Plug and play!

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.”

High demands

“A new line of EC fans with a diam­eter ranging from 450 to 990 millime­tres and with bus commu­ni­ca­tion was specially devel­oped for and with Güntner and these fans were aero­dy­nam­i­cally adapted to Güntner vents – and all that was done in a required devel­op­ment time of 12 months,” explains Martin Schulz, summarising the devel­op­ment require­ments.
With these marginal condi­tions, the engi­neers at Mulfingen started iden­ti­fying 26 motor/electronics/impeller combi­na­tions and assigning each of them to the oper­ating ranges. The complete series was equipped with energy-effi­cient EC motors using the very latest HyBlade® fan tech­nology. Once the Mulfingen engi­neers had devel­oped the elec­tronics, they constructed the fan types as proto­types. Air perfor­mance and acoustic capacity in the Güntner vents were measured in the multi­pur­pose measuring chamber. “This allowed us to provide Güntner with exact measured data for the fans in their appli­ca­tions,” reports Schulz.

Conve­nient controls

The Güntner Motor Manage­ment (GMM) system was devel­oped at Fürsten­feld­bruck in parallel to the fan devel­op­ment at ebm-papst. This control system performs the tech­nical regu­la­tion func­tions, the program­ming and the data eval­u­a­tion of the EC fans in the refrig­er­a­tion cycle. Within this closed loop, the fans act as actu­a­tors, ensuring that heat is dissi­pated via the heat exchanger. Commu­ni­ca­tion via a bus system gives the GMM detailed infor­ma­tion that helps to make the control system more precise and more user-friendly. Because the controller knows the char­ac­ter­istic curves in the fans, it knows which response it can expect in the closed loop even as it actu­ates. The controller is still able to make use of speed, elec­tric power, current draw, oper­ating status, error messages and many more items of data from the fans. These are all addi­tional bene­fits that goes to enhance the infor­ma­tion content and thus increase the oper­ating reli­a­bility of the system. More­over, the controller also checks the fan type, regard­less of whether it is a new unit or, in a service case, one that has been installed for a number of years. In either case, the GMM will auto­mat­i­cally assume the task of program­ming. “The problem with the old solu­tion was that absolutely no visu­al­i­sa­tion was possible. It was like taking the display off of a microwave. We were unable to change any values, we couldn’t see which oper­ating state the control system was working in, we simply couldn’t see what was happening inside,” explains Jörg Köcher. Apart from more straight­for­ward controls, the precisely config­ured func­tions mean all in all consid­er­able savings are possible for commis­sioning and for running costs.

Optimal manage­ment

One of the main advan­tages of the intel­li­gent control system is its optimal energy manage­ment. At all times, the fan will only deliver exactly the air volume that is actu­ally required. “In combi­na­tion with the already extremely energy-effi­cient EC tech­nology, a package can be offered that cannot be beaten in terms of energy effi­ciency,” stresses Schulz. And Köcher adds: “Our advan­tages are our customers’ advan­tages. We now offer energy-effi­cient, intel­li­gent equip­ment with extended func­tions. Here, we have devel­oped an inno­v­a­tive system that gives us the edge on the market. More­over, the multiple use of the EC fans in different equip­ment means that our stock levels are much lower.” The success of the devel­op­ment part­ner­ship can also be seen in sales. Quan­ti­ties have risen greatly since the launch in April.