China Academy Works | "Green House", a low-carbon creation that shows the bigger picture through small details

This is a case study of the renovation of a small office space. The renovation project is located in a 1950s-era office building in Beijing, with an area of approximately 900㎡. As a team specializing in green design, we aim for "full life-cycle decarbonization." This project served as an opportunity to conduct a "low-carbon creation" experiment, and two full years of operational data verified the energy-saving and carbon-reduction effects of the renovated space throughout its lifecycle.
 

Common renovations of existing building spaces mainly focus on functional and spatial modifications, involving the extensive demolition of existing facilities, generating construction waste; using heavy materials to partition spaces, wasting resources, and lacking the possibility of spatial changes; relying on mechanical facilities to increase comfort, ignoring the regulating effects of spatial layout and ecological greenery.

Natural elements such as wind, light, heat, and green plants improve the microclimate, which is essential for human health. We define the renovation of the office space as " low-carbon creation ", aiming to create an environment that is both energy-efficient and material-saving, and surrounded by nature and greenery, transforming a "grey" functional space into a "green" ecological and healthy space.

▲ Existing building exterior ▲ Before renovation floor plan. The renovation area is approximately 900㎡ on the west side of the office building. ▲ After renovation floor plan. The existing floor slab has been reinforced with steel structure, with a net height of approximately 2.85m under the beams. ▲ Renovated entrance space ▲ Renovated reception space

" Less decoration 、 More nature 、 Lightweight construction 、 Large amount of greenery " became the main approach to low-carbon creation. We propose Space energy use 、 Flexible adaptability 、 Lightweight construction 、 Increased greenery 、 Recycling 、 Intelligent control and six other strategies. ▲ Summary of low-carbon creation strategies

01 Space energy saving Energy decomposition and extension of the transition season. While dividing functions, we also considered the decomposition of spatial conditions and energy use. The south side is the glare wind-inducing area. The workstation layout gives way to an open corridor, which acts as a buffer against direct outdoor sunlight, avoiding the direct impact of glare on users. Plants can be placed in the corridor, or artwork can be exhibited.
▲ South side open corridor solves glare problem ▲ South side green corridor
The north side is the wind-buffering area, suitable for non-long-term activities. Partially enclosed meeting rooms are set up in the gaps to prevent the north wind from affecting the interior during winter; a transparent grid wall is used as a partition between the north and south sides, with many openings between the grid wall modules, ensuring the connectivity of the physical space and allowing for air convection inside; the east side entrance is the area with the greatest wind pressure, and an entrance ecological exhibition hall is set up to reduce personnel stay, and the large ventilation volume also promotes the good growth of plants; the middle part is the high-comfort area, with open offices for long-term personnel stay.
▲ The north wind-blocking area and the south wind-inducing area jointly affect the central high-comfort area
▲ Public area (high-comfort area) and green corridor (glare wind-inducing area)
Zoning of space energy use reduces the energy-consuming area. Combined with good natural lighting and natural ventilation from north to south, the annual energy consumption is significantly reduced. According to research and calculations, the extended transition season duration through energy decomposition, natural lighting, and natural ventilation can reach 612 hours, reducing building carbon emissions by approximately 24.2 tons/year.
02 　Flexible adaptability From space to interface to facilities, future variability. Space is freely variable, interfaces and furniture are movable and detachable. This flexibility fundamentally represents the intensive use of resources. The northeast side of the renovated space is an open activity area, with daily functions mainly for discussion, reading, and leisure; when hosting lectures, exhibitions, and other social activities, the space form and functional layout can be transformed using sliding partitions.
▲ Schematic diagram of the use of the multi-functional comprehensive open area
▲ Actual use of the multi-functional comprehensive open area
Single-piece rotatable sliding partitions made of polycarbonate panels can independently control the position of each partition and define the function type of the partition according to spatial needs, such as sliding walls, rotating doors, and display back panels.
▲ The polycarbonate pivot partition in the lobby can adjust the angle to control the amount of light entering.
In addition, the interface system extensively uses assemblable grid partitions, combination partition walls, and electro-fogging glass partitions to create diverse functional experiences through rapid interface conversion; movable furniture and detachable grids are used to achieve the diversity of spatial layout.
▲ Separation and connection between meeting rooms and offices are achieved through sliding partitions.
03 　Lightweight construction Lightweight construction, minimizing material use according to low-carbon principles, represents material savings and is a direct manifestation of low-carbonization. The project uses lightweight steel structures, which have greater material-saving and environmental benefits compared to wood. The project adopts a modular prefabrication concept, independently designing a detachable grid system, and integrating a series of lightweight methods such as thin steel rod frames, acrylic partitions, and steel sheet book supports.
▲ Modular steel frame assembly schematic
▲ Modular steel bookshelf with plants forming a "green wall"
Lightweight partitions use polycarbonate panels, and the furniture system uses lightweight methods such as steel plates and steel rods, releasing usable space and saving materials. The lightweight and rapid construction and self-installable and adjustable processes shorten the construction period, improve the construction environment, and meet the conversion of multi-functional needs in the later stage. According to research and calculations, the material saving through lightweight assembly construction is about 1.8 tons, and the reduction of carbon emissions throughout the building's life cycle is about 1.8 tons/year.
▲ Lightweight building materials and simple and adaptable node structures ▲ Polycarbonate panels with varying degrees of transparency showcase a multi-layered material texture
04 　Increased greenery Surrounding ecological health, maximizing the carbon sink's three-dimensional ecosystem utilizes biological organisms to regulate air quality and achieve carbon sequestration, reducing carbon emissions during operation and creating a green space. On the south side of the open office area, there is a shared green path defined by green walls, landscape pots, and workstation greenery, serving as both a public walkway and a shared space for external display and internal rest and relaxation.
▲ Green Enhancement Strategy ▲ The green corridor system forms an indoor garden ▲ Before and After Comparison of Green Corridor Renovation ▲ Green Corridor in Sunlight ▲ Employees resting and communicating in the green corridor space
Three-dimensional greening systems are installed at the entrance exhibition area and the south side of the office area. The ceiling uses a mirror composite panel with reflective effects, magnifying the ecological interface of natural light and green walls upwards, expanding the range of ecological space.
▲ The mirror composite panel ceiling at the entrance extends the ecological space. The green wall on the inner side of the south wall also regulates the wall's heat storage performance, creating a warm winter and cool summer effect in combination with natural ventilation. The ecological atmosphere created by the multi-layered three-dimensional greening, including green walls, workstation greenery, frame greenery, and potted plants, creates a healthy and natural spatial feeling for users, relaxing their minds and stimulating their thinking. According to research and calculations, increasing greenery can reduce building carbon emissions by approximately 0.2 tons/year.
▲ Greenery Everywhere ▲ Furniture installation "Qu Shui Liu Shang" in the green corridor and multi-layered three-dimensional greening
05 　Recycling Low-carbonization of waste material reuse and renewable energy building renovation prioritizes maximizing the use of existing facilities. The design retains the original enclosure, bare top, and some usable equipment. The ground of the main office area retains the original base layer, and PVC is directly laid after cleaning the floor tiles and filling the gaps with self-leveling.
▲ Directly laying PVC rolls on the original base layer, reusing air conditioning equipment
We crushed and cut the removed glass waste and metal profiles to make aggregates and incorporated them into terrazzo. After multiple cuts and polishing, a special texture different from traditional terrazzo was formed.
▲ Incorporating removed keel glass into the concrete floor
We recycled discarded plastic bottles, re-melted, woven, and utilized them to create unique polyvinyl chloride woven carpets. These seemingly ordinary wastes are re-presented through recycling and processing, also showcasing diverse green aesthetics.
▲ Polyvinyl chloride low-carbon material made from dissolved and woven plastic bottles
The entire renovation process uses green building materials, adhering to biodegradable and recyclable standards, making extensive use of industrial virgin materials and integrated wood, and reducing secondary brushing. The delicate and refined small-pattern galvanized steel plate, the simple and hazy polycarbonate plate, the infinite mapping of the mirror plate, the rough metal steel mesh and steel plate, and the warmth of solid wood integrated materials all create surprising spatial effects through the use of different material properties.
▲ Using industrial virgin materials, reducing secondary brushing ▲ Traditional waterproof material—galvanized iron plate slow reflection, rich visual effect formed by green plants
The facade partially uses a composite BIPV solution—vacuum low-carbon photovoltaic glass. This product is a double-glazed window composed of photovoltaic glass and vacuum atomized glass, integrating power generation, heat insulation, sound insulation, shading, and dimming functions; the electricity generated by the external photovoltaic glass can directly control the internal atomization effect, and the product itself builds a complete energy self-circulation system.
▲ Application of integrated BIPV photovoltaic glass

06 Smart Control Guiding the use behavior and facility matching throughout the entire life cycle. In the entire life cycle, the low-carbon effect is largely closely related to the user's behavior. In order to better serve diversified "smart" objects such as space, resources, behavior, and equipment, the project has established a smart office platform based on the circular logic of "perception-transmission-analysis-feedback," performing environmental perception and information collection on changes in space lighting, temperature, airflow, and behavior, transmitting the collected data to the central platform, completing data analysis based on intelligent algorithms, and then feeding back the equipment response strategy to the intelligent terminal, and the intelligent terminal synchronizes the central platform to carry out system control.
▲ System Construction with "Wisdom" as the Center

▲ Smart Low-Carbon Internet of Things Office Interaction and Release System

▲ Daily Operation Data Release of Office Space (Real-time Update)

▲ Sensors and Smart Terminals Used in the Project

For example, environmental perception management will gradually open and close the interior lights according to the intensity of natural light. When natural light is insufficient, the lighting equipment uses the method of "automatic detection and zonal supplementary lighting" to achieve optimal illuminance in the entire area, meeting both comfort and energy-saving effects; controlling the air conditioning based on the indoor temperature to avoid user energy waste; energy control data will feedback to users when it is suitable to open windows for ventilation or air conditioning; space usage management will allocate more reasonable resources for users to avoid waste. Smart methods provide all-round protection for the realization of low-carbonization and better guide users' behavior and the optimal matching of facilities.
 

▲ Light intensity automatically adjusts according to natural light flux

07 Seeing the Big Picture in the Small An experimental
▲ Average annual energy saving rate (2022-2024) of office space electrical system (actual measurement) 
▲ Low-carbon construction strategy diagram
Project Location  Xicheng District, Beijing Renovation Time   2022
Design Team   China Architecture Design & Research Group Green Building Design Institute
Design Lead  Liu Heng Architectural Design   Liu Fei  Xu Feng  Cui Chenyang  Xu Changyu  Huang Jianzhao  Yang Qian  Cao Yang M&E Design   Gao Zhihong  Xu Hongxing  Ren Zhihui Smart System Coordination   Huang Jianzhao On-site Control   Xu Changyu
Photovoltaic and Partition Technology Consultation   Xinliji Energy-saving Glass (Tianjin) Co., Ltd. Polished Concrete Technology Consultation  Beijing Dagu Architectural Technology Development Co., Ltd.