Alternative low-GWP refrigerants for transport refrigeration
140 papers were presented during the successful 12th IIR Gustav Lorentzen conference on Natural refrigerants. CO2 was the most addressed refrigerant (74 papers), followed by hydrocarbons (34), ammonia (21) and water (4). We present below the summary of a paper along with the direct link where the paper can be downloaded in Fridoc database.
C. Poolman et al* presented the flammability risks and benefits associated with the use of alternative low-GWP refrigerants in refrigerated transport. They focused on refrigerated containers and considered five refrigerants (R290, R744, R32, R1234yf, R1234ze(E)) with R134a as a baseline. They conclude that:
While R290 (propane) is an attractive refrigerant from an energy efficiency standpoint, a design using propane has not been identified for container refrigeration equipment that is able to adequately mitigate the flammability risks and comply with today’s and – to date – future standards.
Regarding mildly flammable R32, R1234yf and ze(Z), a double circuit/double compressor design allows charge reduction but charge/circuit is still too high and the lower flammability limit (LFL) can be reached, leading to explosion risks.
For all alternative refrigerants, the indirect cycle is not able to adequately mitigate the safety risks outside the box.
Given the safety risk and operational and service complexity associated with the use of either mildly flammable or flammable refrigerants in transport refrigeration, R744 (CO2) emerges as the best alternative among the options analysed.* Poolman C, et al. (2016). Low GWP refrigerants in transport refrigeration: risk and benefit assessment of flammable and mildly flammable alternatives.. Paper presented at the 12th IIR Gustav Lorentzen Conference on Natural Refrigerants, Edinburgh, United Kingdom.