National Ecological Day丨For the sake of environmental protection, is it wrong to turn on the air conditioner? Scientific and reasonable use is the key

There is a saying circulating on the Internet that there are three treasures in summer: WIFI, watermelon and air conditioning. This year in particular, record-breaking heat waves have swept across the world, and even the southern hemisphere in winter has seen rare weather exceeding 30°C. Although it is now past the beginning of autumn, the heat is still there, especially in the southern region, which makes people sigh that the life in summer is all given by air conditioning!

A comfortable temperature is inseparable from air conditioning, and naturally even more so from the refrigeration technology behind it.

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How does ubiquitous refrigeration technology improve our lives?

01 Ancient Refrigeration “Black Technology”

Do you think that the ancients only relied on "calming down and cooling down naturally" to cool down? In fact, they also had advanced technological inventions.

When people found that low temperature can prolong the shelf life of food, they began to seek new technologies to preserve food. "Xia Xiaozheng" (Xia Dynasty calendar, about 21st century BC to about 16th century BC) records: "In March, the sun is shining... The ice is distributed to the officials." It can be seen that our ancestors began to store and use ice in the Xia Dynasty.

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During the Tang and Song dynasties, people not only used natural ice, but also invented mechanical refrigeration. So a special pavilion was built in the palace with a water storage tank next to it. Mechanical transmission was used to deliver cold water to the roof, creating the effect of an artificial water curtain. At the same time, the fan wheel was rotated to generate wind to deliver cold air into the pavilion. Although it was not as good as today's air conditioning, it was the most comfortable cooling method at the time.

02 Modern Industrial Development and Innovation of Refrigeration Technology

Active refrigeration in the true sense came with the emergence of the steam engine after the First Industrial Revolution, which used processes such as vaporization, condensation, and compression in the thermodynamic cycle to achieve the cooling of objects.

With the development of technology, people gradually applied refrigeration equipment in industry and synthesized refrigerants for refrigeration systems. Refrigerant, also known as refrigerant or snow seed, is the working medium of the refrigeration cycle of air conditioners and refrigerators. The refrigerant achieves the purpose of refrigeration by absorbing heat when vaporizing in the evaporator and releasing heat when condensing in the condenser. The most common refrigerants are ammonia, freon, water and some hydrocarbons. Today, refrigeration technology is widely used in food preservation, cold chain logistics, building environment, steel smelting, electronic textiles, medicine and health, aerospace and even superconductivity, remote sensing and other high-tech fields, becoming an indispensable key technology for the development of modern science and modern society.

Is refrigerant really the culprit behind environmental damage?

Industrial development has promoted a qualitative leap in human science and technology, but at the same time, people are increasingly aware that in addition to the high temperatures in summer mentioned above, extreme weather such as typhoons, rainstorms, and hail are becoming more and more frequent. This is mainly due to the negative impact of large amounts of greenhouse gases emitted by human production activities.

01 Could air conditioning become an accomplice of global warming?

Indeed, when we use air conditioners, we are also "heating" the earth. People have found that powering air conditioners consumes electricity, and the power generation process emits a large amount of greenhouse gases (except for air conditioners that can use pure renewable energy); at the same time, the refrigerants used in air conditioners and cold storage contain chemicals such as Freon and chlorofluorocarbons, which themselves also release greenhouse gases and are therefore regarded as "accomplices" of global climate change.

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Since air conditioners exhaust hot air outside when they are running, they make the surrounding environment hotter. For this reason, if your neighborhood is equipped with a lot of air conditioners, your home will also become hotter.

At the same time, large-scale deforestation has also reduced nature's efficiency in absorbing carbon dioxide, the most important greenhouse gas.

02 How to advance the sustainable development of refrigeration

The Earth is now hotter than it has been in the past two thousand years. If the situation continues to deteriorate, by the end of this century, the Earth's temperature will have climbed to its highest level in nearly two million years. As the climate warms, people will become more dependent on air conditioning, which will undoubtedly lead to a "vicious cycle" of ecological destruction.

Fortunately, countries around the world have long been aware of the impact of air conditioning on the climate and are working hard to develop clean energy technologies. In April 1985, the United Nations Environment Programme adopted the international convention on the protection of the ozone layer, the Vienna Convention for the Protection of the Ozone Layer, in Vienna, the capital of Austria; in 1987, the Montreal Protocol on Substances that Deplete the Ozone Layer was adopted at the Montreal Conference in Canada, which began to control the production, sale and use of related products by member states and clarified the phase-out schedule. In 2016, the parties to the Montreal Protocol reached the Kigali Amendment, which aims to limit the greenhouse gas hydrofluorocarbons (HFCs).

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my country also attaches great importance to environmental protection. In the 1990s, the National Environmental Protection Administration led 18 ministries to form the National Ozone Layer Protection Leading Group and compiled the "China National Plan for the Phase-out of Substances that Deplete the Ozone Layer", marking my country's commitment to the world environment as a responsible major country. In June 2021, China's permanent representative to the United Nations deposited with the Secretary-General of the United Nations the Chinese government's acceptance of the Kigali Amendment to the Montreal Protocol on Substances that Deplete the Ozone Layer. China attaches great importance to the protection of the ozone layer, carries out solid compliance governance actions, and strives to reduce the impact of air conditioning on the global environment through policy implementation and technology upgrades.

Cooling down the Earth starts with turning up the air conditioner by one degree

Many people think that energy conservation and emission reduction only concern "big carbon emitters" such as high energy consumption and high pollution, but this is not the case. As one of the important sources of household energy consumption, the rational use of air conditioners is not only beneficial to health, but also an important way to reduce pollution and carbon emissions and improve the ecological environment.

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Since humans cannot live without air conditioning, what can we do to protect the ecological environment?

01Save electricity and reduce carbon emissions

Nowadays, the proportion of clean energy in my country's power generation is getting higher and higher, but thermal power generation still accounts for more than 60-70%, so saving electricity can reduce carbon emissions. Do not turn on and off the home air conditioner frequently, otherwise it will not only affect the life of the compressor, but also consume more electricity. If you go out for a short time for one or two hours, the air conditioner does not need to be turned off.

02 Raise the temperature by one degree, healthy and energy-saving

We have done an experiment: in the same room, same air conditioner, same temperature and humidity environment in summer, one air conditioner is set to 25℃ and the other is set to 26℃. After running for 8 hours, the indoor temperature is around 25.7℃, but the air conditioner set to 26℃ saves 4.6 kWh of electricity compared to the air conditioner set to 25℃. If an air conditioner is raised by one degree every 8 hours, it can save nearly 5 kWh of electricity. If so many air conditioners in the country are raised by 1℃, how much electricity will be saved? It can be said that the country recommends that the air conditioner be set at 26℃ in summer. It is a relatively reasonable cooling temperature proposed by many experts after testing and demonstration, which meets the comfort of most people and energy conservation and environmental protection.

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03 Reduce refrigerant emissions

Air conditioning refrigerant is a strong greenhouse gas. Generally speaking, one kilogram of refrigerant is needed to operate a 1-horsepower air conditioner. If this kilogram of refrigerant leaks into the atmosphere, taking the common R410a leakage in our air conditioners as an example, the carbon dioxide emissions from this kilogram of refrigerant are equivalent to the emissions of a 1.6-liter car driving 8,400 kilometers. Therefore, if the air conditioning maintenance personnel at home ask to add refrigerant (commonly known as adding fluorine), you must ask the maintenance personnel to find the leak point and repair it before adding it. Otherwise, not only will the maintenance effect not be achieved, but the refrigerant will also be wasted, exacerbating climate change.

04 Clean the air conditioner regularly to avoid accumulation of debris around the outdoor unit

After using the air conditioner for a long time, it is best to ask a professional to clean and maintain it, because the outdoor unit will accumulate a lot of dust, which will affect the heat dissipation of the air conditioner and increase the power consumption; the indoor unit will easily breed bacteria or viruses and affect health. At the same time, make sure that there is no accumulation of debris around the outdoor unit and do not cover it with a dust cover such as a plastic bag, which will also affect the heat dissipation and increase the power consumption.

Low-carbon life means doing small things within your ability. Choosing environmentally friendly and low-energy air conditioners and developing good habits of using household refrigeration equipment can indeed reduce the impact of air conditioners on the environment, thereby enhancing the ideological and behavioral awareness of ecological environmental protection. Let us work together to improve the concept of green environmental protection and build green mountains and clear waters!

Author: Li Jinhao, Senior Engineer, Director of the Science Popularization Department of the Chinese Society of Refrigeration

Reviewer: Chang Lin, Senior Engineer, Secretary General of the Science Popularization Committee of the Chinese Society of Refrigeration

Produced by: Science Popularization China

Produced by: China Science and Technology Press Co., Ltd., China Science and Technology Publishing House (Beijing) Digital Media Co., Ltd.