Condensed water, commonly known as “condensation”, is shown in pipes, air conditioning panels, vents and other objects on the water trace or even water droplets.Causes the wind pipe and the hanger to be soaked, the tuyere dripping water, the smallpox dripping water, the metope seepage moldy, the metope coating falls off and so on the phenomenon.Although it will not cause too big accident, but has affected the looking and using function, bring a lot of inconvenience to the user.
Accordingly indoor condensation problem draws the attention of concerned professional personage gradually.Most users have two misconceptions:
1, condensed water is produced by the vent;
2, steel vents more likely to produce condensed water than aluminum alloy vents
1. Theoretical analysis of condensed water
The dew point temperature of wet air is an important basis to judge whether or not dew is formed.Condensed water is produced when the temperature drops below the dew point temperature.Therefore, if the air temperature is lower than the indoor dew point temperature, it is easy to condensation. Tuyere condensation is caused by the surface temperature of tuyere is lower than the dew point temperature of indoor air. At the same temperature, the higher the relative humidity is, the greater the vapor pressure is, the higher the dew point temperature is, and the easier the condensation is. Similarly, when relative humidity is the same, the higher the temperature, the higher the dew point temperature. It’s easy to get dew.
PS：Dew point temperature is the temperature at which air is cooled to saturation without changing water vapor content or air pressure.
2. The actual cause of condensed water analysis
The root cause of air condensation is condensation when indoor air temperature drops below its dew point temperature.
In the actual air conditioning engineering, there are many reasons causing condensation, mainly including the following:
1. Unreasonable exhaust system design
Due to the unreasonable setting of exhaust air system in the air conditioning area, excessive negative pressure is generated, which makes the disorganized outdoor air enter into the indoor air, thus improving the humidity of the air and its condensation dew point. The surface temperature of the tuyere is lower than the temperature of the disorganized air dew point that has just penetrated into the indoor air, thus leading to the condensation of the tuyere.
2. Insulation materials do not meet the requirements
Thermal insulation is key link in air conditioning engineering, heat preservation effect is good or bad will directly affect the amount of air conditioning cold loss and indoor air conditioning effect, increase the operation cost of air conditioning, more serious is the insufficient thickness of insulation layer thermal conductivity overweight, or insulation layer falls off, do not conform to the requirements of the design, material properties and thickness can cause condensation phenomenon.
3,In order to reduce the project cost, the low-temperature air supply technology is blindly adopted to reduce the air supply quantity, so as to reduce the fan power and the size of the air pipe.But because the cold air temperature of the air supply outlet is too low, the water vapor in the air quickly condenses near the air supply outlet due to low temperature, forming condensed water.
4. High relative humidity
Due to poor air distribution, or forced use of humidifier, the air relative humidity within the air conditioning tuyeres area is larger, the dew point temperature increases, easily produce condensed water.
3.Method to prevent condensation of water
- Reasonably design the new exhaust air systemReduce the exhaust air and increase the air supply, so as to ensure a certain positive pressure value in the room and prevent the condensation water generated by the infiltration of hot and humid air.Doors and Windows should be closed when the air conditioning system is running.
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Correct selection and reasonable calculation of insulation materials
The parameters such as bulk density, thickness and heat transfer coefficient of heat preservation materials used in air-conditioning water pipes and air pipes must meet the design requirements.The thickness of insulation layer should also be calculated according to the principle of preventing condensation instead of blind estimation.
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Reduce the temperature difference of supply air
Increase air supply to increase air supply temperature, reduce air supply temperature difference, prevent condensation.The air supply temperature should meet the design requirements to prevent the occurrence of condensation caused by low temperature air supply.Generally, it can be solved by adjusting the flow of chilled water (reducing the flow of chilled water), raising the temperature of air supply or increasing the speed of air supply.
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Reduce indoor relative humidity
Indoor optimal relative humidity should be 49%- 51%.we can use dehumidifier and other tools dehumidifier, reduce indoor relative humidity.
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Use wooden tuyere, or ABS material tuyere
we can use woodiness tuyere, Wooden tuyere is the most difficult dew, it is ABS material tuyere next.But wooden tuyere is more expensive, and wooden tuyere has a lot of defects, such as: not flame retardant, easy to fade, easy deformation and so on.Therefore, the current market anti – dew mouth or ABS – based tuyere.Of course, a thin layer of PE insulation board can also be pasted on the side of the central air conditioning tuyere to increase insulation and reduce temperature difference.
Post time: Apr-15-2019
