FEATURE
INCORPORATING COLD CHAIN
Companies are spending more money
on the significant parts of an installation
while trying to reduce cost by utilising
inferior piping, fittings, and controllers.
These are causing a substantial
amount of problems on site. The influx
of Chinese copies in particular, are
problematic. These are not always
made exactly to spec and although
they are cheaper, they could cause
the system to run less efficiently and
increase the amount of failures.
There is also a lack of technical
information being passed from the
older generation to the younger
generation, says Hadfield. This will be
noticed in the design of the system.
The older generation would allow for a
larger safety factor which would permit
the system to have enough of a buffer
for those extremely high ambient days.
While the younger generation would
rather design to the exact specification,
causing the system to run less efficiently
or unable to hit the desired set points
during higher peak temperatures.
Kuzma notes that some common
errors include not catering for the
increasing ambient conditions. “We are
seeing companies using water-based
systems in a water-scarce country.”
ON-SITE MISTAKES
and end user (if possible) to educate them
on what you want to put in and why. “But
not everyone does that because it’s a
competitive environment,” says Hanssen.
Generally, manufacturers like Cubicool
don’t deal directly with the end user; they
deal through the installers and contractors.
Which can make things difficult to help the
client understand what is possible. Though
in all their designs, they are always looking
at reliability and ease of maintenance. “It’s
important as a manufacturer to stay abreast
of new technology.”
The client often gets convinced to
accept a system that doesn’t deliver
under high stock volumes or high ambient
temperatures. These systems will be cheaper
and all goes well until some hot or busy days
arrive. All too often, the competitive nature
of the industry means capital expenditure
cost is placed over operational expenditure
when deciding on which plant to install. “An
energy-efficient and well-designed plant
can pay for itself in the long term through
savings,” explains Smith.
Kriel agrees that a big design mistake is
not considering the total cost of ownership.
“The total cost of ownership is 66% driven
by energy cost.” Also not considering the
different characteristics of alternative
refrigerants is another mistake.
Naidoo highlights the biggest design issue
as engineers designing synthetic refrigerant
systems instead of natural refrigerants, as it is
perceived as cheaper. “They need to think
more about the overall picture and move
forward towards a more holistic approach
which combines all systems and not only the
refrigeration applications.”
Another problem is cutting corners to
save costs. “Most of the jobs going out are
cost-based and as such, sometimes this
means that some engineers will skimp on
products to bring down cost,” says Hadfield.
COLD LINK AFRICA • March/April 2019
But it’s not just about the design; on-
site work and maintenance can be
problematic, too.
“General contracting standards are
good; however, the shortage of skills
does have an impact with quality of
workmanship in preventing gas losses
for example,” says Kuzma.
But sometimes there is only so
much the contractor can do. When
it comes to the evacuation process,
retailers are usually so desperate to
keep trading that when installations
are done during revamps, the
contractor is not afforded enough
time to pull proper vacuums, explains
Smith. Residual moisture remains in
the system, which turns the oil acidic.
“Oil changes and drier core changes
now become necessary and result
in more downtime than possibly a
proper evacuation process would
have taken.”
Also, tight installation programmes
sometimes lead to rushed pipe
installations where joints aren’t
properly welded and tested, causing
leaks down the line, explains Smith.
When pipe routing is being planned,
there is often not enough thought put
into the expansion and contraction of
the pipes.
Another common mistake when
doing pipe work is not considering the
vibration in the system. Plant vibration
is also a serious contributor of pipe
failure and pipes must be properly
clamped. Insulation of piping is a vital
aspect of the system, which is often
not given the importance it deserves.
Insulation should have proper glued
joints and insulated pipes need good
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