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Are natural refrigerants the way of the future?
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tefan Jensen is managing director of Scantec Refrigeration, and he offers his ideas on the future of refrigerants in refrigeration and heat pumps. While his expertise is largely in industrial and commercial refrigeration systems and supermarket chilling, his observations on refrigerants are worth considering as they also apply to some degree any systems using refrigerants, including commercial heat pumps. “Conceptually, there is no difference between a refrigeration system and a heat pump,” he says. “In a heat pump, the focus is on the heat output. The heat is emitted from the condenser, which condenses the refrigerant. “In a refrigeration system, the focus is on refrigerating a space by means of the cold side of the system. The cold side is often referred to as the evaporator. The heat emission from a refrigerating system is mostly rejected to the general environment where it sometimes causes heat islands in built-up areas. “In aquatic centre applications there are opportunities of utilising both the cold and the warm side of the refrigerating system/heat pump. For example, the cold side can be used to cool exercise areas/offices, and the like. It can also be used to extract heat from humid exhaust air. “Aside from warming the pool water, the warm side can be used for showers, therapeutic pools, and for regeneration of dehumidifiers, if these are applied.” The International Institute of Refrigeration says there are approximately three billion refrigerating systems in the world. “In Australia alone there are approximately 56 million,” says Jensen. “It is obvious that even small leakage rates of <1 per cent of the refrigerant inventory per annum add up to very large global emissions of harmful gases.” He adds that if there was no leakage, there would be no need for the Montreal Protocol which was introduced around 1987 to limit CFC refrigerants and foam blowing agents from depleting the ozone layer. Thanks to that protocol, evidence shows that the ozone layer is now recovering.
The evolution of refrigerants
“The successors of CFC refrigerants became HFC or hydrofluorocarbon refrigerants,” he says. Jensen says these are global warming agents, with one of the most commonly used in supermarket refrigeration, R404A, having a global warming potential (GWP) of around 4000 56
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(100-year basis). This means that is has a global warming effect 4000 times greater than CO2. In 2016, the Kigali Amendment was made to the Montreal Protocol. Its purpose was to phase down HFC refrigerants, and most countries including Australia are signatories. The Australian HFC phase-down started in January 2018 and is now in its sixth year. The Australian phase-down only applies to bulk imports of HFCs such as in cylinders, and will not apply to gas imported in pre-charged equipment such as air conditioners and heat pumps. However, issues may arise when pre-charged units need to be recharged. Jensen says the phase-down is in the form of an import quota based on CO2e (CO2equivalent), applying to bulk imports of HFC refrigerants. By 2036, the quota will have reduced to around 15 per cent of what was previously imported in the baseline year. “The replacements for HFC refrigerants are the so-called HFO refrigerants (hydrofluoroolefins) or blends of HFCs and HFOs. These are referred to as fourth generation refrigerants by the synthetic refrigerant industry.” He says that while many of the HFOs are low GWP, many can break down into PFAS or “forever chemicals”. The European Chemicals Association ECHA has recently proposed a total ban on all HFO refrigerants that are classified as PFAS substances. This proposal has passed the first of three votes in the EU-commission with an overwhelming majority of around 80 per cent. If the proposal is accepted, there will be a ban on the use of HFO refrigerants in all new systems in Europe from 2027 onwards.
ABOVE: The phase down of HFCs in Australia
“The strength of their carbonfluorine chains becomes a problem when they enter the environment, as the bonds cannot be broken apart by natural processes.”