design option is based on a parametric (application of a parametric façade) approach whilst taking sustainable design approaches. The newer design options are compared to the existing villa and a traditional extension villa attached to the existing villa in terms of annual electricity consumption. The process of design and energy modeling of all cases used the Estidama baseline standards for technical and construction specifications. The process started with selecting an existing six-bedroom villa in Al Ain. Moreover, the selected villa had a planned extension to be constructed in the future. Then, an annual energy model of the existing villa was created in Rhinoceros 7.0 with the Grasshopper 3D plug-in. The energy results were validated against the real energy bills of the villa. Once the energy model was validated, the newer options of the design were modeled, and the projected energy consumption was compared with the base case results to see how energy-efficient the newer model would be. The research shows that it is possible to save up to 60% of electricity annually by carefully selecting a sustainable design in the early stages.

1. Introduction

1.1. Energy Consumption for Building Cooling

Electricity consumption can be divided into four main sectors: buildings, industry, agriculture, and contracts. In Al Ain, buildings, particularly those in the residential sector, account for 45.9% of the total electricity consumption [1]. While reducing energy consumption is a challenge in every sector, reducing residential cooling consumption is strikingly straightforward. According to estimates, just implementing passive cooling in buildings would reduce energy bills by 80% [2]. This would translate to an immediate 40% decrease in consumption.

The city of Al Ain (located in Abu Dhabi Emirate, UAE) consists of mostly low-rise residential buildings and villas organized in compounds or as separate units. Unfortunately, from a climate perspective, the recent predominant construction style is contemporary, which ignores traditional construction methods that were already climate-adapted. Hence, the inhabitants rely heavily on active cooling for thermal comfort [3,4]. Because of this dependency on active cooling systems, energy consumption dedicated to cooling now represents a whopping 39% of the total national electricity consumption [5], one of the highest in the world [6], and it has risen dramatically along with living standards in the last two decades. For context, as a global average, the residential sector consumes nearly a quarter of all global electricity produced.

To tame this trend of consumption increases, the local government bodies in Abu Dhabi, such as the Urban Planning Council (UPC), have launched a number of initiatives since 2010, including the Abu Dhabi 2030 Plan and a five-point building sustainability rating system called Estidama [6] (Arabic for sustainability). The consumption of energy by buildings currently accounts for 80% of the total electricity consumption in the Emirate of Abu Dhabi, and 70% of this energy consumption is accounted for by the cooling load [5]. In addition, according to a study based on the existing residential building stock, buildings built before 2003 did not adhere to any such regulations in either the Emirates of Dubai, Sharjah, or Abu Dhabi. For instance, the thermal insulation requirement in Al Ain, Abu Dhabi, was only established after 2010. According to the data, all of the residential buildings in the UAE built before 2003 are exempt from any thermal insulation requirements or guidelines [6].

Over the last few decades, the housing typology and size have experienced significant changes. Government housing programs, for example, have increased the average house area from an average of 100 m² in the 1960s to about an average of 400 m² per house today. The majority of housing programs develop detached houses, the most energy-intensive to cool [7]. These changes in the type of houses built and the increase in the population explain the increase in energy demand recorded in the last two decades. In addition, citizens’ bills are subsidized. For example, while the cost of producing a kWh of electricity is estimated to be USD 0.12 to USD 0.13 in the UAE, its retail price in Abu Dhabi is USD 0.04 per kWh (with a further significant additional discount for UAE nationals). In Dubai, the rate ranges from USD 0.06 to USD 0.10 per kWh [8]. Regarding the bills per house or villa, a study mentioned that in the UAE, expat-occupied villas consumed 32,100–97,000 kWh per year, while the UAE nationals’ villas consumed 93,000–97,000 kWh per year [9].

The UAE’s hot climate makes it a challenge to maintain acceptable indoor comfort levels. In particular, the HVAC-equipment-related electric load makes up 40% of the total annual load. However, in summer, it peaks at 60% [6]. In this context, to reduce the HVAC load, it seems advisable to explore, test, and apply passive and active measures during the early building design phases.

1.2. Passive Cooling Design

1.2.1. General Overview of Passive Cooling Strategies

Passive cooling is related to methods or design elements implemented to decrease building temperatures without the use of energy. Passive design for heating or cooling has grown in popularity recently, especially over the last ten years, in association with the trend toward sustainable architecture. In the summer, well-designed envelopes maximize air movement and control the sun’s heat. There are several passive cooling strategies suited for use in hot, arid climates like the United Arab Emirates (UAE) [5]. Some of these are evaporative cooling, shading, parametric shading, heat insulation, light-colored and highly reflective coatings, and green roofing [8,10].

One study aimed to evaluate the effect of applying a set of selected passive cooling strategies to a residential building. The study tested eight passive cooling strategies. The results of the study revealed that the total annual energy consumption of the residential building can be reduced by 23.6% with passive cooling strategies [5]. Another study aimed to test the impact of a set of retrofit measures in a villa using a calibrated model. These were cool roofs, cool walls, shading devices, window louvers, and changes in the cooling set-point. The study demonstrated a 34% reduction in annual energy consumption [11]. Another study conducted in Al Ain tested the effect of spatial distribution and orientation on the cooling loads of a typical unit in a housing project in Al Ain. The results of the study demonstrated that considering the building orientation and the spatial distribution during the design phase can achieve significant energy savings and lower the electricity cooling load [7].

In this context, this study aims to compare the energy consumption of a building when it is fitted with a shading device in various scenarios. The new design is based on sustainability principles of design utilizing passive strategies, as well as an advanced parametric design, where the analysis considers several parameters. In particular, the evaluation is a comparison between four scenarios: the current building, the retrofitted building with shading, an extended version of the building, and an extended version with shading. This analysis was conducted considering local sustainability standards such as Estidama [6,12].

1.2.2. Application of Shading Devices (Mashrabiyas) in Residential Buildings (Low-Rise and Mid-Rise) in Middle East and United Arab Emirates

“Mashrabiya” (also spelled “Moucharabieh” or “Mushrabiyah”) is an Arabic term that refers to a type of architectural element in traditional Arabic architecture. It is a form of a projecting oriel window enclosed by carved wood latticework located on the second story of a building or higher, often lined with stained glass. The purpose of the mashrabiya is multifaceted: it allows for privacy, provides shade and cools the indoors (as the design promotes airflow), and adds an aesthetic element to the building.

The term “Mashrabiya” is derived from the Arabic root “Shariba”, which means to drink. It is said to originate from the traditional shelves built to hold earthen jars for cooling drinking water. Over time, the term came to refer to the distinctive window type that is often seen in Middle Eastern architecture.

Mashrabiyas are notable for their intricate geometric designs and have been used in various forms for centuries across the Middle East and also in North Africa. They are not only a practical architectural feature but also a recurrent element in those regions’ art and architecture.

1.2.3. Historical Overview of the Application of Mashrabiyas in the Middle East

In a study carried out in Saudi Arabia, mashrabiya devices were analyzed not only as energy efficiency elements in the building envelope but also as elements of the culture. The analysis was performed on a mid-rise residential building. It was found that mashrabiyas led to a reduction of 5.7% in the monthly cooling load and a 35.5% improvement in daylight. The recommendation of the authors was to preserve the identity of these shading structures by improving their efficiency through the application of different designs and materials (Figure 1) [13].

A recent study in Jeddah, Saudi Arabia, compared several types of historical mashrabiya applications in mid-rise residential buildings. The application of this device can reduce the indoor temperature by 2.4 °C. The study showed that the temperature fluctuations inside were lower than those recorded outdoors. The detailed analysis showed the relevance of this device as a cooling strategy for indoor areas (Figure 2) [14].

According to research carried out in Egypt in relation to a smart green mashrabiya shutter, the material and craftsmanship costs to build a traditional mashrabiya are not feasible. Therefore, it was proposed to design a mashrabiya that looked like a shutter, where the main elements of the design are preserved. Interestingly, this novel proposed device is more flexible in operation (opening and closing). This device was designed in Rhinoceros 7.0 with Grasshopper 3D and also has a circuit connected to it in order to operate automatically based on a predefined schedule [15].

In an analysis of a vernacular house in the UAE, various strategies of sustainability were considered. The application of the mashrabiya in the windows with the same materials as the walls (clay and coral) was shown to improve sustainability. The application of such a design to windows, besides the shade and natural ventilation provided, also has social implications (Figure 3) [16].

1.2.4. Recent Applications of Shading Devices in United Arab Emirates

The current application of shading devices in the UAE varies among building typologies and various types of materials. According to the modern language in terms of design and application, shading devices are mainly applied in office buildings and mid-rise residential buildings. The example of Al Bahar Towers, located in Abu Dhabi, shows a parametric shading façade. It starts with a modular unit and multiplies in the south façade of the buildings. This façade is also kinetic. The units open and close based on the movement of the sun. The material for these elements is fiberglass. The number of panels is over 2000 (Figure 4) [18].

Another example of a modern application of the concept of mashrabiya is in Masdar City, an innovative smart city that is located near the Abu Dhabi Airport. Currently used as a university campus, the city is a mix of mid-rise residential buildings and office buildings. The mashrabiya, in this case, is integrated into curved panels made of compressed sand. These panels cover the balconies, creating shade and privacy at the same time (Figure 5) [19].

1.3. Parametric Design in Architecture

Parametric design principles refer to a parameter-driven approach to the process of design, in which parameters represent everything that can be designed [20]. Computational design tools and rapid generative evolutionary algorithms are efficient methods for developing concepts in the early stages of design [21]. Parametric design is defined as the “Process of developing a computer model or description of a design problem. This representation is based on relationships between objects controlled by variables. Making changes to the variables results in alternative models. Selection of a solution is then based on some criteria which may be related to performance, ease of construction, budget requirements, user needs, aesthetics, or a combination of these” [22].

To generate parametric structures, there are a variety of software programs and plug-ins, such as Dynamo in Revit [23], CATIA (which stands for Computer-Aided Three-Dimensional Interactive Application) [24], Marionette for Vectorworks [25], and Grasshopper 3D for Rhinoceroses 7.0 [26].

Grasshopper 3D is an open-source “plug-in software that uses a visual programming language to allow architects to easily isolate the driving parameters of their design while iteratively tuning them. It lowers the entry-level for using complex parametric tools” [26]. Various plug-ins can be connected to Grasshopper 3D for parametric structural analysis, such as Ladybug for environmental analysis and Karamba for structural analysis. Both are compatible with Rhinoceros 7.0 software.

Regarding visual programming (VP), such systems were created to assist designers in the development of scripts for the construction of parametric models that take into account various parameters, such as climatic conditions and energy consumption systems, defined as “any system that allows the user to specify a program in a two-(or more)-dimensional fashion” [16]. Non-programmers can use VP systems to create fairly complex systems with little or no programming experience. Thanks to the popularization of consumer graphic cards, VP systems have been widely adopted. Software like Grasshopper 3D, Dynamo, and Generative Components have made parametric modeling more accessible to designers [10,17].

One related study aimed to apply a parametric shading structure as a retrofit to an existing villa. It evaluated the design, cost, and energy savings. The study found a reduction in consumption of 10%, which led to a reclassification of the UTCI (Universal Thermal Climate Index) from “extreme heat stress” to the “strong heat stress” category. The software used in the study to develop, optimize, and test the performance of the parametric structure was Grasshopper 3D for Rhinoceros 7.0 [27].

Furthermore, another study found that, throughout history, in Middle Eastern countries, parametric shading screens have actually been part of the façades. Using traditional devices, such as the mashrabiya, can reduce the sunlight intake through the building’s glazed components and lower the cooling load demand [12]. In another study, it was demonstrated that adding kinetic parametric shading to a library building in the UAE reduced the electricity consumption of an office building by about 25% [28]. Moreover, the daylighting energy efficiency metrics increased compared to the “no-shading” performance values. The building model was created with Rhinoceros 7.0 and Grasshopper 3D. Ladybug, Honeybee, and Grasshopper 3D plug-ins were used for daylight and energy modeling [29]. Another study applied a well-known Islamic geometric pattern to a shading screen. The pattern allowed sufficient levels of daylight and reduced the energy consumption by 17% [30]. In another study, the author optimized a list of critical visual comfort preferences using the rosette pattern as a parametric shading system. To investigate the indoor daylight quality through different geometrical and physical properties, two geometrical elements, rosette modules and louvers, were used in conjunction with the Grasshopper 3D plug-in for Rhinoceros 7.0 and the DIVA daylighting plug-in [31,32,33].

2. Methodology

A linear method was followed during this study. The selected case study is located in the city of Al Ain. This selection was made mainly because of the need for strategies to reduce the energy consumption in Al Ain. The city is a growing urban development that recorded the highest energy consumption in terms of electricity for cooling in the residential sector in the UAE. Additionally, the villa was selected because of the available data. The data for modeling were collected by conducting site surveys using local sources and site analysis. The modeling and simulation work started by modeling the base case as per the current construction conditions. Then, a validation process was conducted utilizing actual electricity bills. Additionally, the mashrabiya design is based on a local survey carried out by the authors on low-rise buildings in the city of Al Ain in terms of local design patterns (Figure 6). This research has two main objectives:

1-

To show, based on the results, that a well-designed house, considering possible social scenarios linked to the expansion of the unit, is a sustainable building model. To support this aim, analytical work was performed on the basis of several scenarios starting from the base case: the initial house design before the expansion. Afterward, various scenarios were added in order to compare and show the difference in design and energy consumption.

2-

To apply an innovative parametric façade for low-rise villas in the city of Al Ain. Based on a local survey of design patterns of mashrabiyas, a parametric shading structure was analyzed. The modeling of the new design with and without this structure supported this aim.

The main steps of the study are listed below:

-

Case study selection (city analysis; building analysis);

-

Climate analysis;

-

Modeling and simulation of:

o

The base case and expanded plan;

o

New building designs without parametric façades;

o

New building designs with parametric façades.

Figure 6. Methodology: schematic view.

Figure 6. Methodology: schematic view.

2.1. Case Study Selection

2.1.1. Al Ain City Analysis

The city of Al Ain is located in the southeast part of the UAE. It does not have access to coastal areas. It borders Oman. The historical city is surrounded by the desert and Jebel Hafeet Mountain (Figure 7). It has palaces and castles in various locations. In the center, there is a historical oasis. The city of Al Ain is also known as the green city due to the large number of trees planted, such as palm trees and the national tree, called Ghaf [34,35].

The majority of the population is Emirati citizens. The city is growing; therefore, the need for housing is increasing. There are governmental programs to expand neighborhoods with predesigned houses. Due to an increase in the number of expats, the need for housing to accommodate this population is also increasing. Based on a local survey conducted by the authors to identify mashrabiya applications in the city, it was found that these shading structures are mainly used for purely decorative purposes. The initial historical function of the mashrabiya was to create shade in indoor areas while allowing a cool breeze and respecting the social environment in creating privacy. In this survey, several patterns of mashrabiyas were included in the analysis for the purpose of designing the shading structure (Figure 8,

Table 1. Mashrabiya pattern in low-rise buildings in Al Ain.

Examples of Mashrabiya Design, AL Ain

).

2.1.2. Building Analysis

This study referred to an Emirati villa built in the year 2005. Local families in the United Arab Emirates usually live in a main house, composed of formal areas such as male and female Majles; the private areas are the family seating area and the bedrooms. A service block is usually located outside the building. As the children grow and create their own families, a new house is usually built on the same land plot. In some cases, additional rooms are built in the main house (

Table 2. Current house areas.

Space	Area (m2)	Space	Area (m2)
Living/Majlis	314	Laundry	16
Sitting Area	24	Flower Base	20
Guest toilet	14	Master Bedroom with Sitting Area	132
Dining	30	Bedroom 5	51
Kitchen	27	Bedroom 6	38
Hallway	47	Bedroom 7	42
Bedroom 1	49	Wardrobe	25
Bedroom 2	40	Maid’s Room	32
Bedroom 3	49	Kids Playroom	39
Bedroom 4	40

).

The architectural composition of the main house is based on modernism, where the form is simple, and the function of the internal space is clearly divided. The building has three entrances: one formal, one for the family, and another one for the service. The main house taken into consideration in this study has large openings to the north and minimal openings to the south. This house has curves integrated into the plan based on the owner’s request for a more modern language of building architecture. According to an initial conversation with the house owner, formal areas such as Majles and the dining area are generally used a few weeks per year, but they are air-conditioned all year long (Figure 9).

2.2. Climate Analysis

AL Ain is in the Emirate of Abu Dhabi, United Arab Emirates. The city has a hot and arid climate, with cool winters from November to March, short spring and autumn seasons, and hot weather from June to September. The temperature ranges from 24–26 °C in the winter to 38–42 °C in the summer (Figure 10) [36].

2.3. Local Social Environment Analysis

The family social dynamic in the Middle East is different from that in other cultures. Referring specifically to the UAE, local families (Emirati nationals) build their main houses on sites given to them by the government. When a family expands (when the children get married), additional rooms are added to the existing house. This additional space and volume tend to adapt to the main building. The other alternative is to build a second house (or a third house, based on the number of children that get married, generally males) with a similar architectural style to the main (parents’) house. The Middle East has a long history of sustainable building design and materials. However, in recent decades, due to the increase in the population, modern buildings, including low-rise buildings, have tended to have large windows on all facades, lack shading devices, and contain large unused internal spaces due to poor design. Therefore, considering such building expansions from the early stages of design can be environmentally and socially sustainable.

2.4. Modeling and Simulations

The simulation was conducted in Rhinoceros 7.0 software through the Grasshopper 3D plug-in. Using an open-source visual programming language, this plug-in is used to create complex geometries, parametric designs, and simulations of various climatic and energy features.

2.4.1. Research Design and Scenario Description

The modeling and simulation analysis referred to several scenarios. Based on the analysis of the selected house in Al Ain (as a representation of a typical Emirati modern house), the current scenario was defined. The current state of the house includes an extension, referring to additional areas, as the first-born son married and expanded the family (in line with the social changes in point 2.3). The current house plan was used for validation, as the electricity bills were obtained from the owner (private Emirati citizen) after the extension was completed and functional. The base case (Scenario 01) is the original house before the extension. Areas such as Majles and the dining area in the original house design are generally used a few weeks per year, but they are air-conditioned all year long. This point has been taken into consideration in the new design proposal, where such formal areas are still included on the ground floor but with a reduced surface. Meanwhile, the number of bedrooms is kept the same, with the possibility of expanding vertically to the second floor. Additionally, the new design proposal has more curves included in the walls, in accordance with the preference of the owner for a contemporary architectural language. The curves in the floor plan represent the waves of the dunes in the nearby desert.

Scenarios 03 and 04 refer to the new proposed design, where the areas of the base house design and the expanded house design can be accommodated. In recent decades, in cities like Al Ain and Abu Dhabi, the traditional architecture of building houses has been replaced with a trend of using modern architecture. Therefore, large glass windows are placed on southern façades; large areas within the house do not have a choice but to use air conditioning. The aim of the four scenarios is to propose a new design, considering the local culture of expansion as the family grows, in the form of modules. The new design starts with the existing ground floor plan and expands vertically rather than horizontally. As mentioned, Scenario 01 is the original house. Scenario 02 is Scenario 01 with shading. Scenario 03 refers to the expanded house, and Scenario 04 is Scenario 03 with shading. Below are listed the four scenarios for which the energy simulations were carried out:

Senario 01:

Parametric one-story villa without shading device;

Senario 02:

Parametric one-story villa with parametric shading device;

Senario 03:

Two-story parametric villa with extension without shading device;

Senario 04:

Two-story parametric villa with extension and parametric shading device.

2.4.2. Software Analysis

The simulation was conducted in Rhinoceros 7.0 software through the Grasshopper 3D plug-in. This plug-in is used to create complex geometries and parametric designs and conduct simulations of different climatic and energy features through the use of an open-source visual programming language. The Grasshopper 3D plug-in consists of different launches, such as Ladybug, Honeybee, Daysim, Pufferfish, Lunchbox, and so on, to accommodate the different purposes of design and simulation. For the energy simulation, Honeybee plug-in software was used with the script in Figure 4. The main simulation tool is EnergyPlus 9.2, and different parameters, such as the material properties, HVAC system, occupancy, and building type, were added to the script. As the software is open-source, the script was obtained from other developers and modified to our use case. The floor plan for the existing house was provided, and the building mass was designed in Rhinoceros 7.0. There were several issues in the simulation, as there were different floor heights, and a problem with the OpenStudio version while performing the simulation was identified and solved. Simulations for each case were run several times to identify any mistakes as well (Figure 11).

2.4.3. Modeling and Simulation of the Existing Design

Base Model Energy Consumption

The script in Figure 4 was used to create the energy model for the base case building, as shown in Figure 12. The most recent climate file of Al Ain city was inputted in an epw format. The script computed the energy usage for each room on an annual basis. The highest energy consumption went to the southern part of the building. The base model results were then compared with the model with the extension and the parametric villa in terms of energy consumption.

As for the construction materials, the villa follows Estidama regulations. In terms of thermal properties, the u value, thermal absorbance, and SHGC values were added for respective construction elements during the energy-modeling process.

Table 3. Estidama building envelope thermal standards.

Description	Value	Material
U value for external walls (W/m2K)	0.3	Concrete blocks with insulation and cladding
U value for floor (W/m2K)	1.65	Concrete slab with insulation and tile finishing
U value for roofs (W/m2K)	0.2	Concrete slab with insulation and roof deck
U value for glazing (W/m2K)	1.9
SHGC for glazing (W/m2K)	0.3
Lighting load (W/m2)	6.8
Equipment load (W/m2)	2.7

shows the construction standards used in the building simulations, as well as the materials. The walls have concrete blocks with insulation and cladding, the floor is a concrete slab with insulation and tile finishing, and the roof is a concrete slab with insulation and a roof deck. The shading device material considered in this study is fiberglass mesh.

According to the information from the villa resident, the villa uses natural ventilation during the winter season, and this was considered in the building simulation. Moreover, the lighting loads and equipment loads were also taken from Estidama standards. The villa uses a VAV HVAC system with a sensible heat recovery system during summer (21 March–21 October).

Validation for Base Model

The validation process started by creating a digital twin of the existing building in Rhinoceros 7.0 software and inputting the properties of the construction materials as provided drawings in the Grasshopper 3D script. The thermal properties of the building’s materials were as per Estidama standards, as listed in Table 2. Once all of the inputs were included in the script, including the HVAC system type and efficiency, the simulation was run several times to make sure proper results were obtained. The validation process was conducted based on annual electricity bills obtained from the villa in the year 2021.

The annual energy consumption for the existing villa from the simulation was 49,259.89 KWh or around AED 14,580.93 in terms of cost. This value was validated against the existing energy bills, showing a total bill of AED 12,986.55 or 43,873.45 KWh annually. As shown in the calculation below, the percentage error in the results is shown to be 12%.

$$\begin{array}{c}\mathrm{G}\mathrm{i}\mathrm{v}\mathrm{e}\mathrm{n} \mathrm{a}\mathrm{n}\mathrm{n}\mathrm{u}\mathrm{a}\mathrm{l} \mathrm{energy} \mathrm{c}\mathrm{o}\mathrm{n}\mathrm{s}\mathrm{u}\mathrm{m}\mathrm{p}\mathrm{t}\mathrm{i}\mathrm{o}\mathrm{n} = \mathrm{43,873.45} \mathrm{KWh}\hfill \\ \mathrm{Obtained} \mathrm{a}\mathrm{n}\mathrm{n}\mathrm{u}\mathrm{a}\mathrm{l} \mathrm{energy} \mathrm{c}\mathrm{o}\mathrm{n}\mathrm{s}\mathrm{u}\mathrm{m}\mathrm{p}\mathrm{t}\mathrm{i}\mathrm{o}\mathrm{n} = \mathrm{49,259.85}\hfill \\ \%\mathrm{difference}=\frac{\left|\mathrm{G}\mathrm{i}\mathrm{v}\mathrm{e}\mathrm{n} \mathrm{a}\mathrm{n}\mathrm{n}\mathrm{u}\mathrm{a}\mathrm{l} \mathrm{c}\mathrm{o}\mathrm{n}\mathrm{s}\mathrm{u}\mathrm{m}\mathrm{p}\mathrm{t}\mathrm{i}\mathrm{o}\mathrm{n}-\mathrm{O}\mathrm{b}\mathrm{t}\mathrm{a}\mathrm{i}\mathrm{n}\mathrm{e}\mathrm{d} \mathrm{a}\mathrm{n}\mathrm{n}\mathrm{u}\mathrm{a}\mathrm{l} \mathrm{c}\mathrm{o}\mathrm{n}\mathrm{s}\mathrm{u}\mathrm{m}\mathrm{p}\mathrm{t}\mathrm{i}\mathrm{o}\mathrm{n}\right|}{\mathrm{G}\mathrm{i}\mathrm{v}\mathrm{e}\mathrm{n} \mathrm{a}\mathrm{n}\mathrm{n}\mathrm{u}\mathrm{a}\mathrm{l} \mathrm{c}\mathrm{o}\mathrm{n}\mathrm{s}\mathrm{u}\mathrm{m}\mathrm{p}\mathrm{t}\mathrm{i}\mathrm{o}\mathrm{n}}\times 100\%\hfill \\ \%\mathrm{difference}=\frac{\left|\mathrm{43,873.45}-\mathrm{49,259.85}\right|}{\mathrm{43,873.45}}\times 100\%\hfill \\ \%\mathrm{difference}=12.2\%\hfill \end{array}$$

Modeling and Simulation of the Existing House with the Extension

Following the validation of the existing building, a 2-bedroom extension house was added to the northern side of the existing building. The functions of the extension rooms are shown in

Table 4. Building extension program.

Room	Area (m2)
Corridor	24
Bedroom	47
Living Area	50
Bedroom	96
Total	217

. The model of this building was simulated using the same energy simulation script, along with the same construction parameters, HVAC type, operative temperature, equipment, and lighting loads, and the results showed an annual energy consumption of 59,204.55 KWh. Here, a difference of 9944.6 KWh every year, which is estimated to be a 20.2% difference, was observed. This value was compared with the energy consumption of the parametric villa with the extension to obtain a perspective on how changing the design of extended parametric buildings could be useful. The extension used the same building envelope materials, and the thermal properties of the materials were the same as those shown previously in Table 2. Moreover, the extension of the building used natural ventilation from late October to mid-March, like the air conditioning use of the existing villa (Figure 13).

2.4.4. Modeling and Simulation of the New Design

Building Design and Modeling

The newer parametric design was designed over an area of 624 m². The idea of the new design was to create a more confined yet functional and comfortable design option. Figure 14 shows the plan for the ground floor for Scenario 02. The villa is designed in such a way that an additional extension option could be added on top of the existing parametric villa. The functions and areas of the villa are shown in

Table 5. Building program of the 1-story parametric villa.

Room	Area (m2)
Master Bedroom	168
Corridor and Majlis	63
Bedroom 2	36
Bedroom 3	54
Bedroom 4	58
Bedroom 5	30
Kitchen	47
Entrance and sitting	34
Corridor and water feature	140

. The villa has two forms, where there is a one-story villa and an additional extension on the first floor, with the functions shown in

Table 6. Building program of the parametric extension.

Room	Area
Bedroom 1	164
Bedroom 2	88
Sitting area and corridor	62
Bedroom 3	63
Bedroom 4	61
Sitting area	41

. Both options were assessed separately, and the energy results were compared to the existing case. Both scenarios have a design with the addition of a parametric shading device that was designed to reduce the impact of radiation on the building. The effectiveness of the shading device was also energy-modeled, and all results were compared with the design without the shading device.

Parametric Shading Device Design and Modeling

The design of the parametric shading structure was inspired by an example of a mashrabiya design observed in Al Ain. Based on the geometry of the initial sample, the model was developed by evolving around the axes and expanding into a stellar-like composition. It comprises six triangular units attached to a single node. Each unit consists of six triangular panels attached to three axes. The angle that the pair of panels makes determines how open these shading devices will be. The angle of rotation is generally larger in the southern part than the one in the north (Figure 15).

The parametric shading devices were placed considering the site (building orientation; north/south façade), the zone distribution and building design (bedrooms, bathrooms, hall, and therefore, window location), and the building materials. The shading device was designed to cover the northern and southern parts of the building. The southern shading device is more closed when compared to the northern one and acts as a double-skin façade without affecting the daylighting and ventilation of the villa (Figure 16).

Figure 17 presents part of the double façade on the southern side, where each panel group is connected to the structure at the nodes, shown as yellow circles. Figure 18 represents the way that the triangular panels are connected with each other and their rotation along the axes, shown in blue lines. The difference in the rotation angles can be seen in a and b, where Figure 18a is used on the southern façade, and 18b is used on the northern façade. Figure 19a shows the structure of this device on the façade. Figure 19b shows the material of the unit and the structure of the unit.

2.4.5. Advantages and Limitations of Rhino/Grasshopper 3D

During the modeling and simulation period, several limitations of Grasshopper 3D were faced. The main issue was the compatibility of the latest version of Grasshopper 3D Ladybug launcher and OpenStudio (the energy calculation interface software).

When the script was written in the latest Ladybug version, it was to be run by the compatible OpenStudio 3.4 version. This phase camera had a pinvoke error, and the simulation could not be run. When this issue was addressed to the Ladybug discourse website, other users and the software developers suggested using earlier versions of OpenStudio with respect to the Ladybug version. However, there were some issues during the installation process, which were solved in the later phase of the process. Like other existing energy-modeling software, Grasshopper 3D has a limitation when it comes to complicated shading parts in terms of directly running simulations from the geometries created. This issue was addressed through a schedule function of the software by creating an annual percentage function of how much of the shading surface is used annually. The energy simulation script is shown in Figure 20.

3. Results

The results are divided into two main parts according to the main aims of this research.

3.1. The Current House Design versus the New Design

The first evaluation of energy consumption is a comparison between the existing design and the new design. The comparison consists of the base case design, the extended case of the existing house, and the four scenarios of the new design.

After obtaining the simulation results, the energy consumption values of the case scenarios were compared with the validated base case and extension. The one-story parametric villa without a shading device showed a reduction of 27,254.94 KWh or 55.3% annually. The difference was largely due to the confinement of space and design improvements in the newer villa. When a shading device was added to the one-story villa, a further reduction of 2285.32 KWh or 10.4% was observed in the annual energy bills. When this was compared with the existing villa, the difference was 60%.

In terms of the two-story villa, the simulation output was compared with the traditional extension, as stated earlier. When the values were compared, the two-story parametric villa was found to consume 135,553.5 kWh less energy than the traditional extension, which can be estimated at 23%. When the calculation was performed for the two-story villa with a shading device, the difference in energy consumption increased to 17,554.9 kWh or 30% annually (Figure 21).

3.2. Innovative Parametric Facade Implication (Energy and Solar Radiation) in the New Design

The results for the scenarios without and with the shading structure of the new design are as follows (Table 7):

Senario 01:

Parametric one-story villa without shading device: 22,004.95 kWh.

Senario 02:

Parametric one-story villa with parametric shading device: 19,719.63 kWh.

Senario 03:

Two-story parametric villa with extension without shading device: 45,651.10 kWh.

Senario 04:

Two-story parametric villa with extension and parametric shading device: 41,649.7

Additionally, based on a solar radiation analysis of the southern façade of the extended new design, a significant reduction is obtained (

Table 8. Solar radiation results for the new design without and with the shading device.

	21 December (kWh)	21 March (kWh)	21 June (kWh)	21 September (kWh)	Annual Value (kWh)
Building with no shading structure	5462.20	3904.56	6416.76	6040.67	2,192,100
3D Image
Building with shading structure	4039.35	3148.79	5693.29	5069.64	1,825,300
3D Image

). The analysis was conducted on the equinox and solstice days. Annually, the façade with no shading has a solar radiation value of 2,192,100 kWh; the façade with shading has a solar radiation value of 1,825,300 kWh.

Table 7. Energy results for the scenarios without and with the shading structure.

	Area (m2)	Annual Energy Consumption (kWh)	Annual Energy Consumption per Conditioned Area (kWh/m2)	Annual Energy Consumption Normalized by Floor Area Visualization
Parametric 1-floor villa without shading device	624.39	22,004.95	35.24
Parametric 1-floor villa with parametric shading device	624.39	19,719.63	31.58
Parametric villa with extension without shading device	1104.36	45,651.10	41.34
Parametric villa with extension and parametric shading device	1104.36	41,649.7	37.7

Table 7. Energy results for the scenarios without and with the shading structure.

	Area (m2)	Annual Energy Consumption (kWh)	Annual Energy Consumption per Conditioned Area (kWh/m2)	Annual Energy Consumption Normalized by Floor Area Visualization
Parametric 1-floor villa without shading device	624.39	22,004.95	35.24
Parametric 1-floor villa with parametric shading device	624.39	19,719.63	31.58
Parametric villa with extension without shading device	1104.36	45,651.10	41.34
Parametric villa with extension and parametric shading device	1104.36	41,649.7	37.7

4. Discussion

4.1. The Current House Design versus the New Design (Four Scenarios)

The methodology used in this study is based on a linear approach in which every scenario is added based on the social development of a local family. The primary objective of this study was to critically evaluate a newly designed parametric villa in comparison to an existing, validated Emirati house in Al Ain, UAE, considering possible social scenarios linked to the expansion of the unit. Based on the results described above, all of the analytical steps lead to the need for a well-studied design from the early stages considering the social environment of the country, which, in our case, is the local culture of the UAE. The analysis considers various design scenarios, encompassing both energy consumption metrics and the nuances of local social environments.

Table 9. Difference ratio between each scenario and the base case.

Scenario	Difference Ratio between Each Scenario and the Base Case in Annual Energy Consumption
01 Parametric 1-floor villa without shading device	55.3%
02 Parametric 1-floor villa with parametric shading device	60%
03 Parametric villa with extension without shading device	23%
04 Parametric villa with extension and parametric shading device	30%

shows the difference ratio between each scenario and the base case.

Figure 22 displays the difference between the annual energy consumption per conditioned area (kWh/m²) for the four scenarios. In Scenario 01 (parametric one-story villa without shading device), the annual energy consumption is 35 kWh/m². In Scenario 02 (parametric one-story villa with parametric shading device), the annual energy consumption is 31 kWh/m². In Scenario 03 (two-story parametric villa with extension without shading device), the annual energy consumption is 41 kWh/m². In Scenario 04 (two-story parametric villa with extension and parametric shading device), the annual energy consumption is 37.5 kWh/m².

The simulation results shed light on some significant observations. In the one-story parametric villa without shading, there was a considerable reduction in energy consumption of 55.3% annually compared to the base case. This substantial reduction could be attributed to more efficient design features inherent in the parametric design and the confined space of the newer villa. While this number on its own is significant, it becomes more impactful when the addition of a parametric shading device leads to a further 10.4% decrease in energy consumption. This indicates the considerable impact of utilizing shading devices in architectural design, especially in areas such as Al Ain, where solar insolation can be intense. On the other hand, when examining two-story parametric villas, a clear trend emerges that underscores the efficiency of the new design, but with some caveats. The two-story parametric villa without shading consumed 23% less energy than the traditional extension. With the incorporation of a shading device, this difference surged to 30%. However, the sheer numbers in energy consumption for the two-story variant, especially when compared to the one-story variant, underscore the fact that while a parametric design can lead to efficiencies, the size and volume of a structure play a non-trivial role in its overall energy consumption.

4.2. Innovative Parametric Façade Implication in the New Design

The second aim of this study was to analyze the application of innovative parametric façades for low-rise villas in the city of Al Ain. Based on a local survey of design patterns of mashrabiyas, a parametric shading structure was designed and modeled. The modeling of the new design with and without this structure showed reductions in energy consumption and solar radiation. If the four scenarios are compared to each other, then the reduction in energy consumption between Scenario 01 (parametric one-floor villa without shading device) and Scenario 02 (parametric one-floor villa with parametric shading device) is 4.7%; the difference between Scenarios 03 (parametric villa with extension without shading device) and 04 (parametric villa with extension and parametric shading device) is 7%.

Table 10. Solar radiation difference in %.

	21 December	21 March	21 June	21 September	Annual Value
Value of solar radiation in %	26	19	11	16	17

shows the reduction in % in solar radiation between the new design with no shading device and the one with the shading device. Based on the results, the reduction is 26% on 21 December; 19% on 21 March; 11% on 21 June; and 16% on 21 September. The annual difference is 17%.

4.3. Customized Solution for a Regional Application

This study developed a new design based on social value analysis. Additionally, a new parametric shading structure was developed based on a mashrabiya pattern found in Al Ain. This is a customized design for the specific city analyzed and applies to the climate of the city. However, the methodology followed in this study for low-rise residential units can be applied in other cities in the region. The Middle East climate has excessive solar radiation; therefore, advanced shading structures based on local design patterns can be developed for sustainable design. Each scenario refers to a design before and after implementing the shading structure. The findings suggest that the shading structure is beneficial for low-rise buildings. This research can be applied in various cities within the same country, such as Abu Dhabi, Sharjah, and Fujairah. Furthermore, other cities in the Gulf countries with similar social values can adopt such an approach. From the academic perspective, this study teaches students about the value of a sustainable design considering local social parameters (besides geolocation and building materials).

Future studies might need to delve deeper into how residents interact with these spaces, with new areas distributed with elements of nature in indoor areas. The impact on indoor thermal comfort can be further analyzed. Additionally, future research can explore whether the impact of the design complements or challenges local architectural norms and whether the energy savings translate to an improved quality of life or any other social benefits.

5. Conclusions

5.1. The Current House Design versus the New Design (Four Scenarios)

This study addresses the need to include social influence in the early stages of the design of low-rise buildings. In cities like Al Ain and Abu Dhabi, the parents’ original house plan is expanded as the family grows, but this is not considered in advance in the design. In order to achieve a sustainable house design, this study aimed to show, through different scenarios, that considering the social impact of society in the Middle East, specifically in Al Ain, can reduce energy consumption. Figure 23 shows the interesting new design created by considering social norms in the early stages of conceptual development. The building shape has a modern architectural language and recalls the waves of the desert. There is an integration of the outdoors with the indoors and the application of natural materials.

5.2. Innovative Parametric Facade Implication in the New Design

Furthermore, adding shading devices proved to reduce energy consumption even more. The current low-rise modern building has an application of excessive glazing, whereas shading devices have minor applications. In cases where such applications exist, there is no optimization/parameterization process such as the one proposed in this study.

Shading devices have been used for centuries in the Middle East; however, the addition of advanced tools, where the same device can be optimized with several parameters, is still new. The current research on shading devices relates mainly to office or academic buildings. The same applies to the current applications of parametric shading devices in the United Arab Emirates, where it relates to office buildings (private and governmental). Therefore, this study is relevant not only for the private sector of housing but also for governmental housing programs. Instead of random shading, where no solar analysis is performed, a parametrically analyzed shading device can be applied based on a selected pattern. As the city of Al Ain expands its population, the need for low-rise houses will increase (following the current trend). The application of an efficient shading design considering the orientation of the building, the sun movement, the dimensions of the windows, and the materials applied will bring about considerable energy savings, aligning with the government directives of sustainable standards for building design, such as Estidama. Figure 24 shows an innovative application of a parametric shading structure (south elevation) on a low-rise residential unit.

5.3. Advantages and Challenges

The advantages of applying sustainable design in the early stages are shown. The advantages of using a parametric shading structure inspired by the traditional design include a reduction in energy consumption. Furthermore, it introduces innovation into the design based on the local cultural element of the mashrabiya and amplifies it through the application of advanced tools such as Rhinoceros 7.0 with the Grasshopper 3D plug-in. Three main challenges were identified:

(a)

There was a need to understand the new design pattern (connecting it to the city of Al Ain); therefore, a survey was conducted in order to understand the various patterns applied in the city of Al Ain in low-rise residential units. The final shading pattern is an evolution.

(b)

Applying an advanced tool to the design of the new mashrabiya pattern and then adapting it to a curved façade proved to be time-consuming and challenging. The various attempts, the modeling of surfaces and solids, the calculation of energy consumption, and the calculation of solar radiation were difficult. Additionally, the tool had continuous updates; therefore, the scripts needed regular updates too. In this case, where time was extended due to the data retrieval process, this task was quite challenging.

(c)

Gathering information: the case study was selected based on the information available. However, the time required to collect all of the necessary data was longer than expected, mainly related to the electricity bills for the validation of the current house.

Future work expanding on this study shall include an investigation of indoor thermal comfort before and after the application of such a structure.

Furthermore, in terms of future applications, this study adds specific and relevant value to the Middle East region, where the high amount of solar radiation consumes large amounts of electricity, especially in modern-architecture low-rise villas (referring to the analysis carried out in this study). We hope that this case of Al Ain can serve as a beacon for other cities, not only in the UAE but globally, that are interested in sustainability. In other words, shading seems to be an underutilized, forgotten architectural resource in modern buildings that nevertheless can effectively reduce the carbon footprint of AC cooling.

Finally, beyond the numbers and benefits, this study underscored one essential narrative: that a harmonious co-existence between modernity and tradition is not only possible but also good for the environment. In this endeavor, the marriage of traditional Emirati housing values and futuristic design principles showcases the benefits of both conserving our roots and embracing modernity.