Many enclosure cooling devices for industrial thermal processing are designed to handle environments where water is present. The off-the-shelf systems incorporate condensate management to handle the water in your enclosures.
What is that? There is no water near your electronics? That is where you are wrong: the water is hidden in vapor form in the air. Fortunately, when managed correctly, it has no effect on the components inside the enclosure.
The key is to manage the water correctly, which in this case means keeping it from condensing into liquid form. This is done by keeping the temperature of the enclosure above the dewpoint — typically by keeping the temperature of the enclosure above the ambient temperature or at 95°F (35°C). This helps because warmer air can hold more water vapor, making it harder to condense.
For example, suppose you are keeping your enclosure at 65°F — a temperature comfortable for you or me — and you are having problems with condensation forming on your electronics. The easiest solution is to raise the temperature. By raising the temperature to 95°F — a temperature comfortable for electronics — you move from 100 percent relative humidity to 40 percent relative humidity, eliminating your problem. Remember that 100 percent relative humidity is the point where the air is holding as much water vapor as it can; likewise, 100 percent relative humidity is the point at which water vapor starts to condense into liquid form.
Products that utilize water as a cooling medium are highly engineered to ensure that the water never comes in contact with the electrical components. For example, figure 1 shows how the water lines running to the heat exchanger coil are physically separated from where the airflow enters the enclosure. If there is a problem with the water lines, the water has no way to get inside the cabinet.
Any condensation that is formed also is prevented from entering the cabinet by directing the condensation to flow along the side of the internal walls and then exit the unit through the drain. When used properly, air-to-water heat exchangers help keep the enclosure safe from water and the heat generated by the electrical components in the enclosure.
Using an air-to-water heat exchanger is safe and can be a good alternative to packaged air conditioners. Air-to-water heat exchangers are durable and can be placed in harsher environments without fear of failure. Also, little maintenance is required to keep them up and running.
An air-to-water heat exchanger is composed of a fan, a controller or thermostat, a solenoid, the heat exchanger coil and the housing. The fan pulls air from the enclosure into the air-to-water heat exchanger and blows it across the coil, cooling the air. Then, the air flows back into the enclosure. Unlike an air conditioner, an air-to-water heat exchanger does not use outside air at all. This allows air-to-water heat exchangers to be put in hot, dusty or corrosive environments without worry about changing filters or having to replace a coil due to corrosion. There is no condenser coil, refrigerant or exposure to the ambient conditions.
Many manufacturing plants utilize chilled water in their manufacturing processes. Typically, they get the chilled water from a large centralized chiller that can be used to also supply chilled water to air-to-water heat exchangers. This would be an ideal application because the plant already knows the value of using water to cool their machines.
Water solutions reduce costs in several ways. First, they lower upfront cost due to the simplicity of the design. No compressor, no refrigerant, only one fan and less sheet metal lead to a lower price than a comparable size air conditioner.
Second, the only power used by an air-to-water heat exchanger is the power needed to run the fan and the controller. So, it can have a lower operating cost than traditional air conditioners.
Third, water cooling solutions often have fewer maintenance requirements. There are no filters to replace or refrigerant to be monitored.
Fourth, air-to-water exchangers may reduce the cost of downtime. By having longer service life, they will not need to be repaired as often. It is easy to keep a fan and a solenoid in stock near the air-to-water heat exchanger to speed up the repair and get the machine up and running if there is a failure. This reduces the mean time to repair (MTTR).
In conclusion, you should not be afraid of using water near electronics in your plant. When managed correctly, using water can exist with electronics and not cause any problems while providing many benefits. Also, using air-to-water heat exchangers can save money and time. It is safe and affordable. Due to the amount of money and energy that can be saved, many states are offering rebate programs to offset the cost of a project which replaces inefficient systems with air-to-water heat exchangers.