Plug and play!

Together we are stronger: Güntner and ebm-papst have taken this motto to heart and entered into a development partnership that makes rational use of energy-efficient EC fans in heat exchangers for refrigeration and air-conditioning

For the end customer, saving is not just saving: Güntner AG & Co. KG has offered power-saving EC fans from ebm-papst in its equipment since 2006 as an alternative to AC fans. The principal argument at the time was the greater energy efficiency. But it took until 2008 before the offer was as well received on the market as the globally leading company in heat transfer technology had envisaged. Güntner researched the reasons for the market reluctance and decided to revise the concept and to integrate ebm-papst.

A good approach

“Güntner recognised that the opportunities provided by EC fans were not being optimally exploited by the customers,” recalls the Mulfingen project engineer Martin Schulz. The Fürstenfeldbruck-based company took a complete line of EC axial fans from ebm-papst ranging from 500 to 910 millimetres in diameter. Depending on the application, the fans were programmed to a certain speed by ebm-papst. This created one-to-one replacement models for the AC fans that had been exclusively used until then. The equipment thus uses less energy and offers long-term savings, even though initial investment costs are higher at first sight. But because the power electronics are already integrated into the EC fans, the customer also saves cost of the control box.
For Güntner, the advantage was being able to use a versatile motor in different units. However, that meant that the fans had to be programmed differently for each model. The EC fans were eminently suitable for this as they have an extensive interface that the end customer is able to use. “That was the crucial point,” remembers Jörg Köcher, head of Güntner Controls. “Customers do not want to do the programming themselves, they want to buy a working heat exchanger that is perfectly configured for noise and performance.” on this basis, Güntner revised the entire concept with respect to usability.

Plug and play

The technical challenges were the bus system, the automatic setting of the operating points and thus the plug-and-play capability. “We wanted the units to work like a new printer –
plug them in and they connect up themselves,” Köcher explains the plan. “That caused us real
trouble. How should a fan connect itself up without first being assigned a bus address, and what happens if two fans have the same address?” Güntner resolved this problem by developing a controller that performs all technical refrigeration control functions and which offers exactly this plug-and-play capability. To this end, a bus system is used to provide the information in the fan and to make this usable for the control system. Data that is important for the settings of the heat exchanger is still written to the fans. The requirements of the fans were discussed. “Initially, it really was a struggle, until we agreed on the concept side,” says Köcher of the coordination process, which wasn’t always plain sailing, but which ultimately produced a successful solution. “Each company concentrated on its core competence. Güntner
on the heat exchanger side. ebm-papst on the motors and the fluid mechanics.”

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