© Danfoss | Climate Solutions | 2022.03
Operating conditions
The scroll compressor application range is
influenced by several parameters which need to
be monitored for a safe and reliable operation.
These parameters and the main
recommendations for good practice and safety
devices are explained hereunder.
• Refrigerant and lubricants
• Motor supply
• Compressor ambient temperature
• Application envelope
(evaporating
temperature, condensing temperature, return
gas temperature)
General information
Refrigerant and
lubricants
When choosing a refrigerant, different aspects
must be taken into consideration:
• Legislation (now and in the future)
• Safety
• Application envelope in relation to expected
running conditions
• Compressor capacity and efficiency
• Compressor manufacturer recommendations &
guidelines
Additional points could influence the final choice:
• Environmental considerations
• Standardization of refrigerants and lubricants
• Refrigerant cost
• Refrigerant availability
R22
R22 is an HCFC refrigerant and is still a wide
use today. It has a low ODP (Ozone depletion
potential) and therefore it will be phased out in
the future. Check local legislation.
When R22 is applied in refrigeration applications
it can lead to high discharge temperature.
Carefully check all other parameters that can
influence the discharge temperature.
R404A
R507
PVE
R404A is an HFC refrigerant. R404A has zero
ozone depletion potential (ODP = 0). R404A
is especially suitable for low evaporating
temperature applications but it can also be
applied to medium evaporating temperature
applications. R404A is a mixture and has a very
small temperature glide, and therefore must
be charged in its liquid phase, but for most
other aspects this small glide can be neglected.
Because of the small glide, R404A is often called a
near-azeotropic mixture.
R507 is an HFO refrigerant with properties
comparable to R404A. R507 has no ozone
depletion potential (ODP = 0). As with R404A,
R507 is particularly suitable for low evaporating
temperature applications but it can also be
used for medium evaporating temperature
applications. R507 is an azeotropic mixture with
no temperature glide.
Polyvinyl ether (PVE) is an innovative refrigeration
lubricant for HFC refrigerant systems. PVE is as
hygroscopic as existing polyolester lubricants
(POE), but PVE doesn’t chemically react with
water; no acids are formed and compressor
evacuation is easier.
The compressor technology applied in MLZ
compressors in combination with PVE lubricant
provides the best possible result in terms of
reliability and compressor lifetime.
Mineral oil
Mineral oil can be applied in system using HCFC
refrigerant because it has a good miscibility
with HCFC and oil that leave the compressor
with refrigerant may not be trapped in lines or
exchangers. The chlorine contained in HCFCs
improves lubricity in bearings used with mineral
oil. Mineral oil has a very low hygroscopicity but
may chemically react with water and form acids.
POE oil
Polyol Ester Oil (POE) is miscible with HFC's
(while mineral oil is not), but has to be evaluated
regarding lubricate ability in compressors.
POE oil has better thermal stability than
refrigerant mineral oil.
POE is more hygroscopic and also holds moisture
more tightly than mineral oil. It also chemically
react with water leading to acid and alcohol
formation.
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AB243586442698en-000601
Application Guidelines
Single compressors
