At 15:20 on Thursday, while the sun warmed the loading yard outside Naivasha, the concrete floor of a produce warehouse registered 20.4°C (68.7°F). Just beyond its open doors, a hand-held sensor read 30.1°C (86.2°F). From a narrow crack beneath a pallet rack came a steady, cool draft — a puzzle that has become an unlikely selling point for Kavu Cold Chain.
The company had spent KSh280 million (about €1.8 million) on modular refrigeration and warehouse space during a rapid expansion completed last year. Customer demand arrived more slowly: 31% of its available capacity was unused in June, according to managing director Isabell Bach-Popp. Now the naturally cooled section is being offered to growers for sorting and short-term staging, reducing the time compressors need to run.
A draft from the floor
Bach-Popp said staff first noticed the breeze when a loose sheet of packing paper repeatedly slid across the floor, even with the roller doors shut. “We thought there was a fan left running somewhere,” she said. “Then we switched everything off and the air kept coming.” The company began logging temperatures after the oddity returned during a warm afternoon in August.
A week of readings showed the floor-level air stayed between 19.8°C and 21.2°C (67.6°F and 70.2°F), while outside temperatures ranged from 27°C to 31°C (81°F to 88°F). A technician measured a draft moving at about 1.2 metres per second (2.7 miles per hour) from a fissure roughly 30 centimetres (12 inches) wide. The crack is now marked off from forklift routes.
We paid for machines to make cold, then found the ground was already giving us a useful head start.
Isabell Bach-Popp, managing director
Geologist Jiya Ghosh, who examined the site at the company’s request, said fractured volcanic rock beneath the warehouse could channel air from cooler ground. She cautioned that one month of readings cannot establish the full route or cause. “It is unusual, but not magical,” Ghosh said. “The next step is to map the temperature and airflow below the slab.”
A cheaper stop for produce
The cool zone is not a replacement for refrigerated storage: cut flowers and other sensitive goods still go into temperature-controlled rooms. But growers can use it to sort crates and prepare loads before they enter those rooms. Paulina Mercado, who coordinates deliveries for a growers’ co-operative, said the area gives workers a less hot place to check produce during afternoon packing.
Kavu estimates the airflow has reduced compressor use in the adjacent packing bay by 18% since the trial began, saving about KSh1.6 million (about €10,300) in electricity over six weeks. The figure comes from the company’s meter readings, and Bach-Popp said it will need a full season of data before making a larger claim. The firm is considering a second naturally ventilated bay rather than buying another chiller.
That possibility matters after the expansion left several rooms quieter than expected. Bach-Popp said the business had planned for more growers to sign up at once and now rents part of one building to a packaging supplier. She said the company has not cancelled its refrigeration plans, but will base its next purchase on confirmed bookings rather than forecasts.
On Thursday, workers wheeled crates past the crack as a thin paper strip tied to a nearby rail lifted and settled in the moving air. Ghosh plans to return with sensors that can track conditions beneath the floor. Until then, Kavu is taking bookings for the cool sorting bay — and keeping its paper strips in place.
