The use of compressed air (CA) as an energy carrier has become common in almost all industries and processes. The current spend for creating CA can equal 20 – 30% of a company’s total energy costs. Experience shows that targeted measures, such as optimising CA production and processing, using higher-level compressor control systems and minimizing leaks and pressure losses can increase energy costs up to 33%.
In general generating energy related performance indicators for a compressed air system can be divided into figures about the generation (e.g. compressors) and the distribution system (e.g. pipes, filters) itself.
With performance describing values like the Specific energy consumption (SEC), compressors can be compared, and the optimal working point of a compressor can be analyzed. This offers already the first optimization potential as a compressor consumes too much of expensive energy if it runs beyond its optimal operating point.
Especially within the CA distribution system it happens a lot that there are leaks and the filters get blocked. Both issues create significant energy losses. Monitoring both, automatically realizes continuous improvement potential as well as the system pressure itself. Each bar beyond the optimal value of the system consumes approximately 6 – 7% more energy than necessary.
Compressed air is used as a power source for many food and beverage operations as it is a versatile, safe and flexible way to transmit energy. However, many operators do not actually realize that it is very costly to produce CA and it is sometimes misused. Typical processes where compressed air is used:
- Product handling – Product transportation with high speed within the production process
- Filling systems – for food or bottles
- Liquid pumps – transport of liquid products in the production and filling process
- Processing – cutting and peeling of raw material such as fruits and vegetables
- Packaging – Packaging processes
The different monitoring systems from Endress+Hauser (Energy Management – Smart Scale Solution) are modular expandable. They start with a stand-alone solution (Memograph M) that can be expanded up to companywide solutions, it can also be easily integrated vertically to Enterprise Resource Systems.
The following efficiencies that can be monitored to improve CA systems:
- Compressor efficiency (SEC, SPC)
- The Key Performance Indicator for compressor performance (efficiency) is the Specific Energy Consumption (SEC) and Specific Power Consumption (SPC).
- Compressor-SEC (SPC) expresses how much energy is required to produce one unit of compressed air (e.g. kWh/Nm³), also expressed in SPC (kW/(m³/min)).
- Depending on customer’s requirement SEC can also be referenced to other units, e.g. KWh/kg, sm³/kWh, kg/kWh, cost/sm³, etc
- Leakage detection and balancing of
compressed air system
- The principle of balancing is used to calculate total leakage by comparing produced and (sum of) consumed air or to monitor pipe sections (for leaks, disruption).
- Apart from leakage detection this value can be used to verify the quality of measurement (to detect installation problems or meter failure).
- Filter and pressure drop supervision
- This application provides an early warning detection of filter contamination and blockage as well as a KPI for the quality of network design (in terms of pressure drop and thus energy loss).