HFCs the coolest ones? Not quite

Warming


The IPCC predicted that emissions of HFCs will triple from 0.4 billion tons carbon dioxide equivalence in 2002, to 1.2 billion tons in 2015, causing a negative impact on the environment File photoThe use of hydrofluorocarbons in cooling systems may save the ozone layer – but it will harm the climate. The Montreal Protocol, set in action in 1987, forced the phase-out of ozone-depleting gases chlorofluorocarbons (CFCs) and later hydrochlorofluorocarbons (HCFCs). But the hydrofluorocarbons (HFC) that are replacing them could have an equally negative impact on climate change.

Hydrofluorocarbons are used as refrigerants and foam-blowing agents, and emitted as leakage from air conditioning and refrigeration systems. They have a global warming potential similar to that of HCFCs and hundreds to thousands of times greater than carbon dioxide.

Unless action is taken, the Intergovernmental Panel on Climate Change (IPCC) predicted that emissions of HFCs will triple from 0.4 billion tons carbon dioxide equivalence in 2002, to 1.2 billion tons in 2015. The Environmental Investigation Agency (EIA) expects HFC emissions to be considerably higher in light of the accelerated phase-out of HCFCs agreed by the Montreal Protocol in September 2007.

The biggest emitters of HFCs are mobile air conditioning (MAC) systems in cars (66 pc of all HFC emissions according to 2002 data from US EPA and ADEME); followed by commercial refrigeration, and particularly supermarket refrigeration (23 pc); and finally stationary air conditioning systems (six per cent) such as found in retail units and offices.

Cooling cars

In 2006, the European Union’s MAC Directive banned the use of mobile air conditioning refrigerants with a global warming potential (GWP) of over 150 in new model cars by 2011 and in all cars by 2017. Since then, there has been a flurry of activity by manufacturers looking for alternatives.

The two contenders are the chemical HFO-1234yf and carbon dioxide (known as R744) as a refrigerant. 

According to the Alliance for CO2 Solutions, a grouping of organisations that support the use of CO2 technology in car air conditioning, there is an estimated $14.5 billion global market for car air conditioning to fight for.

As the debate rumbles on, car manufacturers are not placing orders. As a result, it is looking increasingly likely that the 2011 deadline for the MAC directive will be delayed.

Without the politics to battle with, the commercial refrigeration industry is making faster progress towards climate-friendly alternatives.

Drink coolers are just the beginning. Much greater emission savings can be achieved by switching supermarket fridges and freezers over to climate-friendly alternatives.

Research from EIA has revealed that supermarkets are the biggest source of HFC emissions in the UK. And refrigerants account for around a quarter of a supermarket’s GHG emissions.

Cool air

The move to climate-friendly alternatives in stationary air conditioning has been slower.

Cost is the major barrier. Most companies are only using HFC-free solutions in new equipment rather than replace existing. But the cost of doing this is still high.

The cost of the natural refrigerants themselves is low, sometimes lower than HFC. But because the technology is newer, the costs tends to be higher, says Daniel Colbourne from the Refrigerants, Naturally! Secretariat. He estimates that a CO2 point-of-sale chiller could cost around twice as much as an HFC equivalent.

Natural refrigerants

Carbon dioxide (R744): Used as a refrigerant before the discovery of CFCs. Global warming potential (GWP) of 1, non-ozone depleting, non-toxic, non-flammable. Carbon dioxide operates at a higher pressure than HFCs, which means it requires new system design and components.

Hydrocarbon (isobutane R600a and propane R290): Negligible GWP, non-ozone depleting, non-toxic, flammable. US and Canada place restrictions on the use this flammable gas. But it is used in over 300 million household refrigerators across Europe, Japan, Russia and China. Unlikely to be appropriate for use in large applications such as supermarket fridges as a result of its flammability.

Ammonia: No GWP and non-ozone depleting. It is a hazardous substance, but used safely around the world in large-scale industrial cooling systems such as food processing and building air conditioning.

Fluorocarbons (F-gases): CFCs and HCFCs - Chloroflourocarbons and hydrochlorofluorocarbons are ozone layer-depleting substances (as well as potent greenhouse gases) regulated by the Montreal Protocol.

HFCs: Hydroflourocarbons are non ozone-depleting and were developed as replacements for CFCs. But they are strong greenhouse gases and are regulated by the Kyoto Protocol. HFC-134a , that accounts for the bulk of HFCs used, has a GWP of 1,430 over a 100-year lifetime.

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