EVENTS AND EXHIBITIONS
INCORPORATING COLD CHAIN
Continued from page 19
level of skills required for installation. On
the other hand, there are pros such as
no concern about the environmental
impact when venting CO 2 to
atmosphere. With ammonia, there are
more safety issues because of its toxicity.”
Manuel gave some background to
the development of CO 2 booster systems
for a wide application in refrigeration,
heat pumps and air conditioning.
Systems with compressors operating
in parallel (low temperature and high
stage) with variable speed drives and
flash gas ejections, were explained
to illustrate options to improve system
efficiencies (COP).
In tandem with the strides made in
CO 2 technology, Bock have developed
the NX34 CO 2 T (four cylinders) and
HGX46 CO 2 T (six cylinders) series of
trans-critical CO 2 compressors, capable
of efficiency performance data that
is unrivalled by any other comparable
product on the market, boasting the
highest energy efficiency ratio (EER)/
coefficient of performance (COP)
value is the wide application limits. This
efficiency is verified by certification
of the performance data at several
displacement stages by Asercom
(European Association of manufacturers
of components for air conditioning and
refrigeration technology). Available
in various frame sizes, the trans-critical
CO 2 series cover a wide range of
swept volumes from 6.2 to 38.2m 3 /h (at
50Hz) and are designed for operating
pressures up to 130 bar.
Specific design techniques covered
by Manuel Fröschle in his presentation,
bore testimony to his expertise in
CO 2 technology and commercial
1
2
applications. He also referred to the global
thermal contours demarcating areas with
yearly average temperatures above or
below 15°C as a guide for sub-critical or
trans-critical CO 2 systems.
Details of actual installations in food
production, fish freezing, hypermarkets and
large cold stores, were shown to further
illustrate the versatility of CO 2 refrigeration.
There was valuable info for each
attendee to leave with. The complexities
in the design of CO 2 systems as dealt with
expertly by Manuel Fröschle, would not
be readily found in textbooks and was
evident from the delegate comments
during the wrap up session. CLA
1. Applications with subcritical and
trans-critical CO 2 across the world.
2. Attendees at the GEA Bock
Johannesburg seminar.
COLD LINK AFRICA • May | June 2017
www.coldlinkafrica.co.za
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