Interpreting the Effect of Air Conditioning and Purifying Return Filter

Interpreting the Effect of Air Conditioning and Purifying Return Filter

1 Overview

China's air-conditioning cleansing industry started late. With the development of society and economy, the HVAC industry has developed rapidly in recent years. People's lives, work, and product production processes have raised the technological level and product quality of the HVAC industry. higher requirement. Industry experts have conducted extensive and in-depth studies on issues such as sick building syndrome, air-conditioning syndrome, and building energy conservation in the construction industry in recent years. However, many unresolved problems still exist, such as unreasonable design, poor product quality, and poor control. Perfection and so on. ( Southern lathes , CNC machines ) One of the important issues that HVAC industry urgently needs to solve is air quality improvement. Some experts and technicians analyzed the causes at various seminars and proposed a series of solutions. However, due to restrictions on investment, energy conservation and other issues in the actual project, it is always difficult to solve the fundamental problems. There are many factors affecting indoor air quality. The system's optimal design, fresh air volume, and equipment performance all have important impacts on air quality. To improve indoor air quality, it is necessary to control every aspect of the air cycle. The filtration function of the purified return air outlet is an important aspect that has been neglected. The return air inlet is one of the necessary devices for air-conditioning and decontamination. Because it has a small proportion of construction cost and a simple structure, it is difficult to attract the attention of designers and users. It is usually used as a small product and only pays attention to it. The appearance of decorative effects and ignored its use of features. In fact, the filter performance of the return air inlet is one of the necessary conditions for maintaining the air conditioning and purification environment to meet the requirements. The quality of the material affects the degree of deformation of the blade, which affects the resistance and aesthetics of the return air. The surface treatment is not easy to accumulate dust and is not easy to clean, the surface oxidation does not cause uneven blackening and so on.

2 status

At present, the return air outlet and filtering of air-conditioning and purification sites usually have the following common forms: one is a return air outlet plus a layer of nylon mesh; the second is a return air filter plus a filter made of multiple layers of metal mesh. The third is only the return air, without any filtering. The practice of non-filtering has proved to be undesirable. It not only fails to satisfy the use of functions, but also part of the return air outlet becomes a passage for small animals and insects, and can also be used as a place where workers of low quality can discard debris at will. At present, the design has no specific requirements on the efficiency of return air filtration. There are no corresponding provisions in the specifications and industry standards. Therefore, only one layer of nylon filter is added to the product. In the common semi-centralized air-conditioning systems with fan coils and fresh air, the single-layer nylon mesh basically does not provide filtration. When particles and fiber contaminants in the air are circulated to the fan coil cooler, they are adhered to the surface air cooler by condensing water, and some of them are dripping into the condensate tray. These pollutants become a hotbed of bacterial attachment and reproduction. The dust deposited on the surface cooler can also reduce the efficiency of the heat exchanger, which increases the energy consumption of the entire air conditioning system and can not achieve the use effect. Some management personnel found that after the air conditioning system was operated for a period of time, the air blowing from the air-conditioning system had unpleasant odors and the temperature could not be adjusted to the design temperature on time. After analysis, the surface cooler is contaminated and the heat transfer performance is a direct cause. Cleaning the cooler is extremely difficult. The multi-layer wire mesh is stamped with a very thin metal plate. Its surface is not smooth and has many burrs. It is attached to fibrous contaminants produced by bedding, carpets, etc. in wards of hotels, offices and hospitals. It is hard to clean. Due to poor management and low quality of employees, some air-conditioning systems do not meet the design requirements for air-conditioning systems during operation. The relevant personnel conducted systematic surveys on the operation of air-conditioning systems in several large-scale shopping malls and hotels in Dalian, Yantai, and Qingdao. It was found that most air-conditioning systems exhibited serious filter blockage and reduced unit efficiency after one year of operation. In order to reduce the workload of manual cleaning, maintenance personnel reduced the filter of the air outlet and the air conditioning unit, resulting in deterioration of the air quality, serious black stain on the air outlet, rapid aging of the interior decoration, and reduced work efficiency of the personnel. In some rooms and hospital wards, there was a lot of fouling on bedding and carpets, and a thick layer of debris was attached to the cooler and condensate tray of the fan coil. After opening the access port, a smell was smelled. It is no wonder that the staff members often report symptoms of dizziness and nausea.

3 improvement measures

Through investigation, it has been found that the filtration effect of the air conditioning purified return air filter is an important factor affecting the indoor air quality. In particular, it is of great significance in protecting end equipment and preventing cross contamination of pollutants. In the cleansing project, increasing the efficiency of the return air filter helps to prevent cross-contamination of pollutants in different workshops and prolongs the service life of the medium-efficient filter. The installation position of the return air filter is convenient to disassemble and replace, does not affect the operation of the entire air conditioning system, and facilitates decentralized management and control. The unfavorable factor is that the efficiency of the filter at the return air filter will increase its resistance, and the foreign part of the design will usually use a method of increasing the area of ​​the air return to reduce the return air speed, thereby offsetting the requirement of the pressure head of the air blower. The above is reasonable. At present, there are many filter materials on the market, which can meet the requirements of filtration efficiency. However, the structure of the tuyere is difficult to disassemble and replace the filter, so that the selection of filter materials is limited. Some openable tuyere is not reasonable in structure, and the seal is not strict. Can not reach the requirements, there is no good connector, easy to relax, rust, blocking. Also, the bead type openable tuyere is too hard to use when opening, which can easily damage the decorative surface and deform the tuyere. Manufacturers and product developers should research and reconstruct the structure of the air-purifying return air outlet, and develop practical new products. At present, the combined tuyere produced by some manufacturers can basically meet the requirements of use, and the filter can be easily disassembled and increased. The return air filtration efficiency. Designers should pay attention to the function of air conditioning purification air return filter to ensure the end of the equipment life and heat transfer efficiency. In order to ensure the normal operation of air quality and air conditioning system. Relevant departments should also organize experts and technicians to formulate relevant industry standards and limit the efficiency of the return air filter so as to better meet the needs of people's lives and work and the requirements of the production process on the production environment.