📍 Fiji Multi-Temperature Zone Cold Storage Customized Electrical Control System Project
This project is a medium-to-large-scale cold chain storage facility covering an area of 4,000 square meters. It consists of 6 cold storage rooms spanning 5 different temperature zones（Anti Room, Chiller Room, Dual-Temp Room, Freezer Room, Wine Storage Room）
Temperature Zones
Dual-Temp Room
Configurable between -5°C and +5°C
Freezer Room
-22°C to -18°C
Wine Storage Room
+12°C ±1°C
System Overview
Refrigeration Units
A total of 13 independent refrigeration condensing units.
Control System
Managed by 3 sets of decentralized PLC control cabinets with a central SCADA monitoring station for fully automated electrical system management.
Our Solution
► Intelligent Temperature Control
- Each cold storage room is equipped with multi-point temperature measurement (primary and backup sensors per room), supports automatic probe failure switchover, and achieves stable temperature control within ±1.0°C for medium/high temp zones and ±1.5°C for low temp zones under normal operating conditions.
► Precision Defrosting
- Each evaporator operates with independent, adaptive defrost control based on time, temperature differential, and compressor run time, featuring dry-burn safety protection and termination on temperature or time.
► Multi-mode Operation
- Supports multiple evaporator fan control modes (continuous, cycling, stop with compressor), enabling delayed start/stop protection, staggered compressor startups, and timed cyclic operation to reduce peak power demand.
► Management System
- The system features a multi-layered safety management system combining electrical protection, refrigerant leak detection, and high/low pressure alarms. In the event of a major fault, the affected circuit initiates shutdown protection and triggers audible and visual alarms. Recovery from critical faults requires manual reset at the local panel. The system adopts a three-tier password-protected access structure (Operator, Supervisor, Engineer). It incorporates interlock logic to prevent misoperation and supports remote monitoring via a secured VPN connection, ensuring comprehensive reliability and controllability.
Results
✔ High Space Utilization Reasonable zoning for different goods allows for efficient inventory management and flexible storage allocation.
✔ Optimized Energy Efficiency Intelligent control, adaptive defrost, and fan speed modulation contribute to an estimated 15-20% reduction in energy consumption compared to conventional on/off systems.
✔ Low Operational Cost High automation reduces manual intervention for routine monitoring and adjustments, lowering labor requirements.
✔ Enhanced System Reliability The decentralized PLC architecture provides redundancy; a failure in one cabinet does not affect rooms controlled by others. Critical alarms are communicated to the central SCADA and via SMS.
✔ Good Scalability for Future Expansion Modular panel design and spare capacity in main electrical distribution facilitate future expansion of additional cold rooms with minimal disruption.
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