Operational Optimization of Compressed Air Networks
Compressed Air
Measure Goal
The goal of this document is to calculate the electricity savings achieved through operational optimizations of a compressed air network.
Examples and Scenarios
Leakage analysis and remediation: A leakage analysis is carried out for an 8 bar compressed air network and a leakage quantity of 250 l/min is found and remedied. The full load hours are 6,000 h/a with an annual electricity consumption of 150,000 kWh/a.
Inputs
250 l/min leakage, 8 bar network
Flat-rate approach leaks: 25 possible leaks in the operation are remedied. The leakage share would thus be 5%, but a maximum of 3% is credited with an annual electricity consumption of 150,000 kWh/a.
Inputs
25 leaks fixed (3% factor)
Pressure reduction: The operating pressure of a compressed air network is reduced by 2 bar with an annual electricity consumption of 300,000 kWh/a. A 1 bar reduction can trigger 6% energy savings.
Inputs
Reduction by 2 bar (12% factor)
Network shutdown: The compressed air compressor is now switched off on weekends and at night by a timer. 100% of the network is disconnected for 3,500 h/a with an annual electricity consumption of 300,000 kWh/a. The leakage losses across the entire compressed air network average 15%.
Inputs
Timer (3,500 h/a, 100% network)
Requirements
Only measures that meet the requirements of the Energy Ordinance (SR 730.01; EnV) can be credited. The additional requirements for the technical characteristics and for the implementation of the measure are set out in Table 1.
| Old system | New system | |
|---|---|---|
| Energy efficiency | Only compressed-air networks operated by compressed-air compressors with a total rated electrical power (motors) of up to 160 kW and in a pressure range of 4 to 15 bar are covered by this measure. | - |
| Savings | - | The various measures can be combined. Nevertheless, the individual and cumulative eligible electricity savings are limited to a maximum of 20%. |
| Reduction of leakage | Flat-rate approach: This approach can only be applied up to a total rated electrical motor power of 30 kW (old system). The eligible electricity savings of the measure are limited to a maximum of 3% of the old electricity consumption. System approach: The leakage analysis must be carried out with a professional leak-detection device. The following results of the analysis must be documented: - Annual electricity consumption of the old state - Leakage quantity - Saving The analysis must show the possible optimisation measures of the new compressed-air system as well as the calculation of the electricity savings based on the leakage quantity (see documentation DL-02). | |
| Implementation | In the case of a system approach, the analysis must be carried out by a qualified specialist / company. | |
Proof of compliance
Compliance with the requirements must be demonstrated by the following documents. The documents listed in Table 2 are an integral part of the proof of measure implementation.
- 1.In the case of an analysis approach: report of the leakage analysis (PDF format), including the date and the company that carried out the analysis (UID, name and registered office)
- 2.Invoice documents (PDF, PNG or JPEG format)
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ContactSymbols, Terms and Units
| Symbol | Description | Unit |
|---|---|---|
E | annual electricity consumption | kWh/a |
ΔEeco | cumulative electricity savings | kWh |
n | number | — |
Ns | standard effective duration | a |
f | factor | — |
Ė | electrical rated power (motor) | kW |
L | leakage quantity | l/min |
Δp | operating pressure difference | bar |
t | full load hours | h/a |
Calculation Formulas
Creditable Savings
The creditable electricity savings of the measure is the difference between the current and the new annual electricity consumption, cumulated over the standard effective duration. To account for the natural renewal and optimization rate, the creditable electricity savings are reduced by a reduction factor f_eco of 0.75. The standard useful life is 3 years.
Leakage Optimization (Flat-rate Approach)
For each leak remedied, the savings factor f_eco,lk of 0.2% can be summed. The savings factor is limited to a maximum of 3%.
Leakage Optimization (Analysis)
The leakage quantity is measured with a leakage measuring device. The specific electrical power Ė_spez is determined based on the operating pressure (4-15 bar, 5.12-10.1 kW/m³/min). The individual measure is limited to a maximum of 20% savings.
Network Optimization (Pressure Reduction)
A 1 bar reduction in operating pressure can trigger energy savings of 6%. The savings factor f_eco,dp is 6%. The individual measure is limited to a maximum of 20% savings.
Network Shutdown
The leakage losses across the entire compressed air network average 15%. The savings factor f_eco,ab is 15%. The network shutdown can be manual or automatic with time control.