Technology  Summary   Approach  

Progress  to  Date  

Compact,  Efficient  Air  Condi<oning  with  Ionic  Liquid  Based  Refrigerants  

William  F.  Schneider.  Brandon  L.  Ashfeld,  Joan  F.  Brennecke,    Edward  J.  Maginn,  Mark  J.  McCready,  Patrick  Murphy,  Steven  R.  Schmid,  Mihir  Sen  and  Mark  A.  Stadtherr:  

   University  of  Notre  Dame    James  Raudabaugh,  DomeJc,  Inc  George  Mozurkewich,  Consultant  

Entropy  

Tempe

rature  

1   2  

3  

4  

Pressure  =  100  –  120  atm  

Compact, efficient air conditioning (AC) using CO2 -IL mixtures as the working fluid offers an opportunity for cooling systems with efficiency well beyond that of existing ACs. ILs are non-volatile liquid salts with zero GWP that can be designed with thermodynamic and tribological characteristics to optimize them as co-fluids in a vapor compression (VC) cooling cycle. Using systems and molecular modeling to guide designs, we will conduct experimental synthesis and characterization of previously undiscovered compounds for investigation in full-scale, compact AC systems.

Transcri<cal  CO2  cycle  

Use  ionic  liquid  to  decrease  the  pressure  aWer  the  compressor  for  CO2  based  air-­‐condiJoning  system  

CO2-­‐based  refrigeraJon  systems  require  approximately  100  Jmes  atmospheric  pressure  for  operaJon.    

Co-­‐fluid  

CO2  

Discovery  -­‐  Chemically  complexing  ILs  designed  to  have  tunable  CO2  uptake  

Inven<on  –  Design  and  synthesis  of  CO2–IL  mixtures  specifically  tailored  for  VC  operaJon  

Goal  -­‐  demonstrate  compact,  efficient  AC  with  low  GWP  IL-­‐based  working  fluids  • Design,  synthesize,  and  characterize  mulJple  CO2–IL  mixtures  

• Demonstrate   opJmal   mixture   in   a   compact  AC  to  show  a  30%  improvement  in  efficiency  over   exisJng   compact   ACs   using   HFC-­‐134a/410a  refrigerants  

PE I: Modeling and Simulation

• Defined VC system level model equations appropriate for CO2-IL co-fluid operations.

PE II: Synthesis and Characterization

• First generation IL (Gen 1 IL) isotherm and pressure-enthalpy models are in place.

• Force field models for Gen 1 IL have been developed. • Validating simulation methods for computing bulk viscosity. •  Initiated first principles calculations of new IL candidates.

PE III: Laboratory Demonstration

• Selected 2 ILs for characterization and testing as VC co-fluids. • Accumulated thermodynamic data for selected ILs. •  Initiated measurement of viscoelastic properties for selected ILs. •  Initiated development of synthesis plans for improved, chemically

complexing ILs.

3D mapping of film thickness for IL 1.

Co-­‐fluid  CO2  cycle  

Ideal refrigeration cycle for refrigerant [IL 1]+CO2 .

References  G.   Mozurkewich,   M.L.   Greenfield,   W.F.   Schneider,   D.C.   Zeitlow   and   J.J.   Meyer,  

“Simulated   performance   and   cofluid   dependence   of   a   CO2-­‐cofluid   refrigeraJon  cycle   with   wet   compression,”   Int.   J.   of   Refrigera/on,   Vol.   25,   No.   8,   pp.  1123-­‐1136,  2002.  

B.   E.   Gurkan,   B.   F.   Goodrich,   E.   M.   Mindrup,   L.   E.   Ficke,   M.   Massel,   S.   Seo,   T.   P.  SenWle,  H.  Wu,  M.  F.  Glaser,   J.  K.  Shah,   J.  F.  Brennecke,  E.   J.  Maginn,  and  W.  F.  Schneider,  “Molecular  Design  of  High  Capacity,  Low  Viscosity,  Chemically  Tunable  Ionic  Liquids  for  CO2  Capture,”  J.  Phys.  Chem.  Le7.,  2010,  1,  3494-­‐3499