1. Introduction
In November 2012, at the 18th Congress of the Chinese Communist Party, China’s President Hu Jintao described building a “beautiful China as the construction of ecological civilization” [
1]. Two months later, reality replaced imagery as a thick and severe smog, blanketing almost all of China’s east coast. In smog-choked Beijing, “peak readings for air pollution during the Chinese New Year were 40 times the World Health Organization’s air-quality guidelines” [
1]. There is perhaps no better demonstration of the urgent need to address China’s environmental issues and green the economy. Is China ready and able to do so? We think so, and are encouraged by the nascent green building movement that is developing in China today.
1.1. Impact of Buildings in China
China is building new commercial buildings at an enormous rate—roughly 2 billion square meters per year, while the U.S. projected growth for the commercial building sector is roughly an order of magnitude lower, at 100 million square meters per year through 2030. The floor area for existing U.S. commercial buildings, 7.6 billion square meters, is slightly larger than the Chinese floor area for existing buildings, at roughly 7.1 billion square meters [
2,
3].
Twenty percent of total primary energy consumption and carbon emissions in China come from the building sector. In 2008, the primary energy consumption of buildings in China was nearly 380 million tons of oil equivalent (excluding biomass energy), or a 1.5 fold increase relative to 1996 [
2,
4].
The energy intensity (energy per unit of floor area) in buildings differs significantly across different climate zones. In China, the long winter heating period in the northern regions has led to a significant increase in energy use in the Hot Summer Cold Winter (HSCW) zone, while cooling energy use has skyrocketed in both the HSCW zone and the Hot Summer Warm Winter (HSWW) zones [
2]. Energy intensity in buildings also differs significantly by building type. For example, electricity intensity in large public buildings (>20,000 square meters) is often 2–3 times higher than that in smaller public buildings.
Carbon emissions associated with building energy use reached 1260 million tons in 2008. Both Chinese and foreign experts estimate that there exists “a huge potential for curtailing the increase in energy demand and greenhouse gas (GHG) emissions reduction by improving energy efficiency in China’s building sector” [
2].
1.2. Status of Green Buildings in China
In 2007, the Chinese Ministry of Housing and Urban-Rural Development (MOHURD) initiated a program entitled “100 demonstration projects of green buildings and 100 demonstration projects of low-energy consumption buildings”.
Figure 1 shows the growth from the start of green building evaluation and labeling in China in 2008 to the conclusion of this initiative at the end of 2011. During this period, a total of 271 buildings were awarded with a green building evaluation label [
2].
Figure 1.
Number of Green Commercial Building Projects in China, 2008–2011. Source: [
2].
Figure 1.
Number of Green Commercial Building Projects in China, 2008–2011. Source: [
2].
By December 2010, the “projects in China that received green building certificates had a construction floor area of 1.3 million square meters. China has targeted more than 80% of government invested new public construction needs to be green buildings by the end of the 12th Five Year Plan in 2015” [
2].
2. Designing the IBR Building
The Shenzhen Institute of Building Research (IBR) designed its new headquarters “as a green experiment” [
5]. As both the architect and client for the project, the design team could pursue a green agenda beyond what their counterparts were doing in China and elsewhere. The team reviewed over 100 sustainable technologies and strategies, and incorporated forty of them, including daylighting, natural ventilation, gray-water recycling, solar-energy generation, and highly efficient Heating Ventilation and Air Conditioning (HVAC) systems. The resulting building is 12 stories high and 18,000 m
2 in floor area. The building was designed between the years 2006 and 2007, with construction completed in March 2009.
According to the building design team, “the IBR design team implemented the green design principals of localization, low-energy consumption, and finely detailed design”. The designers wanted the IBR headquarters to “showcase the best sustainable building practices, while differentiating it from other expensive technology performance green buildings that were being built in Chinese cities” [
5]. The designers of the IBR Building had the goal “of a fully sustainable building, one that would use resources wisely, provide a comfortable work environment, and serve as a model for others interested in designing low-energy buildings” [
5].
Figure 2 shows the schematic diagram for green building design that was used for the IBR. The design for a green building starts with the three elements at the center of the diagram: people, resources, and the environment. To serve these three core elements, the design was carried out to meet six criteria shown in the next ring: land savings, water savings and use of natural water resources, good indoor air quality, energy efficiency and renewable energy harvest, materials savings and natural materials utilization, and good operation and management. To achieve these goals, the building design considers the elements in the final ring: climate, economy, policies, culture, technology, and management.
Figure 2.
Concept of green building design.
Figure 2.
Concept of green building design.
2.1. Climate and Design
China is divided into a diverse set of climate zones, ranging from “severe cold” in the North and Western plateaus, to the “Hot Summer/Warm Winter” (HSWW) in the South (
Figure 3). Shenzhen is located in the HSWW zone, and has mean monthly winter temperatures generally above 10 °C (50 F) and mean monthly summer temperatures in the range of 18–25 °C.
Figure 3.
Climate zones in China. Shenzhen is located in the Hot Summer Warm Winter Zone. Source: Huang and Deringer (2007) and MOHURD (1993) [
2].
Figure 3.
Climate zones in China. Shenzhen is located in the Hot Summer Warm Winter Zone. Source: Huang and Deringer (2007) and MOHURD (1993) [
2].
Climate is one of the most important factors in determining the energy use in a commercial building. The IBR design team worked closely with the local climate features to minimize the amount of energy needed to condition and illuminate the workspaces. Their climate strategies included working with sunlight for passive heating and shading the envelope to reduce overheating, often using PV materials to take advantage of the incident sunlight.
2.2. Sustainable Strategies for the IBR Building
The IBR design team started with the passive principles suitable for their hot-summer and warm-winter regional climate. They then took the strategy of integrated design, through the selection of the best technologies and coordination of multiple systems. They did multiple simulations and applications with their Building Information Modeling (BIM) models to arrive at optimal strategies. The result was a systems analysis that led to their novel layout of the building, including structural design, and functional zoning.
2.2.1. HVAC System and Zoning
The IBR building has different HVAC systems to accommodate the building’s different cooling needs. The basement and 1st floor use a water source heat pump (WSHP). The heat pump is located close to the landscape water pool, so the close-loop condenser water exchanges heat directly with the water pool, which further reduces condenser water temperature and increases the WSHP system efficiency.
The rest of the floors use high chilled water supply temperature chillers (18 °C CHW supply temperature), with solution-based, dehumidification air-handling units, and fan coil units. Since the CHW temperature is high, the fan-coil units just condition the building’s sensible heat load, which avoids condensing moisture and saves energy used for latent heat. Solution-based dehumidification air-handling units are used to control the indoor relative humidity. This system not only controls sensible and latent heat separately, thereby saving energy, but also provides good indoor thermal comfort.
The building is zoned to have relatively smaller AC zones. The intent was to try to use natural ventilation to meet occupants thermal comforts whenever possible, and thereby reduce AC operating hours. For example, the balconies, hot water rooms, restrooms and elevator rooms do not have AC and rely entirely on natural ventilation.
2.2.2. Natural Ventilation
The building is designed with horizontally pivoted windows to control the natural ventilation and direct the airflow above the work surfaces. The designers modeled the natural ventilation using computational fluid dynamics (CFD) that showed that pivoted windows could provide better natural ventilation than other traditional window designs.
2.2.3. Hot Water System
Solar thermal collectors are installed on the building’s rooftop. The collected hot water is used for the building’s cafe and shower rooms. It is estimated that the solar thermal system can produce hot water at around 4350 tons per year, with energy savings of 91.2 tons of coal equivalent per year.
2.2.4. Lighting
The building uses LED lights for its outdoor lighting, primarily for the building’s signage on its west and south side. Daylight tubes are installed in the basement garage, providing 100% of the daytime lighting needs. The building integrates daylighting throughout the office spaces, which controls indoor lighting fixtures based on the lighting from the outdoor environment.
2.2.5. Building Envelope
The IBR building uses low-E double-paned windows with frames made from an aluminum alloy, for good daylight, thermal, acoustic and anti-freezing performance. Based on the IBR specifications, the windows have a visible light transmittance (VT) of 0.45, shading coefficient (SC) of 0.4, a thermal conduction coefficient (K) of 2.0 W/m2 K, and acoustic isolation performance of 60 dB(A).
Different window to wall ratio (WWR) numbers are used for different areas of the building. The lower areas of the building are mainly designed for labs and conference rooms, where a WWR value of 0.3 was used for the South, East and North elevations to minimize daylight impact on lab testing and conference space. The upper part of the building is used for office space, where a WWR value of 0.7 was chosen to make use of daylight and reduce artificial lighting energy consumption.
Shading is important for buildings located in Hot Summer Warm Winter (HSWW) climate region in China, and the IBR building adopted different shading strategies for different elevations. Overhangs with interior screens are used for office rooms. Vegetation is planted to cover parts of the building’s west side facade. The opaque part of building envelope applies insulation materials and aluminum exterior finishing on cast concrete, which makes the building envelope easy to clean and maintains good thermal integrity. The west side of the building facade is integrated with thin film PV. The PV-integrated facade has a visible transmittance of 0.2, which maintains acceptable visibility and harvests renewable energy for the building.
The design team considered several other green design features that did not make it into the final design. Technologies that were considered but didn’t get used included adjustable exterior shades and a greater use of recyclable building material.
2.2.6. Building Massing and Integration
The architects designed the building as a set of “building blocks” explains IBR Dean Qing Ye. “The three-dimensional stacked functions are the unique aspects of the building”. By organizing portions of the building into various blocks and stacking them, the architects were able to create a 12-story outdoor atrium on the east side that captures southeasterly breezes and brings daylight deep inside (
Figure 4). Photovoltaic panels covering the atrium provide clean energy as part of China’s first state-level renewable energy demonstration project [
5].
Figure 4.
Shenzhen Institute of Building Research (IBR) building floor plan (7–12 floors).
Figure 4.
Shenzhen Institute of Building Research (IBR) building floor plan (7–12 floors).
2.3. Building Costs and Savings
The architects kept the total per-square-meter construction cost to RMB 4300 Yuan/m2 ($700/m2 or $70/ft2), which is a remarkably low number considering all of the sustainable measures included in the project. Because the design was done in-house, they did not track the design costs, or the incremental costs for the sustainable design features. We do have data for two new green “3-Star” buildings in Shenzhen, and the incremental costs for the green measures were 376 RMB/m2 and 254 RMB/m2 for “2-star” green buildings.
According to the IBR, the average cost for high-end, new commercial office buildings in Shenzhen is between RMB 6000 and 8000 Yuan/m2 ($950 to $1270 per m2 or $88 to $118 per ft2). For middle level new buildings in Shenzhen, the average cost is between RMB 4000 and 6000 Yuan/m2 ($635 to $950 per m2 or $59 to $88 per ft2). There are a few reasons for how the IBR building was able to achieve low cost construction. One is the “design-build” model, where IBR managed the entire building’s design, construction and operation stages through an integrated approach. Another reason is the simple interior design and finishes. We don’t have the results of the energy model to compare a “standard” building with the IRB building, but the IBR has reported that the building reduces annual electricity costs by 15 million RMB ($2.4 million/year), water costs by 54,000 RMB ($8800/year), and carbon dioxide emissions by 1600 tons per year.
4. Building the Future—Building the IBR in Different Climates and Regions
One of the questions about designing a building such as the Shenzhen IBR is whether it can be replicated elsewhere. Can the process that was used by the owner and designer of the IBR be translated to other climates and cultures?
The original building, as explained earlier, was designed for the hot summer, mild winter region of south China. However, the design team also asked the question “What if the buildings were to be located in other regions of China, with different urban/rural conditions, and different climates?”
Figure 16 shows the initial ideas from the IBR design team for how the same program for the building would look in different regions and climates of China.
Figure 16.
IBR building designs in four different Chinese climates (Chinese text in the figure: IBR Building in different climate zones). From left to right: Urban hot summer (existing building); Urban cold winter; Rural hot dry/cold winter (above); and rural hot summer/warm winter (below).
Figure 16.
IBR building designs in four different Chinese climates (Chinese text in the figure: IBR Building in different climate zones). From left to right: Urban hot summer (existing building); Urban cold winter; Rural hot dry/cold winter (above); and rural hot summer/warm winter (below).
The design for the Cold climate features a building with a low surface-to-volume ratio, e.g., a cube-like form. The building has a double-glass envelope to reduce heat loss, and an interior sealed courtyard for bringing landscape to the inside of the workspace. The building is designed as a high-density urban solution.
The design for the hot climate is for a location outside the city on the South China coast, in a less-dense rural area. The building is designed to capture the steady sea breezes both for natural ventilation and electricity generation. Green roofs take advantage of the local high rainfall and the large roof area is used for PV panels as well. The building form maximizes envelope and interior courtyards to allow for cross ventilation and daylighting throughout.
The design for the dry rural region in the northwest of China calls for maximizing the roof surface for PV collection to take advantage of the extensive solar resource. The windows are heavily shaded by overhangs and strategic landscaping. The courtyard design allows for oasis-like outdoor spaces that are protected from the strong winds.
5. Conclusions: A View to the Future Revisited
We started this investigation with a profound pessimism that the current growth in the building industry in China would not address, but rather exacerbate, the daunting environmental challenges faced by the country, and by extension, the world today. What we have seen has been the growing awareness of the environmental challenges by individuals and organizations alike has led to government action, and that environmentally sensitive design is possible. While awareness alone will not slow the environmental impacts facing China, the example of the Shenzhen IBR has shown that a very-low-energy building is not only possible, but that it can provide an exemplary work environment for its users.
Recent research findings by the Energy Foundation and China Academy of Building Research reported that, “under conditions where green building practices were implemented and building energy conservation standards were strengthened and promoted, the greenhouse gas emissions of the building sector in China would witness an inflection point around 2020, and its potential for emission reductions would equal approximately one third of total building sector emissions by 2030” [
2].
For this to happen we see the need for two efforts that are currently administered by two separate government agencies—energy saving (jieneng) and emission reduction (jianpai)—will have to become fully integrated in practice. When this cooperation happens, we see the potential for the design of buildings and cities in China to make the “Green Leap Forward”.
Acknowledgments
Our deepest thanks to our many friends and colleagues at the Shenzhen IBR who made this work possible. They provided warm hospitality for our visits, answered our numerous questions over the course of writing this study, and shared their extensive data and information about the building. Among the many people at IBR who helped include: Vice Dean Junyue Liu, and staff members Zongyuan Liu and Zhen Yu. We also want to thank our LBNL colleagues, starting with Mark Levine, founder of the China Energy Group, who made the initial connections with Dean Ye that led to the development of this work. Our China Energy Group colleagues Lynn Price, Nan Zhou, and Brian Heimberg all played supporting roles throughout the project, offering excellent advice and helpful direction.
This work was supported by the Shenzhen Institute of Building Research and the Assistant Secretary for Energy Efficiency and Renewable Energy, Building Technologies Office, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.
Conflicts of Interest
This work was co-funded by the Shenzhen Institute of Building Research to assess the performance of their building. To avoid conflict of interest, the LBNL team submitted a formal data request so that they could perform independent analyses of the raw data of the building performance.
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