Practical Considerations Shifting from HCFCs to Low GWP Refrigerants in HVAC&R Equipment
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Practical Considerations Shifting from HCFCs to Low GWP Refrigerants in HVAC&R Equipment
- 1. Practical Considerations: Shifting from HCFCs to Low GWP Refrigerants in HVAC&R Equipment Ozone2 Climate Technology Road Show, Male, Maldives William F. McQuade May 8-9, 2011
- 3. No Ozone Depleting Potential (ODP)
- 4. Lowest Global Warming Potential (GWP) Practical
- 5. Can be safely applied
- 8. How Can We Relate Performance to Low GWP?: 3 Safety Considerations Indirect Effects Total Equivalent Warming Impact (TEWI) Direct Effects Cost Considerations
- 11. Equipment life
- 12. Recovery / End of Life
- 13. 95% of global HFC use is currently between 700 and 4000 GWP
- 14. TEAP proposed to classify GWPs by considering “Use Patterns”
- 15. Application
- 16. Charge size
- 17. Leak rateLow and High GWP are relative terms, applications need to be treated differently 4
- 18. Safety Considerations: When can Flammable Refrigerants Be Used? Commercial air conditioning and refrigeration (AC&R) safety codes will need to be modified to permit the safe and affordable use of flammable natural and synthetic refrigerants. This will take time require cooperation between governments, manufacturers and end-users. Experience in the industrial refrigeration sector as well as early adoption in northern European commercial AC &R sectors provides experience for the future. Safe use in developing countries will require a significant amount of training and education throughout the supply and value chain. Infrastructure will need to be created to ensure safety codes and procedures are followed. Until this happens, HFCs and non-flammable HFO blends will need to remain available. Johnson Controls 5
- 20. Oslo, Gardamoen, and Copenhagen International Airports are cooled with NH3
- 21. District heating systems are being installed in Norway with ammonia heat pumps
- 22. Aarhus University Hospital, Skejby in Denmark is cooled and heated by HC chillers and heat pumps.
- 23. Hotel Scandinavia and the connected Aarhus Congress Centre in Aarhus installed NH3 chillers in 1996.
- 24. McDonald’s in Denmark has installed cascade system using HC and CO2 in their restaurants.Johnson Controls 6
- 26. C02 cascaded systems for supermarket refrigerators/freezers
- 27. Propane and isobutane in domestic refrigerators and appliances
- 28. Hydrocarbons in small packaged air-cooled equipment Energy efficiency of resulting systems must remain at HFC levels or better. System cost and application cost can be a barrier to adoption. 7
- 29. When do HFOs and HFCs Refrigerants Make Sense? Because of the requirements of safety, efficiency, and cost, synthetic refrigerants must remain an option in many regions and applications: HFCs and Blends of HFOs and HFCs can provide highly efficient non- flammable solutions for developing regions. Large commercial air-conditioning systems with significant charge amounts Large refrigeration applications in densely populated areas Equipment Size and application will dictate types used: Most economical solution when higher GWPs can be tolerated 8
- 31. Cost of an increases in heat exchange surface, compressor modifications, structural changes needed to meet or exceed capacity or efficiency requirements
- 32. The cost of any safety features or controls to ensure safe operation of the machine
- 33. The installed cost of any safety features or alarms that ensure safe application to the built environment
- 34. Maintenance and service cost over the life of the equipmentJohnson Controls 9
- 35. How does the availability of refrigerant options affect short term decision making? Synthetic Refrigerants are used in many other applications than just stationary HVAC&R equipment. Often the justification for refrigerant manufacturers to bring a product to market depends on quantities well beyond our demand level. While the various refrigerant companies have been actively researching new alternatives, very few, if any are available now in production quantities. Industries such as mobile AC and the production insulating foams will dictate the timing and composition of synthetic refrigerants that enter the marketplace in the future. Johnson Controls 10
- 37. As we move toward natural refrigerants and flammable synthetic options, training, education, and safety codes will be essential for universal adoption.
- 38. Synthetic refrigerants serve an important role where efficiency and safety are a primary concern.
- 39. Cost and availability will pace the adoption of Low GWP alternatives. Johnson Controls 11
- 40. 12 Questions?
Editor's Notes
- Our industry chose CFCs, HCFCs, and then HFCs in the past for commercial applications because they were non-flammable, non-toxic, highly efficient, affordable and available refrigerants. With the necessary elimination of ODP and now the focus on global warming, our available refrigerant options have reduced significantly. The next generation of equipment will require designers to compromise on working fluid characteristics and choose the best refrigerant on a per application basis.As a manufacturer, the following dimensions must be considered when choosing a refrigerant:Performance: By performance I mean that the refrigerant must be capable of achieving the necessary capacity and efficiency in an economical foot print. No Ozone Depleting PotentialLowest GWP Practical: It is obvious that we want to choose the lowest GWP possible, but the acceptable level will depend on may factors for different applications.Safety: Many of the likely candidates, both natural and synthetic, have some level flammability, and in some cases even, toxicity. Equipment and installations must be engineered to address these risks in a practical and affordable manner. Training and Education of all stakeholders in the value and chain will be a must.The last two characteristics, Affordability and Availability are seldom discussed in academic studies or in the trade media but are vital to adoption in the marketplace. The majority of customers have a first cost mentality and will choose the least expensive option that meets minimum energy efficiency and regulatory standards. The more expensive the option, the least likely it will achieve broad usage. Along the same lines, refrigerants must be plentiful in both production and service quantities. This can be a significant barrier for proprietary synthetic refrigerants and blends if it is not used my multiple product sectors.
- THIS SLIDE HAS ANIMATIONPerformance in the terms of energy efficiency cannot be considered separately from GWPAs has been discussed many times in the past days, a substantial reduction the total CO2 equivalent emissions from our equipment requires minimization of both direct and indirect effects. Low GWP cannot come at the cost of efficiency. In addition, containment must remain a focus, regardless of refrigerant choice or GWP, as charge loss has a significant affect on equipment operating performance.CLICK TO ADVANCE SLIDE (the Safety and Cost Considerations will automatically fade in)Many have rightfully called for the selection of alternatives using “Total Equivalent Warming Impact” or TEWI as a measure. We agree this is the proper measure. However, from a practical standpoint, the optimum environmental solution for a given application will require a holistic approach. Trade-offs between the TEWI, safety concerns, and applied equipment cost will be needed made to ensure responsible adoption in the marketplace. It is likely that we will end up with different levels of acceptable GWP depending on application.
- A question often asked is “how low is low GWP?” The truth is that it will likely be a moving target. If you consider that the GWP of R-12 was 8100, R-134a at about 1400 is low. The MAC directive in Europe recently set an upper limit for GWP of150 for future automotive systems. Some have tried to generalize GWP levels into categories of low medium and high (TEAP Report 2010), however, we feel the answer is “it depends”.Although GWP should always be minimized, the maximum acceptable GWP limit should depend on various characteristics of the equipment and how it can be safely applied or used. For example, statistics show that automotive A/C systems have relatively high leak-rates (upto 15% per year) and the useful life of a car is around 8 years (according to Consumer Reports). In this instance, the likelihood that most of the refrigerant charge will end up in the atmosphere is very high and a MAC directive limit of GWP =150 makes allot of sense. Lets look at large water cooled chiller as the other extreme. The average leak rates for a well maintained machine in developed countries are less than 2% per year and the average life of this type of equipment is between 25 and 35 years. Additionally, in these developed nations, the average end-of-life refrigerant recovery rate is in the 80% range. In this scenario, the likelihood of the majority of the refrigerant charge being recovered is very high. Therefore a higher level of GWP could be tolerated if it gained you significant improvements in energy efficiency or a margin of safety, say GWP=600. The location of the market must also be considered. In developing countries where maintenance practices result in higher leak rates or where infrastructure limitations reduce the end of life recovery rates, acceptable GWP levels would need to be revised downward.Many of the lowest GWP refrigerants available have some level of flammability or toxicity. For small charge applications, like refrigerators, or equipment that is located outside the building, this can be affordably addressed. For large charge applications or units that are located inside a building or a heavily populated area, these refrigerants may not be a practical option. The choice of a higher GWP HFC or a blend of HFC and HFO will need to be used.
- Our industry chose CFCs, HCFCs, and then HFCs in the past for commercial applications because they were non-flammable, non-toxic, highly efficient, and affordable refrigerants. As we now realize the importance of eliminating ODP and minimizing GWP, our choices are not as easy. Many of the best low GWP natural and synthetic options have some level of flammability and, in the case of ammonia, toxicity. To use these refrigerants safely in occupied spaces will require many of the relevant equipment safety codes and procedures, like ASHRAE Standard 15 in the US, to be revised for their use. As many stakeholders are involved in developing these types of codes, this will be a lengthy process. Inevitably, the resulting requirements will add additional installed cost where flammability, toxicity, or high pressure systems are applied.In the industrial refrigeration sector, there exists a long history of safe use ammonia, hydrocarbons and CO2 in process applications. In recent years, there are regions such as Northern Europe (Denmark, Germany, Austria, and the Netherlands) and market sectors where this is already being in done in commercial refrigeration and air-conditioning . They are matching systems that have been designed specifically for safe operation with HC or ammonia applications that are located remotely or not in confined spaces (for instance air-cooled roof top packaged equipment.) This same experience will be used to safely apply flammable synthetic refrigerants.It must be remembered, however that what makes these successes possible is a highly trained and educated technicians, and end users and the strict enforcement of safety codes and regulations throughout the supply and value chain. It cannot be expected that the same success could be achieved in other regions or the developing world with out significant investments of resources to train and educate as well as enforce safe practices. This is an opportunity for UNEP to play in important role. Until this investment happens, HFCs and the non-flammable HFO blends will need to remain available and in use.
- Natural Refrigerants remain excellent solutions in the right applications. Wide spread use in the refrigeration industry has paved the way. For instance:Industrial Refrigeration: Ammonia Used in 95% of ApplicationsC02 can be very efficient at low temperature refrigeration duty (Currently used in some Supermarkets in Europe)Hydrocarbons have very high efficiency and low/no GWP. Air-Cooled HC chillers are beginning to enter the marketAll refrigerants have their limitations, however. At some mid and high temperature air conditioning conditions, the energy efficiency of resulting CO2 systems are typically less than those using HFCs. As mentioned before, in heavily populated areas or in occupied buildings the cost of safety precautions for some natural refrigerants, such as Ammonia and Hydrocarbons can be a barrier to adoption. It should be remembered when considering these choices :Remote locations or secondary loops are many times required for safety mitigationOperating pressures, safety devices, or material compatibility can result in higher installed equipment costs. Natural Refrigerants should never be “retrofit” for use into systems originally designed for HCFCs or HFCs without involvement and approval from the original equipment manufacturer.
- When are HFOs and HFCs going tomake sense if the future? Equipment size and application will dictate types used:Large Commercial Air-Conditioning Applications will likely remain HFC or possibly HFC/HFO blends due to safety concernsMost Unitary and Light Commercial Roof-top Equipment will be able to tolerate Low GWP 2L refrigerants (Such as 1234yf)due to their location outside of the buildingRefrigeration Applications in Populated Areas/Buildings will likely remain HFOs, HFC/HFO blends or even HFCs to minimize safety concerns.Appliance and Specialty Healthcare Device Applications where flammability cannot be tolerated will likely remain HFC.HFCs are typically the safest, most efficient and economical solution and that’s why they are used today. They will however have relatively high GWP. Most HFOs alone have very low GWP and good efficiency but have some flammability and the costs are currently not known. Blends of HFCs and HFOs provide a safe and efficient compromise with a much lower GWP than HFCs by themselves. Some reasons to use them are:Technology and material compatibility already existViable solution for conversion/retrofit of existing equipment
- All refrigerants have different performance characteristics and will therefore require modifications to existing equipment designs for use. Therefore, the equipment manufacturers must consider the resulting cost considerations beyond the value of the refrigerant alone.Refrigerant options that are lower in cycle efficiency require increased heat exchanger surface or enhance technology like Variable Speed Drives at part loads to close the performance gap.Those options that have flammability or toxicity will require significant equipment design changes in the pressure vessels materials, wiring, and safety control and monitoring systems.Options that have flammability or toxicity may need modifications to the building itself to ensure safe use. This is much less burden for new construction than a retrofit scenario.An lastly, the cost of service quantities of the refrigerant as well as those of any changes in transportation method, charging equipment or disposal practices cannot be ignored.Although all of our customers support efforts to reduce high GWP gas emissions, the reality is that the majority of them purchase the least expensive machine that meets required (or enforced) energy efficiency standards and environmental regulation. In the absence of regulatory mandates, affordability will drive adoption.
- In the case of low GWPsynthetic refrigerants, we are much earlier in the development timeline than was the case for CFC alternatives when the Montreal Protocol was signed. Availabilty, for development testing is very limited at this time.Synthetic refrigerants are used in many other applications that just stationary equipment. Often the justification for developing a production plant depends on quantities much greater than the stationary HVAC&R market. Other sectors like mobile AC and the production of insulating foams with dictate the timing and types of synthetic refrigerants that enter the market. While various refrigerant manufacturers are actively researching new alternatives, very few, if any, are available now in production quantities.
- Manufactures of HVAC& R equipment must consider many factors when selecting future refrigerants beyond GWP. As our industry embraces natural refrigerants and flammable synthetic options, training, education, and safety codes and procedures will be essential for universal adoption. For certain applications where safety and or high efficiency are of paramount concern, HFCs and HFC/HFO blends will need to remain an option.Lastly, costs at all levels of the value chain and the short term availability of alternatives must all factor into the regulatory discussion about GWP limitations and reduction timelines.Thank you for your attention.