The mechanism by which condensation occurs
Before considering measures to prevent condensation in panel, it is necessary to understand why condensation occurs.
Water droplets forming on the surface of a cold beer bottle, lots of water droplets on the surface of a window in a warm room in winter, and the cool air from an air conditioner turning into a mist during the rainy season...these are some of the common symptoms.
These are common condensation phenomena that occur around us.
The air around us contains moisture in the form of water vapor (gas). The maximum amount of moisture that air can contain at a certain temperature (100%) is called the saturated water vapor amount. This saturated water vapor amount fluctuates depending on the air temperature. If the air is cooled at this time, the maximum amount of moisture that the air can contain decreases, and eventually it reaches a saturated state. This temperature is called the dew point temperature. When the air is cooled below the dew point temperature, the water vapor in the air condenses (liquefies), condenses, and appears as condensed water.
A quick explanation of condensation
When the temperature is high, the amount of moisture that can be absorbed increases, and when the temperature is low, the amount of moisture that can be absorbed decreases. Condensation is the phenomenon in which moisture exceeds the limit that can be absorbed.
A quick explanation of dew point temperature
This is the temperature at which air at a certain temperature reaches the limit at which it can contain water vapor (relative humidity 100%), and the water vapor in the air condenses and appears as droplets.
The mechanism by which condensation occurs on panel
When the surface of panel cools and the amount of water vapor that the air in contact with the surface of panel can contain exceeds its limit, condensation will form on the surface.
Example 1
cooler temperature is too low, the temperature inside and on the surface of panel becomes cold, and the air on the outer surface of the board is cooled and condensation occurs.
Example 2
Although cooler temperature is set to an appropriate level, the surrounding humidity rises suddenly during the rainy season, causing the humid air on the outside surface of the panel to cool and condense.
Countermeasure 1: "Prevent moisture from entering the board"
Reduce door openings
When electrical repairs are carried out on equipment, if the panel door is left open, moisture will flow into the cabin at once.
In addition, if the door is left open for emergency heat countermeasures, the humidity in the cabinet will increase rapidly.
Put gasket on the door, replace gasket
If the gasket on the back of panel door is missing or damaged, panel will not be airtight and moisture will enter through the gaps.
Note: Please consult a specialist manufacturer regarding packing.
Caulk the dustproof connectors and gaps at the wire entry point.
There are various types of incoming lines in panel, but at the incoming lines, dustproof cable gland connectors are used and gaps are caulked.
Moisture-proofing measures for the entry point from the underground pit,
Fill gaps with foamed urethane or other materials to insulate
If panel is designed so that the wiring enters from an underground pit, moisture will rise from underground, so take moisture-proofing measures such as using foamed urethane spray.
Note: For connectors and urethane foam sprays, please consult a specialized manufacturer.
Eliminate ventilation fans and vents
In humid locations or outdoors, the presence of ventilation fans or vents will increase the humidity inside the panel, increasing the risk of condensation.
Turn the ventilation fan on/off with the temperature switch
If the ventilation fan is operated only when the temperature inside the panel becomes hot and is stopped when the temperature inside the panel drops, less moisture will enter than if it were operated continuously.
Countermeasure 2: "Dehumidify the inside of the panel"
Install desiccants and dehumidifiers
There are desiccants and dehumidifiers available on the market for use in closets and furniture. Dehumidifiers have better moisture absorption properties for dehumidifying purposes. They are effective because they have a dehumidifying effect, but they must be replaced regularly.
Install a dehumidifier for panel
Dehumidifiers that use Peltier elements are common. They remove moisture by causing condensation on the cooling plate side of Peltier element. The dehumidification capacity is estimated to be around 10 to 30 cc/h. However, in winter, there is no temperature difference on the cooling plate, so the dehumidifying effect is almost zero. Electrolytic dehumidifiers that do not use Peltier elements are also available on the market.
Install control panel cooling unit
cooler equipped with freezing cycle not only cool but also have a dehumidifying function. The dehumidifying capacity depends on cooling capacity, but is approximately 200 to 2000 cc/h.
Reference link → What is control panel cooling unit? Explaining the benefits of introducing one
Control panel cooling unit to best condition environment in the board!
control panel cooling unit protect electronic devices inside panel from heat, dust, and humidity, contributing to the stable operation of production lines.
Please check the catalog for the latest lineup, functions and features.
Countermeasure 3: "Warm up the inside of the board"
Installing panel heater
In winter, the temperature inside the panel drops rapidly. If the amount of moisture inside the panel remains the same, as the air temperature drops, the amount of saturated moisture decreases, the relative humidity increases, and the amount of moisture the air inside the panel can hold decreases. When the inside of the panel is heated with a heater, the relative humidity inside the panel decreases, the amount of saturated moisture increases, and the amount of moisture the air inside the panel can hold increases. However, since the absolute amount of moisture remains the same, the dew point temperature remains the same.
Moist air h-x diagram
(Total pressure P = 760 mmHg)
Introducing heat problems in panel and key operational and energy-saving tips!
This book focuses on heat problems in panel, and provides information on the basics of heat problems, as well as a summary of some key points that can lead to efficient operation and energy conservation of panel.
