A new passive coating developed by Barcelona-based Cooling Photonics cut the internal temperature of a standard 20-foot shipping container by as much as 22°C during a pilot at Transbase Soler's facilities in Valencia, with the treated box never exceeding 34.2°C under direct solar exposure.

The 15-day trial, supported by Valenciaport's open innovation hub Opentop and Fundación Valenciaport, monitored four identical 20-foot containers exposed to identical solar conditions. Independent sensors logged internal temperatures every 15 minutes, generating more than 5,600 readings over the period.

The untreated reference container reached 53°C, with temperatures exceeding 40°C for more than a third of the monitoring window. A second box fitted with a conventional internal thermal blanket performed only marginally better. The two containers coated with the Cooling Photonics material — one on the roof only, the other on both roof and side walls — recorded average daily peak reductions of 17.5°C, with the maximum 22°C gap logged on the hottest day.

Unlike conventional insulation, which can trap heat inside the steel shell, the new material reflects solar radiation before it penetrates the container wall and allows the box to cool naturally overnight without consuming energy.

What does the technology offer ports and operators?

According to Valenciaport, the material has several potential applications across terminals, depots and logistics operators:

• Cargo and equipment protection: keeps internal temperatures below 35°C without energy consumption, limiting peak thermal stress and reducing material fatigue on stored goods.
• Staff safety: lowers heat exposure inside containers repurposed as warehouses, workshops or offices.
• Asset protection: cooler electrical cabinets and power electronics at terminals could mean fewer shutdowns and improved reliability.
• Climate adaptation: a passive resilience tool as summer heat intensifies across major handling hubs.

The technology targets hot-region corridors where prolonged solar exposure accelerates container degradation, shortens service life and raises maintenance costs. Valenciaport flagged China, the Mediterranean, the Middle East and parts of Africa as priority markets.

What does this mean for shippers and carriers?

For shippers moving non-temperature-controlled cargo through hot lanes, a passive coating that keeps containers below 35°C without power input addresses a recurring source of in-transit degradation. Cargoes susceptible to thermal stress include certain chemicals, batteries, pharmaceuticals and agricultural products; the coating does not replace refrigerated containers for genuinely temperature-controlled freight.

For terminals and inland depots, the technology offers a way to manage heat in idle container stacks and in boxes converted to on-site offices or storage, reducing thermal exposure for personnel and equipment alike.

Transbase Soler provided the operational testbed for the pilot. Opentop, Valenciaport's open innovation hub, connected Cooling Photonics with port infrastructure and the operational data needed to validate performance under real solar conditions.

Cooling Photonics is a Barcelona-based startup developing passive radiative cooling materials for industrial surfaces exposed to solar radiation, positioning it within a growing cluster of port-backed climate-tech ventures targeting the decarbonisation of handling and storage operations.

What comes next?

The commercial rollout will depend on cost-per-container data not yet disclosed and on further durability testing under routine handling, wash-downs and long-term UV exposure, which Valenciaport indicated would follow the pilot.