On the trail of energy loss in compressed air systems
Authors: Dipl.-Ing. Jürgen Billep, Service Portfolio Management Energy Savings Services, Festo, Dipl.-Ing. Uwe Hessmer, MSR Electronics GmbH
Small but powerful: the all-round talents of mini data loggers are increasingly being discovered by the manufacturing industry. This is no coincidence. As this user report on MSR data loggers at Festo's Energy Savings Services shows, the small data recording devices can do far more than is known from the typical applications - e.g. monitoring transportation, climate and process conditions.
The Energy Savings division of Festo, the world's leading automation company, offers compressed air users customized services for identifying and exploiting compressed air savings potential. According to Dipl.-Ing. Jürgen Billep, Auditor at Festo's Energy Saving Services, the demand for energy analyses has increased steadily in recent years. According to the engineer, many companies are looking for potential savings in their production in order to survive in the face of tough competition. And they very often find this in their compressed air systems and installations, most of which have been in place for years.
Reduce energy costs in compressed air systems by up to 60%
Compressed air is relatively expensive: a cubic meter currently costs around 1.8 cents. This makes compressed air around eight to ten times more expensive than the direct electric drive of machines and tools (source: HS Esslingen). For systems with few operating hours, electricity costs account for an estimated 20% of operating costs; for systems that run around the clock, this can be up to 80%. (Source: energie.ch) It is therefore worth taking a closer look at compressed air consumption in order to increase energy efficiency in a process or production environment and reduce costs. However, this requires a holistic view of a company's compressed air system. Festo's analysis therefore ranges from compressed air generation/preparation to compressed air distribution with leakage detection through to the pneumatic application itself. The compressed air energy efficiency analyses carried out by the Festo specialists are performed in accordance with ISO 11011 and are certified by TÜV SÜD. "We strive for holistic and independent pneumatic system engineering for the benefit of the customer. We are proud of the fact that we have been able to achieve savings of up to 60% for our customers while increasing productivity," reports Jürgen Billep. "Festo is significantly supported in these tasks," says the engineer, "by the MSR145 MSR data loggers with analog inputs for connecting our external pressure sensors."
Determining cost savings by means of pressure value measurements
Festo uses the data loggers for flow measurements on the one hand and for recording pressure values on the other. To record pressure values, engineer Billep positions at least three time-synchronized MSR145 data loggers at the pressure generator, after the compressed air preparation and at the furthest point of the compressed air network. The loggers measure and record the ambient conditions (pressure, temperature and humidity) as well as the actual air pressure generated. Additional measuring points can be provided for analyzing the applications themselves.
A pressure drop of more than 0.6 bar after compressed air preparation and distribution, for example, is already classified as negative, and a pressure drop of 1.0 bar in the downstream compressed air system is even dramatic. If the system operator succeeds in reducing a pressure loss of 2.1 bar in his overall system, for example, this alone can result in cost savings of over 10% in compressed air generation.
However, Festo's experts not only identify such potential savings, but also conceptual improvements, such as in pipe design, compressed air quality, filter loads and efficient use of applications.
Flow measurements with integrated MSR logger
Festo uses flow measurements in the customer's system to determine the idle consumption and thus leaks in the system, which are then checked by means of a check analysis after the repair has been carried out.
The flow measurements and leakage detection are also carried out using MSR145 MSR data loggers. The Festo measuring box has a built-in MSR145 with two analog inputs for 0...10.0 V. In just a few hours of measuring time, the auditors use the measuring box to obtain a detailed overview of the status of the system and can present the customer with a differentiated target/actual analysis and forecast of the savings potential as well as a ranking of the necessary measures.
"The intuitive and clear software that is available with the data loggers from MSR makes it much easier for us to evaluate the data, not least because MSR is continuously expanding the functionality of the software," says Jürgen Billep, "We can very easily integrate the relevant measurement curves of the individual data loggers into a display and thus obtain the results for our analysis."
For further analysis, the MSR PC software can also be used to mathematically calculate and graphically display various measured values.
Data loggers solve measurement challenges at manageable costs
Festo selected the MSR145 data loggers primarily because they are very small and multifunctional. They are also characterized by high flexibility, for example in the sampling rate, explains the engineer. A high sampling rate is required for the actual pressure measurements, as the air can move at up to 20 m/s in the pipe, which leads to considerable pressure fluctuations in a short space of time. With the MSR data loggers, precise statements can be made about the pressure ratios and pressure curves per time unit and, in particular, the pressure drop can be observed. The manageable costs were also one of the reasons for purchasing MSR data loggers.
The loggers: all-rounders in measurement technology
With the help of highly sensitive sensors, the MSR loggers record almost any physical and electrical measurement data such as temperature, humidity, pressure, brightness, vibrations and also externally supplied electrical voltage values. As Managing Director Wendelin Egli mentions with a grin, his data loggers are now used worldwide "from the very top - transport monitoring in NASA space transporters - to the very bottom - for measurements in offshore facilities in the Atlantic. Egli is particularly proud of the order from Festo. According to the Managing Director, being able to work for the number one in automation technology is not only good for his reputation, but the exchange and fruitful cooperation also ensures that his future innovations will also meet the wishes and needs of his customers.
