PROJECT
INCORPORATING COLD CHAIN
water chiller approach needing to provide
massive cooling for a few hours a day.
Conversely, the ice banks build ice
during the night gradually to be melted
off in a much shorter period the following
day during production. This way they
drop the peak energy demand down
and shift the load into the evening when
other plant is off and ambient conditions
are more favourable. This prevents the
grid from being overloaded and reduces
Douglasdale’s peak kVA draw during the
day by shifting this load out to the nighttime
period.
Douglasdale
continues to look
for ways to improve
to ensure they run
a clean and unobtrusive
operation.
UNIQUE ELEMENTS
Running a plant like this in the heart of
Fourways obviously has some very unique
challenges, and examples include noise
LIST OF PROFESSIONALS:
Owner
Project Name
Architect / Designer
Project manager
Contractors:
HVAC&R
Insulation
Product Suppliers:
Douglasdale Dairy
Rental freezer store in Johannesburg
Douglasdale Dairy
Douglasdale Dairy
Lutz Refrigeration
Precool
FOCUS ON THE ICE BANKS
There are two ice banks on site at
Douglasdale’s Fourways facility. The
original plant (over 20 years old now) still
runs well but was recently supplemented
by a much larger Italian machine with the
following specifications:
limitations, water and sewerage overload,
electricity supply limitations and local
resident buy-in. Douglasdale continues to
look for ways to improve to ensure they
run a clean and unobtrusive operation in
harmony with this relatively quiet suburb to
produce their dairy products at the heart
of the demand.
GEA Compressors
Colcoil and HC evaporators
HC Condensers
Carel controls
Sulzer water cooling tower
Direct online cooling capacity new plant:
Ice storage capacity:
Equivalent ice melt capacity:
200 kW (Nominally)
est. 18 tons
18 tons ice storage = 835 kW for two hours
Baltimore air coil Ice bank (Ammonia)
Ice bank (Freon)
As indicated above, the ice bank recently
commissioned can provide the cooling
of 800kW for two hours from stored ice
capacity alone which is built up with a
more gentle 200kW cooling system during
the course of the night when other loads
are offline.
PLANT SUSTAINABILITY ASPECTS
INCLUDE OTHER EFFICIENCIES
In addition to Douglasdale’s various
refrigeration systems that aim to reduce
their power usage and shift loads into
evenings, they also run a full water
processing system which takes cleaning in
place (CIP) water and through a series of
algae, aeration, flocculants, mechanical
aggregate filtration, natural reed filtration,
ultraviolet (UV) light and chlorination,
cleans the approximate 30 000 litres/hour
of water back to a potable state again
ready to re-use in the CIP processes. This
reduces their water usage significantly
which is a major challenge at most dairy
processing facilities.
Lutz Refrigeration
Cold Link Africa
Cold Link Africa
Blast Chiller condensing Units.
Facility operations manager, Andrew Edwards (right), showing Kevin Lutz maintenance
being done to their in-house plastic crate-moulding equipment.
Part of the facility’s water filtration system is passage through various aggregates.
COLD LINK AFRICA • September 2020 www.coldlinkafrica.co.za 21