Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Keeping beverages cool in summer: It’s not just the heat, it’s the humidity

26.04.2013
In spring a person’s thoughts turn to important matters, like how best to keep your drink cold on a hot day. Though this quest is probably as old as civilization, University of Washington climate scientists have provided new insight.
It turns out that in sultry weather condensation on the outside of a canned beverage doesn’t just make it slippery: those drops can provide more heat than the surrounding air, meaning your drink would warm more than twice as much in humid weather compared to in dry heat. In typical summer weather in New Orleans, heat released by condensation warms the drink by 6 degrees Fahrenheit in five minutes.

“Probably the most important thing a beer koozie does is not simply insulate the can, but keep condensation from forming on the outside of it,” said Dale Durran, a UW professor of atmospheric sciences.

He’s co-author of results published in the April issue of Physics Today that give the exact warming for a range of plausible summer temperatures and humidity levels. For example, on the hottest, most humid day in Dhahran, Saudi Arabia, condensation alone would warm a can from near-freezing temperature to 48 degrees Fahrenheit in just five minutes.

“Condensation, atmospheric motion, and cold beer”

The authors describe their results

Watch UW graduate students test the theory

The investigation began a couple of years ago when Durran was teaching UW Atmospheric Sciences 101 and trying to come up with a good example for the heat generated by condensation. Plenty of examples exist for evaporative cooling, but few for the reverse phenomenon. Durran thought droplets that form on a cold canned beverage might be just the example he was looking for.

A quick back-of-the-napkin calculation showed the heat released by water just four thousandths of an inch thick covering the can would heat its contents by 9 degrees Fahrenheit.

“I was surprised to think that such a tiny film of water could cause that much warming,” Durran said.

Though he’s normally more of a theoretician, Durran decided this result required experimental validation. He recruited co-author Dargan Frierson, a UW associate professor of atmospheric sciences, and they ran an initial test in Frierson’s little-used basement bathroom, using a space heater and hot shower to vary the temperature and humidity.

The findings corroborated the initial result, and they embarked on a larger-scale test.

“You can’t write an article for Physics Today where the data has come from a setup on the top of the toilet tank in one of the author’s bathrooms,” Durran said.

Univ. of Washington

A test subject being weighed to measure the amount of condensation. The cap prevents air from moving through the opening on top.

First they recruited colleagues in Frierson’s beachside hometown of Wilmington, North Carolina, to duplicate the experiment and compare results with those taken on a hot, dry Seattle day. But they decided they needed to test a wider range of conditions.

Finally, last summer undergraduates Stella Choi and Steven Brey joined the project to run a proper experiment in the UW Atmospheric Sciences building. They unearthed an experimental machine with styling that looks to be from the 1950s, last used decades ago to simulate cloud formation.

With funding for educational outreach from the National Science Foundation, the students first cooled a can in a bucket of ice water then dried it and placed it in the experimental chamber dialed up to the appropriate conditions. After five minutes they removed the can, weighed it to measure the amount of condensation, and recorded the final temperature of the water inside.

The phenomenon at work – latent heat of condensation – is central to Frierson’s research on water vapor, heat transfer and global climate change.

“We expect a much moister atmosphere with global warming because warmer air can hold a lot more water vapor,” Frierson said. Because heat is transferred when water evaporates or condenses, this change affects wind circulation, weather patterns and storm formation.

Durran’s research includes studies of thunderstorms, which are powered by heat released from condensation in rising moist air.

As for his demonstration of the heat released during this process, he and Frierson are now working with the National Center for Atmospheric Research to develop an educational tool that will let students around the world try the experiment and post their results online for comparison.

The example promises to become as classic as a cold drink on a hot summer day.

For more information, contact Durran at 206-543-7440 or durrand@atmos.washington.edu and Frierson at 206-685-7364 or dargan@atmos.washington.edu

Hannah Hickey | EurekAlert!
Further information:
http://www.uw.edu

More articles from Health and Medicine:

nachricht Why might reading make myopic?
18.07.2018 | Universitätsklinikum Tübingen

nachricht Unique brain 'fingerprint' can predict drug effectiveness
11.07.2018 | McGill University

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

Im Focus: Chemical reactions in the light of ultrashort X-ray pulses from free-electron lasers

Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.

Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

Machine-learning predicted a superhard and high-energy-density tungsten nitride

18.07.2018 | Materials Sciences

NYSCF researchers develop novel bioengineering technique for personalized bone grafts

18.07.2018 | Life Sciences

Why might reading make myopic?

18.07.2018 | Health and Medicine

VideoLinks
Science & Research
Overview of more VideoLinks >>>