Case Study: Automotive Plant Saves $180,000 Annually with Sequencer

This detailed case study examines one of Emergent Energy Solutions' most impactful compressed air optimization projects—a large automotive parts manufacturing facility that achieved $239,000 in combined annual savings through intelligent sequencing, VFD integration, and utility rebate capture.

Facility Profile

• Industry: Automotive parts manufacturing (stamping, welding, painting)
• Location: Mid-Atlantic region
• Compressed air capacity: 2,500 HP total — five 500-HP water-cooled rotary screw compressors (4 fixed-speed, 1 VFD)
• Average demand: 3,200 CFM during production, 450 CFM during non-production (leak load)
• Operating schedule: Three shifts, 24/7 operation, 8,400 hours/year
• Annual compressed air electricity cost: $720,000 (including demand charges)
• Average electricity rate: $0.09/kWh blended (including $8.50/kW demand charge)
• Compressor room age: Equipment ranging from 3 to 18 years old

Challenges Identified During Emergent Energy Assessment

Emergent Energy Solutions was engaged to conduct a comprehensive compressed air system assessment using our cloud-based monitoring platform. We installed power meters on all five compressors, pressure transducers at three system points, and flow meters on the main header and two critical distribution branches. Data was collected continuously for 21 days, capturing all three shifts, weekday production, and weekend patterns.

Finding 1: Massive Unloaded Running Waste The data revealed that during a typical production day, five compressors ran continuously even though average demand required only 3.2 compressors' worth of capacity. Two units spent 40–60% of their operating time in unloaded mode, consuming 25–30% of full-load power while producing zero air.

Finding 2: VFD Operating Incorrectly The facility had invested $120,000 in a 500-HP VFD compressor two years prior, expecting significant energy savings. However, without a sequencer to coordinate it with the fixed-speed units, the VFD was fighting the other compressors for load—alternately ramping up and being pushed to minimum speed by competing fixed-speed machines. The VFD spent 65% of its operating time below 40% speed—outside its efficient range. The actual energy savings from the VFD investment were negligible.

Finding 3: Extreme Run-Hour Imbalance Compressor #1 (the oldest unit, 18 years old) had accumulated 126,000 run hours—nearly twice the hours of Compressor #2 (72,000 hours) and four times the hours of Compressor #5 (32,000 hours). Unit #1 was the perpetual "lead" machine and was overdue for an airend rebuild estimated at $65,000.

Finding 4: 14% Leak Load The 450 CFM measured during non-production hours represented 14% of production demand. While better than the 20–30% industry average, this still represented approximately $45,000/year in wasted electricity.

Finding 5: Over-Pressurization The system operated at 110–115 PSI header pressure to compensate for a 15 PSI drop across aging filters and undersized distribution piping. Actual point-of-use requirements ranged from 80–95 PSI. The facility was generating—and paying for—20+ PSI of unnecessary pressure.

Solution Designed and Implemented

Phase 1: Sequencer Installation A multi-compressor sequencer was installed with pressure and flow monitoring at the main header. The sequencer was configured to: - Designate two fixed-speed compressors for base load (running at full load when needed) - Assign the VFD as the exclusive trim compressor - Use remaining fixed-speed units as swing capacity - Implement run-hour equalization across all five units - Maintain a ±2 PSI control band at 98 PSI header pressure

Phase 2: VFD Re-Integration The VFD compressor was reconfigured to accept speed commands directly from the sequencer rather than operating on its own pressure signal. The VFD's operating range was set to 45–95% of rated speed, keeping it within its efficient range at all times.

Phase 3: Pressure and Distribution Optimization Saturated coalescing filters were replaced, reducing the pressure drop from 15 PSI to 3 PSI. A dedicated 1,060-gallon receiver was installed near the sequencer's pressure sensor to provide control stability during rapid demand changes.

Phase 4: Leak Repair Program Using the sequencer's monitoring data to prioritize repairs, the maintenance team conducted ultrasonic leak surveys and repaired 67 leaks over a 6-week period, reducing the non-production leak load from 450 CFM to 180 CFM.

Results — Measured and Verified by Emergent Energy Cloud Platform

Energy Savings The sequencer reduced the average number of compressors running from 5.0 to 3.2 during production and from 2.0 to 0.8 during non-production periods. Combined with pressure reduction and leak repair:

• Annual electricity savings: $180,000 (25% reduction)
• Demand charge savings: $24,000 annually (200 kW peak demand reduction)
• Total energy savings: $204,000/year

Maintenance Savings Run-hour equalization extended projected airend rebuild intervals by 40%. The immediate benefit was avoiding the $65,000 rebuild on Compressor #1, which could now be deferred by approximately 3 years as its run hours normalized with the rest of the fleet.

• Deferred airend rebuild value: $65,000 (present value)
• Annual maintenance budget reduction: $35,000 (from $95,000 to $60,000)
• Emergency service calls eliminated: 3/year (savings: $9,000)
• Total annual maintenance savings: $35,000 ongoing + $65,000 one-time

Utility Rebates Captured Emergent Energy Solutions managed the entire rebate application process:

• Custom rebate for verified energy savings: $48,000 (based on 500,000+ kWh/year documented savings at $0.096/kWh incentive rate)
• Prescriptive rebate for VFD re-commissioning: $37,500 (the utility treated the VFD integration as a qualifying measure since it was not previously functioning as intended)
• Total rebates received: $85,500

Financial Summary

Ongoing Performance Monitoring

Emergent Energy Solutions' cloud analytics platform continues to monitor this system in real time, providing: - Weekly performance reports to the facility engineer - Monthly executive summaries to plant management - Real-time alerts for any performance degradation - Quarterly optimization reviews to fine-tune sequencing as production demands change - Annual rebate documentation for any additional efficiency measures

Two years after implementation, the system continues to perform at or above projected savings levels, with the sequencer automatically adapting to production changes including a new stamping line that added 15% to compressed air demand.

For a complimentary compressed air system assessment, contact Emergent Energy Solutions at 215-645-7141 or sales@emergentenergy.us. Our team serves facilities throughout the Mid-Atlantic, Northeast, and Midwest regions.