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C3F8 cooling @ NIKHEF

C3F8 cooling @ NIKHEF. Design Compare Does it work?. Two-stage cooling. Standard cooling C3F8 coolant only Dual-system @ NIKHEF: R404A primary coolant C3F8 secondary coolant Cheap & easy …….. Do not need oil-less compressor. FRONT VIEW. REAR VIEW. snoop. P sensors. T sensors.

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C3F8 cooling @ NIKHEF

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  1. C3F8 cooling @ NIKHEF Design Compare Does it work? Auke-Pieter Colijn

  2. Two-stage cooling • Standard cooling • C3F8 coolant only • Dual-system @ NIKHEF: • R404A primary coolant • C3F8 secondary coolant • Cheap & easy …….. • Do not need oil-less compressor Auke-Pieter Colijn

  3. FRONT VIEW REAR VIEW Auke-Pieter Colijn

  4. snoop P sensors T sensors Freon “doggy” My favorite tools Auke-Pieter Colijn

  5. Pressure control Main evaporator Expansion valves T sensor Hot gas bypass T sensor Sub-cooler Compressor H2O condenser R404A 1) Regulate C3F8 T with R404A evaporator P 2) Expansion valves regulate P [0-3kW@-25C] 3) Explain sub-cooler in a bit Auke-Pieter Colijn

  6. A-B: Compress R404A B-C: Liquefy hot gas in H2O condenser C-D: R404A expansion D-A: Evaporate R404A. Heat is absorbed from C3F8 LIQUID B C P [bar] A D GAS+LIQUID GAS Enthalpy [J/g] • dH = dQ • P = flow*dH Primary cooling: R404A Auke-Pieter Colijn

  7. C3F8 system for Testbox Main evaporator= C3F8 condenser C3F8 10-12 bar P control HEAT LOAD a.k.a. detector R404A C3F8 Sub-cooler Restrictors R404A Pump Can adjust C3F8 flow! Auke-Pieter Colijn

  8. LIQUID D C B P [bar] • A-B: compression • B-C: condensing • C-D: sub-cooling w. heat exchanger on outlet • D-E: expansion • E-A: absorb heat from detector (+ sub-cool inlet) E A GAS+LIQUID GAS C3F8 Cooling@CERN Enthalpy [J/g] Auke-Pieter Colijn

  9. LIQUID • A-B: condensing • B-C: sub-cooling • C-D: pump to 12bar • D-E: expansion • E-A: absorb heat from detector D P [bar] E C A B What is BAD about point E? GAS+LIQUID GAS Enthalpy [J/g] C3F8 Cooling@NIKHEF Auke-Pieter Colijn

  10. LIQUID D E • A-B: condensing • B-C: sub-cooling • C-D: pump to 12bar • D-E: heating • E-F: expansion • F-A: absorb heat F P [bar] A C B GAS+LIQUID GAS Enthalpy [J/g] C3F8 Cooling@NIKHEF Auke-Pieter Colijn

  11. Run it! Auke-Pieter Colijn

  12. Start-up Run Warm-up • I want -10C, I get -10C • Need to study fluctuations Run: Temperature Auke-Pieter Colijn

  13. Start-up Run Warm-up Inlet pressure = 11bar Return pressure = 2.8bar = -10 C Run: Pressure Auke-Pieter Colijn

  14. Start-up problems • Lots of leaks • Broken R404A expansion valve • Controller (unwired) • Cooling water stability • No manual: safety/operations Auke-Pieter Colijn

  15. To do • Adjust controller: limit temperature fluctuations • Adjust pressure: 12 bar C3F8 • Adjust flow: each disk circuit • New pump: need one without leaks • Heater element: avoid sub-cooled cooling Auke-Pieter Colijn

  16. Summary • Cooling plant @ NIKHEF • Different design • Works • Make final adjustment Auke-Pieter Colijn

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