1. 6/3/2015Auke-Pieter Colijn1 C3F8 cooling @ NIKHEF Design Compare Does it work?

2. 6/3/2015Auke-Pieter Colijn2 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

3. 6/3/2015Auke-Pieter Colijn3 FRONT VIEW REAR VIEW

4. 6/3/2015Auke-Pieter Colijn4 T sensors Freon “doggy” snoop P sensors My favorite tools

5. 6/3/2015Auke-Pieter Colijn5 R404A H2O condenser Compressor Main evaporator Pressure control Expansion valves Sub-cooler Hot gas bypass T sensor 1) Regulate C3F8 T with R404A evaporator P 2) Expansion valves regulate P [0-3kW@-25C] 3) Explain sub-cooler in a bit

6. 6/3/2015Auke-Pieter Colijn6 Primary cooling: R404A GAS GAS+LIQUID LIQUID A B C D 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 P [bar] Enthalpy [J/g] 1.dH = dQ 2. P = flow*dH

7. 6/3/2015Auke-Pieter Colijn7 C3F8 system for Testbox Pump 10-12 bar P control Sub-cooler Main evaporator= C3F8 condenser Restrictors HEAT LOAD a.k.a. detector R404A C3F8 R404A C3F8 Can adjust C3F8 flow!

8. 6/3/2015Auke-Pieter Colijn8 C3F8 Cooling@CERN A B C E 1.A-B: compression 2.B-C: condensing 3.C-D: sub-cooling w. heat exchanger on outlet 4.D-E: expansion 5.E-A: absorb heat from detector (+ sub-cool inlet) D LIQUID GAS+LIQUIDGAS P [bar] Enthalpy [J/g]

9. 6/3/2015Auke-Pieter Colijn9 C3F8 Cooling@NIKHEF A B C D E 1.A-B: condensing 2.B-C: sub-cooling 3.C-D: pump to 12bar 4.D-E: expansion 5.E-A: absorb heat from detector P [bar] Enthalpy [J/g] What is BAD about point E? LIQUID GAS+LIQUID GAS

10. 6/3/2015Auke-Pieter Colijn10 C3F8 Cooling@NIKHEF Enthalpy [J/g] 1.A-B: condensing 2.B-C: sub-cooling 3.C-D: pump to 12bar 4.D-E: heating 5.E-F: expansion 6.F-A: absorb heat A B DE F C LIQUID GAS+LIQUID GAS P [bar]

11. 6/3/2015Auke-Pieter Colijn11 Run it!

12. 6/3/2015Auke-Pieter Colijn12 Run: Temperature Start-upRunWarm-up 1.I want -10C, I get -10C 2.Need to study fluctuations

13. 6/3/2015Auke-Pieter Colijn13 Run: Pressure Inlet pressure = 11bar Return pressure = 2.8bar = -10 C Start-upRunWarm-up

14. 6/3/2015Auke-Pieter Colijn14 Start-up problems –Lots of leaks –Broken R404A expansion valve –Controller (unwired) –Cooling water stability –No manual: safety/operations

15. 6/3/2015Auke-Pieter Colijn15 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

16. 6/3/2015Auke-Pieter Colijn16 Summary Cooling plant @ NIKHEF 1.Different design 2.Works 3.Make final adjustment