ASHRAE Journal - September 2014 - 73

COLUMN REFRIGERATION APPLICATIONS

Strangeness and Charm

Andy Pearson

BY ANDY PEARSON, PH.D., C.ENG., MEMBER ASHRAE

I was recently reminded of the weirdness of subatomic particles when a friend commented
that they didn't understand how an electron could be both a wave and a particle at the same
time. I had to dredge my memory to the depths of high school chemistry and physics and
concluded that this was indeed what we appeared to have been taught. An electron behaves
like a particle but also behaves like a wave and so exhibits "wave-particle duality." However,
it seems to me that the electron is neither.

I share some characteristics with women (two eyes, two
plausible than to send a technician to site to recalibrate a
ears, nose, mouth and so on) and also share some characsingle sensor each year. Each data point could be moniteristics with bicycles (usually when in motion I have two
tored by 10 or more instruments, with a multiple voting
points of contact with the ground, I derive my motive force system to evaluate the actual reading. Sensors will not only
from calf muscles). However to say that this means I am
be fitted to the compressor; it is likely that food packagboth a woman and a bicycle at the same time is obviously
ing will contain scanable data gatherers that can give the
nonsense. The electron is neither a particle nor a wave, but consumer a detailed plot of the time-temperature history
could perhaps be called a "pave," or maybe a "warticle."
of the produce before they lift it off the supermarket shelf.
Why all this subatomic chat? The growing understanding This could reduce food wastage by replacing the "bestof this field, which started 50 years ago with the discovery
before" date with a weighted average shelf life based on the
of quarks and resulted in the recent comproduct's temperature history. We might
Captain, my sensors indicate that this
missioning of the large hadron collider
see systems that facilitate dialogue between
pie will go off in 17.4 seconds
underneath Geneva, is likely to cause some
the food on the shelf and the refrigeration
significant changes to all aspects of life.
system in the back of the shop. If food is
Sensor and actuator technology is getting
aging too quickly the temperature can be
cheaper all the time. We already see the
reduced. If new stock is selling rapidly, the
result of this in mass-produced items like
operating temperature can be nudged up
car engines and washing machines but the
to make the system more efficient.
continued deployment of ever-cheaper
However, we need to be careful about
sensors will be seen in refrigeration equipment, too. This
how we deploy this extra measuring capability. "Too much
could result in the adaptation of existing compressor types information" is a common complaint. If important mesinto machines that monitor their performance and advise sages are buried in a blizzard of information then they will
when maintenance is required, or which adapt to differlikely be ignored. If more sensors equals more calibration
ent operating conditions to maximise efficiency or even to this will be an expensive mistake. The incoming technolprotect against liquid carryover or changing temperatures. ogy must be deployed in ways that make operation and
The sensors could also be used to calculate operating effi- maintenance easier, not difficult.
ciency and determine the optimal mode of operation for
In his recent address to the Cold Chain and
the system. All aspects of the system will be measurable,
Sustainability conference, ASHRAE's Refrigeration
enabling easy comparison between different machines or
Committee chair, Richard Royal said "We need systems
even across different sites.
to be simpler, but I mean simple like a smartphone, not
If, as physicist Michio Kaku predicts, sensors become
simple like a hammer." Considering the ways in which
substantially cheaper than the box they are delivered in
cellphones have changed over the last 20 years it looks like
how will they be used in practice? It will be more economic an exciting time to be working in refrigeration.
to fit a large array of sensors in each monitored location
Andy Pearson, Ph.D., C.Eng., is group engineering director at Star Refrigeration in Glasgow, UK.
and use software to decide which of the readings is most
SEPTEM BER 2014

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