Grundfos performs pump audits at the Volkswagen plant in Braunschweig, Germany

Company background

Ecological sustainability is an important corporate goal of the Volkswagen Group worldwide, and it is not limited to making more fuel-efficient cars. Behind the "ThinkBlue.Factory" plan, Volkswagen is convinced that "efficient cars should come from efficient production". This is why the Group has set a target of reducing global energy consumption by 25% by 2018. The factory in Braunschweig was built as early as 1938, the first ever for Volkswagen, when it was still called "Vorwerk". At present, about 8,500 employees at the Braunschweig plant produce chassis parts, post production

The axle and front axle, shock absorbers as well as brakes, brake discs, steering and various pedals (hence the name "Fahr-Werk" today). In addition, the plant carries out the construction of machine tools and tools as well as the production of plastic parts. Production ranges from development to final assembly. Almost every car produced by the Group is equipped with products from the Braunschweig plant.

Initial situation - pump audit as a pilot project

Whether it is electricity for plant and equipment, or gas for plant heating or technical processing, companies want to tap into the savings potential and use efficient technologies to save energy. In 2011, Plant Energy Officer Paul-Gerhard Romermann, together with Grundfos, launched a pilot project to record the current state of pump energy consumption (i.e., pump audit). Specifically, this involves three metal cutting machine cooling lubricant supply pumps for the rotating bearing processing area (there are six such cooling lubricant supply systems in the production area). In the past, pumps here were operated in cascades: at least one pump worked all the time; The second or third pump will be turned on as needed, depending on the quantity.

Grundfos Solutions

After monitoring selected cooling lubricant units and discussing the monitoring results, we found that the pumps themselves do not have much energy saving potential, but their control should be optimized. The challenge for Grundfos pump energy efficiency experts is how to achieve this optimisation as cost-effectively as possible. Finally, we installed an external frequency converter for each pump, which is controlled by a higher level pump controller. The result is an autonomous control system that doesn't require any modifications to the old control cabinet (because, as practitioners know, such modifications are expensive!). .

The system now uses the MPC pump controller developed by Grundfos, which detects changes in pump pressure and controls and coordinates the pump's external CUE frequency converter as needed. In this way, the improved system can self-regulate as a standalone solution, without the need for a central control system to regulate through the bus system and PLC.

Effective energy saving 37%

It was a groundbreaking decision, and it paid off quickly: "After monitoring the actual situation, our expectation in 2011 was to save 22 per cent, but after using Grundfos' drives, we achieved 37 per cent savings." Mentioned in the plant energy officer report. How to account for such high energy savings? Previously, the factory controlled the switch of the pump through a conventional contactor. Today, these power contactors (Romermann calls them "clunky snap-snapping devices") are replaced by frequency converters (" intelligent, teachable systems because they can set parameters "). Practice has shown that coolant is not actually needed at all times ⸺ for example, the machine is at a standstill during several tool changes a day. "Only the newly installed control technology is able to identify when the machine does not need the cooling lubricant, so the pump can stop working completely at this point." "Romermann said.

What was initially surprising about this pilot project was that it didn't use Grundfos pumps, so why entrust Grundfos with a pump audit?

"Because we have confidence in Glen to carry out this pilot project in a reliable and open way." Paul-Gerhard Romermann. In addition, Grundfos' approach is very different from other suppliers, focusing on collecting data that is truly relevant to the public: "Only by knowing this data can I do meaningful work and achieve our most important goal: safety processes!"