Electrical equipment such as VFDs, contactors, and PLCs generate heat through power losses. This same equipment can lose efficiency, operate erratically, or even fail prematurely due to excess temperatures, resulting in reduced productivity, customer dissatisfaction, and lost revenue.
Adverse effects such as these can be avoided if the panel or enclosure containing the equipment is maintained at or below each component’s maximum operating temperature. Depending on the total heat load of the components, thermal conduction or convection—even with forced air ventilation—may not be able to keep the interior of an enclosure within the manufacturer’s recommended range.
This is especially the case if the enclosure is located outdoors, in direct sunlight, or near a furnace or industrial oven. Even a passive closed-loop heat exchanger will not be able to cool an enclosure below the ambient temperature.
Closed-loop cooling required
In addition to excess temperatures, additional factors which may contribute to unwanted failures include high humidity, splashing liquids, salt water, hazardous gases, large amounts of dust and debris, and metal filings. If any of these elements are present in the location, enclosures must be sealed, making it impossible to cool them with filtered fans or natural ventilation.
In situations like this, a sealed enclosure will require an enclosure air conditioner to maintain long-term reliability of the electrical components and prevent unwanted failures. These units, which can be attached to the side of an enclosure, use a refrigerant cycling through an evaporator coil to cool the air, which is then circulated through the enclosure through a set of vents.
Correct air conditioner sizing
In order to determine the air conditioner cooling capacity required to prevent unwanted failures, it is important to know how much heat will be generated by each of the components in the enclosure. This can be calculated mathematically or determined by using heat dissipation data from the component manufacturers.
An additional amount of heat transferred through the control panel wall—whether positive or negative, depending on the temperature difference between interior and exterior—will also need to be factored into the total cooling capacity requirement.
It is important to calculate the cooling capacity fairly accurately in order to prevent either undercooling—which could result in temperatures exceeding the maximum rated temperature for a component—or oversizing, causing the air conditioner to cycle on and off too frequently, making it less efficient, increasing operating costs, and shortening its useful life.
Selecting and sizing the proper enclosure air conditioner can protect valuable electrical equipment, reduce maintenance and downtime, increase productivity, and maximize profits, all while preventing unwanted equipment failures.
An online enclosure temperature management calculator can be used to determine the cooling capacity required for a particular enclosure. For more help in properly sizing an enclosure air conditioner in order to prevent unwanted failures, contact the experts at Thermal Edge.