Fluoroketone C2F5C(O)CF(CF3)2 as a Heat Transfer Fluid for Passive and Pumped 2-Phase Applications

C<sub>2</sub>F<sub>5</sub>C(O)CF(CF<sub>3</sub>)<sub>2</sub>, a new Fluoroketone (FK) working fluid with an atmospheric boiling point of 49degC and Global Warming Potential (GWP) ~1, is proposed as an alternative to Perfluorocarbons (PFCs) and hydrofluorocarbons (HFCs) for passive and pumped 2-phase systems. Its thermophysical properties are very similar to those of the PFC C<sub>6</sub>F<sub>14</sub>C<sub>2</sub>F<sub>5</sub>C(O)CF(CF<sub>3</sub>)<sub>2</sub> exhibits low acute toxicity and bears a recommended 8-hour exposure guideline of 150 ppmv. Pool boiling experiments conducted with a porous metallic boiling enhancement at P<sub>atm</sub> showed h>8 W/cm<sup>2</sup>-K at >30 W/cm<sup>2</sup>. Metal corrosion and elastomer compatibility testing show the material to be very inert. 120 hour thermal stability tests conducted with C<sub>2</sub>F<sub>5</sub>C(O)CF(CF<sub>3</sub>)<sub>2</sub> at 230degC in sealed glass ampules with copper and aluminum coupons showed purity changes -0.02%. It will hydrolyze in the presence of a separate water phase and the implications of this incompatibility for water-cooled systems require further investigation.

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