Imagine stepping out to a shaded outdoor space on an ordinary day in Singapore. The air temperature around your body is hot – over 30 °C and relative humidity stands at 75%. This outdoor space is not air-conditioned, nor is it ventilated by a fan. Yet, as you stand in this space, you begin to feel an unexpected sensation of cooling down.

You touch the surfaces around you and search for the source of cooling, but exposed surfaces feel hardly different from the hot ambient environment. What becomes even more bewildering is that, after a few minutes in this space, even though the air temperature has not changed, you begin to feel cold… outside… in Singapore… in the middle of the day.

“The Cold Tube” explores new applications of selected materials for radiant cooling in tropical climates. It involves studying the use of infrared-transparent membranes that allow one’s body to experience the cooling effect of actively chilled surfaces hidden behind these membranes. Yet, they are sufficiently separated from these surfaces to avoid the problems of condensation. The goal of the project is to demonstrate how this new energy-efficient technology might provide outdoor thermal comfort in Singapore without air-conditioning.

The Cold Tube is an Intra-CREATE seed project launched in 2018 that brings together researchers from the Singapore-ETH Centre, University of British Columnbia, UC Berkeley and Princeton University.