Cold Link Africa July/August 2019 - Page 34

FEATURE INCORPORATING COLD CHAIN Future legislation on HCs – who is responsible? By John Ackermann As hydrocarbons such as propane and isobutane become more common in local applications, there is a concern about the regulations. Hydrocarbon systems have high energy performance and require much less charge than HFCs for similar cooling capacity.For safety reasons, the refrigerant charge per circuit is (currently) limited to 150g to avoid possible “explosions” in the event of all the charge leaking into the surrounding environment and the 34 concentration level exceeding the safe limit. Although hydrocarbon refrigerants offer many environmental advantages, such systems require special skills for the servicing, maintenance and repair. Hydrocarbon systems require specific design considerations and the selection of components that do not pose the risk of explosions. Having the refrigerant charge limited to 150g, the required safety compliance falls within that for household appliances and outside that of SANS 10147. Because of its low environmental impact and high performance levels, there was an international call to increase the maximum HC charge to 500g per circuit as this will extend the benefits to larger split air conditioners, packaged commercial refrigeration units and equipment for transport refrigeration. (This regulation regarding the proposed increase to 500g was passed in April after a recount of initially unfavourable votes.) A higher charge will most likely result in more stringent compliance with safety standards similar to all other refrigerants. With South Africa being solely reliant on imports of all the available synthetic refrigerants, a swing towards natural refrigerants (hydrocarbons, ammonia, CO 2 ) offers a sustainable long-term 1 M any bottle coolers seen in shops, stores and restaurants in South Africa are charged with propane (R290) while many domestic fridges are charged with isobutane (R600a). Hydrocarbons (HCs) have zero ozone depleting potential (ODP) and a very low global warming potential (GWP) i.e. less than 4 GWP. COLD LINK AFRICA • July/August 2019