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 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 kW Substation296 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 96.3 kW Substation281.2 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%.

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 R- 22 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 one- semester 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.