Some refrigerant
gasses are known to damage the ozone layer.
However, they can only do this if
they are allowed to escape from the system.
It is estimated that
20% of refrigerant based systems will develop a leak resulting in a complete loss
of refrigerant charge during their operational lifetime. Depending on the type
of refrigerant the risks from this vary from fire and toxicity to global
warming and ozone depletion. There are a number of methods of minimizing or
avoiding these problems. These include reducing the volume of refrigerant in
the equipment, developing benign refrigerants, good practice including servicing,
designing systems to avoid leaks and detection and rectification of leaks.
REDUCTIONS IN REFRIGERANT
CHARGE
If a leak occurs the
amount of damage caused depends on the volume of refrigerant that has escaped.
It follows therefore that if the volume of refrigerant used to charge the
system can be reduced the effects of a total leak will be minimized. This can
be achieved in a number of ways. The first method is to reduce dependence on
refrigeration equipment. This can be achieved using passive cooling techniques.
This may eliminate the need for refrigerants completely or reduce the size of the
system required. The second involves choosing equipment that has a high
efficiency. This means more cooling can be carried out with fewer refrigerants.
Hydronic systems can be used where the chilled water is created in a local plant
room. This is then used in the building rather than use refrigerant pipework
through the building which would increase the number of refrigerant components through
which a leak could occur.
LEAK DETECTION
Refrigerant leak
detection takes two forms, visual and gas analysis. Visual systems require a
fluorescent dye to be added to the refrigerant. If the refrigerant begins to
leak out of the system say through a loose joint then this will be revealed
under an ultra violet light as a glowing patch of dye. In this way the exact
location of the leak can be pin pointed. Unfortunately the leak can only be
detected if the system is inspected regularly. The second type of leak
detection involves drawing a sample of air surrounding the refrigeration
equipment into a gas analyzer. The analyzer will detect and warn of the
presence of refrigerant in the air sample indicating that a leak was occurring.
This system can be set up to continuously monitor a plant room for the signs of
a leak. Pin pointing the leak would require a further inspection of the system
using either a hand held detector or searching for the presence of escaped dyes
as described above.
RECYCLING OF REFRIGERANTS
The production of a
number of refrigerants has been banned under the Montreal Protocol and EU regulations.
However existing stocks can still be used to service older equipment. It
follows therefore that the refrigerant contained in systems about to be
replaced has considerable value to existing users. It is illegal under the
environmental protection act to release substances into the environment which
are known to cause damage. Because of this all refrigerant should be removed
from the system and stored before repair or decommissioning. If the recovered
refrigerant is of good quality it can be re used without further treatment. If
the refrigerant is contaminated with oils, acids, moisture or particles then the
refrigerant must be cleaned by filtration and distillation before being
re-used. Heavily contaminated refrigerants must be reclaimed this requires that
they are taken off site and purified to their original state.
A good network of
refrigerant reclaimers and recyclers is important to manage refrigerants and
deter the growing trade of smuggling illegal refrigerants into the country.
