In automotive production, a good quarter of the energy used goes towards producing the car body. In the innovation alliance Green Carbody Technologies, 60 ‘energy detectives’ from science and industry got together to halve this figure. Together with its project partners as part of a sub-project, Festo closely investigated the energy consumed by compressed air in car body construction.
Energy consumption under scrutiny
Until now, the process chain from production and distribution to the utilisation of the compressed air had not been looked at as a whole. To start with, therefore, a close look was taken and the data measured along the compressed air chain in a production hall. How are the compressors configured? Are there losses in the distribution of compressed air? How much energy do individual pneumatic components need from the valve through to the servo-pneumatic welding guns? The data from the measurements gave the the project partners a hot lead revealed the consumption of compressed air and enabled them to find starting points for overall improvement measures for the first time.
Three software tools developed
Further important aids for increasing energy efficiency are software tools, which put together the countless data at the hall, machine and component level. Festo developed three simulation tools in the research project together with its project partners:
1. The first one enables the production and distribution of compressed air to be viewed holistically and to be configured an optimal manner.
2. With the help of the second one, the energy consumption can be estimated and the total costs regarding the life cycle of machinery (total cost of ownership, TCO for short) can be calculated.
3. The third simulation tool can be used as an integration platform to help exchange planning data about compressed-air technology via various application software programs.
Potential savings up to 35 %
The biggest energy consumers were identified: automotive manufacturers can save up to 35 per cent of energy in the compressed-air chain in car body production. This potential can easily be tapped when it comes to planning new facilities. The planning guideline developed from the project lists the measures – for example, how the right components are to be selected for the respective applications, how to make a compressor the optimal size and to make use of the waste heat, and how the compressed air distribution can be optimised.
2,232 megawatt hours saved in the reference plant
A reference plant was defined in the research project, which means a standardised, average production plant for the calculations. The compressed air used in the car body construction in the reference plant only has a share of 3.7 per cent of the plant’s total energy consumption. Based on the calculations from the standardised production plant, the potential to save up to 35 per cent of the energy here corresponds to an annual consumption of 2,232 megawatt hours and a CO2 equivalent of 1,257 tonnes a year on average.