45% Energy Saving at an Auto-Mould and Aerospace-Parts Plant in Sichuan

The client is a manufacturer in Sichuan Province that produces automotive moulds and machines aerospace components. A review of its existing compressed air station found several sources of waste:

• Capacity mismatch. The installed compressors did not match actual demand, so the station ran inefficiently.
• Pressure mismatch. The compressors were designed for 0.85 MPa and 0.8 MPa, but the network only needed about 0.7 MPa, so energy was spent producing pressure that was never used.
• High room temperature. Heat built up in the compressor room, and extra air conditioning had been installed just to keep the machines running, adding further electricity cost.
• Pipework losses. Poor routing caused an estimated 2–3% air loss.
• No monitoring. There was no real-time view of station status, which made daily management and fault prevention difficult.

The plant wanted a more efficient station without a large upfront investment.

The station was rebuilt as an integrated system:

• Compression: two 132 kW SIND DUALLUBE-VPM series two-stage, permanent-magnet variable-speed screw compressors, sized to actual demand and set to the real network pressure.
• Drying: refrigerated dryers configured for high ambient temperatures, so the machines run reliably in a warm compressor room without extra air conditioning.
• Distribution: re-routed, low-loss pipework.
• Control: a remote monitoring and control system with built-in alarms. Station status can be checked from a smartphone, and set-points are adjusted to operating conditions and energy data.

The project was financed under an energy performance contract (EMC), so the plant needed no initial capital outlay and shares in the electricity savings.

The rebuilt station delivered the following results.

• About 45% lower energy consumption than before the upgrade.
• More than 600,000 kWh of electricity saved per year.
• No upfront investment, thanks to the EMC model.
• Real-time monitoring and alarms, which improve reliability and reduce maintenance effort.

Matching capacity and pressure to real demand, fixing the room-temperature problem and adding monitoring turned an oversized, hard-to-manage station into an efficient, transparent one.