Cold Link Africa November / December 2019 | Page 17

PROJECT
INCORPORATING COLD CHAIN
“Sometimes packing stores don’t
have any fresh air supply, despite the
obvious importance of this inclusion
in the design,” says Neethling.
“Otherwise the humidity increases too
much inside, causing unfavourable
working conditions.”
The packhouse was designed for
maintaining 20° C inside, but it is often
turned down to 18°C even. The client was
very happy with the end-result and says
sometimes it could even feel like it’s too
cold inside.
To achieve the desired temperatures
and humidity, two Midea chillers are
located outside of the packhouse. The
130kW and 200kW chiller provide a total
cooling capacity of 330kW. Both chillers
run on R410a refrigerant. To ensure the
temperature inside the packhouse
is maintained, insulated panels from
Specialised Panel Manufacturing (SPM)
were used.
TEMPERATURE MATTERS
“It’s been proven that the quicker
grapes reach under 4°C, the longer
Inside the pre-cooler.
your shelf life,” explains Neethling. “It’s
humidity in the packing store is kept at
all about the respiration on the grapes.
about 60 to 68 %. To achieve this, the
Otherwise you run the risk of dry stem,
incoming water temperature on the
which can drastically bring down the
cooling system is 7°C.
price of your product, cutting into
Just for the packing store alone, 154kW
profit margins.”
of cooling is required. This is mostly made
Grapes can have a shelf life of as
up of 8kW evaporators and a 22kW one
long as 8 to 12 weeks if the cold chain is
for the fresh air supply – built locally by
properly maintained. It’s key to achieve
Colcoil. “You must allow for 8ℓ of fresh air
the longest possible shelf life for export
per person per second in your design,”
table grapes as it usually takes about a
explains Neethling.
month just to reach its destination.
A problem that persists everywhere is
that the attics are too hot. Cooling them
down is difficult and it is expensive to put
up panels, explains Neethling who once
measured temperatures above 60°C in a
pack store attic. There is a hot water tank
as well as a cold-water tank on site for
circulating the water through the chillers.
Four evaporative coolers are also used to
There are 167 refrigeration points connected to the CO 2 refrigeration plant.
help cool the attic.
CLA
LIST OF PROFESSIONALS
Owner Modderdrift Boerdery
Architect / Designer Johan Louw
Project manager   Johan Louw and owners
Consulting engineer
Contractors
Product suppliers

COLD LINK AFRICA •
November/December 2019
Electrical Reynolds Electrical
Mechanical Wespak
Main building Atlas Staal & FM Civils
Refrigeration JA Neethling Verkoeling
Electrical Reynolds Electrical
Evaporators Colcoil
Insulated panels SPM
Chillers Midea
Evaporative coolers Evapco
Pumps Spilhaus
Racks Cubicool
www.coldlinkafrica.co.za
17