Insu­lating coolers success­fully converted

Ever more frequently, large refrig­er­a­tion cham­bers are equipped with centralised air coolers. A special type is made by the ther­mofin company, from Heins­dor­fer­grund in the German state of Saxony. “An insu­lating cooler is, in prin­ciple, a container with flaps, into which a cooling unit is built,” explains Michael Hanning, Regional Director of the ebm-papst outside sales office in Halle/Saale. The device is located outside the refrig­er­a­tion chamber. From there, the insu­lating cooler is flange-mounted on the cold storage area. The refrig­er­a­tion that the insu­lating cooler trans­fers into the air is then led through the opened flaps into a duct, and from there into the cold storage area. In this way, no space is lost in the storage area itself, and there is more space for shelves and merchan­dise. As has long been common in insu­lating coolers, the company used double-flow centrifugal fans with belt drive and frequency inverter for this appli­ca­tion.

Müller and Hanning view the new insu­lating cooler

Idea during tour

All that changed as a result of a visit from Michael Hanning and his sales colleague Martin Schulz, who together toured produc­tion with Frank Müller, Tech­nical Manager at ther­mofin. During it, the ebm-papst employees noticed the belt-driven AC fans installed in the insu­lating cooler. “We suggested thinking about a back­ward-curved Green­Tech EC fan, because the device could be signif­i­cantly more effi­cient that way,” Hanning remem­bers. The suggested solu­tion, however, required a revi­sion of the insu­lating cooler and the corre­sponding skills and knowl­edge. Tech­nical enthu­siast Müller fancied the idea, and agreed to look into the option in detail.“
First we had to find out what compo­nents we needed for the replace­ment of the belt-driven fans,” Müller remem­bers. Then, ebm-papst sent 3D data, with which the Tech­nical Manager and his team could redesign the insu­lating cooler on the computer and compare various arrange­ments of the fans within the device. The effort led to an ideal solu­tion: Along­side effi­ciency and ease of main­te­nance, the air conduc­tion and the cleaning options of the heat exchanger were signif­i­cantly improved. After the theo­ret­ical design on the computer was completed, ebm-papst deliv­ered a sample of the centrifugal fan for a proto­type. The tests and measure­ments confirmed signif­i­cant energy savings.

The pay-off for the work

While the input power of the insu­lating cooler with the belt-driven AC fans was just under 27 kilo­watts, it is now only 17 – a whole 37 percent lower. And the noise level was also reduced by 4.5 deci­bels. In addi­tion, the insu­lating cooler became more reli­able: Lubri­ca­tion inter­vals are omitted, which makes service easier – and through the omis­sion of the belt, slip losses are a thing of the past.The new design with the Green­Tech EC fans could be imple­mented at ther­mofin almost cost-neutrally compared to the conven­tional solu­tion, and the reno­va­tion brought addi­tional posi­tive effects with it. Due to the high effi­ciency of the system, the company was awarded the contract for equip­ping the cold storage ware­house for a large German super­market chain.

The new end product, used for the first time, is thus perfectly suited for the market; as a result, ther­mofin secured protec­tive rights for the combi­na­tion of compo­nents. “One partic­u­larly nice thing about the project was that the customer agreed to the reno­va­tion of the insu­lating cooler, and in the end, we were all rewarded by the fact that the hoped-for savings was achieved,” Hanning summarises.