As the industry moves away from ozone-depleting and high global warming potential (GWP) substances, it is important to take a more holistic analysis in the selection and regulation of refrigerants and the systems that use these chemicals, as ASHRAE president Tom Watson writes.
Much progress has been made concerning the use of refrigerants to heat and cool indoor environments.
At a recent conference on this topic hosted by ASHRAE and the National Institute of Standards and Technology (NIST), keynote speaker James Calm shared his thoughts on refrigerant transitions and categorised the transition of refrigerants into four generations.
The first generation spanned from the 1830s to 1930s and could be characterised by “using whatever worked”.
The second generation (1931 to 1990s) focused on safety and durability, which included the introduction of chlorofluorocarbons (CFCs) and hydrochlorofluorocarbon (HCFCs) as well as continued use of ammonia and, to a lesser extent, hydrocarbons.
More recently was the third generation (1990 to 2010s), when industry concern turned to ozone protection and began the phaseout of CFCs and later HCFCs.
Now, the industry has entered the fourth generation of refrigerants with a focus on low GWP options. In his presentation, Calm emphasised the need to address both application requirements and looming environmental concerns together.
Piecemeal approaches will not meet the eventual targets. The industry must be forward-looking and make selections beyond minimum mandates. Otherwise, stakeholders will be forced to face still another generation of refrigerant transitions.
While traveling during 2012 for both my ASHRAE service and my work, I heard a lot of discussion about using low GWP refrigerants in high efficiency HVAC/R systems.
Improving efficiency in air conditioners, heat pumps and refrigeration will remain critical as the energy used and resulting combustion emissions has a more significant impact on climate change than the refrigerants themselves.
So, it is critical to address not only refrigerant selection and leak minimisation, but system efficiency.
Currently, there are several programs and initiatives underway that focus on the technologies, methods and means needed to accommodate the imminent phase-down of high GWP refrigerants.
One such measure is the cooperative Low GWP Alternative Refrigerants Evaluation Program (AREP) by the Air-Conditioning, Heating, and Refrigeration Institute (AHRI).
Launched in March 2011, the program aims to identify and evaluate alternatives to high GWP refrigerants for major product categories, and to provide common sets of quality data.
Products covered include air conditioners, heat pumps, chillers, water heaters, ice makers and refrigeration equipment.
The AREP program seeks to help the industry select the most promising refrigerants, avoid duplicative work, understand technical challenges, and identify the research needed to use these new refrigerants.
The program will not prioritise these alternatives; rather, it will identify potential replacements for high GWP refrigerants and present the performance of these replacements in a consistent, standard manner. There are currently 38 alternatives being evaluated.
The program should be complete in coming months.
Another project in development is the Guide for Sustainable Refrigerated Facilities and Systems by ASHRAE and the United Nations Environment Program.
This resource, slated for release in early 2014, addresses the entire range of facility and equipment design and efficiency alternatives for refrigerated processing, storage, and distribution (the cold chain) in both developed and developing countries.
The guide is also important as parties to the Montreal Protocol face upcoming compliance deadlines. For developing countries, that meant a freeze in HCFC consumption and production by January 1, 2013, followed by a 10 per cent reduction in 2015 and a 97.5 per cent reduction by 2030.
Currently, R22 is the preferred refrigerant for many systems, particularly for small and medium-sized conditioners; this ozone depleting gas is being phased out under the Montreal Protocol.
Meanwhile, ASHRAE is creating a voluntary refrigerant management plan, with initial publication planned in the US. In addition to proper cradle to grave management, the document will provide guidance on suitable refrigerants to be used to meet growing demand.
The goals for this project include tracking and reporting refrigerant use and life cycle, minimising the environmental impact of refrigerant use, and raising public awareness of the environmental issues and the economic impact of refrigerant use.
So what can we as an industry do to reduce refrigerant impact on the environment? We need to focus on our efforts where they will have greatest effect.
We need to match the technology to the need. The contributions of all stakeholders across our industry are needed to identify not just new options but those that will provide maximum benefit.
About the author - Tom Watson is a fellow and life member of ASHRAE, and is the 2012-13 ASHRAE president. He is chief engineer at Daikin McQuay, where he oversees new product development for centrifugal compressor technology.