Thermal storage devices containing phase-change materials that absorb heat while maintaining constant temperature during melting, providing passive cooling without mechanical refrigeration. Eutectic plates work like thermal batteries—charged by freezing, discharged by absorbing heat during delivery operations—offering silent, fuel-free temperature maintenance for limited durations.
How Eutectic Systems Work
Eutectic solutions are carefully formulated salt-water mixtures with specific freezing/melting points:
- Frozen preparation: Plates are frozen (typically overnight) at 5°C below their eutectic point
- Phase change storage: Frozen solution stores latent heat energy (far more than sensible heat alone)
- Controlled release: During delivery, plates absorb heat while melting at constant temperature
- Thermal duration: Properly sized systems maintain temperature for 8-24 hours depending on thermal load
Different eutectic formulations provide different temperature maintenance:
- Frozen applications: -18°C to -21°C eutectic point
- Chilled applications: +2°C to +5°C eutectic point
- Ambient protection: +15°C to +20°C eutectic point
Eutectic vs Mechanical Refrigeration
| Factor | Eutectic Plates | Mechanical Refrigeration |
|---|---|---|
| Operating noise | Silent | Significant |
| Fuel consumption | Zero during delivery | Continuous |
| Duration | 8-24 hours (limited) | Unlimited |
| Recovery capability | None (depletes) | Full recovery |
| Door opening tolerance | Limited | High with adequate capacity |
| Maintenance complexity | Minimal | Significant |
| Initial cost | Lower | Higher |
| Thermal capacity | Fixed | Adjustable |
South African Application Considerations
Eutectic systems face specific challenges in South African conditions:
Advantages for SA:
- No fuel consumption during load shedding
- Silent operation in residential areas
- Lower capital cost for small operations
- Reduced maintenance requirements
Limitations for SA:
- Johannesburg summer heat (35-40°C) rapidly depletes capacity
- Multi-stop routes with frequent door openings exceed eutectic recovery ability
- No active cooling means no temperature recovery after excursions
- Requires overnight freezing infrastructure at depot
When Eutectic Works
Eutectic plates suit specific applications:
- Short routes (under 4 hours) with few stops
- Ice cream delivery where vibration-free transport matters
- Backup cooling during mechanical system failures
- Applications where noise restrictions prohibit TRU operation
For multi-stop courier operations with 15-40 door openings across 6-8 hour routes, eutectic systems cannot maintain temperatures. Mechanical refrigeration provides the active cooling and recovery capability professional frozen delivery requires.
Related Terms: Phase Change Material (PCM), Mechanical Refrigeration, Passive Cooling