TABLE OF CONTENTS - Everything R744

cooling for the whole university. To ensure safety, such
systems include a minimal refrigerant volume through
plate heat exchangers, separate sealed compartments,
leak detection systems, ammonia scrubbers, and
electrical switching outside the compartments.
With regards to tropical countries, in Mauritius, two
government buildings had their CFC-12 and CFC-11
chillers replaced with open screw ammonia chillers,
helping save 1560 tons of CO 2
per year.
HC: In the last decade hydrocarbon (HC) chillers have
started to gain acceptance as providers of comfort air
conditioning and heating for buildings around the world.
According to one estimation, the global market potential
for HC chillers is $4 billion. In Europe, for example, R290
(propane) chillers have been installed in the historic
Church House Westminster Abbey in London, UK, while
Arhus University Hospital Skejby, Denmark has installed
R600a (isobutane) heat pumps and R290 (propane)
chillers. In Asia, several conversions to hydrocarbon
chiller systems have taken place, including the Gaisano
Country Mall, the Legenda Hotel and the Mandarin
Restaurant in the Philippines. The Jusco Melaka shopping
center in Malaysia also converted its cooling system
to hydrocarbons, installing 50 25-50kW water-cooled
packages and 100 split systems. A plan for industrial
scale production of HC chillers has been put into action
by one large supplier, which will be followed shortly by
R290 heat pumps. This should further reduce the costs of
these technologies and increase their uptake.
In addition to their use in chillers hydrocarbons can be
used in ground source heat pumps (GSHP). This is the
case in Buntingsdale Infant School in the UK, where heat
is extracted from the ground and upgraded to a useful
temperature by a R290 heat pump unit.
H 2
O: The development of smaller air-cooled absorption
chillers (10 RT to 150 RT sizes) promises residential and
small commercial co-generation systems at high-energy
efficiency levels. While such trends can already be seen
among European manufacturers, it is expected that
North America will also be an attractive market for smallscale
sorption technology products in near future.
Data center cooling
CO 2
/HC: Data centers that house computer systems
and components such as telecommunications and
storage systems need to have rigorous temperature and
humidity control to maintain the environment of the
server components within the manufacturer’s specified
range. Recently, CO 2
, which poses no danger to electrical
equipment and is more efficient than air or water, was
implemented as the refrigerant for data center air
conditioning systems in London. The computer blade
servers cool both the ABN Amro Data Center and Imperial
College University’s e-science computer suite.
In Denmark, the office building of EnergiMidt
supplemented the traditional glycol-based free cooling
system with a pumped CO 2
system for server cooling.
The installation encompasses a cascade CO 2
system with
propane compressors.
TRANSPORT APPLICATIONS
Cars & electric Vehicles
CO 2
: The development of CO 2
MAC as an energyefficient
way to combine air-conditioning with heating
capabilities is especially advanced in Europe, Japan,
and the USA. Prototypes have been tested extensively,
although, across the world, the commercialization of
CO 2
MAC in passenger cars has been delayed. However,
progress in Europe (status: January 2013) could revitalize
developments in CO 2
MAC. Since one European
automaker has announced that on safety grounds it will
not use suggested low-GWP HFCs in its models, new
activities in national and international fora have started
to re-investigate the technical and commercial viability
of CO 2
. At the time of publication, no final conclusion
about the renewed application of R744 in the future had
been made.
New impetus for the use of CO 2
in mobile air-conditioning
(MAC) systems could also come from the rapid evolution
of hybrid electric vehicles and electric vehicles with
electrically driven compressors. Here, CO 2
MAC optimizes
the combined cooling and heating of vehicles with no
or limited motor waste heat. Successful prototypes were
already presented in 2011.
HC: Over 20 million car mobile air-conditioning
(MAC) units worldwide have safely used hydrocarbon
refrigerants, many converted from the high global
warming refrigerant HFC-134a. An Australian vehicle
manufacturer was the world’s first to use hydrocarbons in
its range of on/off road vehicles. Today, it is estimated that
the share of hydrocarbons exceeds 10% in the Australian
motor vehicle air-conditioning service sector. In 2011, an
Australian supplier of hydrocarbon refrigerants reported
12% average sales growth. Hydrocarbons can work as
a primary MAC system refrigerant or they can be used
in secondary loop systems to ensure safer use. It should
be noted that hydrocarbons are particularly suited to
hot climates and applications with limited space such as
mobile air conditioning systems.
Buses, trucks & trains
CO 2
/HC: Outside North America CO 2
MAC has so far been
commercialized in around 30 buses, of which two were
hybrid electric buses and one had a reversible operation
for combined heating. In total, these busses have covered
more than 3.3 million kms in Germany and Luxembourg.
CO 2
systems for trains, which operate like a modern airheat
pump, are currently being tested in Germany, this
time by the national train operator Deutsche Bahn.
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