A case study of compressed air line optimization: 80% of energy cost-saving and other added benefits within a 16 month ROI.
You are probably aware of the fast-growing trend involving manufacturer sustainability, which not only involves producers but also governments and consumers.
Forbes’ survey showed that “In the past 12 months around 68% of millennials bought a product with a social or environmental benefit ” and, “87% of consumers tend to sympathize more with a company supporting social or environmental issues.”
Also, Governments are always more inclined to sustainability; the EU, in particular, tailored an in-depth plan, which obliges companies to adopt a more sustainable manufacturing standard not to incur additional taxation.
What thought would pop up in your mind when you think about compressed air optimization? Probably, greater compressor efficiency, leak repair, heat recovery?
Today’s story will take you beyond compressor room optimization. We will take a look at the holistic approach of the compressor line optimization starting from the compressed air usage and finishing at the distribution and compressor. In this project the energy savings were about 80%.
The preliminary analysis produced an innovative plan to bring many advantages: some of them were immediately tangible, such as the power saving, while others indirectly improved production:
- Reduced risk of eye injures due to the use of high pressure application when it is not necessary
- Reduced noise level of blowing application and high leak rate
- Easier maintenance thanks to the resolved issue of accessibility
- Reduced CO2 impact per production piece.
Nonetheless, the most considerable advantage remains the manufacturing sustainability: complying with the new EU regulations and energy saving plans, achieves the investments’ refund in 16 months.
Figure 1: Cumulative cost saving by optimizing compressed air system
at the studied factory.
These results were achieved by implementing step-by-step energy-saving measures on the production line:
- Adequate sized components on production machines
- Repair of leaks
- Optimized distribution line to reduce pressure drops
- Reduced compressed-air demand through compressor room excellence
- Integrated condition monitoring with the decision support system.
Figure 2: Overview of energy-saving measures (excluding compressor). Blue dots are related directly to air saving measures, green indirectly – design-related measures
Figure 1 shows the overview of principal energy-saving measures and the location where it has to be applied. For example, actuators including cylinders, motors, nozzles and others should be sized correctly according to the application. Practice shows that 50 mm cylinder diameter under 6 bar consumes 55% more compressed air than cylinder diameter 40 mm with the same stroke. At the same time, nozzles are usually oversized or operate under high-pressure levels. In this particular project, the operating pressure level of nozzles was reduced keeping the required mass flow rate for the cleaning process and a separate low-pressure line was integrated into the system. Lowering system pressure directly has to be calculated for every single case to achieve the most efficient system operation. Another big issue is high-pressure drops due to the under-sizing of the distribution line. They need to be carefully calculated while designing the line according to ISO 6358.
Other saving measures concern the reuse of energy, for example pressure recycling from higher to lower levels. One of the less challenging is the reduction of tube length between valves and actuators that is part of dead volume elimination.
Of course, one of the most important along with system optimization is leakage detection and repair.
Only after all the above measures are implemented and required pressure levels and mass flow rates are identified, should suitable compressor technology then be chosen.
Here is a short report of the strategic analysis:
Figure 3: Strategic analysis of CAS optimization at the studied factory.
A competitive environment forces companies to run faster and any implementation of a new project requires an application “on the run”, in a parallel new line while the full operation is taking place.
Sooner or too late, entrepreneurs are forced to acknowledge the great impact of compressed air on the energy bill which might lead to the highest costs they’re already paying without even being aware of it.
Nowadays, this company provides a brand new opportunity potential for the next years to come, allowing clients to obtain such competitive advantages by only optimizing CAS.