New urban buildings will fully implement green building standards in 2025

Source: Environmental Ecology Network

The construction sector is a major contributor to carbon emissions. Statistical data shows that the total carbon emissions of the entire society in 2020 were approximately 9.88 billion tons. Among the four major areas of carbon emissions in China, namely industry, transportation, construction, and energy, the emissions from the construction sector are approximately 3.95 billion tons, accounting for 40%. With the advancement of urbanization and deep adjustment of industrial structure, people's living standards continue to improve, and the carbon emissions of primary and secondary energy consumption in urban and rural construction will continue to grow, and the proportion will gradually increase.

It is imperative to implement the action of carbon peaking and carbon neutrality in the construction field. Building energy efficiency should be a full lifecycle energy-saving approach. Not only should more green buildings be built and existing buildings undergo energy-saving renovations, but energy should also be saved during the use of the building. The green construction process has good effects in water conservation, material conservation, and pollution reduction, and is being vigorously promoted.

Vigorously improving energy conservation level

Recently, the Ministry of Housing and Urban Rural Development completed the review of the first batch of three-star green building identification projects for the year 2023 and made them public. Six civil construction projects, including the Beijing Daxing International Airport project, and two industrial construction projects are listed. According to the current green building evaluation standards in China, green buildings are divided into four levels: basic level, one star level, two star level, and three star level. Three star level green buildings have higher energy efficiency levels.

Promoting green buildings is an important lever for building energy conservation. China continues to promote the construction of high-quality green buildings, and by 2025, new urban buildings will fully comply with green building standards.

Green buildings are high-quality buildings that save resources, protect the environment, reduce pollution, provide healthy, applicable, and efficient usage space for people throughout their entire lifecycle, and maximize the harmonious coexistence between humans and nature. The concept of green building has gradually penetrated into people's hearts, and under the guidance of institutional mechanisms such as green building evaluation standards, there are more and more green buildings around us.

At the International Campus of South China University of Technology in Guangzhou, the construction team has innovatively developed a complete set of technologies for "Lingnan Green and Low Carbon Campus Design and New Building Industrialization Construction". Bai Simin, the chief technical engineer of the project, introduced that they had developed a campus layout mode suitable for the regional climate by optimizing the shape, orientation and energy saving performance of materials of the buildings, and formed a "cold lane ventilation system" conducive to cooling in summer and transitional seasons. The maximum wind speed of pedestrians walking in the campus could reach 1.1 meters/second, achieving the effect of ventilation and carbon reduction. At the same time, the transition space of office buildings utilizes a "climate chamber" to promote passive ventilation during summer and transition seasons; In winter, the top air outlet of the "climate chamber" is closed, forming a concentrated heat storage space that actively adjusts the indoor thermal environment in conjunction with the building. Fully utilizing natural conditions to achieve energy conservation and consumption reduction, the building energy consumption index is reduced by 23.1% compared to the standard value, which can achieve an annual electricity saving of 5.48 million kilowatt hours. It is reported that the ventilation and heat dissipation technology of the building's "climate chamber" has reached an international leading level.

In terms of existing buildings, China vigorously promotes energy-saving renovation and renovation of old residential areas. Renovating old residential areas not only improves the living environment of residents, but also contributes greatly to energy conservation. Many old residential buildings do not have insulation layers outside, and the windows are not well sealed, resulting in excessive energy consumption in the buildings themselves. The renovation of old residential areas has increased the thickness of the insulation layer on the exterior walls of buildings, and installed hollow plastic steel windows with better sealing properties for residents' homes. At the same time, insulation layers are added to the walls and basement roof to form a closed insulation system. After the renovation, the temperature of residents in the old residential area increased in winter and decreased in summer, reducing the use of air conditioning. Residential buildings that have undergone energy-saving renovation can increase the indoor temperature by 3 to 5 degrees Celsius in winter and reduce it by 2 to 3 degrees Celsius in summer. While improving residents' living comfort, it also greatly reduces building energy consumption and saves expenses for residents.

The relevant person in charge of the Ministry of Housing and Urban Rural Development stated that China will continue to promote the implementation of green building standards for new urban buildings, continue to carry out green building certification, continuously increase the proportion of star rated green buildings, and improve building energy efficiency through the research and application of new technologies, products, and materials.

Increase the proportion of renewable energy applications

In the process of building use, there is also a great potential for energy conservation that needs to be explored. Improving the utilization rate of renewable energy during the use of buildings is an important measure to reduce carbon emissions. The Implementation Plan for Carbon Peak in Urban and Rural Construction proposes that the renewable energy substitution rate for urban buildings will reach 8% by 2025. Building solar energy (7.000, 0.00, 0.00%), photovoltaic integration, solar hot water systems, air source electric heat pump technology, and various waste heat utilization measures are all optional measures. Various regions can choose measures tailored to local conditions to increase the proportion of renewable energy applications.

Install photovoltaic exterior walls on the building surface, which usually have a service life of no less than 25 years. The Implementation Plan for Carbon Peak in Urban and Rural Construction proposes that by 2025, the photovoltaic coverage rate on the roofs of new public institution buildings and new factory buildings should strive to reach 50%.

The roof of the Xiong'an High Speed Railway Station is a photovoltaic power generation project. It is understood that 17700 pieces of 42000 square meter polycrystalline silicon photovoltaic modules are laid on both sides of the roof of the Xiong'an High Speed Railway Station building. The project adopts a "self use, surplus power grid connection" mode, with a total installed capacity of 6 megawatts. It was officially connected to the grid for power generation on December 25, 2020, and can provide 5.8 million kilowatt hours of clean electricity to the Xiong'an High Speed Railway Station annually. It saves 1800 tons of standard coal and reduces carbon dioxide emissions by 4500 tons, equivalent to planting 12 hectares of trees.

Vigorously promoting "light storage, direct and flexible" buildings has also become a widespread consensus. The Action Plan for Carbon Peak before 2030 issued by the State Council clearly states that the electrification level of building terminals should be improved, and "light storage, direct and flexible" buildings should be built that integrate photovoltaic power generation, energy storage, DC distribution, and flexible electricity use. The "14th Five Year Plan for Technological Innovation in Urbanization and Urban Development" issued by the Ministry of Science and Technology and the Ministry of Housing and Urban Rural Development also clearly states that the basic theory, safety protection methods, and related standards of the new type of power supply and distribution system for optical storage, direct and flexible power supply will be studied.

The office building of China Construction Green Industrial Park in the Shenzhen Shantou Special Cooperation Zone is the world's first "light storage, direct and flexible" building in operation, which has been running smoothly for over a year. It stores the electricity generated by rooftop solar photovoltaic power generation devices and achieves flexible use, achieving significant energy-saving and emission reduction effects, transforming the building from an energy consumer to a producer, storage and regulator, making it a "green power plant".

Wu Yong, President of the China Building Energy Conservation Association, suggested that the design of light storage, direct and flexible systems can be included in the planning stage for new office and residential buildings, promoting the improvement of wind power and photovoltaic energy consumption capacity. For example, hospitals and school buildings have a high demand for electrical reliability, and the optical storage direct flexible system has the ability to operate independently. In the event of external power grid loss, it can ensure continuous power supply for important loads for a period of time according to user needs.

Promote green and energy-saving construction

Energy conservation during the construction process is also an important aspect of building energy conservation. Developing prefabricated building is an important part of promoting green construction. Prefabricated building has many advantages. It can not only shorten the construction period and reduce labor, but also reduce the construction waste discharge by 70%, save wood by 60%, save cement mortar by 55%, reduce water resource consumption by 25%, significantly reduce the dust and noise pollution on the construction site, and improve the building quality.

In the words of engineering builders, prefabricated building are the most "trendy" construction technology at present. The Beijing Urban Sub center Employee Turnover Housing Project is a key promotion project, with a design standard of two star green buildings, including 11 residential buildings, 2 supporting commercial buildings, 1 opening and closing station, and an underground garage. There are a total of 756 housing units. All prefabricated components are processed and produced by the prefabricated component factory, hoisted and installed on site, greatly reducing construction noise and construction waste, and minimizing the impact on the surrounding area.

Not only can new buildings be constructed using prefabricated methods, but the prefabricated decoration of old houses is also gradually entering our vision. Taking the internal reinstallation of a certain residential building as an example, it can be completed in 23 days, with a speed increase of over 50% and a labor reduction of over 40%. The site is clean and tidy, with less dust, which can effectively reduce carbon emissions and reduce noise, effectively avoiding interference with neighbors.

Prefabricated decoration in newly built buildings has a more significant effect on economy and intensification. Taking the Beijing Urban Sub center Employee Turnover Housing Project as an example, the entire interior of the house is fully assembled, with a construction efficiency improvement of over 30% compared to traditional decoration. The ground is equipped with modular quick installation heating floors, and the walls are equipped with quick installation lightweight partitions. By installing keel brackets on the walls and hanging integral decorative panels on them, the flatness of the walls is greatly improved, making it easier to clean. The various pipelines of the project are hidden in the wall decorative panels, which reserve positions at key nodes to solve the worries of maintenance.

According to the person in charge of the Ministry of Housing and Urban Rural Development, China will continue to strengthen the construction of prefabricated building, promote the application of green building materials, and promote the recycling of waste. China has basically reached the world's advanced level in building insulation and energy-saving technology. Technology leads the future, and breakthroughs have been made in the "bottleneck" technologies related to green construction, such as BIM software technology platforms, high-end equipment and measurement sensors, building demolition and recycling. The construction of digital homes such as smart homes, online services, and home office is accelerating, and practical technologies such as prefabricated decoration and building efficiency and energy conservation will continue to innovate.