Chillers -
The phase-out of ozone depleting refrigerants in chillers is going well. The use of HCFC-22 in chillers has been phased out in developed countries but use still continues in some Article 5 countries. The primary refrigerants currently used in chillers are HFC-134a, R-410A, and HCFC-123. HC-290, R-717 and R-744 are used as refrigerants, however, to a lesser extent.
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A number of new refrigerants with lower global warming potentials have been proposed for use in chillers. Evaluations by manufacturers and other laboratories are underway, but it is not clear which ones will be selected for commercialization. Tradeoffs are apparent among GWP, energy efficiency, safety, and applied costs.
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Climate effects from chillers are dominated by their energy use. Thus, the ultimate goal in choosing new chiller refrigerant alternatives is to achieve the highest energy efficiency while remaining viable to chiller manufacturers, regulators, and users.
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Now, at the end of 2014, it looks like as if more than one refrigerant will be used in the coming years for new car and light truck air conditioning. HFC-134a will remain largely adopted worldwide, HFC-1234yf will continue its growth in new models at least in the near future, and R-744 is expected to be implemented by German OEMs starting in 2017.
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New refrigerant options have GWPs enabling the GHG credits in US and are below the EU threshold of 150; both can achieve fuel efficiency comparable to the existing HFC-134a systems with appropriate hardware and control development.
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The worldwide spread of the two new refrigerants (HFC-1234yf and R-744) will be governed significantly by additional aspects like safety, costs, regulatory approval, system reliability, heat pump capability (especially for electric driven vehicles) and servicing.
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At the moment, it cannot be foreseen whether or not the old and new refrigerants will remain parallel in the market for a long period of time. It is also unclear if the bus and train sector will follow these trends. The use of hydrocarbons or blends of hydrocarbons has not received support from vehicle manufacturers due to safety concerns.
Sustainable refrigeration -
Refrigeration addresses fundamental human needs. In order to become more sustainable, the industry may consider the enhancement of current practices to: minimize the extraction of natural resources; avoid the emission of man-made substances such as refrigerants and solvents; protect fertile ecosystems from mining, water usage, and landfill of waste; promote education for sustainable production and consumption.
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From the persepective of refrigeration, air conditioning, and heat pumps, sustainability mainly refers to energy efficiency, use of renewable energy, and other options to reduce GHG emissions and the use of natural resources. In aparticular, the responsible choice and management of refrigerants are important sustainability aspects.
Abstract Executive Summary Refrigerants
Current status
Whatever refrigerant is chosen will always have to be a balance between several factors, the availability and cost of the refrigerant (and the associated equipment), the system energy efficiency, the safety and convenience of applicability, environmental issues and many more. The refrigerant options emerging today address the phase-out of ODS, especially HCFC-22, as well as concerns about climate change. The perfect refrigerant does not exist and is unlikely to come into existence. Choices will therefore include existing low GWP refrigerants (e.g. R-717, R-744 or HCs) and the newly applied or developed chemicals. Many new alternatives are proposed, which create a challenge in finding the right refrigerant for each application. One of the important aspects is that refrigerants with a low direct impact on climate change are often flammable to some extent.
What is left to be achieved
The industry will keep searching for the right candidate for each application. In some cases this may be as simple as changing the refrigerant, while in other cases this will require redesign of the system or even a change of system topology. The search is a trade-off between cost, safety, energy efficiency, while limiting the need for redesign. One particular concern is the acceptance of flammability in some form or the other.
The way forward
There is a complex selection process ahead, where the market will need to find out which of the many proposed new and old refrigerants will be used in each application. Part of the complexity is that the market is unlikely to be able to support many different refrigerants for the same application.
This will result in a period in time, likely to last a couple of decades, where the industry will have to work with both the currently established refrigerants as well as new refrigerants addressing ozone depletion and/or climate change concerns. In the long run, the number of candidates is likely to fall, but it is too early to tell which or even how many of the current refrigerant candidates will survive.
Domestic appliances
Current status
Globally, new refrigerator production conversion from the use of ODS was essentially completed by 2008. HC-600a or HFC-134a continue to be the refrigerant options for new production. Initial efforts to assess the use of HFC-1234yf in domestic refrigeration have begun, but it is not being pursued with high priority, as in automotive applications, due to cost implications and flammability.
The heat pump clothe (laundry) dryer (HPCD) using HFC-134a is fastly growing in the EU, with manufacturers from both the EU and Japan. HPCDs using R-407C and HC-290 have also been introduced.
What is left to be achieved
It is projected that, by 2020, about 75% of new refrigerator production will use HC-600a (possibly with a small share applying unsaturated HFC refrigerants) and the rest will use HFC-134a. Alternative low GWP refrigerant solutions are being explored for HPCDs. This includes R-744, HC-600a and low GWP HFCs.
The way forward
A number of improved energy efficiency design options are fully mature, and future improvements of these options are expected to be evolutionary. Extension of these to an all-global domestic market would yield significant benefit, but is generally constrained by the availability of capital funds and related product cost implications.
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