Rittal has further improved its Blue e+ series cooling units to deal with the dynamic loads experienced on the high seas. For the first time, the manufacturer now includes DNV-tested cooling units for maritime applications in its product portfolio under the name Blue e+ dynamic. In addition to the usual EMC compatibility testing for ships, the units’ vibration resistance and safe operation when tilted were also tested. Testing in accordance with the DNV CG 0339 (Class A) standard ensures that energy-efficient appliances cool safely and reliably, even when subjected to high dynamic loads.
Not only wave movements but – above all – vibrations from the ship’s engine cause severe damage to systems and components. Cooling compressors and other heavy components installed in cooling devices are subject to violent vibrations; for example, after a short time, refrigerant lines break and suspended objects are destroyed. The reason: Cooling units are generally not designed for dynamic applications but only for static ones. Compressors traditionally mounted with vibration dampeners to avoid disturbing sensitive equipment like spindles on machine tools in industrial operations may achieve precisely the opposite effect at sea and literally “swing about” and cause many other problems.
That is why Rittal has adapted its Blue e+ series cooling units for maritime applications and made them suitable for use on the high seas. The devices were tested at Phoenix Testlab GmbH in Blomberg and DNV-certified. This also makes them interesting for dynamic applications on land – for example, use in crane systems or airport baggage handling systems.
Numerous DNV tests
A sine sweep test, in which a defined frequency spectrum was traversed, was first performed to test the vibration resistance. A broadband noise test over the entire frequency range then followed. The test piece was vibrated for 2.5 hours in each spatial axis, for a total of 7.5 hours. After the vibration test, the test pieces were placed in the climate chamber, where they were subjected to several temperature cycles, sometimes at high humidity. The inclination, in other words, the ship’s movement, was then simulated on another test bed. The final stage comprised EMC measurements, including interference emission and immunity tests.
Devices in the output classes 1.0 and 1.6 kW and 2.0 and 2.6 kW were tested. The DNV-tested devices will go into series production as “Blue e+ dynamic” in early 2025. The cooling units have a very high energy efficiency with a Seasonal Energy Efficiency Ratio (SEER) of >6.2.