TABLE OF CONTENTS - Everything R744

North American Policies: AHRI Standards 571 (SI) and 570 (I-P)
Addressing natural refrigerants in performance
standards, AHRI, the USA based Air-Conditioning,
Heating, and Refrigeration Institute, has published
CO 2
compressor performance rating standards 16 . They
are in line with the soon to be finalized corresponding
standards in Europe, which are currently being reviewed
in order to accommodate for the increased interest in
transcritical CO 2
refrigeration in the region.
With a view toward harmonizing the rating conditions
of CO 2
standards under development in Europe and
China, AHRI developed Standards 571 (SI) and 570 (I-
P), titled ‘2012 Standards for Performance Rating of
Positive Displacement Carbon Dioxide Refrigerant
Compressors and Compressor Units,' in cooperation with
the Association of European Refrigeration Component
Manufacturers (ASERCOM) and the China Refrigeration
and Air-Conditioning Industry Association (CRAA). The
AHRI standards, which concern CO 2
compressors for
subcritical and transcritical refrigeration applications,
provide, for the first time, a rating method for compressors
and compressor units that use CO 2
as a refrigerant in the
USA.
The new AHRI standards apply to electric motor driven,
single and variable capacity, single and two stage positive
displacement refrigerant compressors and compressor
units operating with carbon dioxide in both subcritical
and transcritical refrigeration applications.
Medium Temperature (e.g. fresh food display cases)
• Suction dew point temperature, -4°F to 32°F (-20°C to
0°C)
• Discharge dew point temperature for subcritical
compression cycle, 32°F to 77°F (0°C to 25°C) or
discharge pressure for transcritical compression
cycle, 1,160 psia to 1,595 psia (80 bar to 110 bar)
• Useful superheat of 18°F (10 K) for all operating
points for subcritical applications, condenser exit
subcooling of 0°F (0 K)
• For transcritical applications, gas cooler exit
temperature of 95°F (35°C)
• Refrigerating Capacity may include increased
refrigeration effect provided by the subcooler per
rating methods of section 5.5 of the standard
Low Temperature (e.g. freezer cases)
• Suction dew point temperature, -58°F to 14°F (-50°C
to -10°C)
• Discharge dew point temperature for subcritical
compression cycle, 32°F to 77°F (0°C to 25°C), or
discharge pressure for transcritical compression
cycle, 1,160 psia to 1,595 psia (80 bar to 110 bar)
• Useful superheat of 18°F (10 K) for all operating
points for subcritical applications, condenser exit
subcooling of 0°F (0 K)
• For transcritical applications, gas cooler exit
temperature of 95°F (35°C)
• Refrigerating Capacity may include increased
refrigeration effect provided by the subcooler per
rating methods of section 5.5 of the standard
compressor behavior and performance on an evenacross-the-board
basis.
55
The standards do not apply to carbon dioxide
compressors used in other applications, such as
heat pumps and air-conditioning, automotive airconditioners,
or household refrigerators and freezers,
etc.
According to the AHRI standards, data should be reported
for the intended use of compressor or compressor unit
applications that meet the following conditions:
The aligned standards establish common guidelines
worldwide and will enable manufacturers to compare
16 AHRI (2012), 2012 Standards for Performance Rating of Positive
Displacement Carbon Dioxide Refrigerant Compressors and Compressor
Units, AHRI Standards 571 (SI) and 570 (I-P). Available from: http://www.
ahrinet.org/ahri+standard+571+_si_2012_+performance+rating+of+p
ositive+displacement+carbon+dioxide+refrigerant+compressors+and+c
ompressor+units.aspx and http://www.ahrinet.org/ahri+standard+570+
_i_p_2012_+performance+rating+of+positive+displacement+carbon+d
ioxide+refrigerant+compressors+and+compressor+units.aspx (Accessed:
January 2013)