For months, workers at a Rayong fruit depot watched condensation bead on one strip of roof while the surrounding metal stayed dry in the tropical heat. The odd patch turned out to be the visible sign of a quiet commercial breakthrough: a Thai start-up has installed passive cooling panels at 29 warehouses without publicising the scale of its business.
The Plausible Post compared six months of electricity bills, temperature logs and export invoices at four sites. The records show refrigeration power use falling by an average 29%, while the chilled rooms held steady near 4°C (39°F), a result that operators had first blamed on faulty meters.
The roof that ran cold
The panels work by radiating heat through a film that lets infrared energy escape towards the clear night sky. A study commissioned by the company and reviewed by two outside engineers found that the panel surface ran as much as 8°C (14°F) below the surrounding air after midnight, cooling water circulated through the depot’s roof pipes.
The firm, Mekha Thermal, has quietly built the system into warehouses used for durian, mangosteen and seafood shipments. Managing director Gunda Wahl said 23 sites were already paying customers, though the company’s public materials described its work as a limited pilot. “We wanted the cold rooms to prove themselves before we made promises,” she said.
The company’s low profile explains why depot staff had no name for the nightly chill. Some thought a nearby refrigeration unit was pulling cold air through the roof; others suspected the temperature sensors were wrong. Engineers installed their own calibrated instruments at two depots and found the surface cooling repeated on 18 clear nights.
“The roof was giving us free hours of cooling while everyone was asleep,” said Tomás Padrão, a thermal engineer who checked the measurements for the company’s customers. “That is not a small efficiency gain. It changes what a fruit depot costs to run.”
The roof was giving us free hours of cooling while everyone was asleep.
Tomás Padrão, thermal engineer
Mekha kept the installations out of view to protect the design and learn which roof layouts worked best, Wahl said. A company filing listed the system as a pilot, but the customer invoices and shipping records show that commercial use had spread across three eastern provinces by early 2026.
Savings spread through the supply chain
At one depot outside Rayong, manager Eileen Reynolds said lower power bills had helped the business keep more fruit in cold storage during peak harvest weeks. The operator’s invoices show monthly refrigeration costs down 26% from the same period last year; staff also logged fewer rejected pallets, though the company has not published a complete spoilage comparison.
The savings matter in a country where electricity is a major cost for cold-chain businesses and tropical fruit exports depend on reliable storage. Allan Elvars, a trade analyst who reviewed the shipping figures, said the four checked sites handled about 74,000 tonnes of produce a year. “If the performance holds at more depots, smaller exporters could compete for orders they used to lose on cost,” he said.
Mekha plans to spend the next year adding panels to 40 more depots and publishing results from a wider customer trial. The roof strips that once baffled workers now point to an unexpectedly simple business: in a region where night air stays warm, the open sky itself can help keep the cargo cold.
