Document gDk9114BZYZQxRbbj5o4qpgJq

Pilot Cooling Supply for the CBM Silicon Tracking System Detector Electronics Ilya Elizarov for the CBM Collaboration GSI Helmholtzzentrum fur Schwerionenforschung GmbH Due to the considerable power dissipation (50 kW), the CBM Silicon Tracking System (STS) detector requires extensive cooling. From 2022, the last EU legislation imposes global warming potential (GWP) limit of 150 on multipack refrigeration with a capacity of 40 kW, except for cascade systems. The refrigeration industry is shifting towards usage oflow GWP refrigerants,one of whichisCO:itself. CO, has disadvantage of high expansion coefficient, high operation pressure, toxicity, and requires qualified personell for the maintenance. TM TM 3M NOVEC 649 or perfluoro(2-methyl-3-pentanone) has advantage of low operating pressure, non-toxicity, low GWP, and being easyto use. TM The STS cooling supplymakes use ofCO.and NOVEC 649 simultaneouslytotake advantage ofthe both. Pilot Cooling Plant: Trial-run A trial-run was performed to test the performance of the pilot cooling plant: electric power of the heaters was increased in steps to check if the plant can keep up the temperature set-point -40 C. 14 - 12 -10 -8 g -6 ooling Supply Pilot cooling plant Balancing heater Cooling test rig i ll lJ PT Experimentall set-up Experimental' set-up TM The pilot cooling is a booster-type CO: refrigeration system that extracts heat from the secondary side coolant through a heat exchanger (evaporator). Outlet heater extends temperature range ofthe pilot cooling plant. Balancing heater covers the mismatch between the minimum cooling demand of the plant and experimental set-ups. With the cooling test rig, various experimental set-ups and the drainage system can be connected to the cooling supply. 2 0 O 2 4 6 8 10 12 14 16 18 Time 10', s TM TM -- NOVEC temperature set point -- NOVEC temperature measured Power of the heaters Steady-state operation is only possible with delivering minimum 1.8 kW of electric power from the balancing heater. The set-point cannot be maintained after 13.5 kW of electric power was reached - nominal capacity was achieved in the previous step. Cooling Test Rig Supports connecting the liquid cooling system of various experimental set-ups through a standard flange connection DN25. Supports connectingthe thermal demonstrator. Supports connecting the STS detector for testing without a beam. Monitors flow parameters: - flow rate; - inlet and outlet temperature; - inlet and outlet pressure. Supports connecting the drainage system. aligagling Plant: Specs The pilot cooling plant 100 \ C 47.3- 12. ai 31.8 3.5 26.7- 67 3 9 /57 9.5- 6 75 -41.7 192 -30 446 550 Enthalpy, kJ/kg P - H diagram of the refrigeration cycle The cooling test rig Drainage System TM The drainage system allows for draining and refilling experimental set-ups with NOVEC 649 without losing the liquid. Refrigerant recovery system Nominal cooling capacity, kW Minimal cooling demand (partial load), kW Primary side refrigerant Secondary side coolant Secondary side outlet temperature', C Refrigeration cycle coefficient of performance (COP) Secondary side flow rate', kg/s Secondary side pressure difference', bar Balancing heater power, kW Outlet heater power, kW 15 6.4 CO: 3MTMNOVECT6M49 -40 ... 10 2.05 0.6 ... 1.4 0.5 ... 2.5 0... 11 0... 24 1) Temperature range from the refrigeration cycle -40 ... -30 C. With the outlet heater -30 ... 10 C. 2) Tested with a bypass line. FAIR Draining: liquid stage Draining: vapor stage O Liquid Refilling Air 3 bar (g) Coolant storage Ilya Elizarov