Transcript ADDRESSING THE CHALLENGES TO HCFC PHASEOUT FOR …

ADDRESSING THE CHALLENGES TO
HCFC PHASEOUT FOR THE
CARIBBEAN
By Alvin C. Daniell BSc MSc
Caribbean Ozone Officers, Regional Workshop
Organized by the United Nations Environment Programme
Regional Office for Latin America and the Caribbean (UNEP/ROLAC)
In collaboration with the Government of the Antigua Barbuda
March 1 to 3, 2011
PHASEOUT Timeline of the Montreal
Protocol
• As at 2010, all HCFC consumption stops to
25% of cap. HCFC-22 and HCFC-142b
consumption stops for new equipment.
• By 2015, all HCFC consumption stops to 10%
of cap, and that reduces to 0.5% by 2020.
• All HCFC consumption stops in 2030.
Preferred Refrigerants
• R-134a and certain blends are now the
preferred option to the chlorinated
compounds.
• One popular blend of R-32 and R-125 now
being substituted for R-22 is R-410A.
• Another option is R-407C, the blend of R-32,
R-125 and R-134a, that has a higher critical
temperature and lower global warming
potential (GWP) than R-410A.
Centrifugal Chillers
• In the large systems that require Centrifugal
Chillers, R-123 was an initial choice for some
manufacturers. However R-134A is now
recognized as a more acceptable option and
most North American manufacturers offer
units with R-134A.
Current Trends
Refrigerant Costs
CASE STUDY
• Alternative A - IMPLICATIONS OF HVAC EQUIPMENT
THROUGH CHANGE FROM R-22 TO R-407C
• The main concern in doing a changeover from R-22 to
R-407C is the reduction in cooling capacity of the
existing equipment. We therefore had to examine the
cooling loads of the two buildings under consideration
and check the expected reduction of cooling capacity
of the equipment. This when compared to the
calculated cooling loads would show whether the
reduction had any impact in maintaining the desired
cooling conditions in the two buildings.
Result – Alternative A
•
The equipment ordered with R22 as refrigerant had the following capacities:
•
Rack Room
•
Substation 296 kW
•
By changing to R407C the TRANE company indicated that a 5% reduction in
capacity could be expected. This resulted in the following capacities:
•
Rack Room
•
Substation 281.2 kW
•
Therefore the equipment with the new refrigerant would have the capacity to
meet the cooling load requirements of the Substation Building but for the Rack
Room Building the capacity of the equipment will be undersized by 4%.
101.37 kW
96.3 kW
CASE STUDY – Alternative B
• IMPLICATIONS OF HVAC EQUIPMENT THROUGH
CHANGE FROM R-22 TO R-410A
• Due to the higher capacity and pressure of R-410A, our
supplier did not recommend it as a retrofit for the
existing R-22 system. They advised that substantial
changes would have to be made to the existing
equipment to handle the higher capacity and
pressures. These changes would include expansion
valves, compressors, condensers and other high-side
components. Also, R-410A requires polyester (POE)
lubricant to ensure complete miscibility between oil
and refrigerant. An evaluation of these costs led us to
the conclusion that this was not a viable alternative.
Advantages of R-410A
• R-410A is an azeotropical mixture of 50 percent R-32
and 50 percent R-125 by mass. One of its greatest
strengths is temperature glide. The temperature
difference between its saturated liquid and saturated
vapour states at any given saturated pressure is
negligible (about 0.50), So it condenses or boils at
almost a constant temperature and behaves as a
single-component fluid.
• Most importantly in these times of heightened
environmental awareness, it has zero ozone-depletion
potential.
Advantages of R-410A (cont.)
• Another benefit of R-410A is efficiency. For new
installations, it has been shown to be 5 to 6 percent
more efficient than R-22.
• It also has a higher capacity and 60 percent higher
operational pressure than R-22, so air conditioning
equipment can be made more compact.
• The availability of more reliable R-410A compressors
• The reduced noise from R-410A compressors because
the shells are made thicker to withstand the higher
pressures
• The lower cost of R-410A vs. the alternative
refrigerants.
Servicing R-410A Systems
• Technicians with R-22 experience will need to become
familiar with working with high and low side pressures
that are much higher when using R-410A. A typical R22 system operating normally with a head pressure of
260 psig at a 120 F condensing temperature and a low
side pressure of 76 psig at a 45 F evaporator
saturation temperature will find the equivalent
pressures in a R-410A system to be much higher. A
normally operating R-410A system with the same
operating temperatures will have a high side pressure
of 418 psig and a low side pressure of 130 psig.
Servicing R-410A Systems
• The metering device used in a 410A system must be about 15
percent smaller in capacity compared to a metering device used in
a R-22 system of the same capacity. It is imperative that only a
metering device designed and properly sized for R-410A be used on
a R-410A system. In fact, no parts designed for R-22 use should be
used on a 410A system.
• Refrigerant lines used for R-410A must be properly sized for R-410A
systems. It is possible to use existing refrigerant lines from an R-22
system in a R-410A system installation if they are of the correct size;
however, they must be cleaned of all debris and oil. The best
practice is to replace the lines with new copper liquid and suction
lines to ensure they are clean and do not have any weak areas that
could be a problem at the higher operating pressures of 410A.
Servicing R-410A Systems
• The higher operating pressures encountered with R-410A
systems require the use of brazing materials rated to
withstand these pressures. Some technicians have used
lower temperature solders when making tubing
connections on R-22 systems. Such should not be the
practice on R-410A systems.
• The hygroscopic nature of the oils used in R-410A systems
cannot be over-emphasized. Moisture can be a significant
problem to the proper operation and life expectancy of any
system operating on the mechanical refrigerant cycle.
Therefore, it is more important than in the past to take
precautions to keep moisture out of a system during
installation and service, to evacuate to 500 microns, and
replace filter-driers when a system has been opened.
Servicing R-410A Systems
• Gauge manifold sets, hoses, recovery cylinders, and the
recovery machine must be rated for the higher
pressures encountered with R-410A. An attempt to use
standard refrigerant service tools on 410A systems is
very dangerous. Recovery cylinders must be rated for
R-410A use.
• Personal safety is always of utmost importance when
working on any job or piece of equipment. Safety
glasses and gloves should be worn no matter what
refrigerant is being used. However, because of the
higher pressures of R-410A, safety is of even greater
significance.
LEGISLATION
• Trinidad and Tobago became signatory to the Montreal Protocol in
August 1989 and has been implementing the obligations under the
Protocol ever since. The National Ozone Unit (NOU) was formed in
1999 within the Environmental Management Authority, and has
been pursuing activities related to saving the ozone layer since that
time.
• In early 2007, the NOU was transferred to the Ministry of Public
Utilities and the Environment, and was responsible for
implementing a programme to completely phase out the import of
the CFCs, into the country. Some of the other activities of the NOU
include public awareness activities, provision of CFC recovery
equipment for air conditioning and refrigeration shops and training
of service technicians in the air conditioning and refrigeration
sector.
TRAINING
• At the University of the West Indies, St. Augustine, Trinidad, the
final year Mechanical Engineering students currently do a onesemester course on Environmental Control. Students from
throughout the Caribbean enrol in this course. The course covers
Climatic Conditions, Comfort Conditions in Buildings, Cooling Load
Calculation, Air Distribution and Life Cycle Analysis.
• It is important for the Engineers graduating in the future to be more
aware of the implications as they will be involved in strategic jobs in
the Caribbean that can influence the relevant Government officials.
• The University of the West Indies also plans to offer Graduate
Research Projects related to HCFC phase-out. A comprehensive
analysis of the use of refrigerants throughout the Caribbean as it
relates to importation, reclamation, and replacement is critical to
ensure that we are keeping pace with the desired timeline of the
Montreal Protocol.
SUMMARY
• Trinidad and Tobago and many countries in the Caribbean, are signatories
to the Montreal Protocol on the HCFC PHASEOUT Timeline. Already most
Air Conditioning companies have opted to utilise equipment operating on
R-410A for domestic and Commercial applications and R-134A for large
commercial and industrial ones.
• The main challenge facing the Air Conditioning companies is to continue
servicing customers who desire to hold on to equipment operating on the
refrigerants being phased out. The other challenge is the tooling and
training to be applied to technicians. Safety is of prime importance
especially with higher pressures associated with R-410A. Future
graduating engineers need to be sensitised to the factors involved so that
they can influence the market direction.
• We all have a responsibility to protect our planet for ourselves and the
future generation. Those of us involved in the Air Conditioning industry
must do our part to ensure that this takes place.