FEATURE
INCORPORATING COLD CHAIN
CO 2 systems, which are becoming the
new standard in retail refrigeration,
discharge a greater proportion of heat
at higher temperatures. “Thus, the exergy
or useful energy of these systems, when
including the heating potential, is much
higher than in traditional HFC systems.”
Full district heating integration is being
explored. A supermarket refrigeration
system can second as a heat pump,
covering not only full space and
tap-water heating, but also heat the
neighbourhood with smart integration to
the district heating grid, explains Naidoo.
“As such, the supermarket of the future
becomes an integral part of sustainable
energy systems, providing heat when the
wind is blowing or the sun is shining.”
NEW TECHNOLOGY
According to this graph by Danfoss, looking at data from 10 000 CO 2 installations and
150 ejector installations, they are confident that CO 2 systems will save more energy than
R404A systems.
GLOBAL TRENDS
CO 2 in supermarket refrigeration is also a
global trend, explains Robinson. A few years
ago, in Europe, if you did a supermarket
with CO 2 versus synthetic refrigerants, the
CO 2 would be 15–10% more expensive
to install. Now, it’s the other way around
because of the increase in the synthetic
refrigerant price.
CO 2 trans-critical historically was not
suitable (high energy consumption at
high ambient) for high-ambient conditions
also known as ‘the CO 2 equator’, explains
Robinson. “New technology has moved the
‘CO 2 equator’ to allow trans-critical systems
to work energy efficiently in high ambients
now, thanks to parallel compression and
ejectors,” says Robinson. South Africa has
been working over the past 10 years to fine-
tune and develop CO 2 trans-critical systems
in high ambients.
Kuzma agrees that the world is going
‘natural’, but notes that they are much
further down the track with natural
Refrigerants are also being pushed to
be energy efficient and environmentally
friendly. “With the three natural alternatives,
propane and ammonia require a secondary
system to be applied in the public space.
This has left CO 2 as the refrigerant of
choice and I believe more and more
development in this will lead to simpler and
more affordable CO 2 systems, wherein it will
become the norm,” predicts Smith.
refrigerants, especially in Europe with the
advanced phase of the F Gas regulation
in place. “Placing doors on refrigeration
cabinets is also a lot more progressed
globally,” he notes.
Definitely the global trend in refrigeration
is trans-critical CO 2 , agrees Smith. “Anyone
visiting Chillventa over the last few shows
would have seen it steadily grow from new
exciting technology to literally dominating
the show last year.” Almost all the major
brands have developed equipment and
materials suited to trans-critical and it is
being driven to be more affordable, more
accessible, and more efficient. “Global
markets have already been living in the
world of HFC phase out as taxes, quantity
limitations, penalties, and high costs have
made CO 2 systems a future-proof solution.”
A lot of the R&D done by manufacturers is
on CO 2 , he says.
According to Hadfield, there also seems
to be a trend globally in terms of looking
at simplifying systems and trying to move
away from electronics and putting in
mechanical valves. “Although this may be
cheaper in terms of initial cost, the system is
far less sophisticated and won’t be able to
offer the energy efficiency that we see on
electronic valves.”
In general, stores are getting more
efficient, says Hadfield. “This is because of
fine-tuning on the refrigeration system. The
savings is coming in from controlling the
set point better. Ensuring that the system is
running according to your set parameters is
where the real efficiency comes from.”
“Natural refrigerants will continue to
grow but not at the expense of energy
efficiency,” says Kriel. “I think that local
shopping (smaller stores) combined with
Internet commerce will be the big driver of
food retail in the future. This will impact what
we do as a refrigeration industry to support
our customers.”
Globally, they are looking at how the
supermarket can be transformed from
energy consumer to energy producer with
a new heat recovery unit and connection
to local smart grids, explains Naidoo. As
well as how digitalisation and electronic
controllers open new opportunities
for one-view store management and
predictive maintenance.
Outsourcing refrigeration plants, like this one at PnP Darras in Johannesburg, is becoming more
popular, too.
Services (CRS). It can be used for domestic
hot water as well as space heating. “When
it comes to using it for space heating, it’s a
no-brainer. The return on investment is very
quick, especially on CO 2 .”
“There are a lot of new things happening
— many of which are data driven,” adds
Breckle. The degree to which the data is
measured, depends on affordability. “But
many customers are starting to at least
wanting to know what is happening in terms
of data,” he says. Even if it’s just measuring
the basics.
The hot-foods section in supermarkets
in particular are being looked at in a
hard way, according to Breckle, as
they are still predominantly using old
technology and design.
Lighting is also getting more intelligent; it’s
not just standard LEDs. A lot of scheduling is
happening now. “Manageable systems are
coming in now too for lighting — it’s not just
about measuring,” says Breckle.
Also, some retailers are starting to look
at solar similar technologies to cut the
peak, adds Hanssen. Some thermal storage
designs are being considered. But it can be
costly and often has to do with the foresight
of the retailer.
“There is a lot of work and R&D being done
to fine-tune existing technology to make it
more efficient,” says Hadfield.
Electronic control, monitoring, and
diagnostics, with the ability to maintain
equipment within design operating
envelopes, is where technology is going,
says Kriel. “This will give rise to the use of
AI in optimising maintenance and plant
performance, improving the utilisation
of scarce skills such as refrigeration
technicians.”
Energy saving is a huge focus — more
so than ever. To optimise this, various
technologies and products are gaining
popularity, explains Kriel. These include:
• Modulating unloading heads on
compressors to cater for variable loads.
• Variable speed drives for capacity
control of fans and compressors.
• EC fans.
• Electronic expansion valves.
• Brushless DC compressors.
• LED lights in cabinets and rooms.
• Perspex and glass doors on chiller
cabinets create large savings.
• Raised suction temperatures and
reduced condensing temperatures,
sometimes using ‘floating’ algorithms
in controls.
• Detailed energy and temperature
monitoring with trend logging and
active management.
Even the local FRIGAIR show boasted a lot of new and exciting developments in terms of retail
refrigeration and energy savings.
COLD LINK AFRICA • March/April 2019
www.coldlinkafrica.co.za
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