China Housing and Construction Corporation's Decade of Ultra Low Energy Buildings

Source: Bang Lvjian

Ten Year Development of Ultra Low Energy Buildings

In recent years, China has vigorously promoted ultra-low energy buildings and achieved remarkable results, catching up with developed countries.

Since 2012, based on international cooperation, China has launched projects such as research and demonstration of key technologies for ultra-low energy buildings, exploring solutions for ultra-low energy buildings that are suitable for China's national conditions. Through pilot demonstrations, ultra-low energy buildings have been fully recognized by various sectors of society, and were first included in national documents such as the "13th Five Year Plan" Energy Conservation and Emission Reduction Comprehensive Work Plan and the "Urban Adaptation to Climate Change Action Plan" in 2016, actively guiding various regions to carry out pilot demonstrations.

With the expansion of construction scale and the improvement of building types, on the basis of fully summarizing experience and practices, in 2019, the national recommended standard "Technical Standard for Near Zero Energy Consumption Buildings" was issued and implemented, which is the first technical document in the field of zero energy consumption buildings issued in the form of a national standard internationally. It proposed constraint control indicators such as indoor environmental parameters and building energy consumption indicators for different climate zones and types of ultra-low energy buildings, We have achieved a breakthrough in the standard system.

China Building Energy Efficiency Research and Testing Center (a benchmark project in the field of building energy efficiency in Shaoxing built by Baoye Group in collaboration with the China US Green Fund and the China Building Energy Efficiency Association)

During the 13th Five Year Plan period, national key research and development projects such as the "Near Zero Energy Consumption Building Technology System and Key Technology Development" were launched, and a series of new equipment such as high-performance energy-saving windows, low-temperature heat pump hot air fans, integrated fresh air environment control machines, and group intelligent building control were developed, achieving technological breakthroughs. As of the end of 2021, China has completed a total of over 10 million square meters of ultra-low and nearly zero energy consumption buildings.

China's ultra-low energy buildings are transitioning from pilot demonstration to large-scale development. Since 2021, Beijing, Hebei, Shandong and other provinces and cities, as well as Shenyang, Dalian and other cities, have clearly defined the development goals of ultra-low energy consumption buildings in their plans for building energy efficiency and green buildings, urban and rural construction development, ecological environment protection, resource conservation, and circular economy. The planned construction scale has exceeded the development goal of 50 million square meters proposed in the "14th Five Year Plan for Building Energy Efficiency and Green Building Development", It has reached more than 5 times the total national construction volume during the 13th Five Year Plan period.

Compared to ordinary buildings, ultra-low energy buildings use materials with better performance, finer construction processes, and longer service life, which can create a more comfortable, air quality, and sound insulation indoor environment. It has become an important measure to achieve the "dual carbon" goal in the field of urban and rural construction in China.

What is an ultra-low energy building?

According to the latest national building technology standards, ultra-low energy buildings can be described as follows: adapting to the local climate characteristics and site conditions of the building, minimizing heating, air conditioning, and lighting needs through passive building design, maximizing energy equipment and system efficiency through active technical measures, fully utilizing renewable energy, and providing a comfortable indoor environment with minimal energy consumption, The energy consumption level of its buildings has decreased by more than 50% compared to newly built buildings around 2015.

China has specific regulations on the annual energy consumption of ultra-low energy buildings. For example, Jiaxing is located in a hot summer and cold winter area, and the comprehensive energy consumption value of residential buildings per year should be ≤ 65KWh/㎡, that is, the average annual electricity consumption per square meter should not exceed 65 degrees.

What is passive architectural design?

Passive architectural design is the use of a series of architectural design and technical means to significantly reduce the energy consumption of buildings in people's production and life processes, such as summer cooling, winter heating, ventilation, and lighting.

These design measures and technical means have already solidified after the construction of the building itself, and are integrated with the building as a whole. In the subsequent operational and usage stages, it is possible to continuously help buildings achieve energy-saving goals without the need for additional operating expenses.

These architectural design and technical means include:

Fully utilize natural lighting and ventilation

High quality insulation materials are extensively used on the exterior walls and roofs of buildings to prevent external heat from entering the interior during summer and loss of internal heat during winter.

The doors and windows are made of frame materials with excellent thermal insulation performance, combined with insulating glass with one or two layers of air interlayer, and the outermost glass is coated with thermal reflection performance.

Doors, windows, and even the entire building have good airtightness design and construction techniques to prevent cold and heat losses caused by large air infiltration when the temperature difference between indoor and outdoor is large.

The external windows are equipped with fixed or movable sunshades to prevent excessive direct sunlight in summer, which can cause indoor overheating. At the same time, it ensures that the indoor winter can obtain sufficient sunshine time and heat, reducing heating demand.

Avoid the design of cold and hot bridges, avoid condensation or condensation on the interior surface of buildings in winter or humid weather, and also avoid the loss of indoor cold and heat.

What are the proactive technical measures?

Active technical measures mainly refer to various heating, cooling, ventilation, lighting, water supply, elevators, intelligent and other equipment used to meet the established usage functions of the building and the health and comfort of the internal environment. These devices require energy consumption during the construction and operation process to complete their intended functions.

High energy efficiency products should be prioritized for the heating and cooling system, and the system's energy efficiency should be improved. Energy consuming equipment such as circulating water pumps and ventilators should use frequency conversion speed regulation, and LED light sources should be preferred for lighting.

Priority should be given to utilizing industrial waste heat and selecting natural cooling and heat sources such as ground sources, water sources, and air sources.

According to the characteristics of building cooling and heating loads, set up a fresh air heat recovery system and appropriate dehumidification technical measures.

Equipped with a building automation system, it can detect the indoor environment, such as sunlight, temperature, humidity, carbon dioxide concentration, and number of users. It can automatically adjust the operation of the main supply equipment and systems based on the end use needs of cold, heat, water, ventilation, lighting, elevators, etc.

Equipped with a building energy consumption monitoring system, it can track, calculate, evaluate, and predict the energy consumption of various energy consuming units, and guide them to optimize poor energy consumption habits.

What are renewable energy sources?

Renewable energy includes solar energy, water energy, wind energy, biomass energy, wave energy, tidal energy, ocean temperature difference energy, geothermal energy, etc. They can be recycled in nature and are an inexhaustible source of energy. At present, renewable energy widely used in China includes solar energy (including photovoltaic and solar thermal), water energy (hydropower station), wind energy (wind power), air energy (air source water heater), geothermal energy energy (geothermal heat pump air conditioning unit)

How to measure a comfortable indoor environment?

The energy-saving of ultra-low energy buildings is based on certain comfort conditions and quality of life. If the temperature reaches 40 ℃ in summer without air conditioning, minus 10 ℃ in winter without heating, and the lights are turned off to sleep when it gets dark, then energy-saving goes against the principles of health and comfort, and goes against the people's desire for a better life.

The national standards stipulate the health and comfort of indoor environments in residential areas as follows:

Temperature: ≥ 20 ℃ in winter, ≤ 26 ℃ in summer

Humidity: ≥ 30% in winter, ≤ 60% in summer

Fresh air volume: ≥ 30m ³/ Hours per person

Noise: ≤ 40 decibels during the day, ≤ 30 decibels at night

Ultra low energy buildings can greatly reduce energy consumption for heating, air conditioning, and lighting by adapting to climate characteristics and site conditions, fully utilizing technical measures such as natural ventilation, natural lighting, and insulation of enclosure structures, and adopting efficient energy equipment. On the basis of ultra-low energy consumption buildings, increasing the application of renewable energy buildings and other technical measures can achieve near zero energy consumption, zero carbon, and zero energy consumption buildings.