INCORPORATING COLD CHAIN
ASSOCIATIONS and CO2 are less common . Waterbased chillers , though efficient , have not surpassed the dominance of HFC and HFO chillers due to their size and cost . Mobile air-conditioning has faced challenges with refrigerant transitions . R-134a replaced R-12 but raised leakage concerns , leading to the European MAC directive . R-152a was initially considered but rejected due to flammability . R-1234yf is now predominant despite flammability concerns . CO2 and propane were considered but did not gain widespread acceptance .
Heat pumps vary by application . Ammonia and HFO-1234ze ( E ) are competitive in district heating , with CO 2 systems emerging but not yet widespread . HFCs are common in smaller heat pumps , with CO 2 used in water heaters for heating mains water .
Over the past 30 years , efficiency improvements have been significant . In the US , residential air-conditioner efficiency increased by 30 % from 1992 to 2015 . Despite this , many systems still fall short of their efficiency potential , with some cold storage facilities consuming ten times more energy than best practices .
NEXT STEPS
Future progress will depend less on refrigerant choice and more on cleaner energy sources and transitioning processes to electricity . Cleaner electricity is essential for reducing CO 2 emissions , and shifting processes from fossil fuels to electricity is equally crucial . Success in one area without the other will not prevent severe climate impacts . The relationship between grid decarbonisation and electrification is key .
In South Africa , the grid emission factor was 985 gCO2e / kWh in 2021 due to coal reliance . The South African Renewable Initiative ( SARi ) aims to add 19 GW of renewable capacity by 2030 , covering 30 % of the country ’ s electricity needs . However , challenges in energy transmission , storage , and supply reliability remain , and the cost of renewable energy must address these issues .
FUTURE DIRECTIONS FOR ELECTRICITY AND REFRIGERANT MANAGEMENT
As we advance toward a cleaner electricity grid and transition from fossil fuels , electricity buying and selling methods will change significantly . Cleaner electricity , especially during high renewable generation periods , could see production costs approaching zero . However , the unpredictability of these times poses a challenge .
Efficiency remains crucial , even with low electricity costs . Efficient refrigeration systems will reduce grid strain , supporting other uses . Incentive schemes may be necessary to encourage efficient energy use , such as compensating users for consuming electricity during high renewable output periods .
Future electricity pricing models might shift from simple unit rates to more complex structures . A higher standing charge could cover intermittency management costs , while variable rates might range from negative to positive values . Efficiency incentives could involve a ‘ free ’ electricity threshold , with
high charges beyond this point . Such systems would require sophisticated control strategies to balance user benefits with product quality and safety , though complex systems may face trust and comprehension issues .
REGULATIONS AND THE FUTURE OF FLUORINATED REFRIGERANTS
The regulatory landscape for fluorinated refrigerants is evolving , with potential bans or restrictions on these substances . Many fluorinated refrigerants are categorised as perfluorinated alkyl substances ( PFAS ), but not all fall under this definition . For example , R-32 is excluded . Ultra-low GWP substances like R-1234yf might face regulation sooner than moderate GWP substances like R-32 .
The focus of environmental regulations has shifted from ozone depletion to global warming and persistent organic pollutants , leading to unintended consequences . Replacing R-22 with R-404A decreased ozone depletion but increased GWP , prompting a shift to lower-GWP alternatives like R-410A .
BREAKDOWN PRODUCTS AND ENVIRONMENTAL IMPACT
Fluorinated refrigerants decompose into various breakdown products , such as trifluoroacetic acid ( TFA ). While TFA is present at low levels , its persistence in aquatic environments raises concerns . R-23 , a degradation product , has a long atmospheric life and high GWP , necessitating caution in adopting shortlived fluorochemicals .
Alternatives like R-1234yf break down into TFA , while R-1234ze forms calcium fluoride , a less harmful substance . R-1234ze ( E ) might be a viable alternative , though it requires a larger compressor . R-1234ze ( Z ) has potential uses in hightemperature applications but is not widely used as a refrigerant .
If PFAS regulations tighten , fluorinated refrigerants may face increased restrictions . This could lead to a rise in hydrocarbon use , necessitating improved safety standards and practices . Updating safety standards to address new hazards and ensuring rigorous enforcement are crucial to prevent accidents and ensure safe use of flammable refrigerants . CLA
BIO :
Dr Andy Pearson graduated from the University of Strathclyde with a degree in Manufacturing Science and Engineering and joined Star Refrigeration in 1986 , working in their design office , as a site manager , a commissioning engineer and sales manager and then as head of the Contracts Group , He completed his PhD at University of Strathclyde with his thesis on “ use of Carbon Dioxide as a refrigerant ” in 2006 , he became the Group Managing Director of Star Refrigeration Ltd in 2016
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