CO 2 as a potential cooling medium

1. CO2 as a potential cooling medium for detector cooling at CERN

2. Abstract: • Project conception • CO2 overview • Reverse Rankine Cycle • Components • Calculations / dimensioning • Heat transmission • Perspective Project Tutor: Prof. Dr.-Ing. W. Czarnetzki M. Renner, S. Erhardt, S. Feghelm, J. Bürkle

3. Project conception Project definition • Today’s state of the art • Existing applications and look for trends • CO2 as cooling medium • Laboratory and test facility design • Correlations for CERN Project Tutor: Prof. Dr.-Ing. W. Czarnetzki M. Renner, S. Erhardt, S. Feghelm, J. Bürkle

4. Project conception Project structure Project Tutor: Prof. Dr.-Ing. W. Czarnetzki M. Renner, S. Erhardt, S. Feghelm, J. Bürkle

5. Project conception Timetable Project Tutor: Prof. Dr.-Ing. W. Czarnetzki M. Renner, S. Erhardt, S. Feghelm, J. Bürkle

6. CO2 overview • CO2sublimates under ambient pressure direct from solid to steam and reaches a temperature of -78,5°C. • CO2is color- and odorless, good soluble in water and not soluble with mineral oil. • CO2has a critical point at 31,06°C and 73,83 bar. • CO2is non flammable, non explosive, non corrosive and does not corrode sealant and lubricant. • 30vol.% (300'000 ppm) of CO2 in the air are lethal. CO2 overview Project Tutor: Prof. Dr.-Ing. W. Czarnetzki M. Renner, S. Erhardt, S. Feghelm, J. Bürkle

7. Reverse Rankine Cycle Reverse Rankine Cycle Project Tutor: Prof. Dr.-Ing. W. Czarnetzki M. Renner, S. Erhardt, S. Feghelm, J. Bürkle

8. Compressor (Bock) Condenser Evaporator Expansion valve Components of the laboratory CO2 cycle Components Project Tutor: Prof. Dr.-Ing. W. Czarnetzki M. Renner, S. Erhardt, S. Feghelm, J. Bürkle

9. CO2 compressor Technical data: • 2-cylinder, semi-hermetic compressor • Limitation of use: • Operation point: Condensing temperature: 0°C Evaporation temperature: -40°C • Cooling capacity at operation point: 6058 W • Attachment: continuous speed control Components HGX12P/60-4 CO2 Project Tutor: Prof. Dr.-Ing. W. Czarnetzki M. Renner, S. Erhardt, S. Feghelm, J. Bürkle

10. Components • Condenser • Evaporator • Throttle valve • Reservoir All elements will be appointed over one company. Components Project Tutor: Prof. Dr.-Ing. W. Czarnetzki M. Renner, S. Erhardt, S. Feghelm, J. Bürkle

11. CO2 Reverse Rankine Cycle in the T,s-diagram 1-2: Isentropic compaction 2-3: Isobar condensation 3-4: Isenthalpe choke 4-1: Isobar evaporation Calculation / dimensioning Project Tutor: Prof. Dr.-Ing. W. Czarnetzki M. Renner, S. Erhardt, S. Feghelm, J. Bürkle

12. Calculation result • It is a obvious difference to the ideal process expected. • The compressor don’t work isentropic. • The condenser has to provide a minimum heat flow of 9 kW. • The evaporator has to provide a minimum heat flow of 6,5 kW. Calculation / dimensioning Project Tutor: Prof. Dr.-Ing. W. Czarnetzki M. Renner, S. Erhardt, S. Feghelm, J. Bürkle

13. Heat transmission Detector cooling with CO2 cycle • Pilot study • Test state • Liquid CO2 through thin and heated capillary tubes • Measuring of heat transmission characteristics • Identify the formula coherences • Correlate formula with the measured data Project Tutor: Prof. Dr.-Ing. W. Czarnetzki M. Renner, S. Erhardt, S. Feghelm, J. Bürkle

14. Heat transmission Flow Boiling Project Tutor: Prof. Dr.-Ing. W. Czarnetzki M. Renner, S. Erhardt, S. Feghelm, J. Bürkle

15. Heat transmission Correlations • Heat transmission separated into two independent rates: Convective Heat transmission heat transmission in nucleate boiling Project Tutor: Prof. Dr.-Ing. W. Czarnetzki M. Renner, S. Erhardt, S. Feghelm, J. Bürkle

16. Yoon • Horizontal microtubes Critical quality • Constant heat flux below xcr above xcr Project Tutor: Prof. Dr.-Ing. W. Czarnetzki M. Renner, S. Erhardt, S. Feghelm, J. Bürkle

17. Steiner - Horizontal • Horizontal thick-walled tubes • Constant heat flux • Start of nucleate boiling: Project Tutor: Prof. Dr.-Ing. W. Czarnetzki M. Renner, S. Erhardt, S. Feghelm, J. Bürkle

18. Heat transmission Steiner - Horizontal • Convective • Nucleate boiling Project Tutor: Prof. Dr.-Ing. W. Czarnetzki M. Renner, S. Erhardt, S. Feghelm, J. Bürkle

19. Heat transmission Steiner - Vertical • Convective • Nucleate boiling no mass flux no quality Project Tutor: Prof. Dr.-Ing. W. Czarnetzki M. Renner, S. Erhardt, S. Feghelm, J. Bürkle

20. Steffen Grohmann – Horizontal microtubes • Working fluid: Argon • No mass flux and quality dependence in microtubes Strong influence of surface tension in microtubes  Phase seperation occures less likely • αB based on VDI-Wärmeatlas correlations for vertical tubes Project Tutor: Prof. Dr.-Ing. W. Czarnetzki M. Renner, S. Erhardt, S. Feghelm, J. Bürkle

21. Options for future work • Ordering the components (condenser, evaporator). • Setup and launch of the cooling machine in the laboratory. • Tests regarding the heat transmission and conventional cycle. • Calculation of the cycle based on the measured data. • Optimization of the cooling machine. Perspective Project Tutor: Prof. Dr.-Ing. W. Czarnetzki M. Renner, S. Erhardt, S. Feghelm, J. Bürkle

22. Future collaboration with CERN Experiments on heat transmission: • with several tubes types • in a evaporation temperature range from -25°C to -50°C • in a pressure range from 7bar to 40bar Correlation of the measurements Perspective Project Tutor: Prof. Dr.-Ing. W. Czarnetzki M. Renner, S. Erhardt, S. Feghelm, J. Bürkle