A switchboard’s heat load is a critical key factor which is frequently overlooked. It is essential to include an evaluated cooling solution which can handle the heat load and ambient conditions, to ensure the reliability and longevity of your investment.
Here are the four most common solutions for cabinet cooling.
Passive Ventilation
When the heat load is minimal and the enclosure is not exposed to temperature extremes, it is possible to simply install fixed ventilation louvres in the sides or doors of the cabinet. Natural circulation as hot air rises, allows it to exit the enclosure via the vents. Making the enclosure larger than required encourages more efficient heat dissipation. While this is the simplest ventilation method, the heat load capacity is limited. Generally speaking, the highest achievable ingress protection (IP) rating using natural ventilation through side vents is IP56. This is based on the installation of a protective hood over the vents. Without a hood, IP54 is the maximum achievable rating
Forced Ventilation
Fitting a dedicated fan is the next level when it comes to cabinet cooling. The fan can be run continuously, started with large heat loads or installed with a thermal cut-out to enable air circulation inside the cabinet and to expel the hot air. As hot air accumulates at the top of the cabinet, the fan will generally be fitted here. This simple method can be very effective. For fans that have external grills the maximum IP rating which can be achieved is IP56, providing there is a protective hood fitted over the vents. Without this hood, the highest rating is IP54.
Heat Exchangers
Another simple cabinet cooling method involves use of a heat sink or a passive heat exchanger, utilising either air or liquid to direct heat away from the heat source. As these systems usually have fewer moving parts, a higher IP rating is achievable. IP55 is the highest rating generally for heat exchangers with the correct seals.
Air conditioning
A dedicated air conditioner is a good option for scenarios involving a higher heat load and greater ambient temperatures. This method works in a similar way to regular split systems by transferring heat outside the cabinet through circulation of refrigerant gas or liquid. Although significantly more costly, these systems are able to handle significantly higher heat loads than other methods. Waterproof models are also available, and the IP rating is typically up to IP55.
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