A Non-Flammable, Reduced GWP, HFC-134a Replacement in Centrifugal Chillers: DR-11

Air conditioning in large buildings is often provided by centrifugal chillers using HFC-134a. Efforts to mitigate climate change are motivating the identification of HFC replacements with low GWPs. HFO-1234yf, with a GWP100=4, has been found promising as an HFC-134a replacement in centrifugal chillers (Kontomaris et al., 2010). However, HFO-1234yf is marginally (ASHRAE 2L) flammable. A new non-flammable developmental refrigerant, DR-11, with a GWP100<600, was evaluated as an HFC-134a replacement in centrifugal chillers. Given the minimal refrigerant emissions from chillers and its higher predicted energy efficiency, DR-11 could enable solutions with comparable or even lower total global warming impact than HFO-1234yf despite its higher GWP. Moreover, the higher predicted DR-11 refrigeration capacity and the lack of DR-11 flammability may allow more cost-effective solutions than HFO-1234yf that can be adopted without any delays for safety code revisions. Flexible climate change regulations would allow acceptance of refrigerants with optimum performance, flammability and GWP trade-offs.