The impact of a kinetic façade on the lighting performance and energy efficiency of a public building: the case of Dubai frame

ABSTRACT

This paper proposes a novel framework for selecting a kinetic system strategy to enhance the performance of the building while preserving its architectural concepts. Dubai Frame, which is one of the most iconic buildings in Dubai, was chosen to act as a case study. A parametric model was developed for adjusting the opening ratios of the panel’s solid parts in the façade geometrics using the Grasshopper plugin in Rhino. Integrated Environmental Solutions (IES) simulation software was used and validated by calibration of the actual monthly electricity bills and real measurement of lux value against the predicted readings. The simulation assessed the total energy savings in terms of electricity and cooling loads and cost savings in terms of the KW per hour of electricity generated. In addition, it examined daylight illuminance levels for nine scenarios of the proposed kinetic system. The research has revealed several important results that include the finding that the optimal kinetic system results in 20% energy savings and 31% reduction in daylight illuminance levels while taking into account the current situation of the building and its aesthetic values.

Abbreviations: UAE, United Arab Emirates; IEQ, Indoor Environmental Quality; PCM, Phase change materials; ASHRAE, The American Society of Heating, Refrigerating and Air-Conditioning Engineers; LEED, Leadership in Energy and Environmental Design system; HVAC, Heating, ventilation and air conditioning; RH, Relative Humidity; WWR, Window Wall Ratio; LR, Literature Review; RSMF, Room Surface maintenance factor; LMF, Luminaire maintenance factor; VAT, Value added tax; IHG, Internal Heat Gains

KEYWORDS:

• Kinetic façade
• lighting performance
• dubai
• illuminance
• grasshopper
• parametric design

1. Introduction

The world is facing a dual challenge of the fast growth in global energy demand, on the one hand, and the urgent need to decrease the carbon emissions associated with energy use, on the other hand (BP 2019). According to The International Energy Agency, based on the current energy consumption trend, 25% more energy will be required by 2040, which will result in a 10% increase of CO₂ emissions (IEA 2019). Currently, one third of the total global energy is consumed by the building sector. In the UAE, the building sector consumes even more energy and accounts for almost 70% of total energy consumption (Karlsson, Decker, and Moussalli 2015). This can be traced to the challenging weather conditions and the extensive use of high energy consuming applications such as heating, ventilation and air-conditioning (HVAC) systems and lighting to maintain thermal and visual comfort for buildings’ occupants (MOEI 2019).

As the largest consumers of electricity, the building and construction sectors have the greatest potential for saving energy and reducing carbon emissions in the built environment. Bearing in mind that a building’s envelope acts as a protective layer, the need for HVAC systems to maintain certain microclimates depends on the capability of the building envelope to counteract the external environment’s influence (Elzeyadi 2017). Consequently, a building’s envelope plays an important role in enhancing the performance of the building. For instance, a study stated that 80% of enhancement strategies are related to the building envelope. Moreover, a building’s envelope has become an essential resource of innovative research where adaptive systems have been introduced to optimise the performance of buildings (BenBacha and Bourbia 2016).

Adaptive systems allow the building envelope to be considered as a climatic moderator that has the ability to benefit from outdoor conditions by accepting or discarding the energy gained from the external environment, which results in reducing the artificial indoor energy required (BenBacha and Bourbia 2016). Previous studies have evaluated adaptive building façades by considering energy performance as the main interest. An interesting review paper suggests that the use of a kinetic façade could produce a 30% reduction in energy consumption for cooling and heating in comparison to a building with no shading system (Alotaibi 2015). Another interesting study stated that the reduction of a building’s operational cost due to the use of kinetic strategies would range from 10% to 40% (Marysse 2015).

This paper recognises the direct relationship between adopting kinetic systems that respond to the outer environment and enhancing the energy performance of the building. Moreover, it presents the main parameters of kinetic design principles that enable architects to create efficient, applicable and creative adaptive systems. To this end, the paper has been led by the goal of developing design and evaluation techniques for a kinetic façade through the use of a digital simulation tool. In addition, it investigated the energy performance of a kinetic façade on an existing building with fixed shading through the implementation of kinetic design strategies. The proposed kinetic strategies include an energy performance-based design strategy, a thermal performance-based design strategy and an aesthetic performance-based design strategy.

2. Literature review

2.1. Kinetic façades: an overview

The concept of a kinetic and responsive façade has been described in many terminologies in the literature. Professor William Zuk, in his book Kinetic Architecture in 1970, described the term kinetic as a division of architecture in which the building components or the building as a whole has the ability to adapt to climatic variables through kinetic movements that can be incremental, adjustable, deformable and changeable through mobile modes (Nashaat et al. 2018). While a façade is defined as a building envelope that is used as a boundary to define indoor and outdoor spaces (Purnam and Sutanto 2018). A kinetic façade is one that is able to respond to changes of the environmental conditions or to react to solar movement and solar radiation intensity based on the functionality and the performance of the building (Sharaidin 2014). The response is either by typological changes of the building’s form or by the transformation of materials’ properties to enable the building to regulate its energy demand (Nady 2017).

Earlier studies suggest that kinetic shading enhances building performance by contributing to a significant reduction in energy consumption in terms of lowering heating and cooling loads, reducing the energy used for lighting, or by providing better daylight and quality of view (BenBacha and Bourbia 2016; El-Zanfaly 2011; Purnam and Sutanto 2018). The results of these studies were varied according to the kinetic strategies that were investigated, the climatic zone, the building type and the reference of the comparison (building with no shading or static façade). Compared to a building with no shading, it is stated that the energy saved by using a kinetic façade could reach up to 43% whereas the reduction in indoor air temperature could range from 4.0 C° to 4.8 C° (Sharaidin and Salim 2006). In terms of cooling and heating applications, a kinetic façade could produce a reduction in energy consumption of 30% (Alotaibi 2015). A study in Athens showed that the cooling loads of a south facing office would be reduced by 9.8% (Purnam and Sutanto 2018). Another study conducted on an office building in Denmark managed to lower the total energy consumption of the building from 50 kwh/m² to 25 kwh/m² while using smart control systems by reducing the transmission heat losses, increasing daylight utilisation and time for natural ventilation, controlling solar gain and controlling the miscellaneous energy (Johnsen and Winther 2015). The implementation of hybrid double façades contributed to 23% energy savings (Wagdy et al. 2015), while a kinetic aluminium window frame led to 18% to 20% energy savings (Ahmed et al. 2016). Assessment of different configurations of kinetic louvres resulted in 28% to 30% energy reduction for heating and 28% to 33% for cooling (Hansanuwat 2010).

Several studies have discussed the impact of dynamic shading in comparison to static shading and concluded that kinetic shading has a higher impact on daylight and better quality of view for the lowest energy demand. Static shading would lead to a slight increase in heating loads in cold climates. However, kinetic shading can be adjusted in relation to solar transmittance and improve the energy consumption of the building. In terms of daylight, kinetic shading would enhance the energy used by lighting from 5% to 11%. In a study that used a dimming strategy for both types of shading, kinetic louvres resulted in energy savings from 5% to 14%. The daylight factor can be increased from 2% to 70–150% with kinetic louvres compared to static louvres. Most of the studies have shown a positive energy reduction in both office and commercial buildings. Indoor Environmental Quality (IEQ) can be enhanced in buildings with kinetic shading. Finally, a study showed that kinetic shading in comparison to traditional static façades with the modification of six dynamic properties of the building’s façade – density, materials’ thermal and heat conductivity, surface absorption coefficient, opaque transparent ratio and glazing typology – would allow an improvement of 16% to 18% in building performance levels (BenBacha and Bourbia 2016; El-Zanfaly 2011; Purnam and Sutanto 2018).

2.2 Kinetic shading typologies

An adaptive façade can take many configurations and shapes. It is stated that adaptive systems contain internal and external systems with different types of shutters and blinds which can be converted to innovative systems and kinetic mechanisms (BenBacha and Bourbia 2016). Recent studies have classified kinetic systems according to three different categories: structures, shapes and motion mechanisms (BenBacha and Bourbia 2016; El-Zanfaly 2011; Elzeyadi 2017; Marysse 2015; Nashaat et al. 2018). Kinetic structures were classified by Michael Fox into three typologies. The first is a deployable kinetic structure that would be located in temporary locations and would be applied in pavilions and self-assembly structures where it can be easily transferred. The second typology is an embedded kinetic structure which is fixed in a building or an architectural system in response to environmental or human factors through flexural, torsion, vibration and many other kinetic movements. The third typology is a dynamic kinetic structure, which is dependent and includes multi-modular components such as louvres, partitions, ceilings, walls and doors (Fox and Kemp 2009). Other classifications were proposed by (Asefi and Shoaee 2018; El-Zanfaly 2011; Elzeyadi 2017; Heidari Matin and Eydgahi 2019; Nashaat et al. 2018; Zuk and Clark 1970).

An interesting study has classified shading systems based on the shape of the kinetic system into six typologies: automated blinds, egg crates, optical panels, thermal change planes, stretched fabrics and automated movable screens. In this study, their impact on energy consumption, glare and daylight control have been assessed for an office unit in Climate Zone 4C in the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) standards. The results showed that automated blinds provide 12% savings for artificial lighting and balance between the thermal performance and daylighting. Egg crates provide the best enhancement when placed in east and west orientations and in hot and dry climates and save from 20% to 38.5% energy for commercial buildings, while automated screens result in 2% to 38% energy savings and improve indoor comfort in contemporary buildings. Moreover, they could result in a 30% annual energy reduction (Elzeyadi 2017).

2.3 Kinetic façade materials

Selecting kinetic façade materials is an important phase for developing kinetic systems. It has been highlighted that the objective of recognising kinetic materials is important to characterise the behaviour of kinetic façades and to build multi-functional adaptive modules (Perino and Serra 2015). Therefore, this phase should be a preliminary step during the design process of kinetic systems. An efficient kinetic system can be identified by using flexible materials, maintaining the materials’ robustness, reducing the use of heavy materials and maintaining kinetic structures (Sharaidin 2014). Moreover, kinetic materials can be divided into two categories: active and smart materials. A study stated that active materials would stretch, bend or fold while adjusting the material properties. On the other hand, smart materials would have the same facilities with the ability to adapt their shapes, colour, transparency and stiffness. However, both categories are usually repeatable and reversible and able to exchange energy with no access to external power (López et al. 2015). Table 1 illustrates some examples of active materials that can be used in kinetic façades with their possible functionalities.

Table 1. Kinetic façade active materials and identification of their function (Marysse 2015).

Function	Components
Heat storage	Phase change materials	Thermotropics	Light reactive materials
De-humidification	Humidity reactive materials	Silica gel
Natural ventilation	Carbon dioxide reactive materials
Daylight	Chromics (thermo/photo/electro)	Thermotropics	Vegitation	Liquid crystals/Suspended particles
Overheating control	Chromics (thermo/electro)	Tropics (thermo/photo)	Vegitation	Phase change materials
Vision	Electrochromics	Thermotropics	Vegitation	Liquid crystals
Wind and water	Breathable fabrics		Vegitation
Acoustics	Piezoelectrics

Researchers listed the most-used kinetic materials that are also related to the typologies of shading systems such as gas filled panels, high-insulated materials, non-conventional glazing and coatings with a membrane and with special behaviour like a photocatalytic coating. It should be noted that these materials, among others, show the most capable applications (Perino and Serra 2015). Examples of materials used on real-case kinetic façades include metal lattice, glass and aluminium in the Arab Institute, a PTFE cladding system in the Al Bahar Tower in Abu Dhabi, fibre glass reinforced polymers for the high tensile skin in the Yeosu Thematic Pavilion and stainless steel in the Kiefer Showroom (Alotaibi 2015; Attia et al. 2018). It could be concluded here that indicating the link between a material’s physicality and its kinetic behaviour should be considered during the design process of kinetic movement to avoid any operational and maintenance issues that could be experienced throughout the development of kinetic systems (Sharaidin and Salim 2006).

2.4 Kinetic façade design development

Designing a kinetic façade is considered to be a design process not an artefact. This process includes creating and evaluating different elements of kinetic façades while considering the façade materials, patterns and mechanisms in response to the surrounding conditions. The involvement of kinetic elements within 3D physical components makes designing responsive façades a complex task (Sharaidin 2014). The purpose of adopting a kinetic system was listed as the main key element of kinetic façade characterisation parameters followed by the responsive function, operation, materials and systems components, response time, spatial scale, visibility and the degree of adaptability (Aelenei, Aelenei, and Vieira 2016).

The main parameters and design elements of kinetic façades include, but are not limited to, the building’s orientation, position and materials, shading devices, window type and location, and roof shape (Nady 2017). Therefore, the selection of the façade should be considered to be a major task during the building’s design process. On the other hand, external factors need to be taken into consideration while designing a kinetic façade, such as solar radiation that addresses visual and thermal comfort, outdoor temperature and humidity, wind and precipitation including natural ventilation and the outdoor noise around the building (Aelenei, Aelenei, and Vieira 2016; Johnsen and Winther 2015). An analysis conducted on 130 buildings to measure the global distribution of external factors found that solar radiation and temperature accounted for the greatest external factors that affected the design of the buildings with 82% for solar radiation and 76% for temperature (Aelenei, Aelenei, and Vieira 2016). A successful process of designing a kinetic façade utilises suitable strategies of design, evaluation and implementation.

2.5 Design strategies

Recent studies have highlighted many strategies for designing kinetic façades that could be placed under one of four categories: energy performance-based design, daylight control-based design, thermal control-based design and aesthetics-based design. Energy performance-based design is the main interest for designers and architects when conducting an effective design of kinetic façades. Current approaches use digital tools and generative principles to provide digital models that have the ability to manipulate geometric properties on the basis of performance analysis. In the literature, designers have established their own design strategies while designing kinetic façades due to the need to generate new design approaches to produce better design applications that achieve the required building performance (Sharaidin and Salim 2006).

Daylight control-based design is appropriate for all design conditions. Using this design strategy, a kinetic façade can be linked to daylight simulation tools where plugins can be connected to perform daylight analysis according to daylight standards such as Leadership in Energy and Environmental Design (LEED) on an existing architectural model. Those parameters can be connected to the rotation, size and opening of kinetic geometrics to determine the optimum configuration that suit the space (Elghazi et al. 2014). The design of the Arab Institute in Paris is a good example of daylight control where circular shutters operate as camera lenses that control the penetration of solar radiation by widening and shrinking using sensors and actuators that respond to daylight (Nady 2017). Managing heat fluxes and minimising transmission losses is the aim of thermal control-based design. The sun’s radiation can be adapted using devices developed to result in efficient designs, whereas protecting and filtering layers, sun breakers, louvres and any other kinetic shading can be designed to control solar radiation while maintaining the visual contact with the exterior (Jekot 2008). Designing kinetic façades to achieve thermal comfort and the required daylight levels can be integrated together, whether they are controlled by the users or a computer, or even based on a natural reaction, as it is important to consider the heat gain and the light admitted to the building to respond to solar radiation (BenBacha and Bourbia 2016).

Designing kinetic façades for their aesthetic value was explored by architects and designers who took their inspiration from geometric shapes, origami and nature (Elghazi et al. 2014). In addition, aesthetic values can be implemented using adaptive decorative structures, such as a pantographic, which looks like scissors. Modules can be transferred to different configurations and patterns to create 2D and 3D geometries in the design of the system (Asefi and Shoaee 2018). It should be noted that designing kinetic façades for their aesthetic value should be integrated with building performance approaches. Furthermore, designing for easier maintenance and using materials with a long life span that can be easily cleaned and repaired should be considered in order not to outdate the aesthetic life span of the building and minimise the operational consumption of the building (Kronenburg, Lim, and YunnChii 2003).

2.6 Evaluation strategies

Evaluating kinetic façades can be achieved in respect of environmental conditions. Hence, evaluating physical prototypes provides significant understanding of kinetic systems to ensure the effectiveness of kinetic façades in adapting to respond to local climate conditions. On the other hand, simulation techniques are more practical to understand kinetic systems’ performance in the early design phases and throughout the year, especially for solar and daylight conditions, where it is difficult to be measure performance using physical prototypes (Sharaidin and Salim 2006). Dynamic façade assessment and evaluation can be achieved through parametric and simulation tools, the performance of small-scale prototypes and on-site actual measurements (Sharaidin and Salim 2006).

2.7 Implementation strategies

The key elements for the successful implementation of kinetic façade strategies are a good understanding of adaptive systems, reliability, movement mechanism simulation and durability. Moreover, successful selection of adaptive systems, materials and fabrics requires a good knowledge of kinetic design. In addition, proper evaluation for designing kinetic façades provides a bigger picture of the design difficulties and obstacles that may occur during the operation of the building, such as mechanical and electronic components that need a proper assessment and prediction of their cost and technology (Sharaidin and Salim 2006). On the other hand, the proper implementation of kinetic façade design can be applied through virtual rapid prototyping to assess materials, oriented systems and to identify alternatives. In addition, there should be exploration of control strategies and HVAC system sizing to maximise the performance of the proposed design of the kinetic façade in reference to virtual testing of occupant behaviour and environmental variable parameters (Loonen et al. 2017). Table 2 is a state of arts, presenting the recent literature in the field.

Table 2. Literature review summary and findings.

No.	Literature section	Authors	Title	Findings	Citation
1	a	Alotaibi	The Role of Kinetic Envelopes to Improve Energy Performance in Buildings	Kinetic façade would achieve a reduction of 30% for heating and cooling compared to a building with no shading system.	Alotaibi (2015)
2	a, f	Bacha and Bourbia	Effect of kinetic façades on energy efficiency in office buildings – hot dry climates	The façade consumes 25% of the building’s total energy demand. Designing a kinetic façade to achieve thermal comfort and the required daylight levels can both be integrated, whether it is controlled by the users or a computer or even based on a natural reaction.	BenBacha and Bourbia (2016)
3	a, c	Elzeyadi	The impacts of dynamic façade shading typologies on building energy performance and occupant’s multi-comfort	Shading would achieve 13.75% of energy savings in all climate zones. Shading systems were classified based on the shape of the kinetic system to six typologies: automated blinds, egg crates, optical panels, thermal change planes, stretched fabrics and automated movable screens.	Elzeyadi (2017)
4	a, d	Johnsen and Winther	Dynamic facades, the smart way of meeting the energy requirements	An office building in Denmark managed to achieve a reduction in energy consumption from 50 to 25 kwh/m^2. The study highlighted the external factors that affect kinetic shading: solar radiation, visual and thermal comfort, outdoor factors. The greatest external factors that affect the design of the building were 82% for solar radiation and 76% temperature.	Johnsen and Winther (2015)
5	a, e, f, g, h	Sharaidin and Salim	Design Considerations for Adopting Kinetic Facades in Building Practice	43% of energy savings can be achieved from kinetic shading whereas the reduction in indoor air temperature would range from 4.0 to 4.8 C°. Designing kinetic façades should start with design sketches and be followed by digital simulation that validates and defines the performance and the required measures of the proposed façade in real conditions. After that, a physical model prototype would be required for on-site experiments. The study adopted a working mechanism related to performance of an environmental simulation by using parametric design modelling in relation to daylight levels that included dynamic façade evaluation. The key elements for a kinetic façade’s successful implementation strategy are a good understanding of adaptive systems, reliability, movement mechanism simulation, durability and the proper evaluation of designing kinetic façades.	Sharaidin and Salim (2006)
6	a, f,	Purnama and Sutanto	Dynamic facade module prototype development for solar radiation prevention in high-rise building	Cooling loads of a south facing office in Athens would be reduced by 9.8% compared to a static façade. The study consisted of shadow simulation of static shading through simulation software, then a kinetic façade was developed based on the percentage of the shadowed area as a thermal design strategy.	Purnam and Sutanto (2018)
7	a	Wagdy et al.	The balance between daylighting and thermal performance-based on exploiting the kaleidocycle typology in hot arid climate of Aswan, Egypt	Hybrid double façades contribute to 23% energy savings.	Wagdy et al. (2015)
8	a	Ahmed et al.	The thermal performance of residential building integrated with adaptive kinetic shading system	Kinetic aluminium window frames would result in 18% to 20% of energy savings compared to a building with no shading system.	Ahmed et al. (2016)
9	a	Hansanuwat	Kinetic Facades As Environmental Control Systems: Using Kinetic Facades To Increase Energy Efficiency and Building Performance in Office Buildings	Different configurations of kinetic louvres contributed to 28% to 30% energy reduction for heating and 28% to 33% for cooling.	Hansanuwat (2010)
10	a, i	Marysse	Structural Adaptive Façades	Kinetic strategies would achieve a reduction from 10% to 15% for HVAC systems with a reduction in operational cost for HVAC and artificial lighting from 10 to 40%. Kinetic materials can be divided into two categories: active and smart materials. Both categories are usually repeatable and reversible and able to exchange energy with no access to external power.	Marysse (2015)
11	b	Romano et al.		There are several factors that affect the performance of shading systems: material, natural ventilation, sun control, daylighting, thermal insulation, moisture control, structural efficiency, mobile screens, technological solutions, automation systems and energy generation.
12	d, f	Nady	Dynamic Facades: Environmental Control Systems for Sustainable Design	The study listed building orientation, position and materials, shading devices, windows type and location and roof shapes as the main parameters and design elements affecting kinetic shading. Designing buildings to have energy conscious façades should be incorporated with strength and stability, control of heat, be durable, offer control of air and vapour, fire resistance and be cost effective. The Arab Institute in Paris is a notable example of daylight control where circular shutters operate as camera lenses in response to daylight.	Nady (2017)
13	c	Fox and Kem	Interactive Architecture	Michael Fox classified kinetic structures into three typologies: deployable kinetic structure, embedded kinetic structure and dynamic kinetic structure	Fox and Kemp (2009)
14	c, f	Asefi and Shoaee	Proposing a novel kinetic skin for building facades using scissor-like-element structures	Mazier Asefi classified two types of kinetic structure: transformable tensile structure and transformable bending and compression structures, and the motion of kinetic architecture into swivel, flap, pneumatic, rotate, slide, expand, fold and gather. Adaptive decorative structures such as a pantographic, which looks like scissors, can be adopted as a kinetic system for their aesthetic values.	Asefi and Shoaee (2018)
15	c	Zuk and Clark	Kinetic Architecture	William Zuk divided kinetic architecture in eight classes and called them ‘Kinetiscism’. Four of them are self-erecting structures, static structures, kinetic components and reversible architecture.	Zuk and Clark (1970)
16	c	Nashaat et al.	Kinetic Architecture: Concepts, History and Applications	Kinetic architecture applications were classified into three categories: kinetic structure systems, kinetic interiors and kinetic façades. Kinetic façade behaviour was classified into four main categories: translation, rotation, scaling and motion.	Nashaat et al. (2018)
17	d	Aelenei, Aelenei and Vieira	Adaptive Façade: Concept, Applications, Research Questions	A summary of adaptive systems’ key elements were identified as follows: the purpose, the responsive function, operation, a combination of materials and systems, response time and spatial. The greatest external factors that affect the design of buildings were 82% for solar radiation and 76% temperature.	Aelenei, Aelenei, and Vieira (2016)
18	d, e, f, g, i	Sharaidin	Kinetic Facades: Towards design for Environmental Performance	The study mentioned that design decisions relating to kinetic façades are associated with kinetic mechanisms and components to ensure the effectiveness of the façade operation. The early design decisions should take into consideration the design system, energy performance, movement mechanism, construction methodology, materials and the consultant’s experience. Multi-design strategies were adopted by researchers to achieve the required building performance. Evaluating physical prototypes gives significant understanding of kinetic systems to ensure the effectiveness of kinetic façades. Efficient kinetic systems can be implemented by using flexible materials, maintaining materials’ robustness, reducing the use of heavy materials and maintaining kinetic structures.	Sharaidin (2014)
19	F	Elghazi et al.	Daylighting Driven Design: Optimizing Kaleidocycle Facade for Hot Arid Climate	Kinetic façades can be linked by daylight simulation tools where plugins can be connected to perform daylight analysis and can be connected to the rotation, size and opening of kinetic geometrics. Adjusting kinetic materials is concerned with a material’s light transmittance properties whereby smart elements are able to adjust their optical properties to modulate daylight levels and solar energy. Origami patterns were explored through paper folding techniques based on shape, sequence and the relationship of geometric rules and folding morphology for kinetic façade development.	Elghazi et al. (2014)
20	f	P. Jekot	Selected study of architectural envelopes controlling sun radiation – the integration of nature into design	Sun radiation should be adapted through development of devices to result in efficient designs by use of protecting and filtering layers, sun breakers, louvres and any other kinetic shading.	Jekot (2008)
21	f	Kronenburg, Lim and Chii	Transportable environments 2	Designing for easier maintenance and using materials with a good life span should be considered in order not to outdate the aesthetic life span of the building.	Kronenburg, Lim, and YunnChii (2003)
22	h	Loonen et al.	Review of current status, requirements and opportunities for building performance simulation of adaptive facades†	A proper implementation can be applied through virtual rapid prototyping to assess materials, oriented systems, identifying alternatives and exploring control strategies and HVAC systems.	Loonen et al. (2017)
23	i	Perino and Serra	Switching from static to adaptable and dynamic building envelopes: A paradigm shift for the energy efficiency in buildings	The objective of recognising kinetic materials is important to characterise the behaviour of a kinetic façade and to build multi-functional adaptive modules. The most-used kinetic materials are gas filled panels, PCM, high-insulated materials, non-conventional glazing, coating with membrane and with special behaviour such as photocatalytic coating.	Perino and Serra (2015)

Literature section: (a) The impact of kinetic façades on building performance, (b) Factors affecting shading systems’ performance, (c) Kinetic shading typologies, (d) Key factors to help in designing kinetic façades, (e) Design stages, (f) Design strategies, (g) Evaluation strategies, (h) Implementation strategies, (i) Kinetic façade materials.

3. Methodology

3.1 Research approach

The Dubai Frame was selected as a case study for assessing the impact of kinetic systems when applied to an existing high-rise building. The building consists of a museum, two towers that contain elevators shafts, stairs and service rooms. Figure 1 illustrates the case study site with the nearest landmarks and an image of Dubai Frame that describes its main design elements. The Integrated Design Solutions (IES) was selected as a simulation tool due to its capabilities and flexibilities in providing quick feedback and manipulating the models. The IES was validated by conducting a field measurement to identify the energy consumption of the building, temperature, Relative Humidity (RH) and daylight through lux levels indicators using an environmental metre provided by EXTECH instruments. The base case was encoded using a parametric tool (Grasshopper) to assess the research and obtain the percentage of both closing and opening ratios of the proposed pattern configuration of the kinetic system, through the Window to Wall Ratio (WWR) parameter that was selected in reference to the targeted performance level of the building cooling loads. A number of studies have identified the potential of parametric modelling in generating various distinct forms by modelling different designs that can be connected through mathematical operations and multi-variables and parameters.

Figure 1. Dubai frame location map (Authors).

Figure 2 describes the methodological framework of this research, from data collection to future design recommendations, which was developed to propose an optimal kinetic system for the selected case study. The research started with field measurement and literature review, modelling the case study by using IES Software, the programme went through validation process and then parametric design was applied. The research compare the results against the base case and then drew future recommendations (Figure 3).

Figure 2. Research approach methodological framework (Authors).

Figure 3. Dubai Frame field measurements locations.

3.2 Simulation process

As previously stated, three conditions of the case study were simulated using IES: the base case (existing building), base case abstract (a new proposed design of the façade) and the optimal kinetic design that was proposed based on a cumulative process. Energy consumption and daylight figures were generated for three days of the year for each condition: March 21, June 21 and December 21 each at 8:30am, 12:30pm and 17:30pm. These scenarios were named SIM 1–9, respectively. The selected days covered all seasons, which should be sufficient to give an indication of the building’s performance during the whole year to be compared with the proposed kinetic system’s performance.

The analysis of luminance was conducted by taking an average of three points located on both the east and west side for each scenario of the Viewing Bridge and the Mezzanine Floor as illustrated in Figure 4. The three points were selected based on their value: highest, lowest and a medium. Further simulations were conducted through the design stage to determine the most efficient WWR on each side of the façade to achieve optimal designs. Five WWR were simulated using IES, 30%, 25%, 20%, 15% and 10% for the south and north façades and 15%, 12%, 10% 8% and 6% for the east and west façades. For each WWR, the reduction in the building’s cooling loads were estimated at the selected dates and times previously mentioned. Moreover, base case sun cast measurements were applied using IES VE to determine the solar exposure of each façade.

Figure 4. Total electricity validation and discrepancy percentage.

3.3 IES VE software validation

The validation was conducted by comparing both the building’s energy bills with the results of the base case simulation, and comparing the daylight levels measured through a site experiment with those obtained from the simulation. In this process, the internal heat gains and default electricity lighting figures were input into the IES setting. The field measurements of daylight levels (lux levels) were conducted using an environmental metre provided by EXTECH instruments which calculates the daylight level and more, on 9 February 2019 for three timings: 12, 3 and 6 PM. Moreover, base case construction materials were used in modelling the building to comply with existing case study conditions and sky model was identified as CIE overcast sky. The ApacheSim application was used to obtain cooling and electricity consumption levels to be compared with actual energy bills, and real climate conditions were applied using the AP-Locate built-in application. Table 3 below indicates the materials assigned for external walls, roof and external windows that were used to validate the IES VE model. Moreover, the materials’ specifications, thickness and thermal conductivity achieved the same U-value of the building’s envelope in reference to the drawings submitted for construction.

Table 3. Base case construction materials.

		Total thickness (mm)		Total U-value (W/m^2 K)		Construction layers (outside to inside)	Thickness (mm)		Thermal conductivity (W/m.K)
External walls		420		0.49		Copper	5		200
						Cavity	45		–
						Expanded polystyrene	50		0.035
						Reinforced Concrete	300		2.3
						Plaster (light weight)	20		0.16
Roof		450		0.30		Copper	5		200
						Cavity	45		–
						Expanded polystyrene	100		0.035
						Membrane	0.1		1
						Reinforced Concrete	300		2.3
	Total Thickness (mm)		Total U-value (W/m2 K)	Construction layers (outside to inside)	Thickness (mm)	Thermal conductivity (W/m.K)	Transmittance	Outside Reflectance	Inside Reflectance
External windows	42		1.6	Outer pane	6	1.06	0.409	0.289	0.414
				Cavity	12	–
				Inner pane	6	1.06	0.783	0.072	0.072
				Cavity	12	–
				Inner Pane	6	1.06	0.783	0.072	0.072

In terms of internal heat gains (IHG), the building has two elevators and one escalator. Therefore, based on the data obtained from the ANSI/ASHRAE/IES Standard 90.1-2016, Performance Rating Method Reference Manual, elevators and escalator account for 3% to 5% of the total electricity usage in the building (Pacific NorthWest National Laboratory, 2017). Furthermore, the building has approximately 26 screens with an average approximate dimension of 2 × 1 M, which contribute 80 w of heat gains according to ASHRAE calculations for screens and monitors. Finally, as the building is considered to be a tourist landmark in Dubai, user profile details for visitors were collated from the operations team who mentioned that the visitor’s tours start from 09:00am to 09:00pm and usually Dubai Frame accept 5,000 visitors at weekends (Saturday and Friday) and 3,000 visitors on Thursdays. However, on normal days the number of visitors ranges from 500 to 1,000 people. It should also be noted that the staff of the operation team range in number from 7 to 15, which varies based on the load required for staffing. Furthermore, it should be noted that the existing HVAC system operates for 24 h a day (Operation Team 2019).

Similarly, electric lighting has been inserted in the default settings of IES VE; illuminance levels were logged as 500 lux whereas the limiting glare index was 19. Working surface height was indicated as 0.85 m and mounted on 2.7, whereas both Luminaire Maintenance Factor (LMF) and Room Surface Maintenance Factor (RSMF) were put as 0.9. Figure 5 shows a comparison between the actual energy bills and the results obtained from the base case simulation through IES VE. The discrepancy between actual and simulated data ranges between 2.9% to 6.5% with an average of 4.7%. Figure 6 shows the discrepancy between data obtained on-site and an average of three points indicated in the luminance images on each side of the building. The discrepancy percentage between the IES VE result and the data obtained in the field measurements for luminance levels ranges from 0.79% to 6.64% with an average discrepancy of 2% as shown in Figure 6, which validated the use of IES VE software for daylight simulation (Table 4, Table 5).

Figure 5. Total daylight validation measures.

Figure 6. Total electricity as a result of adjusting the facade WWR.

Table 4. Mezzanine Floor and Viewing Bridge luminance and radiance contour images.

Table 5. Viewing Bridge luminance and radiance contour images at 12:00 PM.

3.4 Kinetic system design development

The development of the design for the proposed façade went through five stages: selecting a kinetic system, selecting a kinetic typology, selecting kinetic mechanisms, selecting a kinetic strategy and selecting kinetic scenarios. It was conducted through a cumulative process that combined all factors related to the proposed kinetic system strategies in order to generate an optimal design of the proposed kinetic behaviour.

The first stage of developing the kinetic façade of the Dubai Frame building started by selecting the appropriate kinetic system for the building. Therefore, five parameters were taken into consideration. First, the façade shape and pattern. This was inspired by an important factor, which is the shape of a ring collected from an archaeological site in Dubai. Next, the movement that can be applied to this pattern, which relates to the typology of geometric shapes. The next step was to select a kinetic system that could be realistically applied on the building and, moreover, that could achieve the targeted energy reduction levels of kinetic systems, as indicated in the literature review. Finally, the design had to respect the functionality and the concept of the building, which is positioned overlooking the new Dubai from one side and the old city from the other side.

In the second stage, and in reference to the proposed kinetic system, a study was made of how to propose a kinetic movement for this system. Based on the literature, the typology that could be selected fell under the automated movable screens, 3D geometric screens typology. The Dubai Frame façade pattern is a combination of a repetitive unit mirrored and rotated to create the configuration described below, which is inspired by the Expo logo and placed in a solid steel gold frame on both the north and south façades. However, on the east and west façades the pattern is only displayed in front of the solid part and glazed windows are placed in its rectangular shape. To convert the existing fixed shading system to a kinetic system, an abstract was made to the façade to result in more identifiable ornamental design components based on mathematics and geometrics to create a variety of geometrical structures. In order to achieve this aim, inspiration for the design was taken from the Arab Institute in Paris. The design abstract was proposed to achieve the aims of the kinetic system and to keep the same look and feel of the building by respecting the concept of the existing design of the façade but adopting the proposed kinetic behaviour. Therefore, the current organic shapes were abstracted to geometric shapes, with each shape opening and closing based on a kinetic movement.

In the third stage, selecting kinetic movement, the classification of the proposed kinetic movement fell under material deformation and scaling. The researcher proposed two types of material deformation: (i) circles transferred to Islamic ornament, and (ii) circles transferred to an octagonal shape that would take the shape of a star while closing. On the other hand, scaling was proposed to both circles and squares. Table 6, Table 7 and Table 8 describe the exact location of the proposed kinetic behaviour, with a description of the behaviour of the kinetic movement of the proposed geometrics.

Table 6. Dubai frame elevations and the proposed façade.

Table 7. Proposed kinetic movement/south and north façade.

Table 8. Proposed kinetic movement/east and west façade (Authors).

In the fourth stage, the kinetic strategies that were expected to affect the proposed kinetic system were implemented to achieve the targeted performance in terms of energy, thermal and aesthetic values. The first strategy, which is an energy performance-based design, was achieved through WWR analysis in addition to parametric design. This allowed the researcher to obtain different kinetic scenarios with an indication of their energy savings. The second strategy was thermal-based design, whereby sun cast analysis was investigated for the proposed kinetic scenarios to determine the most effective ratios in terms of sun exposure. The third strategy was aesthetic performance-based design, where the proposed kinetic scenario was adjusted based on the functionality of the building.

In this paper, the impact of WWR on electricity and cooling loads was determined using IES VE software as shown in figures. The existing WWR of the south and north façades base case WWR equal 40% and the east and west façades WWR equal 22%. On the other hand, in the base case abstract, the south and north façades base case WWR equal 30% and the east and west façades WWR equal 15%. After calculating both base case and base case abstract WWR, a reduction of 5% in south/north WWR and 2% in east/west WWR was investigated through IES VE software to calculate the reduction in the building cooling loads. The proposed WWR showed an average of 12% reduction in cooling loads in the base case abstract for the selected dates and timings. This would reach up to a 21% reduction when the WWR is 10%, when these indicators were investigated in IES VE if the WWR was adjusted on the south façade only. While the cooling loads of the north façade along with the same proposed WWR of the south façade, which ranges from 25% to 10%, showed an average of 1% reduction in cooling loads in the base case abstract for the selected dates and timings, and would reach up to 11% reduction when the WWR is 10%. Similarly, the cooling loads of the east façade when WWR is reduced by 2%, ranging from 15% to 6%, showed an average reduction range from 2% when WWR is 15% up to 4% when WWR is 10%. This average was calculated for each ratio, selected dates and timings’ cooling loads. While, the cooling loads of the west façade when WWR is reduced by 2%, ranging from 15% to 6%, showed an average reduction range from 2% when WWR is 15% up to 4% when WWR is 10%, which is similar to the east façade reduction percentages.

To design the kinetic movement based on these results, a parametric model was created to identify the behaviour of the façade based on these ratios using the Grasshopper environment that runs within the Rhino 3D application. The parametric model evaluated, in the moment, the ratio between the void area and the total area (WWR). This allowed the researcher to capture the exact façade configuration in various movement scenarios. The script of the developed parametric model consisted of three groups of components: (i) void area component, (ii) façade total area component and (iii) components to evaluate and measure the ratio between the façade and the void total area (WWR). To control the different types of movement mechanisms, all were connected to a factor that ranged from 0 to 1; where 0 represents the least value of void area and 1 represents the highest value of void area that both could reach from the movement of the solid plates in each mechanism. Figure 7 shows the complete script of the parametric model in Grasshopper (Figure 8, Figure 9, Figure 10).

Figure 7. Adjustments to glazing area through IES VE to identify the reduction in total electricity.

Figure 8. The complete script of the parametric model in Grasshopper.

Figure 9. Void area parametric model script.

Figure 10. Circular shading to star configuration movement mechanism.

After generating a parametric model that represented the kinetic behaviour of the building in reference to the selected WWR, a study of the sun exposure of the building was generated through IES VE. The sun cast images of the case study were generated for the same proposed dates and timings of the previously discussed WWR analysis, which are 21 December, 21 June and 21 March, each scenario at 8:30 AM, 12:30 PM and 17:30 PM to indicate the areas that would require more shading and less WWR. Based on the result, lower WWR should be allocated to the areas that have higher sun exposure on each façade and some façades would have a combination of two WWR when there is partial sun exposure on some of its area, as shown in Table 9.

Table 9. An example for the sun exposure analysis of the south façade to be used for WWR selection.

To achieve aesthetic performance-based design, the functionality of the building was taken into consideration for the areas that would close and open in reference to the proposed WWR. These areas were identified in reference to the human scale of the building’s visitors especially for the Viewing Bridge. For example, the WWR of the geometrics located at the human scale height for the Bridge and the Mezzanine would need to remain open to allow users to enjoy the view and the purpose of the building to achieve the required aesthetic values.

To select the kinetic scenarios of each façade, a cumulative process was implemented to describe the impact of each strategy on its kinetic movement that was represented in different WWRs. The process identified how each façade WWR would be adjusted to reach to an optimal design (optimal WWR) that fulfilled the required levels of energy, thermal and aesthetic values. The targeted energy reduction was used as a set point for selecting each façade WWR in reference to the resultant energy saving indicated in the literature, which ranged from 20 to 50% (Table 10).

Table 10. Dubai Frame Viewing Bridge and Mezzanine exhibition stands.

The average targeted energy saving of the proposed kinetic behaviour when the kinetic system was proposed based on the first strategy – energy performance-based design – would reach up to 31%. Next, each scenario WWR was adjusted based on the sun cast images obtained that represent the sun exposure of the proposed scenarios to achieve the required daylight levels based on the thermal performance-based design strategy. The proposed WWR was reduced by 5% in the areas that had higher exposure on the south and north façades. However, on the east and west façade it was reduced by 2%. The last process implemented to achieve the optimal kinetic behaviour of the selected case study was the aesthetic performance-based design strategy. The areas of the geometrics that needed to remain open was calculated in AutoCAD to be added to the void area used to obtain both the north and south façades WWR. The functionality of the building was one of the main parameters used during this process to prove to the designer that kinetic systems can also be adapted to the building architecture. Table 11 highlights the proposed WWR that was adjusted based on the aesthetic performance-based design strategy to result in an optimal WWR that describes the kinetic behaviour of each scenario.

Table 11. Optimal WWR as a result of the aesthetic performance-based design strategy (Authors).

Kinetic scenario/Simulation	Optimal WWR
	South façade	North façade	East façade	West façade
SIM01	16%	12%	6%	8%
SIM02	26%	17%	8%	12%
SIM03	12%	22%	10%	6%
SIM04	26%	12%	6%	8%
SIM05	29%	17%	8%	10%
SIM06	12%	12%	10%	6%
SIM07	12%	26%	6%	12%
SIM08	17%	17%	10%	10%
SIM09	12%	12%	12%	6%

At the end of this stage, each scenario WWR was adjusted in AutoCAD and collated in respect to the optimal WWR to enable the researcher to investigate the performance levels in terms of energy consumption and daylight levels through IES VE software, in real life conditions, as a result of all the strategies and the kinetic mechanisms conducted in the process of developing the proposed kinetic system.

4. Results and discussion

4.1 Energy consumption results

The comparison between the base case, abstract and the proposed kinetic system for each scenario – SIM 1 to SIM 9 – in terms of electricity and cooling loads is presented in Figure 11. The highest electricity load savings were achieved in SIM 8 with 27.02%. However, the lowest electricity loads saving is shown clearly in SIM 7 with 11.4%.

Figure 11. Shading with a shape of circles and polygons based on its own centroid.

After comparing the result of each scenario, an investigation of the average performance of the proposed kinetic system was conducted between the time period 8:30 AM to 17:30 PM to test the performance of the proposed kinetic system’s behaviour during the day. The process of conducting this analysis was to measure the energy performance levels of each scenario from SIM 1 to 9 from 8:30 AM to 17:30 PM in March, June and December. After that, SIM 1, 4 and 7, which were implemented at 8:30 AM, were tested for the period from 8:30 AM to 10:30 AM. Moreover, SIM 2, 5 and 8, which were designed for implementation at 12:30 PM, were applied on the period from 11:30 AM to 13:30 PM. On the other hand, SIM 3, 6 and 9, which were designed for implementation at 17:30 PM, were used for the period from 14:30 PM to 17:30 PM. The average electricity savings of the optimal design from 8:30 AM to 17:30 PM is presented in Figure 12. The highest savings are shown in December in the period from 11:30 AM to 13:30 PM with 32.2%. However, June has the lowest electricity savings with an average of 22.8% in the period from 11:30 AM to 13:30 PM. The average of the total electricity savings equal 27% for March, June and December from 8:30 AM to 17:30 PM (Figure 13).

Figure 12. Total electricity and cooling loads for SIM 1–9.

Figure 13. The average electricity savings of the optimal design from 8:30 AM to 17:30 PM.

Furthermore, annual energy savings were investigated by applying the data provided for each scenario throughout the year. This process was conducted using the data for March to represent the Spring and Autumn months represented by SIM 1, 2 and 3 and the data results for June for the Summer months represented in SIM 4, 5 and 6. The December results were tested for the Winter months and represented by SIM 7, 8 and 9. In order to test the annual performance of the kinetic system, the new design abstract results were used for the period with static movement that ranged from 17:30 PM to 8:30 PM. As a result of calculating the annual performance of the proposed kinetic system, a summary of the total electricity and cooling loads are presented in Table 12.

Table 12. A summary of the annual electricity and cooling loads for the base case, abstract and the optimal design.

Month	Base case		Abstract		Optimal design
	Room cooling (MW)	Total electricity (MW)	Room cooling (MW)	Total electricity (MW)	Room cooling (MW)	Total electricity (MW)
Jan	430.5	240.9	392.9	222.1	351.8	201.5
Feb	418.0	232.1	377.8	212.0	336.3	191.3
Mar	475.6	263.4	432.4	241.8	396.7	224.0
Apr	506.0	277.8	458.3	253.9	420.0	234.8
May	572.8	312.0	515.6	283.4	470.9	261.1
Jun	579.2	314.4	521.5	285.6	475.6	262.6
Jul	618.5	334.9	554.5	302.9	506.1	278.7
Aug	624.4	337.8	559.0	305.1	511.4	281.3
Sep	584.8	317.2	523.1	286.3	480.0	264.8
Oct	564.0	307.6	504.7	278.0	461.6	256.4
Nov	494.9	272.3	445.6	247.6	407.9	228.8
Dec	453.4	252.3	412.6	231.9	370.5	210.8
Total	6322.13	3462.73	5698.02	3150.65	5188.83	2896.07

The annual energy savings of each month presented a total reduction of up to 18% for cooling loads and 16% for total electricity loads. The highest energy savings were indicated in February. However, the lowest reduction in energy savings was identified in March and April, as described in Figure 14.

Figure 14. Base case and optimal design illuminance levels of SIM 1–9/Mezzanine floor and Viewing Bridge.

4.2 Daylight results

Indoor illuminance levels due to daylight were evaluated to measure the effectiveness of the proposed kinetic scenarios SIM 1 to SIM 9 with respect to the base case illuminance levels using the simulation tool IES VE using the RADIANCE plugin in this case. Accordingly, the difference in the illuminance levels was identified in each scenario as an average of the daylight distribution on the east and west side for the Mezzanine Floor and the Viewing Bridge in the selected case study. Tables in Appendix A1 show a comparison between the base case and the optimal design for the Mezzanine Floor and the Viewing Bridge illuminance and Radiance contour levels of SIM 1–9. Moreover, average of illuminance lux levels is indicated. Illuminance plans highlight the areas that have a daylight illuminance above 500 lux in light green. However, the radiance contour images show the glare that is caused by the reflection of sunlight with a threshold of 500 lux.

To summarise the impact of the proposed kinetic system on the selected case study daylight measures, Figure 14 shows the areas of the base case that have undesired daylight illuminance levels in comparison to the optimal design in the Mezzanine Floor and the Viewing Bridge. In the Mezzanine Floor, most of the proposed scenarios achieve a luminance level that ranges from 100 to 500 lux; that is considered to be effective based on daylight standards. However, in SIM 2 and SIM 5, illuminance levels are 824 and 1544.6 lux due to the south façade WWR, which resulted from the targeted overall energy savings of these scenarios. Nevertheless, the proposed kinetic behaviour managed to convert the space from uncomfortable in terms of visual and thermal aspects to a desirable and tolerable space based on daylight standards.

In the Viewing Bridge, a significant impact was found in the reduction of sun glare areas in both illuminance and radiance contour plans. However, in terms of illuminance levels, most of the scenarios kept the same range of lux levels, from 500 to 2000 lux, which is considered to be either desirable or at least tolerable in reference to daylight standards.

On the other hand, SIM 7 reduced the base case illuminance levels from 2098 to 734.2 lux which makes the space desirable instead of uncomfortable in terms of thermal and visual aspects. Whereas SIM 05 was still in the discomfort zone, but mostly close to the desirable range by reducing the base case illuminance levels from 3090.4–2527.9 lux.

Following the final daylighting results and the calculations presented in Figure 14, a total reduction of illuminance levels was achieved at 31%, as a result of proposing the kinetic system in the optimal design from SIM 1–9.

4.3 Linking the research results to the published literature

Following the literature review summary and findings, an indication of the enhancement in kinetic façade systems in terms of cooling loads, energy consumption and daylight performance is illustrated in this section and compared with the actual results generated from IES VE software for the proposed kinetic design of the selected case study. Based on the literature cooling loads indicators, the average kinetic façade reduction of heating and cooling could reach 30%, as indicated by Alotaibi (2015). On the other hand, cooling loads were reduced by 9.8% in a south facing office in Athens (Sega Sufia Purnam and Sutanto 2018). Whereas, Elzeyadi (2017) mentioned that shading strategies’ enhancement of cooling and heating would range from 13.3% to 26.9%. In the proposed kinetic system, cooling loads were enhanced by 31% when based on the energy performance-based design strategy. However, after the cumulative process to adjust the WWR based on sun exposure and aesthetic values, the optimal design reduced cooling loads by 18%. In addition, Wagdy et al. (2015) mentioned that a hybrid double façade contributes to 23% energy savings. However, Ahmed et al. (2016) stated that kinetic aluminium window frames would result in 18–20% energy savings. Sharaidin and Salim (2006) added that 43% of energy savings can be achieved from kinetic shading.

In the proposed kinetic system for the selected case study, an energy saving of 23% was achieved in SIM 1 to SIM 9. On the other hand, the annual reduction of energy savings was equal to 16% with 68037$ cost savings. Nevertheless, the proposed kinetic system results in a significant drop in daylight illuminance levels equal to 31% and reduction of the area of sun glare in both the Mezzanine Floor and the Viewing Bridge of the selected case study. However, the impact of the kinetic façade daylight levels is not defined in the literature, as most of the applications used daylight sensors based on the comfort levels of the space to control the rotation, size and opening of kinetic geometrics (Elghazi et al. 2014; Nady 2017).

5. Conclusion

5.1 Summary of the research

This paper set out to develop a kinetic system strategy selection framework focusing on environmental sustainability criteria and architectural aspects for an existing public building in Dubai – Dubai Frame. The main methodologies that were used to implement the kinetic façade strategies to investigate the performance of kinetic systems consisted of field experiment measurements, parametric tools using the Grasshopper plugin and simulation tools using IES VE software. In addition, this paper introduced the use of WWR as an energy performance-based design strategy for selecting the kinetic behaviour of the building and proposed a parametric model for adjusting the opening ratios of the panel’s solid parts in the façade geometrics. This was achieved by developing four group of movement mechanisms that evaluated, in the moment, the ratio between the void area and the total area (WWR). This allowed the researcher to capture the exact façade configuration in various movement scenarios. The results of the simulation showed that the proposed kinetic system provided an energy saving of 23% for SIM 1 to SIM 9. However, when the scenarios were implemented for a period of time, such as applying SIM 1 that was tested in March at 8:30 AM for the period from 8:30 to 10:30 AM, average energy savings would reach up to 27% for March, June and December during the period 8:30 AM to 17:30 PM. On the other hand, when the proposed scenarios were applied seasonally and the data of the base case abstract was used for the time period from 17:30 PM to 8:30 AM, an annual reduction of energy savings equal to 16% for electricity loads and 18% for cooling loads with 68037$ cost savings could be achieved.

Ultimately, the proposed kinetic system results in a significant drop in daylight illuminance levels that equals 31% and reduced the area of sun glare in both the Mezzanine Floor and the Viewing Bridge of the selected case study. However, the impact of the WWR were clearly shown in the daylight results of SIM 2, SIM 5 and SIM 7, which have the highest south façade WWR, showing the least reduction in their daylight illuminance levels especially in the Viewing Bridge.

5.2 Future work

Future research should involve evaluating and measuring the operation and the installation of the proposed kinetic system to test the energy loads of the façade embedded in control devices, computers and mechanical systems. Furthermore, the structural load calculation for the kinetic façade needs to be compared with the existing shading system and used to propose fixation strategies for efficient application. On the other hand, the kinetic typologies in the literature previously discussed can be also investigated to identify the optimal performance of these typologies and the parameters that would affect their kinetic behaviour, movement mechanism, energy performance, aesthetic performance and daylight measures.

In addition, further assessment of kinetic systems parameters should be addressed in future studies, such as the geometric depths required for the movement of the proposed kinetic surfaces. This can be tested using laboratory small-scale prototypes. Furthermore, additional studies of applying the proposed design strategies of kinetic systems can be tested on commercial buildings, different scales of buildings or even on an urban level. Moreover, multi-simulation programs can be proposed as simulation tools to accredit and to validate the targeted performance of kinetic systems applied in the research, whether in the UAE climate or even in different climatic zones. Eventually, the time required for installing the kinetic system and a cost analysis of its materials and mechanical devices should be investigated at an early design stage, and on existing buildings, to determine the payback period required for proposing this kind of innovative system.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Appendix A1

In SIM 1, Table A1 shows the area of sun glare that is reduced significantly in the Viewing Bridge optimal design, as illuminance levels are reduced from 1139.13 to 966.88 lux. On the other hand, in Table A2, on the Mezzanine Floor, illuminance levels are reduced from 809.55 to 360.94.

Table A1. SIM 1 – base case vs. optimal design illuminance and radiance contour plans/Viewing Bridge.

Table A2. SIM 1 – base case vs. optimal design illuminance and radiance contour plans/Mezzanine Floor.

In SIM 2, in Table A3, although the area of sun glare in the illuminance plans is reduced, the average illuminance lux levels remain almost the same, as it is reduced from 1577 to 1506 lux on the Viewing Bridge. However, in Table A4, in the Mezzanine Floor, illuminance levels are reduced from 1219 to 824 lux. It should be noted that in this scenario, the proposed WWR on the south façade is 26%, which resulted from the targeted overall energy savings of this scenario.

Table A3. SIM 2 – base case vs. optimal design illuminance and radiance contour plans/Viewing Bridge.

Table A4. SIM 2 – base case vs. optimal design illuminance and radiance contour plans/Mezzanine Floor.

In SIM 3, the highest illuminance levels are shown in the edges of the Viewing Bridge illuminance plans in Table A5. Nevertheless, illuminance levels dropped from 1110.65 lux to 999.63 lux. On the other hand, in the Mezzanine Floor, in Table A6, the area of sun glare in the radiance contour plans reduced significantly from 855.95 lux to 314.22.

Table A5. SIM 3 – base case vs. optimal design illuminance and radiance contour plans/Viewing Bridge.

Table A6. SIM 3 – base case vs. optimal design illuminance and radiance contour plans/Mezzanine Floor.

In SIM 4, average illuminance levels dropped from 1435.55 lux to 1299 lux in the Viewing Bridge, as indicated in Table A7. The reduction in the area of illuminance levels above 500 lux are clearly illustrated in the optimal design illuminance plans. However, Table A8 presents the enhancement in the average illuminance lux levels in the Mezzanine Floor, where it dropped from 1094.49 to 543 lux.

Table A7. SIM 4 – base case vs. optimal design illuminance and radiance contour plans/Viewing Bridge.

Table A8. SIM 4 – base case vs. optimal design illuminance and radiance contour plans/Mezzanine Floor.

In SIM 5, the average illuminance lux levels remain almost the same in the Viewing Bridge as presented in Table A9 where it dropped by approximately 170 lux. However, in Table A10, in the Mezzanine Floor, illuminance levels dropped by approximately 1000 lux. On the other hand, SIM 5 proposed WWR that would achieve among the highest reduction at 29% WWR on the south façade, as a result of the targeted overall energy savings of this scenario.

Table A9. SIM 5 – base case vs. optimal design illuminance and radiance contour plans/Viewing Bridge.

Table A10. SIM 5 – base case vs. optimal design illuminance and radiance contour plans/Mezzanine Floor.

In SIM 6, Table A11 shows a reduction in the area of sun glare in the Viewing Bridge where illuminance levels dropped from 1201.16 to 1072.72 lux. On the other hand, in Table A12 illuminance levels reduced from 906.21 to 371.78 in the Mezzanine Floor.

Table A11. SIM 6 – base case vs. optimal design illuminance and radiance contour plans/Viewing Bridge.

Table A12. SIM 6 – base case vs. optimal design illuminance and radiance contour plans/Mezzanine Floor.

SIM 7 results in a significant reduction in both the area of sun glare and illuminance levels with an average reduction of 1370 lux, as presented in Table A13. Furthermore, in the Mezzanine Floor, illuminance levels dropped from 596.48 to 257.72 lux, as shown in Table A14.

Table A13. SIM 7 – base case vs. optimal design illuminance and radiance contour plans/Viewing Bridge.

Table A14. SIM 7 – base case vs. optimal design illuminance and radiance contour plans/Mezzanine Floor.

In SIM 8, average illuminance levels dropped from 1666.10 lux to 1501.71 lux in the Viewing Bridge, as identified in Table A15. The reduction in the area of illuminance levels above 500 lux are clearly illustrated in the optimal design illuminance plans. However, Table A16 presents the enhancement in the average illuminance lux levels on the Mezzanine Floor, where it dropped from 1301.07 to 676.20 lux.

Table A15. SIM 8 – base case vs. optimal design illuminance and radiance contour plans/Viewing Bridge.

Table A16. SIM 8- Base Case vs. Optimal Design Illuminance and Radiance contour plans/Mezzanine Floor.

The area of sun glare in the Viewing Bridge was reduced, where illuminance levels dropped from 692.30 to 610.27 lux. On the other hand, in Table A17, illuminance levels reduced from 552.48 to 211.70 in the Mezzanine Floor.

Table A17. SIM 9 – base case vs. optimal design illuminance and radiance contour plans/Viewing Bridge.

Table A18. SIM 9 – base case vs. optimal design illuminance and radiance contour plans/Mezzanine Floor.