ASHRAE Journal - December 2019 - 65

COLUMN REFRIGERATION APPLICATIONS
Andy Pearson

Part 3

Still Frozen?
BY ANDY PEARSON, PH.D., C.ENG., FELLOW ASHRAE

Last month's column considered how the rapid growth of urban populations in the
nineteenth century was the catalyst for the growth of the mechanical refrigeration
industry. It is doubtful that those pioneers could have foreseen the diversity of applications for their new technology that is now used in everything from cryosurgery to high
temperature heat pumps and is an essential utility in keeping society functioning.

PHOTO: iSTOCK TOMJAC80

Natural ice gave way to mechanically produced ice at
customer orders whisky on the rocks the barman will take
the end of the nineteenth century, but the ice sellers
a chunk of ice from his cabinet and attack it with a small
were driven from the streets just a few decades later
pick until he has chiselled it into a perfect sphere that sits
with the advent of the domestic refrigerator; initially
snugly in the glass. Of course, this means a cubic block
with sulfur dioxide or methyl chloride and then with the
of volume (2r)3 has been manipulated into a ball with
volume (4/3)πr3. 8.0 has been reduced to 4.2; in other
new range of "safety refrigerants," the freons. Although
words, almost half of the block has been
cooling was no longer delivered to the
Our addiction to ice cubes is bananas.
chipped away and runs down the drain
home in the form of a block of ice for
as melt water. When a Japanese refrigerthe "ice box" our love affair with the
ation equipment manufacturer needed a
simple ice cube continued. When I was
heat load to run their R&D test chamber
growing up we had small plastic trays to
they installed a small ice making plant
fill with water and place in the freezer
and ended up supplying half the bars in
compartment to make ice cubes and a
the neighborhood, making enough revmore recent innovation was a plastic bag
enue along the way to make a healthy
divided into small pouches that could be
contribution to the research budget.
filled with water and hung on the back of
The value of cubed ice can be seen by the number
the freezer door. Each frozen pouch could then be ripped
of commercial facilities making it by the bagful. One
out of the bag when required. A novel use of this system
high-end retailer told me that they reckoned to make
was for freezing batches of concentrated sauce, where
more profit from ice cubes and bananas than any other
each pouch was one portion of sauce that could easily be
product lines in their stores. When you consider the
added to a saucepan when cooking a casserole or soup.
luxury items on offer, ranging from caviar and lobster
Now we have refrigerators with built-in ice dispensthrough exotic fruits to expensive wines and chocolates
ers to provide cubes on demand. These always make
this seems odd. The answer is that not everyone buys
me wonder about the energy efficiency of the system.
these other luxuries, which are expensive to make from
On paper these fridges are as good as the models on the
expensive ingredients, expensive to ship and expensive
market that don't have automatic dispensers, but if the
to store, but everyone loves an ice cube which only takes
ease of delivery encourages an increase in use and the
tap water and a little bit of energy in a fairly simple
system is plumbed into the main water supply so there
automated process. Even at Christmastime the superis no more fiddling about with trays of water then elecmarkets will do a roaring trade in ice.
tricity use must surely go up steeply.
Another impressive but somewhat wasteful use of ice
Andy Pearson, Ph.D., C.Eng., is group managing director at Star Refrigeration in Glasgow, UK.
can be seen in the bars and restaurants of Tokyo. When a
D E C E M B E R 2 0 19

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