Alternative cooling strategies could mitigate COVID-19 and climate change

https://www.eurekalert.org/pub_releases/2020-08/pues-acs081820.php

 

News Release 18-Aug-2020
Princeton University, Engineering School

 

When most people think of cooling, they automatically imagine air conditioning (AC), or cooling the air in a room. But, there is a much more efficient way to cool people, using your body's radiation.

To demonstrate the effect of radiant cooling, Forrest Meggers, assistant professor of architecture and the Andlinger Center for Energy and the Environment, and a team of researchers built a "Cold Tube," in Singapore last year. It was an outdoor pavilion lined with novel insulated radiant panels that held cold water pipes inside. Because your body is constantly exchanging radiation with objects around you, and radiation flows from hot to cool surfaces, the participants who walked through the exhibit shed their radiation toward the panels, similar to what would happen if you stood near a freezer. The participants reported feeling cool, despite the air itself having temperature and humidity levels that would ordinarily feel sweltering. The new research showed that people could feel comfortable in hot and humid outdoor environments using only radiant cooling, which could use far less energy than cooling large volumes of air.


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This system uses at least 50% less energy than a comparably-sized air conditioner. Letting the air warm up by five degrees while cooling surfaces, can lower energy demand by up to 40% and maintain occupant comfort. Allowing even hotter air temperatures would result in higher energy savings.

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Most of my coauthors and I have traveled around Southeast Asia and have seen firsthand how quickly AC units have been deployed at scale. Adding AC window or split units to buildings is done with little contemplation of the effects on surface temperatures, and the climate and heat in a city. The units work by rejecting the heat from the air in a room to the outside. Rejecting heat outside the buildings, along the façade, leads to sidewalks and areas around buildings becoming very hot, and many spaces becoming unusable. Our technology does exactly the opposite; it provides opportunities to regain thermal acceptability in various parts of the city without having to build a huge park. You can install these cooling panels outside in hot and humid environments, and build "cool havens" where people can gather, eat, and play.

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