Project Background
A 12,000 m² mixed-use building in Jiading, Shanghai, needed to retrofit 240 metering points across 18 distribution rooms to support tenant sub-billing and central energy monitoring. The existing infrastructure had no communication wiring between cabinets.
Original Plan: Wired RS-485
The original design used shielded twisted-pair RS-485 in conduit from each cabinet to a centralised data collector. Estimated cost: ¥96,000 in materials and 25 person-days of installation labour, plus 14 days of post-installation commissioning and verification.
Industrial Bluetooth Alternative
Rynon proposed replacing the daisy chain with Industrial Bluetooth power meters (one per circuit) plus 4 IoT gateways (one per cluster of 60 meters). Estimated cost: ¥9,600 in devices plus 6 person-days of installation.
Cost Comparison
Wired baseline: ¥96,000 materials + ¥18,750 labour (at ¥750/day) = ¥114,750.
Industrial Bluetooth: ¥9,600 devices + ¥4,500 labour = ¥14,100.
Net saving: ¥100,650, or roughly 88% reduction in communications installation cost.
Installation Timeline
The wired plan required 25 days of installation plus 14 days of commissioning (total 39 days). The Industrial Bluetooth plan required 6 days of installation plus 2 days of commissioning (total 8 days). The project completed in one-third of the original schedule.
Ongoing Operation
Twelve months after commissioning, the system reports 99.94% packet success rate and zero truck rolls for meter-related issues. Two firmware updates have been pushed over the air without site visits.
Why the Cost Dropped
Three factors: (1) no signal cable between cabinets — eliminates shielded cable, conduit, connectors and termination labour; (2) no daisy-chain wiring topology — eliminates the need to physically route cables through floors and ceilings; (3) faster commissioning — QR-code provisioning removes manual address configuration.
Lessons Learned
The key enabler was the project site's electrical design: most distribution cabinets were within 80 m of the gateway location, well within the Industrial Bluetooth range budget. For sites with longer distances, additional gateways may be required, raising the cost.