Design and Climate-Responsiveness Performance Evaluation of an Integrated Envelope for Modular Prefabricated Buildings

Modular prefabricated buildings effectively improve the efficiency and quality of building design and construction and represent an important trend in the development of building industrialization. However, there are still many deficiencies in the design and technology of existing systems, especially in terms of the integration of architectural performance defects that cannot respond to occupants’ comfort, flexibility, and energy-saving requirements throughout the building’s life cycle. -is research takes modular prefabricated steel structural systems as its research object and sets the detailed design of an integrated modular envelope system as the core content. First, the researcher chose two types of thermal insulation materials, high insulation panels and aerogel blankets, in order to study the construction details of integrated building envelopes for modular prefabricated buildings. Focusing on the weakest heat point, the thermal bridge at the modular connection point, this work used construction design and research to build an experimental building and full-scale model; the goal was to explore and verify the feasibility of the climate-responsive construction technique called “reverse install.” Second, as a response to climate change, building facades were dynamically adjusted by employing different modular building envelope units such as sunshades, preheaters, ventilation, air filtration, pest control, and other functional requirements in order to improve the building’s climate adaptability. Finally, based on the above structural design and research, this study verified the actual measurements and simulation, as well as the sustainability performance of the structure during the operational phase, and provided feedback on the design. -e results highlight the environmental performance of each construction detail and optimized possibilities for an integrated envelope design for modular prefabricated buildings during both the design and renovation phases.


Research Background.
e energy and environmental crisis of the 1970s gave birth to a global awareness of and widespread attention to the issue of sustainable development [1].In this context, the field of architecture has also expanded, and sustainable architecture has become an important and rapidly developing research proposition [2].Owing to the environment's potential for sustainability, society's needs, and certain economic aspects (such as saving construction time, improving building quality, reducing material waste, alleviating environmental loads, and reducing cost) [3][4][5], prefabricated buildings have become an important research topic in sustainable architecture, now playing an essential role in Western urban construction [6,7].
Modularization is one means of operation in the manufacture of industrial products.Its production efficiency and delicacy are well established in production [8,9].If we look at the problem of building industrialization with an eye towards product manufacture, modular design, and the overall construction methodology, most components are prefabricated at the factory and assembled on-site.In such cases, building space is integrated, construction time is minimized, and on-site construction errors are reduced (as shown in Figure 1) [10,11].Modular design also embodies the concept of sustainable development and "green" construction.However, there are currently many de ciencies in both the design and certain technical aspects of the existing system [12], especially with regard to defects in architectural performance and integrated design (as shown in Figure 2).Currently, they cannot respond to occupants' requirements for comfort, exibility, and energy-saving throughout the building's life cycle [13].
e form of the building envelope has a decisive in uence on building performance during the operating phase; it is also one of the most important elements of modular prefabricated buildings [14].
erefore, this research focused on the sustainability-related performance of modular prefabricated buildings, mainly exploring the construction details of integrated building envelopes and their climate responsiveness.
A master of modernist architecture Le Corbusier rst proposed the idea of a "drawer-type residence" in 1947. is served to introduce the topic of modularization and standardization in building design (as shown in Figure 3) [15].In the 1960s, a Dutch scholar named Habraken proposed the notion of open architecture, creating the SI housing system for residential architecture [16].e e ective separation of S (the skeleton) and I (the in ll) led to houses that o ered structural durability, exibility in the indoor space, and quality lling [17].e German and American architects, Konard Wachsmann and Walter Gropius, respectively, jointly developed the assembly-type General Panel System in 1945.According to the modules, these buildings were decomposed into composite panels, thermal insulation, inside and outside walls, oors, ceiling, roofs, and so on.
ese architects also developed a connection node system between the plates to meet the requirements of rapid development and system expansion [18,19].Ochs invented a prefabricated timber structural envelope module to integrate active equipment such as microheat pumps and full heat exchangers into single building components [20].e design not only saved time and labor during the construction phase but also satis ed the energy-saving and thermal comfort aspects of building performance [21].

Objective of is Study.
is research focused on the construction details, design, and e ective evaluation of integrated building envelopes for modular prefabricated buildings.ree goals were pursued: (1) to use a rational integrated building envelope design to improve the physical environment and energy-saving performance during a modular prefabricated building's operational phase, (2) to resolve weaknesses related to thermal bridges at the connection points of modular prefabricated buildings and advance their sustainable performance during the operational phase, and (3) to improve the climate adaptability capacity of the overall building environment by optimizing the design of integrated building envelopes.

Methodology
is research examined modular prefabricated buildings with steel structural systems and set the details of an integrated module design for an envelope system as the core content.Buildings with steel structures o er advantages during prefabrication, transportation, modular hoisting, and installation and thus are the preferred structural system in prefabricated architecture [22].However, compared with PC and wooden structural systems, the heat transferability of steel structures is stronger and faster, obvious disadvantages in terms of thermal insulation performance [23].erefore, this research chose two types of thermal insulation materials, high insulation panels (HIPs) and aerogel blankets (ABs), to study the construction details of integrated building envelopes for modular prefabricated buildings.Focusing on the weakest heat points, the thermal bridges at modular connection points, this study employed construction detail design and research to build an experimental building and full-scale building model.e goal was to explore and verify the feasibility of the climate-responsive construction detail technique called "reverse install."Moreover, the envelope's structural component system featured modularization,   2 Advances in Materials Science and Engineering standardization, and prefabrication [24], characteristics that can be optimized for climate responsiveness.To accommodate new needs stemming from climate change, building facades were dynamically adjusted by using different modular building envelope units, including sunshades, preheaters, ventilation, air ltration, pest control, and other functional requirements.e goal was to improve the building's performance related to climate adaptability.Based on the above structural design and research, this study veri ed the actual measurements and simulation, as well as the sustainability performance of the construction during the operational phase, and provided design feedback.

e Reverse Install Integrated Building Insulation
Envelope Technique 2.1.1.Using HIPs to Improve Heat Preservation and Solve the ermal Bridge Problem.Research on ultra-thin vacuum insulation panels began in Europe in 1972.At rst, this type of insulation was primarily used for heat preservation in transportation equipment, sophisticated cold storage machinery, and so on.As the research developed, the panels were increasingly applied in the eld of architecture, to oors, doors and windows, roofs, interior walls, and building exteriors [25].HIPs are composed of two parts: a high barrier composite lm and the core material.e high barrier composite membrane comprised inorganic ber cloth, a multilayer aluminum foil, and a multilayer compact material that protects and a xes the HIPs.e high-quality barrier diaphragm guarantees the service life.
e core material is made up of porous inorganic substances such as nanometer-super ne silica.
e porous structure of the vacuum is bene cial in facilitating low thermal conductivity [26].
e wall construction details for the building used in this research, from inside to outside, were as follows: the interior panel was a 9 mm thick OSB panel that served as a structural layer.ere was also a light steel structural in ll with an 80 mm thick rock wool insulation panel.
ere was another 18 mm thick OSB panel that also served as a structural layer, and a waterproof layer composed of a 15 mm thick double-layer HIP with a wood keel and an air gap exterior panel [27], as shown in Figure 4. e building used a 300 mm module, which included the axis, size of the openable doors and windows, and vertical dimensions of the building.erefore, the HIP dimensions were also controlled according to the following four types: 300 mm × 300 mm, 300 mm × 600 mm, 300 mm × 400 mm, and 400 mm × 600 mm (as shown in Figure 5).
Di erent from the other ordinary aspects of envelope construction, modular connections must be installed after the module is transported to the site.Installation relies on an integrated envelope panel to improve construction efciency.erefore, an integrated envelope unit must rst be constructed in a factory, according to the following steps: the OSB panel is used as the basement material, and the HIP's insulation layer is attached to the OSB, with the keel frame in between.It is then covered with a layer of nishing material, while the other side of the OSB is covered with a waterproof layer.en, the integrated envelope units (including the structural, insulation, moistureproo ng, and nishing layers) are installed entirely as a hanging board at the module's connection point (as shown in Figure 6).Advances in Materials Science and Engineering 3

Using ABs to Improve Heat Preservation and Solve the ermal Bridge Problem
(1) Integrated Building Envelope Using ABs.In 1931, the American researcher S. Kistler developed silica aerogels via an ethanol-based supercritical drying technique.In the 1970s and 1980s, aerogel was used in Cherenkov detectors and to store rocket fuel.In the 1990s, the material was employed as heat insulation for the space shuttle and in US jet propulsion laboratories [28].In architecture, aerogel is of interest because of the microvoid nanometer-restrained heat transfer of air molecules.Also, the refractive index of silica aerogel is close to 1, and the ratio of the extinction coefficient to infrared and visible light is more than 100; the result is the effective pass-through of sunlight, preventing infrared radiation and related increases in ambient temperature.erefore, aerogels have become an ideal transparent insulation material, applied in both solar energy utilization and building energy conservation [29].By means of synthetic methods, aerogel can be combined with glass fiber cotton or preoxidized fiber felt.AB's thermal conductivity can be as low as 0.015 W/(m•K) at a normal temperature and atmospheric pressure.Compared with traditional materials, the thermal conductivity of AB is three to five times better than rock wool of the same thickness [30].
In addition, AB offers certain advantages such as A1 fire protection; it is also easy to cut, lightweight, and has a high hydrophobicity and thus is the insulation material most suitable for prefabricated buildings (as shown in Figure 7).e construction details of the building envelope using AB as insulation were as follows: a 15 mm thick OSB panel was used as the basement material, and a 10 mm thick AB was attached to the OSB structural layer.e other side of the OSB was attached with a waterproof layer, an upper layer covered with keel, and an exterior finishing layer (as shown in Figures 8 and 9).Since the AB layer had no size constraints, the size of the thermal insulation material could be adjusted according to the modular building's modules.
(2) Design for ermal Bridge Prevention at Module Connection Points.When the four corners of a module are supported by steel columns and double-steel columns are used at the connection points of a building module, the two modules must be spliced.In the absence of a well-designed thermal insulation, the steel columns may be directly exposed to the outside on the integrated external wall. is can lead to weaknesses in the thermal bridge to the building environment.A detailed construction plan designed to avoid this weakness must be based on the basic modules of the building and an integrated building envelope unit; after the two building modules are assembled on-site, these modules will hang on the construction.In this case study, the integrated building envelope unit was 600 mm at the two building modules' connection points, as determined by the experimental building's module size.
e specific process used a reverse install technique to attach the AB, waterproof layer, keel, and exterior finishing layer to the OSB structural layer.After the integrated envelope unit was constructed, it was installed with the reserved connecting piece of the main steel beam structure and fastened with self-tapping nails.
is method integrated the structural, thermal insulation, moisture-proofing, and exterior finishing layers into a single unit, which will be beneficial in the multiple assemblies and disassemblies that often accompany prefabricated buildings (as shown in Figures 10 and 11).

Replaceable Modules Based on Climate Adaptation.
ere are two kinds of climate regulation characteristics related to building envelopes and the spaces they form: climate defense and climate utilization.Climate defense reflects the "buffer" strategy of auxiliary functional space, while climate utilization refers to the dynamic regulation of the joint actions of the building's envelope and space.omas Herzog believed that architecture's form can be conceptualized as similar to human skin, and the internal function can be understood like bones.e clothing people wear, its different styles and materials, expresses human diversity and societal individuality.Clothing and building envelopes are similar in that they are both public and private "interfaces" [32].A building's envelope contains a variety of mass flows and therefore requires multiple functions [33].According to the time, climate, status of use, and other factors, a building skin incorporates a combination of functions, some complementary and some in competition with one another, including sight penetration, sight view, natural lighting, shading, heat preservation, heating, ventilation, air filtration, natural risk barriers, sound insulation, and climatic buffers.
e southern-facing outer layer of a building's doubleskin facade (DSF) was designed and studied in this research.Various replaceable modular designs based on climate adaptation and occupants' requirements were imparted to the outer interface [34,35].In the southern facade's vertical direction, the outer interface of the DSF was divided into three segments from bottom to top (according to the human scale and occupant requirements); these included the protected, sight, and shading zones (as shown in Figure 12).e aluminum material panel provided the possibility of numerically controlling the machined processing of the outer layer.
rough a computer parameterization algorithm, the bottom of the facade's outer layer (called the protected zone) was designed to be the smallest aperture; this was to guarantee the sturdiness and compactness of the  Advances in Materials Science and Engineering building's envelope and also to prevent natural creatures near the ground from entering into the building through the hole.e middle of the outer layer, 60 degrees up and down to a height of 1.7 m, was considered the sight zone, with larger holes to ensure users have an adequate view.e southern facade also needed to consider shading during the summer.erefore, the hole size was reduced at the upper part of the interface, which prevented excessive solar radiation from entering.
e climate adaptation design is also embodied in the opening mode of the DSF interface.e outer interface could turn from 0 to 90 degrees by using an intermediate axis (as shown in Figure 13).In addition, in order to maximize the exibility of the usage mode, the detailed design combined a middle axis rotating shaft together with a horizontal pushand-pull rail.us, the standard-sized outer interface could be completely retracted at both the western and eastern ends of the building in order to provide an unshielded view or multiple interface forms (as shown in Figure 14).
Important aspects of prefabricated buildings are the standardization and modularization of their design [36].Besides the outer layer of the DSF, this design tested in this research was also based on the building components' standardization with multiple functions in order to realize various approaches to climate responsibility and adaptability.To achieve goals such as sight penetration and occlusion, natural lighting, shading, thermal insulation, preheating, ventilation, air ltration, the provision of natural risk barriers, sound insulation, and climate bu ering, ve basic facade treatments were designed: perforated aluminum plates, glass panels, air lter membranes, mosquito net panels, and AB insulation panels.e ve interfaces formed a dynamic building interface with di erent functions that replaced more climate-orientated arrangements (as shown in Table 1).Each interface module was designed to t the same component size, could be prefabricated as standardized in the factory, and was installed on the metal frame.
ere were also three trough-cable rails that could be inserted into the metal frame.With a single-slice, doublelayer, or three-layer combination arrangement, users could set up these prefabricated interface modules according to their requirements, ultimately achieving a higher building environment performance (as shown in Figure 15).Advances in Materials Science and Engineering thermal insulation performance of a building.According to the official Chinese standard in the Design Standard for Energy Efficiency of Public Buildings, if a building's shape coefficient is less than 0.30, the heat transfer coefficient of the exterior wall should be no higher than 0.50 W/(m 2 •K).If a building's shape coefficient is between 0.30 and 0.50, the heat transfer coefficient of the exterior wall should be no higher than 0.45 W/(m 2 •K) in cold climate zones [37].If a building's shape coefficient is less than 0.30, the heat transfer coefficient of the building's roof should be no higher than 0.45 W/(m 2 •K).If the building's shape coefficient is between 0.30 and 0.50, the heat transfer coefficient of the building's roof should be no higher than 0.40 W/(m 2 •K) in cold climate zones [37].e comprehensive heat transfer coefficient achieved by using two kinds of thermal insulation is shown in Table 2.As compared to the national standard, the heat transfer coefficient achieved when using HIPs as the insulation material was calculated as saving 73%∼76%.e heat transfer coefficient achieved by using ABs as the thermal insulation material was 43%∼49%, as compared to the national standard.

Results and Discussion
e equation for calculating the comprehensive heat transfer coefficient of a building's exterior (nontranslucent) envelope is shown here as (1).erefore, the comprehensive heat transfer coefficient, K 0 , of the external walls and roofs, based on the two kinds of thermal insulation materials, can be calculated as shown in Table 2: where R i is the heat transfer resistance value of the inner surface.According to the shape relation of the building and climate conditions, the value can be obtained as 0.11 m 2 •K/W.e variable R n represents the comprehensive heat transfer resistance of the wall, and R e is the heat transfer resistance value of the outer surface.According to the surface features of the building and the climatic conditions, the value can be obtained as 0.05 m 2 •K/W.e variable  Advances in Materials Science and Engineering δrepresents the thickness of the material (in mm), and λ is the material's thermal conductivity (in W/(m•K))

Experimental Setup and Measurement Conditions.
e building used in this experiment was located in a cold climate zone in Beijing, China.It was a net-zero independent house that had adopted a modular prefabricated building system.
e shape coe cient was 0.44, and the building construction footprint was 82 m 2 (as shown in Figure 5); HIPs were used as the insulation material (as shown in Table 2) [38].To test the e ectiveness of the insulation construction detail in di erent climate conditions over the course of an entire year, the test period was divided into four separate phases.Together, the four phases lasted more than  8 Advances in Materials Science and Engineering one year, beginning in the December of 2013 and ending in the January of 2015. is research selected two physical quantities, temperature and heat flux, which were determined to reflect the thermal environment quality of the building.e goal was to test the actual thermal performance of the structure during the operating phase (Table 3) [39].

Results and Discussion
. Figure 16 shows a comparison of the building's indoor and outdoor temperatures during winter, transition seasons, and summer.rough the temperature curve, it can be seen that the outdoor temperature fluctuated conspicuously in winter.During the test period, the highest temperature was 16 °C and the lowest was −3.2 °C.While the amplitude of the indoor temperature's fluctuation was very small, its actual fluctuation ranged ±3 degrees above or below 5 °C.e indoor temperature was influenced very little by the external temperature, indicating the good insulation ability of the building (as shown in Figure 16(a)).During the transition season (spring), the highest outdoor temperature was 33.8 °C and the lowest temperature was 6.7 °C; the indoor temperature fluctuated within a range of ±6 degrees above or below 18 °C (as shown in Figure 16(b)).In summer, the highest outdoor temperature was 50.3 °C, while the lowest temperature was 14.1 °C; this meant that the maximum temperature difference in the outdoors reached  Details and parameters (i) Four layers of low-e insulating glass with a thickness of 5 mm/42 mm and a U-value of 0.48 W/(m 2 •K), a shading coefficient of 0.443 for the south glazing wall (ii) Wall material: 80 mm mineral wool + HIP, a U-value of 0.2 W/(m 2 •K) (iii) Roof material: 130 mm mineral wool and HIP, a U-value of 0.1 W/(m 2 •K) Other strategies (iv) PV system: 70 m 2 PV panels with a capacity of 11.5 kW, thin film photovoltaic panels (v) Solar thermal: solar vacuum tube collectors (vi) HVAC: WSHP (cop � 6) and ASHP (vii) Water system: membrane bioreactor water treatment technology Source: authors' own data.10 Advances in Materials Science and Engineering 36.2 °C, while the indoor temperature di erence was only 8.5 °C. is indicates the building's excellent thermal insulation performance (as shown in Figure 16(c)).e curves in Figures 16(d) and 16(e) illustrate the heat ow densities for the test building's southern, western, and northern walls during summer weather conditions.As can be seen in Figure 16(d), although the southern facade absorbed a considerable amount of solar radiation, the di erence among the average heat ux densities for the three facades was very little: southern facade (2.27 W/m 2 ) > northern facade > (0.86 W/m 2 ) > western facade (0.48 W/m 2 ).erefore, the overall heat gain was relatively small.Figure 16(e) illustrates the changes in the hourly heat ux density curve and thus the di erences among the three facades.e uctuation was more obvious in the southern facade than in the northern and western facades, due to the in uence of summer solar radiation.

3.3.
e Climate Adaptability of an Integrated Structure throughout an Entire Life Cycle.Section 2.2 addressed an integrated changeable module facade based on a DSF.Combining the di erent open and closed status modes of the inner and outer layers simulated the usage pattern of the building throughout an entire year's climatic conditions.Figure 17 illustrates the four modes and all statuses, including the shading/air lter mode in the summer during the day, natural ventilation mode in the summer at night, sunspace mode in winter during the day, and sunspace/air lter mode during the transition season.e simulation of thermal conditions focused on the typical climatic week of an entire summer day and an entire winter day.e comparisons of indoor and outdoor temperatures and cooling and heating loads before and after changes in the variable interface are discussed below.
During summer days, the interface was used to block excess sunlight.e result was that the outer interface of the changeable DSF facade had three layers of modules, including (from outside to inside) a perforated aluminum plate, an air lter, and a mosquito net, all of which played a role in shading and air ltration.Figure 18 shows the thermal environment data for the perforated aluminum plate shading in the experimental building (the building used in this experiment is shown in Figure 5. e shape of the building was rectangular.e size ratio was 12 m (L) × 5.7 m (W) × 3 m (H).e DSF facade was located on the Advances in Materials Science and Engineering southern facade of the building) in the hot summer and warm winter zones of Shenzhen, during a typical work week (from July 1 to July 7).e red curve indicates the interior temperature environment without shading, and the blue curve illustrates the interior temperature when the sun shading board was in use. is clearly illustrates that the sunshaded plate inhibited heat transfer, especially during hightemperature times (over 35 °C).e maximum temperature di erence with and without sun shading was 3 °C.Figure 19 shows the corresponding cooling load histogram, which shows that the cooling energy load saving was 10.5%∼14.2%from 7 am to 6 pm.
During winter days, the greenhouse e ect in the sunspace will preheat the indoor space, improving the indoor temperature and reducing the energy consumption demand.erefore, a single layer of glass or ETFE lm was inserted into the outer interface of the DSF; its e ect is shown in Figure 20. is research simulated the combined glass interface and corridor of the experimental building, which were used as a sunspace.e building was located in a cold area, Beijing, during a typical work week (from January 1 to January 7).e red curve illustrates the interior temperature environment without the glass interface, and the blue curve indicates the interior temperature with the combined glass interface and corridor.Under the DSF preheating function, the indoor temperature improved throughout the day and had a positive e ect on the indoor thermal environment.Especially during the daytime when there was ample solar radiation, the DSF mode was able to raise the indoor temperature by 2 °C, and the highest temperature di erence between the interior and exterior reached 5.7 °C. Figure 21 shows the corresponding heating load in winter.Depending on the daily solar radiation, there was a marked di erence in solar gain in the sunspace.Under typical conditions, this design mode saved heating energy consumption, on average, by approximately 24.6%; at its highest point, these savings reached 38.3% during the daytime, from 7 am to 6 pm, which obviously underscores the usefulness of preheating.

Conclusions
is research designed and evaluated a modular prefabricated building in an e ort to improve its performance in terms of sustainability.Certain prefabricated construction details of the modular building envelope were studied, beginning with the steel frame of the modular structural system.In order to improve construction e ciency in this type of modular prefabricated building, as well as to enhance the physical environment and reduce energy consumption during the operational phase via integrated thermal insulation, two basic prefabricated envelope units were developed.
e rst employed high-performance thermal insulation materials to produce an integrated building envelope and modular connection points, the goal of which was to improve the building's performance in terms of sustainability.e second used the DSF principle to study how changeable module envelope units respond in terms of  12 Advances in Materials Science and Engineering climate adaptability.By constructing an experimental building, full-scale model, and computer simulation, this research veri ed the feasibility and e ectiveness of several integrated building envelope units.is research has contributed to the literature in three key ways: (1) is study selected two types of thermal insulation materials, high insulation panels and aerogel blankets, in order to study certain construction details of integrated building envelopes in modular prefabricated buildings.e comprehensive heat transfer coe cients for the two integrated envelopes were 0.124 W/(m 2 •K) and 0.257 W/(m 2 •K).With energy savings of 75% and 45%, respectively, both o ered insulation capacities signi cantly better than the current national standard.
(2) Focusing on the weakest heat point, the thermal bridge that occurs at modular connection points, this study attempted to use construction detail design and research to build an experimental building and full-scale building model.e goal was to explore and verify the feasibility of the climate-responsive construction technique called "reverse install."Longterm monitoring of the physical environment proved the e ect of the integrated envelope on the connection points of two modules comprising a prefabricated building.When the outdoor temperature di erence reached 36.2 °C during summer days, the interior temperature di erence was only 8.5 °C. is illustrates the excellent thermal insulation performance of the building envelope's design.(3) To address issues related to climate change, building facade units were dynamically adjusted via di erent modular building envelope units; these included sunshades, preheaters, ventilation, air ltration, pest control, and other functional elements designed to improve the building's climate adaptability performance.e e ects of the changeable building envelope units were veri ed by the computer simulation.Advances in Materials Science and Engineering

Figure 2 :
Figure 2: Hoisting and installation of a modular prefabricated building prototype (source: authors' own data).

Figure 4 :
Figure 4: Exterior wall construction detail using the HIP's insulation layer (source: authors' own data).

Figure 5 :
Figure 5: Building's exterior wall with HIPs employed during the building process (source: authors' own data).

3. 1 .Figure 7 :Figure 8 :
Figure 7: Contrast of infrared imaging with the rock wool panel and AB as insulation materials (source: [31]).(a) Pipe photo, (b) infrared thermal imaging of the pipe, (c) rock wool panel as the insulation layer, and (d) AB as the insulation layer.

Figure 11 :
Figure 11: Full-scale model and connection details (source: authors' own data).

Figure 12 :
Figure 12: Vertical division of the sample outer layer (source: authors' own data).

Figure 13 :
Figure 13: Detailed design of a combined middle axis rotating shaft and horizontal push-and-pull rail (source: authors' own data).

Figure 14 :
Figure 14: A combined middle axis rotating shaft and horizontal push-and-pull rail to realize multiple interface forms (source: authors' own data).

Figure 16 :
Figure 16: ermal environment test of a modular prefabricated building using HIPs as the insulation material (source: authors' own data).(a) Winter temperatures; (b) transitional season temperatures; (c) summer temperatures; (d) oating box line diagram of summer heat ux density; (e) hourly curve diagram of summer heat ux density.

Figure 17 :
Figure 17: e climate adaptation mode of the integrated changeable modules throughout the building's entire life cycle (source: authors' own data).(a) Shading/air lter mode (summer day); (b) natural ventilation mode (summer night); (c) sunspace mode (winter day); (d) sunspace/air lter mode (spring and autumn days).

Figure 18 :
Figure 18: Temperature comparison with and without shading/air ltration mode (source: authors' own data).

Figure 21 :
Figure 21: Heating load comparison with and without sunspace mode (source: authors' own data).

Table 1 :
Dynamic combinations of replaceable interface modules.
Integrated design of the building facade, sun shading, heat preservation, and preheating bu er zone 11 Perforated aluminum plate + AB insulation panel + air lter membrane Building facade, sun shading, heat preservation, and air ltration 12 Glass panel + AB insulation panel + glass panel Bu er layer, preheating, and heat preservation, suitable for winter and nighttime in cold climate zones Source: authors' own data.

Table 2 :
Heat transfer performance of the integrated envelope.
Source: authors' own data.
Figure 20: Temperature comparison with and without sunspace mode (source: authors' own data).Cooling load comparison with and without shading/air ltration mode (source: authors' own data).
Sun shading in Shenzhen was shown to save cooling energy load consumption by 10.5%∼14.2%during the daytime; similarly, in Beijing, sunspace was shown to save the average daily heating load consumption by approximately 24.6%.data used to support the ndings of this study are available from the corresponding author upon request. e