Harm of central air conditioning if not cleaned in time
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2. The dust attracts the bacteria to breed: Because the central air conditioner relies on the air duct and the air outlet to send the treated air into the room, the air duct is a confined space, and the suspended particles in the outdoor air cannot be completely blocked by the air conditioning filter device. Therefore, fine dust enters the air duct and adheres to the inner wall of the air duct. In addition, most of the air ducts are narrow, and a large amount of dust is formed over time. Due to dust accumulation, it is easy to breed all kinds of harmful microorganisms, such as viruses, bacteria, endomycin, fungi, Legionella, and coronavirus.
3, the cradle of parasites and insects: Because the air duct layout is mostly in the ceiling panel of the building, and the temperature and humidity of the four seasons are more suitable, it is often the activity space of parasitic animals and insects (such as: mice, cockroaches, etc.). According to Shanghai reports, a building in Shanghai cleaned the central air-conditioning air duct and cleaned up two tons of garbage, including a large number of mouse insect carcasses.
Harm caused by dust accumulation in central air conditioning duct：
1. Breeding bacteria, infectious diseases: As the air duct forms a relatively closed space through the air outlet and the return air inlet, the dust in the air duct (which is generally invisible to the naked eye) and the germs will gradually blow into the corners of the room along with the air-conditioning wind. The source of indoor air pollution; at the same time, the germs of a certain room are also prone to cross-infection with other air-conditioned circulating air. For example, during the SARS period, the Ministry of Health of the People's Republic of China ordered that all central air conditioners without fresh air be stopped to prevent the spread of the epidemic.
2. Increased wind resistance and energy loss: Air flows in the air duct. Due to the relative movement of viscosity and fluid, internal friction is generated. When air flows in the air duct, it is necessary to overcome this resistance and consume energy.
The friction resistance expression is：△Ｐm=λ*１／４Ｒs*ρν2/2
In the formula: λ: frictional resistance coefficient Rs: duct hydraulic radius
l:Air duct length ρ: air density ν: average air velocity in the air duct
In the passage of time and the increase in the number of years of use of the equipment, the surface of the duct will adhere to a large amount of dust (suspended particulate matter). This destroys the boundary layer formed by the side walls, that is, destroys the laminar flow state of the fluid in the air passage. The turbulence phenomenon is formed, the internal friction force is increased, the wind force is blocked, the load of the fan is increased, the capacity of the unit is decreased, the service life of the device is reduced, and the energy consumption is increased.
Current status of central air conditioning cleaning industry at home and abroad：
1. The status quo of foreign central air-conditioning industry: Foreign developed countries have applied many central air-conditioning systems long ago, and they have a deeper understanding of the dangers of air quality to human health (the Legionella of Philadelphia in 1976 in the United States) After the outbreak, it was determined that the source of infection was the central air conditioner in a certain venue of the city.) The pollution caused by the environment of foreign health institutions has a relatively perfect method, and more stringent central air-conditioning use and cleaning regulations have been introduced, such as: The industry standard “Evaluation, Cleaning and Restoration Standards for HVAC Systems” (ACR2002 Edition) developed by the National Air Duct Cleaning Association and the “Technical Standards of the Japanese Air Duct Cleaning Association” (1990 version) formulated by Japan and the newly enacted legal requirements of Finland Hotel, hotel, laundry room, industrial processing ventilation system that produces dust substances, clean once a year; hospitals, schools, etc. every 5 years. Similar laws can be foreseen to be implemented throughout the world. At present, central air-conditioning duct cleaning associations have been established in developed countries and have formed a complete industry.
2. Status of domestic central air-conditioning cleaning industry: According to reports, there are more than 5 million types of central air conditioners in China that need to be cleaned and maintained, and they are increasing at a rate of 10% every year. Most of these central air conditioners have been operated for more than 20 years but have never been cleaned. At present, no matter from the professional cleaning service company of central air-conditioning ducts or from the domestic and foreign air-conditioning duct cleaning robot equipment manufacturers, we can't cope with this huge cleaning market, because China's air-conditioning duct cleaning industry has just At the beginning, we can have a first-class cleaning service team, and there are only a handful of cleaning companies that can meet the needs of various customers. In addition to the mature products of developed countries, the equipment manufacturers can adapt to various wind tunnel characteristics and mature technology. The manufacturers of cleaning robots are even rarer. Although the performance of robots from foreign manufacturers is mature, it is based on the manufacture of its own central air-conditioning ducts, and a large part of it cannot contribute to the central air-conditioning ducts in China. Because the central air-conditioning ducts in foreign countries are standard and standardized, and the central air-conditioning ducts in China are designed and installed according to the building area, each air duct is not the same, and it is a non-standard product. According to the "Jinghua Times" reported on January 13, 2004: According to the "Beijing Indoor Environmental Situation" survey report organized by the Center for Preventive Medicine Research, which has been completed for six years, there are 50% of five-star hotels in Beijing. bacteria. In August 2003, the China National Institute of Standardization and the Ministry of Health jointly drafted a discussion draft for the “China Air Conditioning Ventilation System Cleaning Code”. The official regulations will be introduced in the near future. With the development of China's economy, people are paying more and more attention to the harm caused by indoor air quality. Especially the spread of SARS epidemic in 2003 has caused people to suffer from the diseases brought by central air-conditioning. Understanding, in the future, with the introduction of national mandatory regulations, the airway cleaning industry will become an emerging development industry with great potential in China.