This 'Cold Tube' can beat the summer heat without relying on air
conditioning
Chilled panels use less energy than conventional A/C and work in open
spaces

Date:
August 18, 2020
Source:
University of British Columbia
Summary:
The 'Cold Tube' can offer relief from the summer heat without
relying on air conditioning. It uses half the energy of conventional
air conditioners and can be used outdoors or indoors.



FULL STORY ==========================================================================
Many people beat the summer heat by cranking the air
conditioning. However, air conditioners guzzle power and spew out
millions of tons of carbon dioxide daily. They're also not always good
for your health -- constant exposure to central A/C can increase risks
of recirculating germs and causing breathing problems.


========================================================================== There's a better alternative, say a team of researchers from the
University of British Columbia, Princeton University, the University of California, Berkeley and the Singapore-ETH Centre.

They call it the Cold Tube, and they have shown it works.

"Air conditioners work by cooling down and dehumidifying the air around
us - - an expensive and not particularly environmentally friendly
proposition," explains project co-lead Adam Rysanek, assistant professor
of environmental systems at UBC's school of architecture and landscape architecture, whose work focuses on future energy systems and green
buildings. "The Cold Tube works by absorbing the heat directly emitted
by radiation from a person without having to cool the air passing over
their skin. This achieves a significant amount of energy savings."
The Cold Tube is a system of rectangular wall or ceiling panels that
are kept cold by chilled water circulating within them. Since heat
naturally moves by radiation from a hotter surface to a colder surface,
when a person stands beside or under the panel, their body heat radiates towards the colder panel.

This creates a sensation of cooling like cold air flowing over the body
even if the air temperature is quite high.

Although these types of cooling panels have been used in the building
industry for several decades, what makes the Cold Tube unique is that
it does not need to be combined with a dehumidification system. Just
as a cold glass of lemonade would condense water on a hot summer day,
cooling down walls and ceilings in buildings would also condense water
without first drying out the air around the panels. The researchers behind
the Cold Tube conceived of an airtight, humidity-repelling membrane to
encase the chilled panels to prevent condensation from forming while
still allowing radiation to travel through.



========================================================================== Cooling down the outdoors The team built an outdoor demonstration unit
last year in Singapore, inviting 55 members of the public to visit and
provide feedback. When the system was running, most participants reported feeling "cool" or "comfortable," despite an average air temperature of
30 degrees Celsius (86 degrees Fahrenheit). The panels also stayed dry,
thanks to the special membrane.

"Because the Cold Tube can make people feel cool without dehumidifying
the air around them, we can look towards shaving off up to 50 per cent
of typical air conditioning energy consumption in applicable spaces,"
said Eric Teitelbaum, a senior engineer at AIL Research who oversaw the demonstration project while working at the Singapore-ETH Centre.

"This design is ready. It can obviously be used in many outdoor spaces --
think open-air summer fairs, concerts, bus stops and public markets. But
the mission is to adapt the design for indoor spaces that would typically
use central air conditioning," he added.

Beyond the energy savings, technologies like the Cold Tube have a great
future, says project co-lead Forrest Meggers, an assistant professor at Princeton's school of architecture and the Andlinger Center for Energy
and the Environment.



========================================================================== "Because the Cold Tube works independently of indoor air temperature and humidity, keeping windows open in our increasingly hot summers while still feeling comfortable becomes possible," said Meggers. "The Cold Tube can
offer relief in different regions, from North American homes and offices
that currently rely on standard HVAC systems to developing economies
that foresee significant need for cooling in the coming half-century."
Keeping indoor air healthy during the pandemic There's another aspect
of the Cold Tube that is particularly relevant in 2020, says Adam Rysanek.

"The COVID-19 pandemic has brought to the public's awareness how sensitive
our health is to the quality of the air we breathe indoors. Specifically,
we know that some of the safest spaces in this 'new normal' are outdoor spaces," said Rysanek. "As the climate changes and air conditioning
becomes more of a global necessity than a luxury, we need to be prepared
with alternatives that are not only better for the environment, but also
our health. The idea of staying cool with the windows open feels a lot
more valuable today than it did six months ago." The team is currently
using the data collected in Singapore to update their projections of
the Cold Tube's effectiveness in indoor spaces globally. They plan to demonstrate a commercially viable version of the technology by 2022.


========================================================================== Story Source: Materials provided by University_of_British_Columbia. Note: Content may be edited for style and length.


========================================================================== Journal Reference:
1. Eric Teitelbaum, Kian Wee Chen, Dorit Aviv, Kipp Bradford, Lea
Ruefenacht, Denon Sheppard, Megan Teitelbaum, Forrest Meggers,
Jovan Pantelic, and Adam Rysanek. Membrane-assisted radiant
cooling for expanding thermal comfort zones globally without air
conditioning. PNAS, 2020 DOI: 10.1073/pnas.2001678117 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/08/200818142116.htm

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