1 Thermal insulation performance
The wall plate of the air treatment unit generally use double -layer color steel plates or cold -rolled steel plate powder spraying (made of stainless steel in the inner plate of the bottom plate). Most of the middle insulation materials are polyurethane foam or flame retardant centrifugal glass wool.From the perspective of thermal conductivity, water absorption and density, both are better thermal insulation materials.However, during the operation of the air treatment crew, the free -speed operation of the aircraft and the aircraft recovery is large, and the vibration of the box is relatively large, and the quality of the glass wool is light. There is a large gap in the structure., Lost the effect of insulation, which causes the air treatment unit wall plate to expose, making the air supply temperature high.
However, the use of polyurethane foam must have a good thermal insulation effect. For example, inferior polyurethane foam insulation materials can also affect the use effect.Therefore, when choosing an air treatment unit, you must not choose the wall board thermal insulation material.
2
The box structure of most air treatment crew manufacturers is composed of panels and aluminum alloy frames or corner steel welding frameworks.Box sealing treatment is also a aspect of high attention when selecting, because if the leakage rate is too much, there are two consequences: one is that the air supply volume is insufficient due to excessive leakage;Treatment room leakage.In the summer, this will make the uncontrolled hot and wet air enter the air supply system, so that the machine dew point cannot meet the design requirements, and the air supply temperature parameters cannot be guaranteed.The manufacturing specifications of the "Combination Air Conditioning Unit" (GB/T14294-08) released by the Technical Supervision Bureau stipulates that "when the static pressure in the unit maintains 700Pa, the leakage rate of the unit must not be greater than 3%."Some manufacturers open a sloppy sealing slot on the framework of the air treatment crew, and with the corresponding rubber sealing strip. Under the rated conditions, the wind leakage rate can be ensured by less than 2%to meet the specification requirements.This is a good way to solve the problem of leakage of the unit.
3 Calculation of surface cooler selection
Surface cooler is the core part of the combined air processing unit, and it is a place for air and refrigerant to exchange heat exchange.The common refrigerators coil structure is aluminum -winged sheet through the swelling tube and copper tube swelling.The wall thickness of the copper tube, the thickness of the aluminum foil is slightly different with the manufacturer. Generally, the wall thickness of the copper tube is 0.2 to 0.6mm, the diameter is 7 to 16mm, and the thickness of the aluminum foil is 0.15 to 0.20mm.It is worth noting that the spacing spacing selected by different manufacturers when calculating the cooler is large.Take a certain system as an example, the processing air volume is 79 000m3/h, and the cold volume is 831kW. The plan used by Factory A is to reduce the spacing (about 1.8mm) of the winger of the surface and increase the heat exchange area.The spacing (about 2.5mm) of conventional wings is used in two -stage cold segment connection form to extend the heat exchange time.Both solutions have their own advantages and disadvantages in terms of fan power consumption, water resistance, and section size.The former may cause a large wind resistance to increase the power consumption of the fan, which may increase the size and water resistance of the crew.After comprehensive technical comparison and comprehensive consideration, it was decided to use Factory B products.This example shows that the rationality calculated by the selection of the cooler is related to the performance and comprehensive cost of the entire air processing unit, which should attract enough attention.
4 Fan Selection
The fan is the energy consumption part of the functional sections of the air treatment unit.Same as a general fan. When the goods are fixed, you should choose the appropriate fan type according to the relationship between air volume and head, such as front -winged or rear -curved chips to ensure that the fans noise and efficiency indicators can reach a better state.Wing -type fan introduced from abroad in recent years has high efficiency.
With the development of computer technology and the improvement of automatic control level, the variable air volume system is becoming more and more widely used in office buildings, clean factories, hospitals, etc., so the selection of air -conditioning crews and the selection of the airback will have a new and higher higher higher and higher.Require.First of all, the characteristic curve of the fan should have a gentle characteristics, so that when the air volume is reduced, the system can avoid increasing unnecessary static pressure; second, the scope of work should be in a more stable and high -efficiency zone when choosing a fan;The exhaust device should be the same or the same type as the model of the air supply device, and has the same or similar performance characteristics, so as to ensure the effective matching of the entire system during runtime.
5 Selection of filters
Filter is divided into: initial effect filter (usually called G -level), medium -efficiency filter (usually called F -Class), high -efficiency filter
The first -effect filter is divided into: G1 \ G2 \ G3 \ G4 (G4 is higher in the initial filter filtering effect, and other arrangements are arranged in turn)
The medium -efficiency filter is divided into: F5 \ F6 \ F7 \ F8 \ (F8 is a higher effect of medium -effect filter filtering, and other arrangements are arranged in turn)
High -efficiency filter is divided into: 300,000 levels of filtration \ 100,000 level filtration \ 100 -level filtration (100 -level filtering is higher efficient filtering effect, other arrangements are arranged in turn)
The mainstream filter in the market is: non -woven filter \ belt filter \ metal filter \ paper filter \ nylon net filter \ glass fiber filter \ 3M filter (a low of 3M company in recent yearsResistance, high -efficiency energy -saving filter).
Dust in the air has an impact on human health and product quality, especially in some special industries, such as precision instruments, electronics, pharmaceutical industries, and hospitals.This requires a combined air treatment unit according to the requirements of different industries.
The air for the comfort of the comfort air -conditioning environment has certain requirements for the dust content.Generally, the indoor dust concentration is 0.15 ～ 0.25mg/m3, and dust particles with ≥10 μm should be filtered.The filtering section of this type of air processing crew can only be configured with coarse effects and medium -efficiency filters.As for the above -mentioned special industries, it is also necessary to configure high -efficiency filters to achieve ultra -net purification. This type of purification is very high. The indoor air -containing concentration is represented by particle counting concentration (granules/L).
6 Sales for maintenance
As mentioned above, the combined air processing crew is mostly used in occasions with large system air volume (usually above 10 000m3/h), so its shape and size are often large.In modern buildings, the size of the machine room is often compressed due to the investment and functions of developers or owners, so it is easy to cause the refrigerator, filter, etc. The components that need to be cleaned daily because the space is too small and the space is too small and the space is too small and the space is too small and the space is too small and the space is too small.Cant draw or it is difficult to draw.After the completion of some buildings, the original equipment maintenance channels are occupied, and the equipment cannot be passed when it needs to be replaced or maintained.Therefore, in the construction, on the one hand, pay attention to reserving the maintenance space and channel as much as possible; on the other hand, when the equipment selection and ordering, the manufacturer can be required to improve the own structure of the air treatment unit according to the actual situation of the computer room.Draw pipes, etc.
The above is an introduction to the performance characteristics of the air -conditioning unit