What is zero carbon building
With the increasing popularity of the green buildings concept, today’s building energy-saving requirements are getting higher and higher. Green buildings and green renovation of existing buildings have become hot topics in the construction industry.
In past 20 years,new concepts, new technologies,such as energy-saving buildings, green buildings, prefabricated buildings, healthy buildings, passive buildings, low-carbon buildings, zero-carbon buildings,all these buildings aims to better cope with climate change and focus on green and low-carbon development, controlling global carbon dioxide emissions.
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What’s Zero carbon buildings?
A zero-carbon building is a building in which all annual energy consumption is provided by renewable energy generated by the site without consuming coal, oil, electricity and other energy sources. Its main feature is that in addition to emphasizing the passive energy-saving design of the building envelope, it shifts the energy demand of buildings to renewable energy such as solar energy, wind energy, shallow geothermal energy, and biomass energy, and seeks the best for the harmonious coexistence of human beings, buildings, and the environment.
Difference between Zero carbon buildings & passive house
Passive house is to use architectural design to make full use of solar radiant heat for heating in winter, and minimize heat loss through maintenance structure and ventilation penetration; It is an environmentally friendly building that relies entirely on strengthening the building’s shielding function and achieves the purpose of a comfortable indoor environment through architectural methods.
Different from passive house that emphasis on passively creating the most comfortable living environment with the lowest energy consumption , zero carbon buildings aims to realize net zero emission with renewable energy generated by the building itself and the comfortable living environment.
Features of Zero Carbon buildings
- Emphasize the energy-saving performanceof the building envelope system.
- Emphasize the use of renewable energy,.
- Achieve zero carbonization in the construction and operation stages.
- Carbon emissions in the building operation phase account for more than 80% of the total carbon emissions in the entire life of the building
How Zero carbon building realized net zero emission?
Zero carbon buildings utilize various carbon reduction measures to achieve zero carbon status:
(1) High performance R value of roof and walls
R-value refers to the ability of an insulation material to resist heat flow. The higher the value, the better the thermal resistance and thermal performance.
Zero carbon construction achieves high radiance value on roofs and walls,Builders ensure that the insulation overlaps to cover all gaps and uses air-sealing techniques such as caulking and weatherstripping at all corners.
(2) vacuum glazed window
In conventional buildings, 25-30% residential heating and cooling costs.are used to offset the heat gain and loss through windows .The zero-carbon construction avoids this problem by installing triple-glazed windows, with better performance vacuum glazed windows,the energy consumption can be decreased even less because vacuum glass U value is 30% lower than triple glass units.
However, this does not mean that each building has fewer windows. Typically, zero-emission buildings have window-to-wall ratios as high as 40%, allowing natural light to enter while maintaining high efficiency standards.
(3) Heat exchange fresh air system
A heat exchange fresh air system is a heating, ventilation and air conditioning system with two separate systems: one for ventilation of the building with the outside air and the other for dealing with the heat generated inside. Such systems use less energy than traditional HVAC systems.
(4) Building automation system
Zero-carbon buildings use building automation systems to control their HVAC and lighting. For example, sensors automatically turn off lights when a room becomes empty. Utilizing this smart system can reduce human-caused energy waste.
(5) Solar energy
Zero Carbon buildings most commonly use solar energy as their primary energy source It’s relatively easy to install and is a zero-carbon energy source. Use it to protect buildings from grid fluctuations, such as blackouts caused by extreme weather.
In 2019, the total amount of carbon emissions in the whole process of China’s construction was 4.997 billion tons, accounting for 50.6% of the country’s carbon emissions , including
- Direct carbon emissions from fossil energy directly consumed in the building operation phase, such as direct heating, cooling and cooking, etc.;
- Indirect carbon emissions from electricity and heat used during the building operation phase, and emissions from building material production, building construction, and demolition—i.e., embodied carbon emissions.
In addition, the annual construction and demolition of buildings in Chinese cities produces more than 2 billion tons of construction waste, accounting for about 40% of the total urban solid waste. It is the largest and most concentrated solid waste of a single type in Chinese cities. Improper use can pollute water bodies, soil and air.
The net zero emission renovation of existing building,and new buildings will contribute to world environment,people’s daily healthy life,and maximum building performance,and recyclable economy.