TABLE OF CONTENTS - Everything R744

systems are Ahold USA’s Giant Distribution Center
in Carlisle, Pennsylvania, which operates on a twotemperature,
single stage ammonia refrigeration system,
as well as Fresh & Easy’s 53,000 sq. ft. (4,942m 2 ) Riverside
Distribution Center for meat & poultry processing and
distribution in California, which has a two-stage pumped
re-circulated ammonia system serving a multitude of 30
to 40°F (-1 to -4°C) processing rooms, -30°F (-1°C) spiral
blast freezers, and other processing equipment.
In recent years, facilities adopting ammonia refrigeration
have begun to receive the recognition of US. Green
Building Council (USGBC), the leading evaluator of
environmentally sustainable buildings in the US In
North America, Canada’s first refrigerated distribution
center with ammonia coolant in its mechanical room
was recognized by the USGBC with the LEED Gold
certification. United Natural Foods’ four distribution
centers in Washington, New York, Providence, and
Lancaster were also awarded LEED Gold and Silver
certifications.
NH 3
/CO 2
: United States Cold Storage is pioneering a
new CO 2
refrigeration technology used in food storage
facilities in Indiana, California, Pennsylvania, and Florida.
The system uses ammonia and CO 2
in a cascade system
that allows for lower operating pressures and confines
ammonia to the machine room only.
Canadian food distribution center Flanagan’s also
combined CO 2
and ammonia in its warehouse expansion
project, eliminating F- gases from its site. The 199,000 sq.
ft. (18,500m 2 ) facility uses a dual temperature ammonia/
CO 2
brine packaged system, able to efficiently store 200
tons of refrigeration at temperatures ranging from 59° to
18.4°F (-15 to -28°C).
HC: Fruit growing companies such as Lake Breeze in the
US and Mansfield’s Fruit Farms both have both reported
positive experiences after using the SRS (Secondary
Refrigerant Systems) incorporated in R1270 chillers.
Supermarkets
CO 2
: There are over 36,500 supermarkets 1 in the US, and
in 2009, the US EPA approved the use of CO 2
in food
retail refrigeration and cold storage warehouses. Shortly
thereafter, US food retailers began making significant
investments in CO 2
refrigeration. Retailers that opted for
CO 2
include the Sprouts Farmers Market Westlake Village
Store, which employs a CO 2
cascade system for both low
temperature and medium temperature applications.
ShopRite, a small independent retailer, has a store
in the Hatfield Pointe Shopping Center in Hatfield,
Pennsylvania, that combines a medium temperature
secondary coolant system using glycol and a low
temperature direct expansion cascade system using CO 2
as a refrigerant. Wegman’s has at least two stores that use
CO 2
as a secondary refrigerant. Giant (Ahold US) uses CO 2
for its primary refrigeration and propylene glycol as a
secondary refrigerant in its Arlington, Virginia store.
In Canada, CO 2
transcritical is rapidly becoming an
established commercial refrigeration technology.
Sobey’s has already installed 36 CO 2
transcritical
systems. At the Maple leaf Gardens store, Loblaws used
a CO 2
refrigeration system, which makes use of the
reclaimed energy from the refrigeration system to heat
the underground parking garage. The system enabled
Loblaws to reduce the total amount of refrigerant leaks
by 9.7% in 2011. In the US, Hannaford Bros., Fresh & Easy
Neighborhood Market, and Whole Foods Market are
planning to install CO 2
transcritical systems in the near
future. Delhaize US applied CO 2
secondary systems and
CO 2
cascade systems in 5 stores. Two stores received a
Gold Certification from the GreenChill (EPA) alliance.
There are three main types of CO 2
system that can be
used in commercial refrigeration:
• CO 2
secondary loop system: in these installations
pumps circulate liquid CO 2
throughout the display
cases at the required case temperature. The systems
can be used for both low and medium temperature
applications.
• CO 2
cascade subcritical direct expansion systems: with
this technology, an HFC centralized DX system is used
for MT loads and the LT system has a separate circuit
that discharges its heat into the suction stage of the
MT system. These installations use compressors to
produce the desired saturated suction and reject
heat to the DX high side rack. They are typically used
only in low temperature applications.
• CO 2
booster transcritical system: this model uses R744
(CO 2
) in both the MT and LT systems. In these systems
the same evaporation and compression occur as in
DX operation but instead of condensing superheated
gas into a liquid, the system cools a superheated,
supercritical gas into a cooler supercritical gas.
Moreover, the transcritical system DX cycle directly
feeds the low temperature discharge into the suction
of the medium temperature, helping to improve
efficiency.
CO 2
systems benefit from the fact that the lines required
for CO 2
transport are typically one to two sizes smaller
than traditional DX piping systems, reducing the weight
of installed copper lines by 50% or more and reducing
installation costs. It should also be noted that for hybrid
CO 2
systems there is a general trend towards using lower
global warming potential (GWP) fluids as the second
refrigerant.
NH 3
/CO 2
: Ammonia has already been accepted under
the EPA ’s SNAP Program as an alternative primary
refrigerant in secondary loop commercial applications.
1 "EIA Global (n.d) New Report Highlights Climate Friendly Supermarket
Refrigerant Technologies to Replace HFC “Super Greenhouse Gases,
Environmental Investigation Agency (EIA) Global [ONLINE] Available
at: http://www.eia-global.org/PDF/Supermarket_Report_Release.pdf
[Accessed 14 January 2013]"
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