Heating even at tropical temperatures - Energy-efficient heating of outdoor switchgear
featured in SCHALTSCHRANKBAU Magazine | Issue No. 2 (April 2023)
PTC Convection Heater Nimbus NG as a versatile allrounder - Increasing demands on the performance of switchgear lead to ever smaller components. These microelectronics are particularly sensitive to dust, moisture, and temperature, which is why the permissible temperature and humidity ranges are becoming smaller and smaller. In outdoor switch cabinets, precise temperature control is essential to prevent the formation of harmful condensation.
Energy efficiency, a very current topic in the industrial sector, has changed the requirements for heating solutions in recent years. Where switchgear used to be equipped with oversized heaters in terms of performance, heating is now provided punctually with the lowest possible power. Sometimes, several heaters are used per enclosure. Thanks to advanced simulations, customers today know exactly how much power a heating element must and may have, which is why their requests to manufacturers are becoming increasingly precise. In addition, the energy consumption of these devices in standby mode is an important issue.
Image 1 | 3D simulation for thermal and flow-technical design of the aluminum profile; natural convection through efficient design of the chimney effect
Effective heat transfer, thanks to the chimney effect, without the need for fans
An economical and effective heating solution for electrical enclosures are PTC Convection Heaters. They transfer heat to the surrounding air through thermal radiation and convection. The Nimbus NG series convection heaters have a unique aluminum profile to make the most of the natural chimney effect. It was designed for effective heat transfer to air using thermal simulation. As a result, there is no need for a fan, which would require a fixed power supply (e.g., 24V) and an additional power adapter. This enables easy installation and leads to lower acquisition costs and fewer failures during operation.
Image 2 | Surface temperatures measured through infrared imaging in different installation positions
Sufficient protection for surrounding components
Due to the high component density in switch cabinets, only limited space is available for the heating element. To protect surrounding components, wiring, and temperature-sensitive plastics, the Nimbus NG features touch protection. This housing protects in any installation position without significantly limiting heat dissipation. The unique feature is the open design of the cover: the ribbed shape ensures substantially better airflow and is much more material-efficient than comparable closed housings.
Heating energy efficiently, even at high outdoor temperatures
High-speed electronics cannot tolerate moisture. That is why even enclosures in tropical regions must be heated to avoid condensation. Thanks to the PTC Heating Technology, this is possible and even energy-efficient! The heart of all Nimbus NG series convection heaters is a PTC heating ceramic inside the aluminum profile, which has the property of self-regulation. As the "Power-Temperature Curve" shows, the heater reduces the generated heating power in a self-regulating manner as the ambient temperatures rise. This is due to the PTC effect.
The PTC effect makes it possible
PTC heating elements have a fixed maximum temperature that cannot be exceeded thanks to the PTC effect: safe heating in protection class II without additional thermal protection. They dynamically adjust their power to their environment. Low power consumption at low heat dissipation: energy-efficient heating without additional temperature control. The heating ceramics can be operated in a wide range of voltages with almost constant power and are approved according to worldwide standards: worldwide heating without additional effort.
Image 3 | Power-Temperature-Curve, Nimbus NG
Reliable in the field
Nimbus NG has proven practical use by allowing targeted temperature control of sensitive components, efficient heat transfer through the chimney effect, and easy handling. With touch protection and without a fan, it can heat energy-efficiently in all installation positions worldwide. Thanks to its multi-voltage capability, the heater can operate in a wide voltage range at nearly constant power - whether in Europe with 230V or the US with 115V. There are no barriers to worldwide use thanks to existing approvals such as CE, VDE, UL, and CSA. The central use of just one type of heater also simplifies procurement and storage for the customer and reduces the risk of confusion and later complaints. Equipped with all the advantages of PTC Heating Technology, the compact convection heater has proven itself in practical use as a cabinet heater, for frost protection in ATMs or ticket machines, for heating fuel dispensers, and more. It was designed to meet the industry's requirements and is available in several power versions.
Compact PTC Convection Heater for moisture and frost protection in electrical cabinets & enclosures
Power 20 - 75W
Multi-voltage capability at 110 – 240V
High safety and energy efficiency thanks to the PTC effect
Worldwide approvals: CE, VDE, UL
Most powerful PTC Convection Heater for moisture and frost protection in electrical cabinets & enclosures
Power 100 - 240W
Multi-voltage capability at 110 – 240V
High safety and energy efficiency thanks to the PTC effect
Worldwide approvals: CE, VDE, UL, CSA
Authors: Julia Orth; Wolfgang Werling | DBK David + Baader GmbH | Industrial Thermal Management