ASHRAE Journal - October 2021 - 70

REFRIGERATION APPLICATIONS
COLUMN
Andy Pearson
Infrastructure
BY ANDY PEARSON, PH.D., C.ENG., FELLOW ASHRAE
Last month we looked at goals one, two and three of the UN's Sustainable
Development Goals (SDGs). The next grouping of SDGs is " affordable and clean
energy " ; " clean water and sanitation " ; and " industry, innovation and infrastructure. "
These are goals seven, six and nine, respectively. So why group them in this order?
The link between refrigeration and energy is obvious.
It is estimated that roughly one-sixth of the electricity
generated in the world today is used in refrigeration
systems of one type or another, ranging from the fridge
in your house to the freezer that prepares your food for
transport and delivery. In between these two are many
links in the cold chain including big warehouses, trucks
and shops, and, of course, don't forget air-conditioners
ranging from individual mini-split systems up to multimegawatt
chilled water cooling systems serving
whole districts. Obviously, any improvement in
the baseline efficiency of these systems means
more generating capacity for other purposes.
The greatest shortfall in access to electricity
is in sub-Saharan Africa-also the region that
will see the largest increase in population over
the next 30 years. It is vital that the infrastructure
built to support that population does not
copy the mistakes of the past. At a local level
throughout the developed world exactly the same logic
can be applied. Increased use of renewable energy
has transformed the way our electricity is produced,
distributed, sold and used. A refrigeration system that
can adapt to that change can save lots of money for its
owner, and in some cases can even earn money in the
right circumstances with some minor changes to operating
patterns.
Clean water and sanitation seems to have less to do
with refrigeration but there are several touch points
where the two worlds collide. In Scotland, where I live,
it is easy to forget that fresh water is a scarce commodity
because it routinely falls out of the sky. Only 3% of
the world's water is unsalted and more than half of that
is locked into polar ice caps, glaciers and permafrost.
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ASHRAE JOURNAL ashrae.o rg O CTO B E R 2021
As easy as 7, 6, 9.
Large refrigeration systems use freshwater in evaporative
cooling systems because it is much more compact
and more efficient than air-cooled condensing, especially
in tropical climates (see goal seven, above). For
coastal locations saltwater could be used instead of
fresh, but brings several challenges to an evaporative
cooling system including slight loss of thermal performance
and corrosion of incompatible materials. The
water may also be highly abrasive if it is not properly
filtered and the level of salt in seawater (about
3.5% by weight) is not enough to ensure biocidal
action against Legionellosis so some
water treatment is still required. The merit
of this approach however is that the freshwater
is conserved for those who really need it.
There are technical challenges in adapting
evaporative cooling systems to saltwater use,
but they are not insurmountable.
The third goal in this set (industry, innovation
and infrastructure) is all about building a sustainable
and resilient world through the application of
advanced technology to infrastructure. I have believed
for a long time that the refrigeration world has been lagging
behind in terms of innovation. Most of our creative
effort over the last 30 years has gone towards addressing
the twin bogeys of ozone depletion and global warming
potentials. To incorporate a truly 21st century cold chain
into the infrastructure required to serve an increasingly
urban world population requires us to get our innovation
mojo on fast. The demands of the heat pump market
will be even bigger. As I have said before, it's a great
time to be a refrigeration engineer!
Andy Pearson, Ph.D., C.Eng., is group managing director at Star Refrigeration in Glasgow, UK.
ISTOCK IVANC7

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ASHRAE Journal - October 2021

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