Control Cabinet Cooling: Preventing Excessive Heat Build-Up

When a control cabinet overheats, it can shorten the lifespan of components, cause system failures, and compromise compliance with standards. That’s why the temperature rise limits specified in DIN EN (IEC) 61439 must be strictly observed. This article walks you step by step through how to realistically assess the thermal conditions, accurately calculate the power losses inside the cabinet, and determine the actual cooling or heating requirements. You will also learn when control cabinet cooling becomes necessary and how to systematically select suitable solutions—such as those based on Peltier technology.

Control Cabinet Cooling Starts with Power Losses

Electrical equipment never operates without losses. A portion of the energy it consumes is always released as heat into the surrounding environment. This power loss within the control cabinet forms the central basis for any thermal design. The most reliable way to determine these values is by consulting the manufacturer’s specifications.

It is advisable to document the power loss already in the bill of materials. In E-CAD systems, it should also be recorded directly when creating the item. This ensures a reliable data basis from an early stage. A calculated verification to ensure compliance with the temperature rise limits is not only technically sensible but is explicitly required by DIN EN 61439.

Properly Accounting for Load and Simultaneity

For a realistic thermal assessment, it’s not just the installed power that matters, but the actual effective power loss.

First, the load factor is considered. The standard recommends operating equipment continuously at no more than 80 % of its rated capacity. If a device is subjected to a lower load in actual operation, the heat generated is reduced accordingly.

Next, the simultaneity of the circuits must be assessed. Not all consumers operate at full load continuously. The standard provides guidelines on the typical degree to which main circuits are loaded simultaneously, depending on their number. These factors often significantly reduce the total power loss to be considered and help prevent an oversized control cabinet cooling system.

The Control Cabinet in the Thermal Context

In addition to internal heat sources, the surrounding environment also affects the thermal balance. That’s why the control cabinet is always considered in the context of its installation. First, the effective surface area is determined based on height, width, and depth. The type of installation also plays a role: a freestanding cabinet can dissipate heat more effectively than a row-mounted cabinet or one mounted on a wall.

Next, the heat transfer coefficient of the enclosure is determined using the material-dependent k-factor. This indicates how much heat is dissipated or absorbed through the cabinet surfaces. A key factor is the temperature difference between the interior and the surrounding environment. If the ambient temperature is higher than the inside of the cabinet, additional heat flows into the enclosure. For large differences, suitable insulation can significantly reduce this heat gain, thereby lowering the required capacity of the control cabinet cooling system.

Finally,

the effective internal power loss
is added to the heat gain or loss influenced by the surrounding environment.

The result is the actual cooling or heating requirement at the operating point.

Properly Designing Control Cabinet Cooling

If the calculation indicates a cooling requirement, a suitable device must be selected. The selection is based on the manufacturer’s performance charts.

Three values are combined in the process:

Required Cooling Capacity
Maximum Allowable Internal Temperature
Maximum Ambient Temperature

Diagramm mit Kühlleistung (x-Achse) und Innentemperatur im Schaltschrank (y-Achse); es zeigt, wie abhängig von der Umgebungstemperatur die notwendige Schaltschrankkühlung berechnet wird

If the operating point falls within the device’s performance range, it is suitable. Otherwise, a more powerful model must be chosen, or the thermal situation improved—for example, by reducing power losses or providing better insulation.

Many manufacturers offer digital design tools for this purpose. These tools help calculate control cabinet cooling requirements and document the results. It is important to note that the manufacturers provide the characteristic curves used in calculating the required cooling capacity. This means that the results can be more accurate than when using general thermal calculation tools.

If you need support in determining the necessary control cabinet cooling, please complete this form. Please complete all required fields to allow for a precise assessment.

Peltier Technology as an Option for Control Cabinet Cooling

One option for cooling is thermoelectric systems based on the Peltier effect. They operate without refrigerants and have few moving parts, making them low-maintenance and capable of maintaining the enclosure’s IP protection in closed systems. Peltier devices are particularly suitable for small to medium cooling capacities and applications with high requirements for tightness or minimal maintenance. Whether they are suitable in a given case always depends on the calculated cooling demand and the surrounding conditions.

Heating and Cooling: A Special Feature of Peltier Technology

One advantage of thermoelectric systems is their reversibility. By reversing the current, the same device can introduce heat into the control cabinet. This allows the system to cover heating scenarios as well, for example to prevent condensation at low ambient temperatures. Whether the heating capacity is sufficient is also determined by the previously performed thermal calculation. In some cases, a separate control cabinet heater can thus be avoided. This unique feature of Peltier devices is particularly used for climate control of outdoor cabinets.

The Peltier-based control cabinet climate system maintains the internal temperature within a preset range—for example, between 5 °C and 40 °C. At high ambient temperatures above 40 °C, the Peltier device cools the cabinet interior, while in winter, at freezing temperatures, it heats the interior.

If you need support in determining the necessary control cabinet cooling, please complete this form. Please complete all required fields to allow for a precise assessment.

Zwei Schaltschränke unterschiedlicher Größe stehen allein in einer sandigen Landschaft.

Don’t Forget the Power Supply Technology

When calculating the power losses in a control cabinet, the cooling or heating devices themselves must also be taken into account. Their electrical power consumption is partly converted into heat and affects the overall thermal balance.

When a cooling device’s power supply is positioned outside the cabinet, the internal thermal load is correspondingly lower. It’s important to document these details in the design process.

Conclusion: Calculation Provides Confidence

A standard-compliant control cabinet cooling system doesn’t start with device selection—it begins with accurately determining power losses and the actual operating conditions. Only the combination of load, simultaneity, enclosure properties, and ambient temperature delivers a reliable result. With a structured thermal design, you increase operational safety, prevent overheating, and meet the requirements of DIN EN 61439 in a clear and well-documented manner.

If you need support with thermal design, temperature rise verification according to DIN EN 61439, or selecting suitable cooling technology, we can connect you with an expert contact.

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