Passive Cooling for Traffic Signal Cabinets
The Challenge
How can municipalities protect their electrical infrastructure from extreme heat without adding power or maintenance?
Most traffic signal cabinets sit in the full sun with no active cooling. In Arizona summers, their interior temperatures run well above ambient for hours at a time, causing undue stress on the electrical components and reducing their service lifetime.
The Solution - PolyFrost
An Arizona municipality equipped 11 traffic signal cabinets with internal temperature loggers. PolyFrost, ChillSkyn’s patented Passive Daytime Radiative Cooling (PDRC) coating, was applied to six of them: two fully coated, and four with only the roof coated. They were measured against five uncoated control cabinets under identical conditions, recording their temperatures across 35 valid days.
What is PolyFrost®?
PolyFrost is a patented spray-applied passive cooling coating, engineered to reduce heat load on sun-exposed assets, such as refrigerated transport, containers, and industrial equipment.
Reduces solar heat load
Prevents surface heat from becoming an internal temperature problem.
Lowers cooling workload
Cooling systems run fewer hours. Less runtime, less energy, less mechanical strain.
Scalable and easy to apply
Standard spray equipment, just like paint, in under 12 hours. Retrofit or factory spec.
Protects asset economics
Supports resale position, maintenance planning, and replacement timing.
Results
Field Trial
- Arizona - Summer 2026
35 valid testing days - Average daily high 103°F
- 5 control • 6 coated
Fully coated (2), roof-only coated (4) - Internal cabinet temperature
30-minute logging intervals
Method
- Internal temperature loggers
- Bare and vinyl-wrapped cabinets compared like for-like
- Local ambient as reference
Fully-Coated Cabinet Roof-only Coated Vinyl-Wrapped Cabinet
Performance Comparison | |
|---|---|
Time above 110°F (5.1 → 1.5 h/day) | ↓ 70% |
Cumulative heat exposure above 110°F | ↓ 84% |
Average daily peak temperature (113.8 → 107.9°F) | ↓ 5.9°F |
Coverage note: Fully coated cabinets received PolyFrost on all sun-exposed surfaces. Where existing vinyl art wraps limited application to the roof, cabinets retained roughly half the benefit (−38% time above 110°F, vs. −68% with full coverage). Full coverage delivers full performance.
Key Impacts
Longer Controller Life
Fully coated cabinets spent 70% less time above 110°F and peaked nearly 6°F cooler, cutting the thermal stress that drives component failure.
Extreme Hours Disappear
Total heat exposure above 110°F fell from 744 to 119 degree-hours over the pilot. PolyFrost removes the conditions that drive thermal failure.
A Path to Corridor Scale
Every cabinet has a defined application: full coverage where the surface is bare, roof-only where a wrap is in place. No replacement or modification needed first.