Manual for Refrigeration Servicing Technicians - UNEP - Division of ...

3
Refrigerant Management
Recycling of refrigerant
Recovered refrigerant may be reused in the same system from
which it was removed or it may be removed from the site and
processed for use in another system, depending upon the
reason for its removal and its condition, i.e., the level and types
of contaminants it contains. There are many potential hazards in
the recovery of refrigerants, and recovery and reuse need to be
monitored carefully. Potential contaminants in refrigerant are acids,
air, moisture, high boiling residues and other particulate matter.
Even low levels of these contaminants can reduce the working life
of a refrigeration system and it is recommended that recovered
refrigerant should be checked before reuse.
Refrigerant from a unit with a burnt-out hermetic compressor is reusable
providing it has been recovered with a recovery unit incorporating an
oil separator and filters and that it has been checked for acidity. To
check the acid content of any reclaimed oil it is necessary to use
a refrigeration-oil-test-kit. Usually it is only a matter of filling a test
bottle with the oil to be tested and mixing it with the test liquid inside.
If result shows purple: oil is safe. If liquid turns yellow this would
show the oil is acidic - and refrigerant/oil should not be used in
system. Such material should be sent for reclamation or destruction.
Refrigerant recycling
There are in the market several units that recovers, recycles,
evacuates and recharges – all in one fast, continuous operation
through one hook-up; these are called refrigerant recycling
machines. If it is to be returned, the next issue is the condition
of the refrigerant. When the oil is separated from the refrigerant,
the vast majority of the contaminants are contained in it. Most
refrigerant recycling machines utilise filter-driers to remove
any other moisture and acid as well as particles. It is generally
acceptable to return this refrigerant to the system.
CHAPITRE 3
The real problem occurs when there is a burnout in a hermetic
compressor. PAGE A 15burnout
is the result of electrical failure inside the
compressor of the refrigeration system. This can be due to variety
of factors. Typical Contamination single pass of system the refrigerant in this situation can
range from mild to severe. Two recycling standard methods are
used by equipment on the market. The first is referred to as single
pass, and the other is a multiple pass. There is equipment that
provides operation in both methods.
• The single pass recycling machines process refrigerant through
filter-driers and /or distillation. It makes only one trip from the
recycling process through the machine and then into the storage
cylinder. This image shows a typical single pass system.
MANIFOLD
PRE-FILTER
RECOVERY
UNIT
CONDENSER
FILTER
DRIER
SYSTEM
Typical single pass system
AC UNIT
OIL
SEPARATOR
ACCUMULATOR
OIL
DRAIN
PURGE
UNIT
RECOVERY
CYLINDER
FILTER
DRIER
73
COMPRESSOR
OIL
DRAIN
OIL
SEPARATOR
OIL RETURN