Dynamic Skin: A Systematic Review of Energy-Saving Design for Building Facades

Abstract

The construction industry is one of the main areas of energy consumption and carbon emissions, and strengthening research on the thermal performance of building facades can effectively promote energy conservation and emission reduction. Compared with traditional static enclosure structures, dynamic skin can adapt its functions, characteristics, and methods based on constantly changing environmental conditions and performance requirements. It has great potential in adapting to the environment, reducing energy consumption, adjusting shading and natural ventilation, and improving human thermal and visual comfort. To comprehensively understand the key technologies of dynamic skin energy-saving design, previous research results were comprehensively compiled from relevant databases. The research results indicate that various types of dynamic skins, intelligent materials, multi-layer facades, dynamic shading, and biomimetic facades are commonly used core technologies for dynamic facades. Parametric modeling, computer simulation, and multi-objective algorithms are commonly used to optimize the performance of dynamic skin. In addition, integrated technology design, interaction design, and lifecycle design should be effective methods for improving dynamic skin energy efficiency, resident satisfaction, and economic benefits. Despite current challenges, dynamic skin energy-saving technology remains one of the most effective solutions for future sustainable building design.

1. Introduction

As a major sector of energy consumption, the construction industry is one of the largest contributors to both direct and indirect carbon emissions. Buildings account for approximately 40% of global energy consumption and over 30% of CO₂ emissions [1]. Heat loss through the building skin—also referred to as the facade, exterior wall, or envelope—is a primary component of heating and cooling energy costs, constituting approximately 30–50% of total thermal energy losses. According to the International Energy Agency (IEA) report Net Zero Emissions by 2050, 50% of existing buildings must achieve net-zero emissions by 2040, and 85% of the built environment must be entirely carbon neutral by 2050. In China, the total carbon emissions from the construction sector account for more than 50% of the national carbon emissions. To achieve the ambitious goal of carbon neutrality by 2060, it is imperative to reduce direct carbon emissions from building operations, primarily stemming from heating, ventilation, and air conditioning (HVAC) systems. Furthermore, data from the China Statistical Yearbook indicate that between 2002 and 2022, approximately 67.5 billion square meters of building floor area were completed in China, with over 80% classified as high-energy-consumption buildings. This suggests a vast potential for energy efficiency retrofitting and technological upgrades in the built environment. A building’s facade functions as a filter between the internal and external environments and serves as the primary enclosure system. In fact, the building facade plays a crucial role in influencing overall energy consumption and carbon footprint. Additionally, by affecting thermal, acoustic, and visual comfort, it has a significant impact on indoor environmental quality and occupant well-being [2]. Energy-saving facade retrofitting not only enhances building quality, extends its lifespan, and increases market value but also represents one of the most effective energy-saving strategies. Compared with demolition and new construction, facade retrofitting has a considerably lower environmental impact [3].

In recent years, domestic and international experts have conducted in-depth research and accumulated extensive experience in energy-saving technologies for building skins. While static facade energy-saving technologies have reached a high level of maturity and have been widely promoted and applied, dynamic facade technologies remain largely confined to theoretical research, with limited practical implementation in real-world projects. Traditional static energy-saving technologies treat the building facade as a “barrier” against environmental loads, relying on high thermal insulation and airtightness to achieve energy efficiency, which often results in a disconnect between the building and its environment. Compared with conventional static facades, dynamic building skins (including “adaptive facade” and “responsive envelope”) consider both weather conditions and user preferences, and can dynamically change facade material properties, exterior form, ventilation status, etc., exhibiting variability, adaptability, and climate-responsive characteristics. The advantages of dynamic facades are particularly evident in temperate regions, where significant daily and seasonal temperature variations occur [4,5,6]. Studies have shown that dynamic facades can reduce energy consumption by up to 50% and carbon dioxide emissions by up to 40% [7,8], while improving visual comfort by approximately 76% and enhancing thermal gain efficiency by approximately 60% [9]. Moreover, dynamic facades help maintain indoor temperatures within a comfortable range by minimizing temperature fluctuations and reducing energy consumption through peak load shifting [10]. Therefore, whether in the retrofitting of existing building facades or the design of new building skins, further exploration of energy-saving dynamic facade designs holds significant practical value.

Although facade technology has evolved from a static barrier to an adaptive component that responds to changing environmental conditions, several challenges remain, including balancing energy efficiency, structural integration, and user comfort [11]. Meanwhile, although the scientific community has extensively studied dynamic facades in terms of energy savings, environmental regulation, and cost-effectiveness, research has often focused on improving the performance of a single technology. Insufficient attention has been given to the compatibility of dynamic facade technologies, variations in spatial requirements, and the complexity of quantifying performance indicators. These limitations have hindered the widespread application of dynamic facades in practical building facade design.

To promote theoretical development, guide practical applications, and keep up with the latest developments, a systematic literature review was conducted on relevant studies from the past eight years using the Web of Science database. The following are the contributions of this review: (1) analyzing the current development status of dynamic facades using bibliometric methods, (2) summarizing the characteristics, performance evaluation methods, and technical principles of dynamic facade technology, and (3) exploring the development prospects and challenges faced in the energy-saving design of dynamic facades.

The main sections of this paper are as follows: Section 1 analyzes the current development status of dynamic skins; Section 2 explores the characteristics and types of dynamic skins; Section 3 describes performance evaluation methods and optimization algorithms for dynamic skins; Section 4 discusses key energy-saving technologies for dynamic facades; Section 5 summarizes the trends in the development of dynamic facades energy-saving technology; Section 6 concludes the study by identifying the shortcomings of current dynamic skins energy-saving design and the challenges of future innovations.

2. Bibliometric Analysis

2.1. Data Sources

The Web of Science (WOS) Core Collection database (https://www.webofscience.com, accessed on 18 July 2025) from Clarivate Analytics was selected as the literature source for a topic-based search on “building dynamic facades,” with search criteria including database selection of Web of Science Core Collection, citation index limitation to Science Citation Index Expanded (SCI-Expanded) from 2018 to the present, search field set to “All fields,” query terms comprising building dynamic facade-related terminology, and document types restricted to Article and Review. This search yielded 427 relevant publications as of 20 April 2025. A review of titles, abstracts, keywords, and main content led to the exclusion of duplicates and publications unrelated or minimally relevant to the research topic, resulting in 90 eligible articles for analysis. The PRISMA diagram used in this study is shown in Figure 1.

2.2. Research Tool

VOSviewer (https://www.vosviewer.com/, accessed on 18 July 2025), a software tool for constructing and visualizing bibliometric networks based on the co-occurrence relationships of knowledge units in scientific literature, was employed for knowledge mapping analysis of research hotspots and trends in “building dynamic facades”. Using VOSviewer version 1.6.20, this study systematically organized and evaluated research outputs in this field through quantitative analysis of annual publications, contributing institutions, authors, and journal distributions, thereby elucidating the overall research trajectory and emerging focal points.

2.3. Analysis of Annual Publication

Analysis of the annual distribution of publications effectively reveals the research history and developmental trajectory of the “building dynamic facades” field. As illustrated in Figure 2, scholarly publications on building dynamic facades have exhibited exponential growth since 2018, increasing from fewer than 10 publications annually to 30 in 2024. Publications from 2024 alone account for 33.3% of the total output, with an average annual publication count of 11. This steady advancement in academic research reflects the combined influence of policy guidance, industrial advancement, and market demands.

2.4. Major Countries and Their Academic Influence

A total of 40 countries/regions contributed publications on “building dynamic facades” between 2018 and 2025. China, the United States, and Italy emerged as the dominant contributors, with China producing the highest output (21 publications, accounting for 23.86% of the total). The United States and Italy ranked second and third, each accounting for 14.77% of publications. Collectively, these three nations represented 53.41% of the total publications.

In the collaboration network analysis, node size corresponds to the publication volume of respective countries/regions, while connecting lines indicate collaborative relationships between entities. Larger nodes denote higher publication counts, and denser connections reflect stronger collaborations. As illustrated in Figure 3, significant cross-regional cooperation exists in building dynamic facade research globally, with distinct geographic clustering: European nations (e.g., The Netherlands, UK, France, Germany) demonstrate strong intra-regional collaboration; Asian countries (China, Singapore, Iran) form a closely linked cluster, likely facilitated by geographic proximity and aligned research priorities. Notably, transnational partnerships (United States–Japan–Vietnam and Australia–Italy–Czech Republic) exhibit robust cooperation despite geographical separation, underscoring a shared scientific understanding of building dynamic facades in pursuit of sustainable building design.

2.5. Institutional Distribution

Analysis of contributing institutions reveals the research capacity and geographical concentration within the building dynamic facades domain. Among publishing institutions, 23 entities produced more than two publications each, collectively accounting for 55.68% of the total publications (

Table 1. Statistics of major scientific research institutions.

No.	Research Institutions	Country	Number	Citations
1	Hunan University	China	4	241
2	Tsinghua University	China	3	102
3	Aalborg University	Denmark	2	15
4	Ajou University	Korea	2	37
5	China Academy of Building Research	China	2	95
6	Delft University of Technology	The Netherlands	2	38
7	Harbin Institute of Technology	China	2	95
8	Hong Kong University of Science and Technology	Hong Kong, China	2	2
9	Huazhong University of Science and Technology	China	2	10
10	Lawrence Berkeley National Laboratory	America	2	110
11	North Carolina State University	America	2	664
12	The Pennsylvania State University	America	2	13
13	Peter the Great St. Petersburg Polytechnic University	Russia	2	21
14	Royal Melbourne Institute of Technology University	Australia	2	59
15	Shenzhen University	China	2	7
16	South China University of Technology	China	2	95
17	Tianjin University	China	2	125
18	University of Liege	Belgium	2	26
19	University of Naples Federico II	Italy	2	59
20	University of Nottingham	Britain	2	72
21	University of Sannio	Italy	2	59
22	Wroclaw University of Science and Technology	Poland	2	1
23	Yanshan University	China	2	52

), establishing them as primary research contributors. These institutions span Asia, North America, and Europe, with China and the United States hosting the highest concentration of active research organizations. This distribution aligns with national publication volume statistics, further confirming the dominant position of China, the United States, and Italy in this research field.

2.6. Analysis of Journal Publications

Analysis of publishing journals elucidates primary research directions in this field (

Table 2. Statistics of major journals.

No.	Journal	Number	Citations
1	Energy and Buildings	10	159
2	Journal of Building Engineering	10	122
3	Building and Environment	8	155
4	Energies	6	107
5	Sustainability	6	30

). Journals publishing over five articles on building dynamic facades collectively contributed 40 publications, accounting for 45.45% of the total. Energy and Buildings emerged as the most prominent journal with 10 publications, followed by the Journal of Building Engineering and Building and Environment, which published significant numbers of articles in this domain. This demonstrates international recognition of the academic standing and influence of building dynamic facade research within authoritative journals, indicating substantial implications for advancing the field.

2.7. Analysis of Research Hotspots

Keyword co-occurrence network analysis constructs a network by counting the frequency of keywords appearing together in publications, where nodes represent keywords and larger node sizes indicate higher keyword frequency and greater influence within the field. A keyword co-occurrence map was generated using VOSviewer (Figure 4), with each color representing a cluster. Four distinct clusters were identified: “#0 Biomimicry”, “#1 Building energy efficienc”, “#2 Adaptive facade”, and “#3 Adaptive building envelop”. This clustering aligns with prior high-frequency keyword and centrality analyses, providing cross-validation. These findings suggest current research primarily focuses on: (1) deep integration of dynamic facades with emerging technologies, (2) optimization methodologies for dynamic facade performance, (3) decision-making and evaluation frameworks for energy-efficient building envelope design, and (4) sustainable architectural solutions for future development.

The keyword co-occurrence timeline analysis conducted using VOSviewer (Figure 5) revealed that keywords emerging in recent years accounted for approximately half of the entire visualization, indicating both growing research interest in emerging dynamic facade technologies and a current research emphasis on the performance optimization of dynamic facades. It cannot be denied that the performance optimization of dynamic facades plays a direct and important role in energy conservation and consumption reduction, as well as improving thermal and visual comfort. However, the authors believe that in addition to this, research on technical feasibility, economy, and adaptability may be more conducive to the promotion and application of dynamic facade technology.

3. Types and Characteristics of Dynamic Skins

Dynamic skins represent an emerging energy-saving facade technology that can be classified into different types based on various criteria (Figure 6). Each type exhibits distinct performance characteristics and mechanisms in building energy-saving design.

3.1. Classification Based on Transparency

(1)

Transparent facades

Modern architecture often incorporates various glass facade designs to enhance aesthetics, allow ample sunlight penetration, and improve indoor vitality while providing cost-effective and safe natural lighting. However, transparent glass facades also have significant implications for building energy consumption, accounting for approximately 39% of heating loads and 28% of cooling loads in buildings [12]. The development of dynamic facade technologies, such as smart glass, multi-layer composite windows, and dynamic shading systems, has led to improvements in daylighting, glare prevention, and expanded outdoor views. These advancements not only enhance occupant comfort but also significantly reduce energy consumption associated with transparent facades, achieving multiple benefits simultaneously [13].

(2)

Translucent facades

Translucent facades in architecture primarily consist of materials such as glass blocks, plastic panels (polycarbonate, acrylic), membrane materials (ETFE film), light-transmitting concrete, photovoltaic panels, and perforated panels. These materials allow light transmission while obscuring direct visibility, thereby ensuring privacy and reducing indoor glare to enhance visual comfort. Additionally, translucent facades effectively express material texture, color, and spatial form, creating a dynamic aesthetic effect influenced by sunlight, moonlight, and artificial lighting. Similar to transparent materials, translucent dynamic facades utilize smart materials, shading systems, ventilation, and heat dissipation strategies, adapting to climatic conditions by dynamically regulating the optical and thermal properties of the building skin. This approach reduces energy consumption while improving indoor comfort.

(3)

Opaque facades

Opaque facades are primarily composed of non-transparent materials such as brick, stone, wood, concrete, and metal panels. These materials provide significant advantages in terms of thermal insulation, soundproofing, noise reduction, and privacy protection. However, opaque facades also have several disadvantages. Firstly, they do not utilize natural daylight efficiently, leading to increased energy consumption for artificial lighting. Secondly, the enclosed interior spaces limit outdoor views, which may negatively impact occupant well-being. Moreover, traditional static opaque facades lack adaptability to climatic conditions, making it difficult to achieve an energy balance between insulation and ventilation. For instance, during winter, they fail to harness solar energy to reduce heating demands. To enhance the energy efficiency of opaque facades, dynamic approaches primarily focus on modifying material properties, such as phase change materials, thermochromic materials, shape memory composites, and airflow regulation within air cavities. Among these, adaptive thermal insulation components, which dynamically adjust heat transfer properties, have the most significant impact on reducing energy consumption [14].

3.2. Classification Based on Actuation Type

(1)

Adaptive (passive actuation)

Due to the automatic response of materials to environmental stimuli, variations in the facade system’s thermal transmittance (U-value), visible light transmittance (Tvis), and solar heat gain coefficient (SHGC) significantly impact energy efficiency, enabling self-adjustment for different purposes. These adaptive components operate inherently without requiring sensors, actuators, external power sources, or manual intervention (e.g., facades incorporating phase change materials, shape memory alloys, or thermochromic coatings), thereby mitigating energy demand and reducing the environmental impact of heating and cooling.

Adaptive building facades intelligently and precisely respond to fluctuating climatic conditions and indoor environmental requirements, utilizing available natural energy sources for lighting, heating, and ventilation. Compared with traditional technologies, they offer energy savings while maximizing thermal comfort [15]. Since passive facades respond to diurnal and nocturnal weather variations, their adaptive transformations are not instantaneously dynamic as expected. Therefore, climatic and indoor architectural conditions must be carefully considered before their future application in real-world buildings [16]. The control strategy of adaptive facades is typically determined by dynamic response time, and advancements in material technologies and control systems have positioned passive facades as integral components of dynamic facade systems.

(2)

Responsive (active actuation)

The integration of computational technologies into dynamic and intelligent buildings enhances thermal performance and aligns with user preferences and routines, a concept broadly categorized as responsive architecture [17]. Responsive building skins share functional and performance characteristics with adaptive skins, incorporating real-time sensing, dynamically climate-responsive components, smart materials, automation, and user-controlled adjustability. These facade systems are designed not only to adapt to environmental conditions but also to accommodate occupant needs, operating through external mechanisms such as manual and/or mechanical activation. Responsive systems integrate sensors, controllers, and actuators to monitor environmental parameters and autonomously regulate facade elements (e.g., ventilated facades, double-skin facades, dynamic shading systems) to optimize solar heat gain through the building skin. Mechanical actuation methods provide precise control and can be seamlessly integrated into insulation systems. The choice of actuation method is critical in achieving both material insulation and dynamic system performance. For instance, thermally actuated systems offer simplicity and energy efficiency but may require careful management of temperature variations and insulation to prevent unintended activation. Electroactuation, on the other hand, provides flexibility and programmability but often necessitates additional power sources and electrical components, increasing system complexity and potentially compromising reliability.

3.3. Classification Based on Material Properties

(1)

Phase change materials

Phase change materials can be categorized into organic and inorganic types, as well as hydrated salt-based and wax-based PCMs. These materials enhance the ability to store energy from solar radiation, thereby reducing heating and cooling demands. However, the main limitations of PCMs include high costs, challenges in encapsulation, and potential flammability risks.

(2)

Chromogenic materials

Chromogenic materials include electrochromic, photochromic, and thermochromic materials. Electrochromic smart materials function as active light modulation systems, whereas thermochromic and photochromic materials, which respond to ambient temperature and light intensity, respectively, are typically considered passive solutions. The integration of chromogenic materials into facade coatings holds significant potential for reducing building energy demand and mitigating the urban heat island effect.

(3)

Shape memory materials

Common shape memory materials include shape memory alloys (SMAs) and shape memory polymers (SMPs). SMAs exhibit a combination of shape memory effects and superelasticity, allowing them to control shading by deforming in response to temperature changes, thereby lowering building energy consumption. When in the martensitic phase at low temperatures, the alloy tends to deform, whereas in the austenitic phase at high temperatures, it reverts to its original shape.

(4)

Hygroscopic materials

By leveraging the intrinsic properties of materials, hygroscopic materials facilitate continuous passive and reversible responses to external stimuli, offering a low-cost, energy-saving approach to adaptive facades. For instance, in adaptive shading devices, the hygroscopic properties of wood enable changes in deflection and curvature in response to fluctuations in relative humidity, thereby allowing dynamic control of shading percentages to accommodate rapid climatic variations.

(5)

Thermo-bimetals

Thermo-bimetals consist of two laminated metal layers with different coefficients of thermal expansion, where the layer with the higher coefficient acts as the active component, while the layer with the lower coefficient serves as the passive component. When exposed to heat, the active layer expands more than the passive layer, causing the thermo-bimetal sheet to bend into an arc. This mechanism allows for self-shading applications on facades without the need for electrical power or mechanical devices, demonstrating considerable potential for sustainable adaptive shading systems [18].

4. Performance Evaluation and Simulation Modeling of Dynamic Skins

4.1. Modeling Tools and Simulation Software

Simulation is typically conducted during the initial phase of research activities to explore novel methods or technologies, whereas experimental evaluation and demonstration are carried out after new technologies have undergone digital validation [19]. Building energy modeling is increasingly employed throughout the entire lifecycle of a building for energy consumption analysis and prediction, measurement and verification, carbon assessment, and cost analysis of energy-saving measures. Studies indicate that in research on opaque adaptive dynamic building skins, experimental and simulation-based approaches account for 15.28% and 84.62% of studies, respectively, whereas in research on transparent systems, simulation and experimental methods are equally utilized at 50% each [20]. The simulation of dynamic facades involves complex multi-domain interactions and energy exchanges with various building systems. Therefore, users should formulate appropriate simulation strategies by aligning performance evaluation objectives with the capabilities and limitations of existing models and simulation tools. Most studies employ parametric modeling and computational simulation, with Grasshopper (version: 1.0.0007), TRNSYS (version: 18), EnergyPlus (version: 25.1.0), and IES VE (version: 2024) being the primary simulation software used [21,22,23].

(1)

EnergyPlus enables simulations of dynamic shading, lighting energy consumption, daylighting coefficients, natural ventilation, skin heat transfer, and life cycle cost analysis. Common user interfaces for EnergyPlus include OpenStudio and DesignBuilder.

(2)

Grasshopper is a visual programming language operating on the Rhino platform, widely utilized in computational design. It also intersects with interactive design, allowing users to generate models, video streams, and visualizations automatically based on predefined algorithms.

(3)

TRNSYS performs dynamic simulations of hourly building energy consumption, solar energy systems (solar thermal and photovoltaic), HVAC systems, and other energy-related components.

(4)

IES VE is an integrated, rapid, and accurate hourly thermal simulation software designed for performance analysis of buildings of any scale and complexity, whether newly constructed or existing.

Building performance simulation tools were primarily developed for static facades, whereas dynamic facades require more sophisticated computational processes to accurately predict performance based on indoor and outdoor variables. To address this, various interface plugins have been introduced to enhance control over such systems. Plugins supporting user modeling and dynamic shading element control include EnergyPlus’ Energy Management System (EMS), APpro in IES VE, W-editor in TRNSYS, and Ladybug, a built-in plugin in Grasshopper. The EMS function in EnergyPlus uses customized algorithms to control commonly used dynamic shading and requires high-level coding to cover the EnergyPlus source code. The built-in Ladybug plugin in Grasshopper is used to simulate processes. The Ladybug tool interfaces with the validated simulation engines OpenStudio and EnergyPlus to perform parameterized energy simulations with high precision and reliability in complex buildings [24]. Among simulation tools, mathematical software such as MATLAB (version: R2024a) and Python (version: 3.12.0) are widely utilized (45.45%) due to the complexity of operational modes and active control strategies involved in integrating dynamic opaque skins with phase change materials. These tools allow for customizable settings to accommodate such complexities [25]. Additionally, CFD Fluent is extensively employed (27.27%) for its robust capabilities in simulating complex heat transfer and phase change phenomena [20]. Occupant behavior is also a key determinant of building energy consumption. Developing advanced simulation modules for building skins, occupant behavior, and energy systems is crucial for enhancing the capabilities of building energy modeling [26]. Various tools have also demonstrated the heterogeneity and high variability of simulation processes, highlighting the intrinsic need for multiple tools to obtain reliable results [27].

4.2. Optimization and Predictive Control Algorithms

Uncertainty is a critical challenge faced by all dynamic shading technologies, primarily arising from two factors: (1) unpredictable weather conditions and (2) uncertain occupant behavior. Adaptive control systems can employ optimization algorithms to achieve optimal control, typically comprising three key components: an optimal control model, a parameter identification system, and an optimization algorithm. Model predictive control (MPC) is the most commonly used technique for regulating adaptive facades, with intelligent control methods including genetic algorithms (GAs), artificial neural networks (ANNs), and fuzzy logic control (FLC) [28]. GA is used to develop a predictive model, derive a simplified equation that fits the problem, and provide multiple final solutions for complex problems. The advantage of an ANN lies in its ability to determine nonlinear relationships between different variables without requiring assumptions, thereby overcoming discretization issues. However, ANNs require a relevant database to obtain reliable solutions [29]. FLC, on the other hand, employs linguistic rules instead of complex analytical expressions, eliminating the need for a specific control model and making it more suitable for complex systems such as indoor environments [30].

Multi-objective evolutionary algorithms (MOEAs) have been proven to be reliable tools for solving complex engineering problems with multiple requirements. Optimization algorithms such as multi-objective particle swarm optimization (MOPSO), analytic network process (ANP), strength Pareto evolutionary algorithm 2 (SPEA2), and non-dominated sorting genetic algorithm II (NSGA-II) have been widely applied to address multi-objective problems. In particular, NSGA-II has been identified as the most popular algorithm for building performance optimization (BPO). NSGA-II uses a domination-based framework where a Pareto-domination selection operator and a genetic operator are used iteratively. The selection pressure of NSGA-II is reduced, and its evolution process is hindered when facing many-objective problems [31]. To enhance optimization efficiency, ANN surrogate models are often coupled with GAs for performance optimization. Furthermore, machine learning algorithms can also be utilized to mitigate uncertainty and account for the impact of occupant behavior on building energy consumption [32].

Numerous studies have applied the aforementioned simulation software and control algorithms for modeling and analyzing dynamic facades (

Table 3. Typical case studies on different methods of building dynamic facades.

DF Type	Building Type	Location	Method	Software	Performance	Ref.
Adaptive facade	Office	Melbourne (AU)	Modified firefly	EnergyPlus (version: 25.1.0)	The proposed adaptive facade system can reduce energy consumption by 14.2–29.0%.	[33]
Adaptive facade	Commercial	–	ANP	Super Decisions (version: 3.2.0)	The limit supermatrix was used to determine the orders of priority for high performance criteria.	[35]
Kinetic facade	Office	Tehran (IRI)	NSGA-II	–	This method provided a variety of optimal solutions using the Pareto front and the Ranking Method.	[36]
Adaptive facade	Office	Atlanta (USA)	Finite-difference (FD)	MATLAB (version: R2024a)	This FD model can potentially shorten the execution time by more than 84%.	[37]
Kinetic facade	Office	Xuzhou (CHN)	–	Grasshopper (version: 3.03.01)	The concentrated skin scheme can improve the useful daylight illuminance by an average of 2.40% and 16.25%.	[38]
Kinetic facade	Office	Incheon (KR)	GA	Grasshopper (version: 3.03.01)	Optimizing the configuration and operating scheme of dynamic shading panels can significantly enhance the quality of indoor daylighting.	[39]

). For instance, Bui et al. [33] employed EnergyPlus to develop optimization methods aimed at improving building energy efficiency. Their findings indicate that adaptive dynamic facade systems can reduce energy consumption by 14.9–29.0% compared with static facades. Shi [34] optimized adaptive facade (AF) systems using DesignBuilder for building energy modeling, demonstrating 14.3–22.4% reductions in energy consumption. Yitmen et al. [35] adopted a hierarchical adaptive facade system decomposition approach. They applied Analytic Network Process (ANP) modeling using Super Decisions software (version: 3.2.0) to construct a supermatrix for pairwise comparison. The study integrated key high-performance criteria, including energy consumption, CO₂ emissions, sustainability, energy savings, daylighting, and operation and maintenance, to establish a priority ranking for optimal adaptive facade performance. Sadegh et al. [36] employed Pareto front and ranking methods to generate various optimal solutions for improving daylighting performance in office buildings. Their study reported a 30% increase in effective daylight illuminance and a 20% improvement in daylight autonomy, while maintaining underlit and overlit values below 10%. Due to the extensive computational time required for Building Energy Simulation (BES) and the limited support for Adaptive Building Skin (ABE) systems, Zeng et al. [37] proposed a Finite Difference (FD) model programmed in MATLAB (version: R2024a) for ABE design and control optimization. Their model reduced execution time by over 84% compared to BES software (version: 9.5.0) such as EnergyPlus (version: 25.1.0). Wang et al. [38] leveraged Rhino Grasshopper and Ladybug tools to optimize dynamic centralized building skin systems, achieving 2.40–16.25% improvements in useful daylight illuminance and 59.35–88.40% reduction in glare.

Designers can leverage simulation modeling to gain an intuitive understanding of the relationship between design parameters and building performance, thereby facilitating the rapid and accurate identification of design prototypes from various potential design directions. However, given the infinite possibilities in facade configurations, parametric simulation is not the most efficient method for determining the optimal solution. Additionally, conducting Building Energy Simulation (BES) for dynamic facades requires specialized training, and the simulation process itself is often overly complex and time-consuming. These factors are particularly disadvantageous during the early-stage optimization and decision-making phases of a project. Therefore, there is an urgent need to develop and adopt a fast and time-efficient algorithm for evaluating dynamic facade design options in the early project stages, while software-based simulations can serve as a means of further verifying the reliability of pre-defined dynamic facade technologies. According to the ISO 13790 standard [40], computational algorithms can identify key factors influencing facade energy performance, aiming to transform the geometric configuration and material properties of dynamic facades into a standardized evaluation process. Gaspari et al. [41] utilized this method to study a residential building incorporating dynamic shading measures with shape memory alloy actuators. The study showed that, without considering the training time required by simulation software, this approach could save approximately 71% of the time. Given the convenience of the above method, it can be applied in the early-stage performance decision-making assessment of dynamic facade design.

5. Dynamic Skin Energy-Saving Technology

5.1. Smart Materials

Smart materials can enhance the thermal performance of building skins through external stimuli such as temperature, electric fields, or radiation. Examples of such materials include shape memory alloys (SMAs), shape memory polymers (SMPs), thermo-bimetals (TBM), thermochromic materials (TCMs), and phase change materials (PCMs). Smart materials (SMs) can be classified based on their control mechanisms: systems driven remotely by CPU-controlled electrical stimulation are categorized as active, whereas systems where control is embedded within the material properties are considered passive. Additionally, some conventional materials exhibiting dynamic characteristics, such as the hygroscopic behavior of wood, can also be included in this category (Figure 7).

Studies have demonstrated that combining cement plaster with thermochromic coatings (TCs) and phase change materials (PCMs) improves the thermal performance of façades, increasing solar reflectance by 23% while maintaining higher solar absorption at lower temperatures [42]. PCMs applied to the inner side of external walls perform optimally when the melting temperature is set to 23 °C, resulting in an 11.7% reduction in primary energy demand in the summer and consequently lowering CO₂ emissions [43]. A photonic structure composed of PCMs doped with vanadium dioxide enables passive, self-adaptive switching of radiative cooling based on ambient temperature, without requiring additional energy input [44]. Furthermore, a coating system synthesized from solid–solid phase change materials (SS-PCMs), including poly (stearic acid) (PSA), poly (glycidyl methacrylate) (PGMA), and poly (hexyl acrylate) (HA), not only reduces summer energy demand but also utilizes solar radiation during winter [45]. PCM has been proven effective in mitigating thermal peaks, regulating daytime solar transmission (by up to 50%), adjusting surface temperature (up to 22 °C variation within three melting phases), and suppressing heat transfer (reducing by up to 30%) [46].

Despite their potential, these materials face challenges associated with durability, cost, energy efficiency, and environmental impact. For example, based on the current advantages and limitations of PCMs (

Table 4. Advantages and disadvantages of PCM application in buildings.

No.	Advantages	Disadvantages
1	Enhance the thermal performance of the enclosure structure.	There are issues such as leakage, flammability, and thermal expansion.
2	Reduce the peak load of buildings.	There is a lag phenomenon.
3	Reduce the daytime cooling load of buildings.	Durability and stability need to be improved.
4	Reduce daily heating load during the heating season.	Heat cannot be released in a timely manner.
5	Adjust indoor lighting.	There is a risk of overheating.
6	Improve indoor thermal comfort.	The difference in heat capacity when in the liquid state.
7	Enhance the environmental adaptability of buildings.	Affects visual comfort.
8	Protect privacy.	The external layout will affect the aesthetics of the architecture.
9	Easy to disassemble and environmentally friendly.	Incomplete phase transition periods can lead to low utilization of latent heat.
10	Improve the safety and durability of building structures.	The mechanism triggering energy storage cannot be controlled.

), future PCM-based building skins must be multifunctional, highly responsive, capable of rapid energy storage and release, and aligned with the development of renewable energy. Moreover, the application of shape memory alloys (SMAs) in sustainable building practices remains limited due to several constraints [47]: (1) the long-term cyclic actuation of SMAs has not been fully validated; (2) absorptive metal shading panels may introduce excessive heat into interior spaces; (3) nickel-titanium sheets are significantly more expensive than conventional building materials. In addition, thermochromic materials can be categorized into two groups: thermochromic materials based on dyes, such as Leuco dyes, and non-dye thermochromic materials. Photo-degradation is one of the major obstacles hindering the outdoor application of dye-based thermochromic materials [48].

From the current research status, in addition to the inherent defects of the materials themselves, the lack of regulations, uneven regional development, and insufficient interdisciplinary collaboration are also major factors hindering the development of intelligent materials.

5.2. Double (Multi)-Layer Facades

Double (multi)-skin facades have a unique two (multi)-layer structure separated by an air cavity, providing a highly adaptable solution for insulation and climate-responsive control. The cavity serves as a buffer zone against extreme external temperatures, providing cooling in hot conditions and insulation in cold climates. The energy-saving efficiency of DSF largely depends on regulating the airflow inside the cavity and adjusting the cavity opening based on seasonal or daily temperature changes. Double (multi)-layer facades can dynamically adjust a building’s thermal properties and reduce overall annual energy consumption [49]. In particular, multilayer climate-adaptive dynamic facades incorporating photovoltaic panels, chromogenic materials, phase change materials, and ventilated cavities exhibit superior performance in lowering building thermal loads, providing auxiliary heating for indoor air, enhancing thermal comfort, and improving indoor air quality. The Trombe wall is a passive solar building system designed for heat collection and storage, consisting mainly of a high-thermal-mass dark-colored wall facing the sun and a glazed panel in front. The glass panel captures solar radiation, heating the air and transferring thermal energy indoors through conduction and radiation. Through continuous technological advancements and innovations, Trombe walls have been improved to dynamically adapt to various climatic conditions, enhance energy efficiency and comfort, and mitigate the risk of overheating during summer [50,51,52] (Figure 8).

Inspired by kirigami, Arauz et al. [53] investigated adaptive ventilation in double-skin facades, demonstrating its potential to reduce HVAC usage and significantly improve a building’s environmental performance under varying outdoor temperatures and wind speeds. Studies have shown that thermal control retrofitting of dynamic shading in double-skin facades (DSFs) can achieve a 20% reduction in energy consumption [54]. Additionally, switchable ethylene tetrafluoroethylene (ETFE) foils in DSFs actively respond to weather conditions and solar intensity, regulating incoming daylight and controlling internal light distribution. This approach reduces the daylight glare probability (DGP) by 59%, ensuring imperceptible glare conditions 94% of the time [55]. Moreover, building envelopes integrating reversible fluid injections for light transmission regulation have demonstrated over 30% annual energy savings in heating, cooling, and lighting compared with state-of-the-art electrochromic windows [56]. Furthermore, airflow-permeable enclosure systems utilizing porous materials can dynamically alter airflow penetration patterns, directly modifying the internal temperature distribution within the building envelope. This approach reduces heat flux through the facade, contributing to overall energy savings by the building [57]. In conclusion, DSFs are versatile systems capable of functioning efficiently across diverse climates. By integrating adaptive shading, advanced materials such as PCMs and electrochromic glazing, and innovative designs, DSFs effectively manage thermal performance and enhance occupant comfort [11].

From the literature review, it is evident that current research on double-layer epidermis still has some shortcomings, including insufficient research on climate adaptability, weak material and mechanism system design, and a lack of life cycle data. In addition, dynamic performance simulation is limited, and the only CFD is mostly based on steady-state conditions, resulting in high prediction error rates.

5.3. Shading Devices

Efficient shading is a crucial strategy for achieving energy savings [58]. Windows without shading are prone to excessive solar heat gain during summer, leading to high seasonal cooling energy costs. Additionally, static shading devices can result in insufficient daylighting in winter, increasing heating energy demand. Dynamic shading represents an effective bioclimatic strategy as it overcomes the limitations of fixed shading systems by adapting to continuously changing solar angles, enabling real-time adjustments to achieve significant energy savings, enhance indoor comfort, and create a healthier lighting environment [59]. Without the transition from static to dynamic systems and responsive design, traditional shading systems fail to optimize energy control.

Automatic response is a key feature of dynamic shading systems, which typically consist of three main components: sensors for data acquisition, controllers for determining actions, and mechanical actuators. The environmental performance of shading systems primarily involves two main objectives: visual performance and solar heat gain control (Figure 9). Dynamic shading systems are generally composed of a static part dominated by shading elements and a mechanical part based on gears and tracks. The physical movement mechanisms of dynamic shading systems include: (1) translation: linear movement of components in one or multiple directions; (2) rotation: circular motion of components around an axis; (3) deformation: shape alterations such as bending, stretching, twisting, or compressing.

External shading devices are influenced by a complex combination of solar radiation intensity, ambient temperature, and radiative heat exchange with surrounding surfaces. The thermal response of shading systems should account for urban temperature conditions [60]. Optimal design solutions should consider spatial functions, climatic characteristics, and energy efficiency requirements [61]. Studies indicate that dynamic shading systems and control strategies can significantly improve energy efficiency, daylighting performance, and visual comfort across nearly all climate zones and spatial configurations [62,63]. Li et al. [64] found that the received total equivalent irradiance was significantly higher under an automatically adjusted photovoltaic shading panel angle mode, leading to daily electricity generation increases of approximately 17.2% and 22.5% compared with fixed-angle modes at 30° and 90°, respectively. Zhang et al. [65] optimized adaptive control strategies for louvers in a subtropical city, achieving an overall energy reduction of 7.3–12.5% while ensuring visual comfort by minimizing glare risks and excessive daylight exposure.

To address the geometric inflexibility of rigid-body kinetic facades, research has advanced toward leveraging material properties to develop continuous, passive, and reversible response mechanisms to external stimuli. This approach represents a low-cost, low-energy adaptive envelope strategy [66]. Zhang et al. [67] explored a dynamic shading system using a smart Kresling origami structure integrating shape memory polymers (SMPs) for intelligent folding and carbon fiber-reinforced polymers (CFRPs) for structural stability, thereby enhancing both energy efficiency and occupant comfort. Although research interest in kinetic shading systems (KSSs) has surged, few studies have integrated daylighting, visual comfort, and lighting energy consumption into control algorithms due to their complexity. Most research has focused solely on daylighting [68]. Additionally, economic analyses, including cost–benefit comparisons and return-on-investment calculations, remain limited in the existing literature [69]. Given the energy inefficiency of traditional dynamic facades with solely shading functions due to their complex actuation systems, current trends are shifting from “single-function, single-behavior” shading systems toward multifunctional and integrated dynamic shading technologies [70]. For example, the integration of shading devices and smart materials, combined with regional climate characteristics, can greatly improve the energy efficiency of buildings and reduce dependence on non-renewable energy. Wang et al. [71] discovered that, compared with buildings without photovoltaic shading devices (PVSDs), setting PVSDs at a fixed optimal annual angle of 65°, adjusting them to the optimal monthly angle, or employing real-time angle optimization resulted in energy savings of 25%, 31.9%, and 36.5%, respectively.

Currently, the research gap in dynamic shading mainly lies in the lack of climate adaptation models, weak collaborative design of devices and controls, and a lack of long-term reliability data. Secondly, due to the error in control accuracy, there is an inconsistency between the theoretical model and the actual application results. Moreover, dynamic simulation is detached from real working conditions, human behavior models are overly simplified, and the defects in construction technology are also the main shortcomings of current dynamic shading research methods.

5.4. Biomimetic Facades

The field of architecture should adopt a nature-inspired approach, specifically a biomimetic methodology, which prevents environmental imbalances and integrates building design into ecosystems rather than isolating it from them [72]. Biomimetic design leverages the inherent adaptability of plants to variations in light, temperature, and humidity, optimizing energy use, enhancing building performance, and creating environmentally responsive structures that promote harmony between the built and natural environments [73]. Biomimetics in architecture operates at three levels: organism, behavior, and ecosystem. At the organism level, architecture draws inspiration from biological forms, applying their physiological, morphological, or structural characteristics to buildings. The behavioral level involves mimicking how organisms interact with, adapt to, and integrate into their surroundings. The ecosystem level extends this concept to the urban scale, replicating the interactions among various environmental components. By studying natural adaptation mechanisms, architects can extract functional features from the expanding body of biological knowledge and translate them into innovative, adaptive, flexible, and high-efficiency facade designs (Figure 10).

Integrating multifunctional biomimetic technologies into facade design enables comprehensive regulation of thermal exchange, air flow, light penetration, water management, and energy performance, making it a cutting-edge direction for enhancing dynamic facade systems [74]. Assoa et al. [75], inspired by biological structures, developed a dual-membrane thermally responsive facade that deforms in response to temperature changes, reflecting solar radiation and enhancing both electricity generation and thermal performance in a bifacial photovoltaic ventilated facade. Similarly, Sommese et al. [76], inspired by Gazania flowers (Figure 11), demonstrated through simulations that a biomimetic kinetic facade system could provide 87.5% to 100% dynamic natural daylighting for office spaces, improving both energy efficiency and user comfort. Research has shown that biomimetic facades have the potential to reduce operational energy consumption by approximately 50% across various climatic zones and building typologies [77]. Additionally, multifunctional biomimetic adaptive building envelopes significantly enhance thermal performance, lowering indoor temperatures by 3 °C solely through natural ventilation [78]. Furthermore, Bio-Adaptive Building Skins (Bio-ABS) have been found to reduce annual cooling demand by 19% while improving occupant comfort by 67.5%. However, most biologically adaptive facade systems remain single-function, typically regulating only one environmental parameter. Multifunctionality is still a largely unexplored aspect, with only 13.4% of published projects addressing more than one parameter [79]. Although various studies are underway, the limitations of materials and manufacturing processes, the high complexity of control models, and environmental adaptability defects are huge challenges currently faced by biomimetic facades, which must rely on interdisciplinary collaboration to promote their rapid development.

The research gap in biomimetic building facades mainly lies in insufficient interdisciplinary collaboration, a lack of sustainability verification, and lagging intelligent response technology. Secondly, the limitations of digital tools are the main shortcomings of research methods. In addition, differences in energy efficiency, cost, and ecological contribution have also led to doubts about the sustainability of biomimetic facades.

6. Trends of the Development of Dynamic Skin Energy-Saving Technology

Facade design is inherently complex, involving a wide array of factors, including cultural, social, technological, policy, economic, and environmental. It also encompasses numerous variables and performance standards, necessitating sophisticated decision-making mechanisms. The optimal facade solution should not only consider the interactions between various standards but also maximize overall performance. Currently, building technologies are rapidly advancing, and dynamic facade technologies, including smart materials, dynamic shading devices, double-skin facades, and biomimetic facades, undeniably play a pivotal role in energy-saving facade design, but also have their own shortcomings (

Table 5. Comparison of different types of dynamic facade technologies.

Technical Types	Description	Benefits	Drawbacks	Research Methods	Ref.
Smart Materials	Smart materials (SMAs, SMPs, PCMs, etc.) reduce building energy consumption by dynamically changing the performance of building facades.	▪ Low running energy. ▪ Improved visual and thermal comfort. ▪ Glare reduction. ▪ Solar radiation control. ▪ Reducing cooling load more effectively.	▪ High installation, maintenance, repair and other costs. ▪ Unstable durability. ▪ Low transparency. ▪ Non instantaneous dynamic.	Anns Energyplus	[16,18,23,44,46]
Double(Multi)-skin Facades	A double (multi)-layer facade is an arrangement based on a ventilation cavity to reduce the energy demand of buildings.	▪ Ventilation inside the cavity enhances its overall performance. ▪ Improve indoor air quality. ▪ Energy storage. ▪ Reduce heat loss. ▪ Reduce heating load more effectively.	▪ High installation, maintenance, repair and other costs. ▪ Complex cavity airflow. ▪ Occupy a significant amount of building space.	CFD BES Energyplus	[50,51,52,53,54]
Shading Devices	The Shading device dynamically controls direct and indirect radiation penetration into the building.	▪ User control flexibility. ▪ Energy generation potential. ▪ Improved visual and thermal comfort. ▪ Reducing cooling load more effectively.	▪ High initial installation costs. ▪ Noise interference. ▪ Complexity of maintenance, etc.	MOEA Energyplus Radiance Grasshopper Rhino	[58,60,65,67,68]
Biomimetic Facades	Biomimetic facade is a natural inspired shading system for facades that can improve the sustainability and energy efficiency of buildings.	▪ Reduces in carbon emissions significantly. ▪ Reduces building energy consumption. ▪ Increases building performance.	Uncontrollable production, installation, and maintenance costs. ▪ Multitude and complexity of bionic organisms. ▪ Interdisciplinary characteristics of bionics. ▪ Limitations of simulation software.	MOEA BES Energyplus TRNSYS FD	[72,73,74,75,76,77,78]

). However, the author contends that in establishing an efficient building energy system, several key aspects must remain the primary focus in dynamic facade design.

6.1. Integrated Technology Design

Integrated technology refers to the creative process of combining two or more individual technologies through reorganization to achieve a unified, holistic function. This approach often fulfills technical demands that cannot be met by a single technology. Dynamic facades directly impact a building’s thermal performance, optical characteristics, ventilation, energy consumption, and power generation. Dynamic envelopes with a singular function typically exhibit low energy efficiency, while multifunctional integrated systems that equip facades with energy production and collection capabilities represent a more promising approach (Figure 12).

Researchers are intensifying efforts to develop integrated response systems aimed at optimizing building energy consumption, thermal comfort, and indoor daylighting conditions, among others [80]. Dynamic facade design also benefits from integrated design methods, including the integration of smart materials, dynamic technology, and research methods. For instance, Chen et al. [81] developed an integrated framework for adaptive facade optimization that incorporates performance simulation, clustering analysis, neural network prediction models, and multi-objective optimization decision-making, thereby improving the efficiency of adaptive facade designs. The results showed that the optimized adaptive façade design enhances useful daylight illuminance (UDI) by 0.52%, quality of view (QV) by 5.36%, and beneficial solar radiation energy (BSR) by 14.93% compared with traditional blinds. In addition, each office unit can generate 309.94 kWh of photovoltaic power per year using photovoltaic shading systems. Building-integrated photovoltaics (BIPVs) have seen rapid advancements. Compared with fixed panels, climate-adaptive, dynamic, variable photovoltaic-integrated shading systems offer a distinct advantage in terms of energy generation. Equipped with optimal control strategies, these systems not only enhance energy generation but also effectively regulate solar heat gain, reducing the building’s heating, cooling, and lighting demands [82]. Zou et al. [83] applied a dynamic and vertical photovoltaic integration technology to optimize high-rise glazed facades, which can provide up to 131% of the annual energy demand of office rooms and significantly increase the annual net energy output by at least 226% compared with static photovoltaic (PV) blinds. However, high initial costs, maintenance requirements, disproportionate investment payback periods, and concerns about long-term durability remain key challenges [84]. It is important to note that dynamic envelope technologies should also be easily integrated into existing buildings. Compared with focusing solely on new constructions, developing adaptive facades for building retrofits will more quickly and significantly reduce energy use and greenhouse gas emissions. Given the substantial advantages and development potential of dynamic facade integration technologies in building energy efficiency, production efficiency, and product quality, they are an indispensable indicator of future high-performance smart building integrated technologies. In addition, the integration of IoT, big data management, artificial intelligence, and dynamic facade technologies can not only improve the quality of life but also greatly assist humanity in addressing sustainable challenges to ensure human and biological diversity as well as the resilience of the Earth.

6.2. Interaction Design

Interaction Design (IXD) refers to the design field that defines and designs the behavior of artificial systems. It specifies the content and structure of the communication between two or more interacting entities, enabling them to cooperate and achieve a common goal. Dynamic facades offer advantages in energy efficiency, but they may also reduce the acceptance and satisfaction of residents. Therefore, the impact on users’ living experience and emotional well-being should not be overlooked [85,86]. Beatini et al. [85] investigated the impact of adaptive facades on residents’ emotions through controlled virtual reality experiments and statistical comparisons. The study confirmed that dynamic changes in adaptive facades can trigger emotional responses, and low frequency of changes, finer patterns, less visual obstruction, and natural element patterns can improve user comfort. Residents also influence building energy consumption through their behaviors, such as operating building equipment and opening or closing doors and windows. The complexity of living and resident behavior leads to the greatest uncertainty in building energy use [32]. As a component of smart buildings, the dynamic facade should function as an interactive, self-regulating closed-loop control system, operated by real-time environmental data and feedback from residents (Figure 13).

Due to the conflicting demands of energy efficiency and indoor environmental quality, interactions between residents and the facade often become disruptive, leading to dissatisfaction. The success of external wall solutions depends not only on the technology itself or the type of control strategy but also on residents’ satisfaction with the interaction strategy [87]. The multifaceted relationship between the facade and residents remains insufficiently understood, and this knowledge gap poses particular challenges for the interactive design of dynamic facades. Dynamic facade design should adhere to a human-centered approach, integrating technological innovation with personalized design. It should emphasize user participation and a diversified interactive experience while also considering humanistic needs such as emotional comfort, privacy protection, and usability, actively contributing to the enhancement of building energy efficiency. Otherwise, it may lead to higher energy demand or lower occupant satisfaction than predicted.

6.3. Life Cycle Design

For architects and building professionals, the trade-offs between energy efficiency, human comfort, and cost-effectiveness have always posed a challenge. Life cycle design (LCD), also known as Eco-Design, considers the carbon footprint of the entire building lifecycle from the perspectives of building performance, environmental protection, and economic feasibility. This includes energy-saving requirements for building design, construction, operation, and post-use recycling and disposal, as well as the multi-stage use of resources and energy to reduce the environmental impact of the building design, construction, and usage processes. The goal is to align these processes with the Earth’s carrying capacity, ensuring that the building meets its green attributes (Figure 14).

Analyses of the returns of developed dynamic building envelopes are lacking; similarly, there is a research gap in lifecycle analysis (LCA), lifecycle cost (LCC), and circular business plans. This is due to the complexity of the materials used in dynamic envelopes, which often have high initial embedded carbon emissions. The annual adaptation cycle of specific dynamic technologies depends on the particular climate, and reducing the complexity of control can extend the service life [88]. Therefore, innovative concepts are needed to continuously explore new materials, technologies, and processes. This approach should aim not only to reduce resource and energy consumption during the usage phase but also to minimize the environmental impact of dynamic building facades throughout the entire lifecycle, including design, production, use, and reuse [89]. Borschewski et al. [90] proposed a workflow for automatically generating, analyzing, and evaluating the LCA results of all potential configurations within a defined parameter space. It combines and processes data from multiple sources. Various methods for combining and analyzing the data are provided in the form of parameter sensitivity and statistical evaluations, as well as visualizations. Typically, dynamic facades have low energy usage during the operational phase; however, energy consumption during the production and processing of building materials is significant over the entire lifecycle. As a result, the facade design should be easy to process, replace, recycle, and reuse. The higher the material reuse rate, the smaller the environmental impact from new material production or old material recycling [91]. China’s construction industry has undergone rapid development in the past 20 years, with a large number of high-energy-consuming buildings being built. The current construction industry has entered an era of stock from the previous incremental era. The authors believe that after scientifically evaluating the structural safety, spatial types, and environmental characteristics of existing high-energy-consuming buildings, and based on their different characteristics, the reasonable use of dynamic facade energy-saving technologies, such as smart materials, shading devices, and double-layer skins, can greatly reduce the life cycle costs of buildings. The authors believe that lightweight, easy-to-replace, and user-friendly technologies such as smart material windows, exterior wall coatings, and movable sunshade blinds are more suitable for energy-saving renovations of existing buildings.

7. Conclusions

The building’s “skin” plays a crucial role in energy efficiency, and the energy-saving design of dynamic facades is a systematic and complex process involving multidisciplinary knowledge and technologies. Through a comprehensive literature review, this study summarizes the types of dynamic skins, commonly used core technologies, and performance optimization methods. It also proposes that integrated technology design, interaction design, and life cycle design are effective approaches for enhancing energy efficiency, occupant satisfaction, and economic benefits of dynamic skins. This review shows that many researchers have made great efforts and achieved fruitful results; however, the authors believe that the following challenges remain:

(1)

Most of the research on dynamic facades is currently limited to the study of single dynamic technologies.

(2)

Current research lacks experimental testing and prototype evaluation during the development process.

(3)

Most studies do not specify whether the developed designs or prototypes are exclusively for new buildings or applicable to retrofitting projects.

(4)

Many studies overlook the intended building function, often developing energy-efficient dynamic facades without considering their suitability for different building types (e.g., residential, office, or commercial spaces).

(5)

Research on dynamic facades rarely focuses on the issues of urban overheating and diverse user needs.

Although challenges still exist, dynamic skin energy-saving technology remains one of the most effective solutions for future sustainable building design. Future research trends should focus on reducing costs, renovating existing building facades, addressing personalized needs, developing performance measurement tools, and establishing standardized building evaluation standards to promote the practical application of these facades.