The Technology of Cooling: Cooling with Closed Loop Cooling Units


Pfannenberg Cooling Units operate on the principle of the Carnot cycle. This means that the cooling unit functions as a heat pump that “pumps” the thermal energy transferred from the electronic cabinet (heat dissipated from the components) up to a higher level of temperature (the ambient temperature can reach levels as high as + 55 °C). The air inside the enclosure is cooled down by the evaporator and at the same time dehumidified.

How do I know if a cooling unit is the right product for my application?

> If the ambient temperature is greater than the target internal temperature of the enclosure, active cooling is required.
> If a NEMA Type 12 to 4x rating is required – closed loop systems can maintain the NEMA Type rating of the cabinet.

Properly sizing a cooling unit:

To properly size a cooling unit you must know the required cooling capacity in Watts, mounting requirements (side, integrated or top mount) and the dimensions of the unit and enclosure.

{PC = PD – PR }
> Pc [ Watt ]: Refrigeration capacity of a cooling unit.
> PD [ Watt ]: Dissipation Loss: Thermal power generated inside a cabinet by the dissipation loss of components.
> PR [ Watt ]: Radiant heat gain/loss: Heat transfer through the skin of the enclosure (insulation factor not included).

{PR = C x A x ∆T }
> C [  W/m2 °C ]: Coefficient of heat transmission.
> A [  M2 ]: Surface area of electronics cabinet.
> ∆T [ °C ]: Difference in temperature between the ambient air and the air inside the electronics cabinet.

Utilizing performance curves to properly size cooling units:

Pfannenberg utilizes the DIN standard 35/35 °C when rating our cooling units. Many other companies use 50/50 °C, which provides a higher, non-usable value.

Customers should use their own application temperatures to determine the proper cooling capacity of the system.

To properly size your Cooling Units you can also use Pfannenberg’s PSS Software which will guide you through the sizing process, to calculate the correct product for your application.


Important information when utilizing cooling units:

  • The refrigeration capacity should exceed the dissipation loss from the installed components by approximately 10%.
  • The enclosure should be sealed to prevent the inflow of ambient air.
  • Use the door contact switch to impede operation with open doors and consequent excessive accumulation of condensation.
  • Use cooling units with maximum clearance between air inflow and air outflow to prevent poor circulation.
  • Make sure that the air inflow and air outflow in the external circuit is not hindered, preventing proper heat exchanging at the condenser.
  • When using top-mounted cooling units, make sure that components with their own fans do not expel the air directly into the cooling unit‘s cool air outflow.
  • Make sure unit is level.
  • Setting the temperature to the lowest setting is not the optimal solution due to the condensation issues. The value we have preset on the cooling unit is a sound compromise between cooling the inside of the enclosure and the accumulation of condensation.

Click here to discover our complete range of Cooling Units!

Topics: Enclosure CoolingCooling UnitsThermal Management

New Thermal Management Solutions with Cloud-Based Remote Monitoring


On the way to Industry 4.0 with Pfannenberg’s innovative Thermal Management Solutions

Pfannenberg will unveil its Thermal Management Solution with cloud-based remote monitoring at Europe’s leading exhibition for electric automation, SPS IPC Drives in Nuremberg, Germany.

Communication is provided by a compact device with an integrated SIM card, which receives the relevant data from the connected cooling units via Modbus – a Building Management Protocol – and transmits it to the cloud over a secure mobile telecommunication link without any need for access to the company’s IT infrastructure.

The solution developed in cooperation with T-Systems enables users or systems to retrieve status data, diagnostic information and alarm notifications from the cooling units, live and independent of location, through a web browser, or to integrate the data directly into their applications.

From November 24-26th,  visitors will have the opportunity to see a working model on display at Stand #339 in Hall 5, and discuss this innovative Thermal Management solution with experts from Pfannenberg to learn more about its functionality and deployment options.

“The smart factory is the wave of the future. As an innovative medium-size company with over 190 patents worldwide, making our cooling solutions fit for networked products is a natural choice”, says Andreas Pfannenberg, Managing Director of the Pfannenberg Group. “With the premium controllers of the newest generation, our cooling units are able to provide a wealth of relevant data. Thanks to the cloud solution, employees in production management, the service department or the maintenance department, as well as higher-level monitoring systems, receive information about possible malfunctions or imminent failures promptly, wherever they are. This enables them to respond quickly before a serious incident occurs, which helps increase machine availability.”

Next-generation of Thermal Management

The Thermal Management demo system on display at the trade show will consist of a two-compartment switchgear cabinet with a semi-recessed DTI cooling unit on one side and a semi-recessed PWI series Air to Water Heat Exchanger on the other side, each equipped with a premium controller. There are three heaters in each cabinet compartments, which can be turned on individually at the front using door-mounted switches to simulate heat loads. On an external monitor visitors will be able to observe how the Enclosure Cooling Unit reacts to changes in the heat load or when opening the cabinet door.


Contact us today to learn more about this innovative solution!

Topics: Air Water Heat ExchangersEnclosure CoolingCooling UnitsThermal Management

Pfannenberg’s Signaling Devices compliant with the Seveso III Directive


Enhance Industrial Safety: with the SIL/PL-compliant Signaling Technology from Pfannenberg, plant operators can guarantee standard alerting in accordance with the Seveso III Directive.

The EU Directive, Seveso III, is based on the catastrophic accident which occurred in the Italian town of Seveso in 1976 which prompted industrial companies that use dangerous chemicals to prevent and control such incidents. This can be achieved by installing appropriate industrial alerting and alarm systems.The amended Seveso III Directive has been enhanced and now stipulates that the authorities must do systematic assessments of all known plants with hazardous incidents as well as random inspections. Therefore, plant operators should, without fail, take the new legal situation into consideration when planning new plants – and check their existing plants for conformity to standards.

More industries concerned by the Directive
The Chemical Industry is no longer the only one affected by the Seveso III Directive legal requirements. Indeed, depending on the amount, type and risk category of the substances which are processed, the revised specifications can now be applied to metal processing and logistics companies or storage facilities for technical gases. A classification system (attachment 1 of Seveso Directive III) can be used to know how the new regulations apply to a company.

More safety with Pfannenberg’s sounders and flashing lights
An important requirement of the Seveso III Directive is to prevent failures and to limit the possible effects of incidents; for example, installing appropriate industrial signaling.

Pfannenberg’s SIL/PL Signaling Devices are therefore compliant to the EU specifications. Pfannenberg’s sounders and flashing lights are equipped with the safety-related parameters and can be integrated to your plant’s safety plan. Our DS Sounders or our Quadro Flashing alarms and PMF Series are, for example, particularly suitable for the compliant implementation of the revised Seveso III Directive.

“The deployment of our SIL/PL compliant Signaling Devices in industrial plants and companies reflects the consistent safety mentality of the planners and operating companies. Our products stand for more safety and reliability in the plants”, says Carsten Hippler, Product Sales Manager Signaling at Pfannenberg.

Topics: Industrial Safety & Signaling Solutions