As Colombo heats up, passive cooling offers a low-energy solution — but at a cost

COLOMBO — Fathima Rinoza lives on the fourth floor of a 14-story apartment block in Dematagoda, a suburb of Sri Lanka’s commercial capital, Colombo. She rarely keeps the two windows in her house open for long. The heat becomes unbearable by midday, she says, and the surrounding buildings obstruct wind flowing in the direction of her home. In addition, the stench from littered surroundings discourages residents like Rinoza from keeping their windows open. “Fresh air is a luxury for us because we can’t keep windows open for too long. By noon the heat becomes unbearable. If I keep the windows open till evening, there’ll be a lot of dust inside the house,” she tells Mongabay. Rinoza keeps the two fans in her house working almost the entire day to cool the house. The heat and poor ventilation make people like Rinoza who live in cramped urban settings heavily dependent on mechanical or active-cooling methods such as fans and air conditioners. According to the International Energy Agency (IEA), the urban residential sector accounts for nearly a third of Sri Lanka’s total energy consumption: to heat and cool buildings, and to run lights, devices, and appliances. As heat and energy demand rise, Sri Lanka is actively exploring the adoption of traditional and modern passive-cooling methods, primarily in the residential sector. Passive-cooling strategies In passive cooling, the building design approach uses natural energy flows like wind and shade to lower indoor temperatures. Research by Sri Lankan engineers in 2021 on natural ventilation for…This article was originally published on Mongabay