PROJECT
INCORPORATING COLD CHAIN
Lutz Refrigeration
Cold Link Africa
Pilot light and alarm system on condensing unit.
Ice coils in the tank showing the ice produced.
and cold chain integrity in the event
of a breakdown. These rooms cannot
go off temperature in order to minimise
any waste or spoiled product. All room
temperatures are also monitored and
logged for record purposes.
Another absolute essential with any
blast chilling process is to maximise air flow
through the product. As such Douglasdale
is constantly improving their product
presentation and packaging to reduce
pull down times of the Amazi and milk.
The most recent butter freezer and
freon ice-bank were both built with a
hybrid air/water cooled condensing
systems which make use of an air-cooled
condenser, shell and tube condenser
and water cooling towers. This allows for
low-condensing pressures all year round
by using cold air in winter and water only
in summer months when the ambient
temperatures rise above 28°C. It also
provides a backup in the event of water
system failures or restrictions where their
systems can still run (albeit a little less
efficiently) on air cooling alone.
CHALLENGES OVERCOME
When considering the elements of
difficulty in meeting design specification,
continually running close to zero degrees
is always challenging as far as freezing of
evaporators goes. An innovative design
in all the blast freezers allows the rooms
to run down to 0°C at night once the
doors are closed to cool the milk faster
without running the same risk of freezing
up the coils. The plant then goes into an
extended air defrost later in the evening
to clean up the coils before operation the
following day where they run at around
2°C during the day when the rooms are
open to the elements during loading and
unloading operations.
IMPACT OF THE SYSTEM ON
ELECTRICAL USAGE
One of the potentially largest energy
users on site is the chilled water system for
pasteurisation. This water is provided by
ice banks. The benefit of these systems is
that they reduce the spikes in electricity
requirements that would come from a
Cold Link Africa Cold Link Africa
Some of the original Freon Cooling systems still working 20 years later.
The products, Amazi and milk in the chiller awaiting dispatch.
20
www.coldlinkafrica.co.za COLD LINK AFRICA • September 2020