Frequently asked questions
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What are the important indicators for the performance evaluation of central air conditioning systems?
The operating status of the central air conditioning system is related to operation and maintenance costs and energy consumption. Engineers have summarized multiple evaluation indicators for diagnosing system performance:
Chiller: The coefficient of Performance (COP) reflects the operational efficiency; the higher the value, the better the condition. External efficiency (ICOP) reflects the ideal COP, while internal efficiency (DCOP) is used to identify the causes of low operational efficiency. The combined analysis of the three can accurately diagnose problems.
Distribution system:The chilled water delivery coefficient WTFchw and the cooling water delivery coefficient WTFcw respectively measure the economic efficiency of the chilled water and cooling water delivery systems. Issues such as "high flow rate, small temperature difference" and overly large pump selection can lead to their values being lower, affecting system performance.
Cooling tower:
The efficiency nct of a cooling tower is defined by the ratio of the temperature difference between the inlet and outlet water to the temperature difference for heat exchange of the cooling water. The water-air ratio (the ratio of air volume to water volume) is a key influencing factor. An imbalance in water-air ratio will reduce the efficiency of the cooling tower.
These indicators are operation and maintenance means. If the selection is done well in the design stage, it can improve system performance and save costs from the source.
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Noise sources and control methods of Central Air conditioning
1. Noise Sources
Airborne sound transmission: Noise is generated by the air spray from the supply air outlet and the friction of air flow within the air duct.
Solid sound transmission: Generated during the operation of equipment such as refrigeration units, water pumps, and fan coil units.
2. Control Measures
The main unit is installed on the floor, equipped with shock-absorbing devices, and the pipelines are fitted with shock-absorbing flexible hoses to ensure smooth air intake and exhaust.
Leave a distance between the indoor unit and the roof to avoid resonance.
Set up supply and return air silencing and static pressure boxes.
The wind speed inside the air duct should be controlled below 3m/s.
A straight-line distance of 3 to 5 times the diameter of the air duct should be maintained between the components of the air duct.
The outdoor unit is far away from the living area, while the indoor unit can be optionally installed in the corridor, storage room or other locations.
Choosing well-known brands, paying attention to reasonable design and installation, standardized use and regular maintenance can effectively reduce noise problems. If you have any business needs related to central air conditioning, please feel free to consult and leave a message.
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What matters should be noted when installing central air conditioning in a factory building?
Function configuration: You can choose functions such as heating, fresh air, and filtration as needed to enhance the comfort of use.
Compressor power: It is advisable to choose a larger power rather than a smaller one to ensure the cooling and heating effects.
Coordination with decoration: The installation and design of air conditioners should be carried out simultaneously with home design. Install the equipment first and then do the decoration, taking into account both functionality and spatial aesthetics.
Indoor unit location: Avoid placing it in the bathroom (if necessary, the return air outlet should be set inside the room), and it is strictly forbidden to place it in the kitchen.
Supply and return air outlet layout: The supply air outlet must ensure that there are no dead corners in air circulation. The return air outlet and the supply air outlet should be kept at a distance to promote air circulation.
Quality proportion: Equipment quality accounts for 20%, design rationality for 30%, construction and materials for 50%, and the installation process should be given due attention.
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The efficiency of the air purification system is insufficient and the cleanliness does not meet the standards
Improper installation of high-efficiency filters and unreasonable design of air duct outlets have led to air flow short circuits or local pollution
When installing, a gas tightness test (such as a scanning test) should be conducted on the filter to ensure that the sealing gasket is intact and free of leakage.
The air duct layout follows the flow direction from the clean area to the non-clean area. The supply air outlet and the return air outlet maintain a reasonable distance (it is recommended to be ≥1.5 meters) to avoid dead zones in the air flow.
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Should H13 or H14 high-efficiency filters be used in a 10,000-level workshop? Is higher efficiency always better?
Standard matching principle
Class 10,000 (ISO8) : An H13 grade filter (filtration efficiency ≥99.97%@0.3μm) is required.
Class 100 (ISO5) : An H14 grade filter (≥99.995%@0.3μm) is required.
Misconception reminder: The resistance of H14 grade filters is 20% higher than that of H13 grade filters. If H14 grade filters are forced to be used in 10,000-grade workshops, it will lead to an increase of 15% to 20% in air conditioning energy consumption, and the filtration efficiency will be excessive (the 10,000-grade standard allows particle concentration ≤ 352,000 per cubic meter).
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Which should be chosen for an electronic cleanroom, PVC anti-static rolls or aluminum alloy raised floors?
Scene differentiation
PVC sheet material: Suitable for workshops without overhead pipelines (such as SMT assembly workshops), conductive type (surface resistance 10°-10°Ω) should be selected, and the welding temperature should be controlled at 180-200 ° C(to avoid carbonization).
Raised floor: Suitable for clean rooms with underground pipelines (such as semiconductor wafer workshops), the height of the floor support should be ≥300mm(for easy pipeline maintenance), and the aluminum alloy material needs to undergo anodizing treatment (anti-oxidation).
Key test: After completion, a ground resistance tester should be used for detection. The resistance value between any two points should be ≤10°Ω.
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