Case Study: Manufacturing Plant Reduces Energy Waste 45% with PIR Sensors

Overview

A 200,000 square foot manufacturing plant in Ohio was spending $180,000 annually on lighting energy. The plant operated two shifts (6 AM to 10 PM) but many areas were only occupied intermittently. Forklift traffic was heavy in some zones while others sat empty for hours.

The Challenge

The plant faced several specific issues:

• Warehouse aisles were lit 24/7 but only occupied 12 hours/day
• Production areas had variable occupancy based on production schedule
• Break rooms and offices were often left lit overnight
• High bay lighting (25W LED fixtures) consumed significant energy
• Manual light switches were ignored by employees

The Solution

The plant implemented a zone-based PIR lighting control system:

• Sensors: OPTEX LX-802 high-bay PIR sensors (30m range)
• Coverage: Each sensor covered 1,500 sq ft (10 sensors per acre)
• Mounting height: 7.5m (25 feet)
• Output: 0-10V dimming for LED high bays
• Quantity: 150 sensors total

The warehouse was divided into 20 zones, each with 5-10 sensors. Production areas had individual sensors per workstation. Offices and break rooms received ceiling-mount sensors.

Lighting logic:

• Warehouse zones: Lights turn on at 100% when motion detected, dim to 30% after 15 minutes, off after 30 minutes
• Production areas: 100% when occupied, 10% night light level when unoccupied
• Break rooms: 100% when occupied, off after 10 minutes

Implementation

The installation was phased over six months:

1. Month 1-2: Warehouse zone 1-10 (75 sensors)
2. Month 3-4: Warehouse zone 11-20 (50 sensors)
3. Month 5: Production areas (15 sensors)
4. Month 6: Offices and break rooms (10 sensors)

Each sensor was tested for coverage and sensitivity to detect forklifts and personnel.

Results

After 12 months of operation:

600,000

300,000

50%

400,000

240,000

40%

200,000

100,000

50%

1,200,000

640,000

47%

$180,000

$96,000

$84,000

表

Additional benefits included:

• Reduced CO2 emissions by 400 metric tons
• Extended LED life (50% fewer operating hours)
• Improved safety (lights only on when areas occupied)
• Employee satisfaction (no more dark areas)
• Eligibility for utility demand response program ($15,000/year)

Key Lessons Learned

1. Zone-based control works: Large open areas need multiple sensors to eliminate blind spots.
2. High-bay sensors need special lenses: Narrow-beam lenses prevented detection of adjacent zones.
3. Dimming saved more energy than switching: 30% dim level prevented total darkness while saving 70% energy.
4. Forklift detection required higher sensitivity: Standard settings missed slow-moving forklifts.
5. Maintenance access needed override switches: Technicians needed ability to lock lights on during repairs.

Conclusion

This case study demonstrates that industrial PIR sensors can deliver 45% lighting energy savings in manufacturing plants. The $84,000 annual savings and 21-month payback period made this a successful investment. The key to success was zone-based control with high-bay sensors and dimming capability.