POTENTIAL OF CARBON DIOXIDE COMPRESSOR TECHNOLOGY FOR REFRIGERATION APPLIANCES

1. POTENTIAL OF CARBON DIOXIDE COMPRESSOR TECHNOLOGY FOR REFRIGERATION APPLIANCES

2. Outline • New Applications for an Old Refrigerant • Making CO2 Refrigeration Technology Feasible • Performance Assessment and Perspectives • Preliminary Results from Appliances Tests • Closure

3. New Applications for an Old Refrigerant Usage in the Past CO2 Refrigeration advertisement in a business magazine in 1921: “1 to 150 tons in single units” “The ideal equipment for Refrigeration purposes” “Carbonic Safety System” Source: South Central Library System’s website

4. New Applications for an Old Refrigerant CO2 Replacement - CFCs Era Begins CFC granted patent by Thomas Midgley in 1931: “...a process of heat transfer in which these desirable properties, such as non-flammability and non-toxicity, are obtained in combination with the desired boiling point.” Source: United States Patent Trade Office

5. New Applications for an Old Refrigerant CO2 Revival • Reasons: • International regulations on HFCs • Lack of long term solutions for refrigerant fluids • Environmental consciousness • “Ecological appeal” • Market demand • ApplicationsEnvisioned: • Automobile Air-Conditioning • Heat Pump Water Supply Systems • Light Commercial Refrigeration (Beverage Cooling, Ice Cream Freezing, ... )

6. Making CO2 Refrigeration Technology Feasible Refrigeration Means with Practical Use • Vapor Compression • Vapor Absorption • Air-Cycle • Solid State (Thermo-Electric, ...) • High Efficiency • Low Cost • Better Cost-to-Benefit Ratio • Simple Mechanical Embodiments ”...the refrigerating effect is produced by making a volatile fluid boil at a suitably low temperature...”

7. Making CO2 Refrigeration Technology Feasible Vapor Compression Systems

8. Making CO2 Refrigeration Technology Feasible Refrigeration Cycle Inefficiency Typical conditions for MBP Application

9. Direct Effect GWP - Refrigerant Global Warming Potential [kgCO2/kg] L - Annual Leakage Rate [kg/year] n - Life time [years] m - Refrigerant charge [kg]  - Recycling factor [%] • Indirect Effect E - Annual energy consumption [kWh/year]  - CO2 emissions on energy generation [kgCO2/kWh] Making CO2 Refrigeration Technology Feasible TEWI Methodology

10. 32oC Ambient Temperature 65% Relative Humidity Making CO2 Refrigeration Technology Feasible Overcoming Inefficiency of the CO2 Refrigeration Cycle

11. Performance Assessment and Perspectives Phase I: CO2-Oriented Compressor Design

12. Performance Assessment and Perspectives Phase II: CO2-Optimized Compressor Design

13. Performance Assessment and Perspectives Compressor Data - Baseline and Benchmark

14. 32oC Ambient Temperature 65% Relative Humidity Preliminary Results from Appliance Tests Beverage Cooling - 405 Cans Vending Machine

15. Closure Concluding Remarks • All the comments stated below take into account HFC technology currently in the field, without considering any improvement on it; • Replacing current HFC refrigerant fluids by CO2 is meaningful only if the overall energy consumption is at least at the same level of the respective baseline; • Theoretical CO2 refrigeration cycles point to efficiencies lower than their respective HFC cycles; the higher the ambient temperature the higher the penalty in efficiency is; • In real applications, optimized CO2 compressors can deliver better compression and volumetric efficiencies than current HFC compressors; • Superior compression and volumetric efficiencies can make the CO2 application feasible, overcoming the intrinsically low cycle efficiency; • Preliminary results from an appliance testing employing optimized CO2 compressors have pointed to competitive performance in terms of energy consumption;

16. QUESTIONS ? Contact Information: Ricardo Maciel EMBRACO - Empresa Brasileira de Compressores SA Rui Barbosa 1020 - Costa e Silva Joinville - SC - Brazil Phone: +55 47 441.2762 Fax: +55 47 441.2650 email: ricardo_a_maciel@embraco.com.br