Responsible Refrigeration
By Barney Richardson
BARNEY RICHARDSON
Barney Richardson is the director of South African Refrigeration and Air Conditioning Contractors Association ( SARACCA ) and sits on various other boards within the HVAC industry , including the South African Qualifications and Certifications Committee for Gas ( SAQCC ) Gas .
THE PRESENT TREND IN SOUTH AFRICA TO USE
CARBON DIOXIDE IN SUPERMARKETS
The future of refrigeration for food preservation in refrigerators and in supermarkets is dependent on how we adopt and adapt to new technologies for refrigerant use .
There is a present trend in South Africa to use Carbon
Dioxide in supermarkets and larger refrigeration systems . However , many refrigerants still have a high global warming potential ( GWP ) and ODP ( ozone depletion potential ).
The HFC and HFO refrigerant blends have been used for a short time as an interim measure in air conditioning and refrigeration while the transition to natural refrigerants takes place . This is a return to the original refrigeration engineering of 150 years ago when natural chemicals like carbon dioxide , ammonia and sulphur dioxide were all that was available . Ammonia has always been with us and carbon dioxide has made a return . It was in the 1930s that CFC refrigerants like R12 were developed and the 1950s when R22 made its appearance . These two refrigerants served us well until the environmental consequences came to light . The ozone problem was discovered in 1970 which led to the Montreal Protocol on CFC and HCFC on ozone depletion . Later , in 1995 global warming reared its ugly head and the search for alternatives began .
GWP is a measure of how much heat of the gas is trapped in the atmosphere as a greenhouse gas over a period of time . ODP is a number which refers to the amount of ozone depletion caused by a substance such as refrigerant in the stratosphere .
The large cold storage and processing industry will always choose ammonia as the preferred refrigerant because it has a low boiling point at -33 ° C , has zero GWP and has a zero ODP and high latent heat of vaporisation . Ammonia systems circulate less F-gas refrigerant for the same cooling capacity .
www . refrigerationandaircon . co . za RACA Journal I March 2023 13