Ancient Egyptian ‘air conditioning’ could help cool modern buildings

While the planet continues to endure scorching, unprecedented temperatures, a 60-square-foot shipping container is serving as a testing ground for passive, sustainable cooling solutions. As detailed in a new study published in the research journal Energies, an engineering team at Washington State University is utilizing the space to find and improve upon ancient cooling methods that don’t generate any forms of greenhouse gas—including water evaporation atop repurposed wind towers.

Buildings require roughly 60 percent of the entire world’s electricity, almost 20 percent of which is annually earmarked to keep those structures cool and comfortable. As society contends with climate change’s most ravaging effects, air conditioning systems’ requirements are only expected to rise in the coming years—potentially generating a feedback loop that could exacerbate carbon emission levels. Finding green ways to lower businesses’ and homes’ internal temperatures will therefore need solutions other than simply boosting wasteful AC units.

[Related: Moondust could chill out our overheated Earth, some scientists predict.]

This is especially vital as rising global populations require new construction, particularly within the developing world. According to Omar Al-Hassawi, lead author and assistant professor in WSU’s School of Design and Construction, this push will be a major issue if designers continue to rely on mechanical systems—such as traditional, electric AC units. “There’s going to be a lot more air conditioning that’s needed, especially with the population rise in the hotter regions of the world,” Al-Hassawi said in a statement.

“There might be [some] inclusion of mechanical systems, but how can we cool buildings to begin with—before relying on the mechanical systems?” he adds.

By retrofitting their shipping container test chamber with off-the-grid, solar powered battery storage, AL-Hassawi’s team can heat their chamber to upwards of 130 degrees Fahrenheit to test out their solutions while measuring factors such as air velocity, temperature, and humidity. The team is particularly focused on optimizing a passive cooling method involving large towers and evaporative cooling that dates as far back as 2,500 BCE in ancient Egypt. In these designs, moisture evaporates at the tower’s top, which turns into cool, heavier air that then sinks down to the habitable space below. In the team’s version, moisture could be generated via misting nozzles, shower heads, or simply water-soaked pads.

“It’s an older technology, but there’s been an attempt to innovate and use a mix of new and existing technologies to improve performance and the cooling capacity of these systems,” explained Al-Hassawi, who also envisions retrofitting smokestacks in older buildings to work as new cooling towers.

“That’s why research like this would really help,” he adds. “How can we address building design, revive some of these more ancient strategies, and include them in contemporary building construction? The test chamber becomes a platform to do this.”