FEATURE
COMMON MISTAKES
What are common mistakes made
when designing and manufacturing a
refrigerated truck body?
The most common mistake is ignoring
all the possible heat bridges, like steel/
aluminium cappings, which are present
inside as well as outside the body while
being connected, explains Gröss. This
allows for the heat from outside to find
a way past the insulation and enter into
the body.
Most of the time the only mistake on
the insulation side happens when there is
a misunderstanding between the client,
dealer and the manufacturer, explains
Marco Martinelli, director of Dalucon,
manufacturer and supplier of insulated
panels.
Another issue is that appropriate and
correct refrigeration unit selection is
overlooked at times, causing units to be
underspecified with regards to capacity
requirements, says Swart. This results in
equipment working continuously instead
of shutting down faster on setpoint. As a
result, refrigeration equipment is operating
more than required, causing an increase
Double stacking can be done inside a refrigerated trailer.
of fuel consumption, and more CO 2
emitted in the atmosphere, which aids
global warming.
“The refrigeration unit must be selected
to ensure that it has the capacity to keep
the product at temperature, taking into
consideration the ambient temperature,
required product temperature, and the
number of door openings during the trip,”
advises Solomon.
According to Heyman, another
big mistake is underestimating the
harshness of the South African transport
environment. This is particularly true about
the loading and offloading processes,
with under-qualified and low-paid
personnel, as well as the condition of our
roads and questionable receiving bays.
“Load securing is also not a high priority in
South Africa and thus product and body
damages are common,” he explains.
IMPROVING EFFICIENCIES
How can you improve efficiencies and
energy usage on insulated truck bodies
for refrigeration?
The body and the refrigeration system
form an integral unit that must provide
the correct solution for the transporter,
says Solomon. “It is therefore extremely
important that we match the fridge and
the body correctly.”
He advises:
1. Ensure the correct type and capacity
of unit is correctly specified. Be sure the
unit is not underspecified and although
over-specifying is often a good option,
this may result inefficiencies.
2. Ensure that the unit is serviced as
specified by the manufacturer, kept
clean and in good running order.
3. Ensure the box is correctly specified
and kept in good condition.
Heyman. “The financial/legal penalties
for delivering products that have been
compromised can be enough to close a
major business.”
More and more of the fresh retailers are
starting to put measures in place to record
the full cold chain and the transporters
will be required to prove that the cold
chain has not been compromised, says
Heyman. This is where telematics will make
its mark.
“I would estimate that about 30-40%
of refrigerated vehicles today have
telematics. There will probably be 100%
within the next five years,” Solomon
predicts.
The insulated body should minimise
the heat leakage through the body to
keep the load within commercial limits,
says Solomon. “As a guide, the rate
of heat leakage should not exceed
0.4W/m².” Prevent a detrimental
increase in product temperature for a
minimum period of eight hours in the
event of a failure of the refrigeration
system, according to the South African
Refrigerated Distribution Association
(SARDA) code of practice.
Another mistake is to use cheaper and
inferior insulation as well as go thinner
on the insulation thickness. This, again,
has adverse effects on the cooling
performance, he says. “Also very common
is the incorrect or poor assembly of the
body which in time allows for moisture
ingress and thus reduces the insulation
performance,” says Gröss.
Proper insulation and wall thickness of
the refrigerated truck body is not always
specified correctly for the temperature
requirements by the client, which means
that heat loss through the insulated walls
is much higher, resulting in temperature
losses and the refrigeration units
working harder to maintain the required
temperatures, explains Swart.
If the vehicle body manufacturer does
not understand the customer requirements
and operating conditions, it is possible
the body can be incorrectly specified,
adds Holcroft. “Also there is cost pressure
on vehicle body builders and they can
compromise by reducing thickness of the
insulation, using lower density foams, or
using polystyrene insulation which has lower
thermal properties than polyurethane to
save costs.”
It is a huge mistake to not understand
exactly what the customer needs to do
with the truck, explains Marks. “Often the
end user will purchase through a third
party, i.e., a truck dealer, or a transport
consultant, and their exact requirement is
not communicated to the body builder.”
INCORPORATING COLD CHAIN
There is a drive towards lower GWP, more efficient, greener refrigerants in
transport applications.
COLD LINK AFRICA • June 2019
www.coldlinkafrica.co.za
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