To demonstrate a method of cooling people without cooling the air, Princeton researchers built a unique pavilion in Singapore last year, dubbed the “Cold Tube.” It was an outdoor structure lined with novel insulated radiant panels that held cold water pipes inside. The human body is constantly exchanging radiation with objects around it and that radiation flows from hot to cool surfaces. The participants who walked through the exhibit shed their radiation toward the panels and reported feeling cool, despite the air itself having temperature and humidity levels that would ordinarily feel sweltering. The research team led by Forrest Meggers, assistant professor of architecture and the Andlinger Center for Energy and the Environment, showed that people could feel comfortable in hot and humid outdoor environments using only radiant cooling, which could use 40%- 50% less energy than cooling large volumes of air. The work was conducted in collaboration with scholars at the University of British Columbia, University of Berkeley, ETH Zurich in Singapore, and the University of Pennsylvania and published in Proceedings of the National Academy of Sciences.