Document pE3YjaLjJVLMEr4LQmmwpyRd

Cooling Supply for the STS Detector: Lessons Learned for the Future Engineering Design Report Elizarov Ilya CBM department GSI Helmholtzzentrum fr Schwerionenforschung GmbH 06.07.2023 Agenda 1. The final vision on the cooling supply for STS detector - power dissipation and heat gains - installation layout - specs for the final cooling plant 2. The pilot cooling supply system - introduction to the set-up - trial-run results TM TM 3. Details on 3M NOVEC 649 usage as a coolant - is there a problem with acidity? - dealing with precipitation due to solubility falling w/ temperature - NOVECTpMroduction discontinuation Elizarov Ilya | 06.07.2023 | 2 The final vision on cooling supply for STS detector Elizarov Ilya | 06.07.2023 | 3 STS Detector Overview Electronic boards are the main contributor to the power dissipation Silicon sensors require a specific temperature to operate, which is related to nominal outlet temperature of the cooling plant: ca. -20 oC The casing (thermal enclosure) acts as an additional source of heat gains Elizarov Ilya | 06.07.2023 | Casing (fragment) Silicon sensors Front end boards (FEBs) Read-out boards (ROBs) and Power boards (PoBS) 4 Electronic Boards Power Dissipation FEBs ROBs PoBs FEB 8 ASICS + 4 LDO 12,20 W Elizarov Ilya | 06.07.2023 | Silicon sensors C-Frame, unit 4 SUMIDA cable (enclosed in metal duct) Electronic boards power dissipation per type ROB 3 FPGA FPoB per FEB 16 FEAST RPoB per ROB 4,89 W 5,75 W 2,04 W SUMIDA cable for one FEB, L=1,6 m 1,28 W 5 Power Flow Summary Pow er supply 38283 SABIX cables 38283 PoBs 37596 Heat gain in external pipelines 1672 Pump 634 Heat gain through the casing 943 Elizarov Ilya | | Inner air 1631 SUMIDA cables 23551 FEBs 21301 Dissipated to FEB cooling plates 22426 External pipelines 41533 Cooling plant 41533 ROBDsissipated to ROB/PoB cooling plates 2817 15170 Side cooling panels 1631 6 Cooling Supply Installation Layout Cooling plant STS detector in magnet E30 level technical building Pipelines 2x76 L=160 m 2 x circulation pump Elizarov Ilya | 06.07.2023 | 7 The Final Cooling Plant Specs TM TM 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 of low GWP refrigerants, one of which is CO2 itself. CO2 has disadvantage of high expansion coefficient, high operation pressure, toxicity, and requires qualified personell for the maintenance. 3MTNMOVECT6M49 or perfluoro(2-methyl-3-pentanone) has advantage of low operating pressure, non-toxicity, low GWP (equals one), and being easy to use. TM The STS cooling supply makes use of CO2 and NOVEC 649 simultaneously to take advantage of the both. Elizarov Ilya | 06.07.2023 | 8 The Final Cooling Plant Render Outlook Specs finalization, tender documentation Ready by Sep, 2023 EU tendering Sep, 2023 - Feb, 2024 Ordering Mar, 2024 Elizarov Ilya | 06.07.2023 | 9 The pilot cooling supply system Elizarov Ilya | 06.07.2023 | 10 The pilot cooling supply A pilot cooling supply system has been built at GSI to verify its suitability for the STS detector electronics cooling. TM The pilot cooling is a booster-type CO2 refrigeration system that extracts heat from the secondary side coolant through a heat exchanger (evaporator). Outlet heater extends temperature range of the 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. Elizarov Ilya | 06.07.2023 | 11 The Pilot Cooling Plant Specs TM TM Elizarov Ilya | 06.07.2023 | 12 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 oC. 25 14 15 12 Temperature, oC Electric power, kW 5 10 -5 8 -15 6 -25 4 -35 2 -45 0 0 2 4 6 8 10 12 14 16 18 Time . 103, s TM TM NOVEC temperature set point NOVEC temperature measured Power of the heaters Steady-state operation is only possible with the heat gain equal to partial cooling capacity of the plant The set-point can be maintained with maximum heat gain from the heaters of 11 kW - nominal capacity was achieved Elizarov Ilya | 06.07.2023 | 13 Cooling Test Rig The cooling test rig was built to allow connecting various experimental set-ups, including the thermal demonstrator, for testing cooling concept for the STS detector Supports standard DN 25 flange connection The STS detector can be connected for testing without a beam Monitors flow parameters: - flow rate; - inlet and outlet temperature; - inlet and outlet pressure. Supports connecting the drainage system Elizarov Ilya | 06.07.2023 | 14 Drainage System The drainage system connected to the cooling test rig TM The drainage system allows for draining and refilling experimental set-ups with NOVEC 649 without losing the liquid. Elizarov Ilya | 06.07.2023 | The drainage system connected to the cooling test rig 15 TM Details on NOVEC 649 usage in the cooling supply system Elizarov Ilya | 06.07.2023 | 16 Acid Formation Mechanism TM NOVEC undergoes a hydrolysis reaction with dissolved in it water: TM TM The consequence of the reaction depends whether water is added to NOVEC from an external source: NOVEC TM water TM NOVEC Reaction without excess of water Reaction with excess of water (two separate phases are formed due to poor solubility) TM Some acid can be present TfMrom off-the-shelf NOVEC, up to 3 mg/kg according to the datasheet - cannot cause corrosion Water solubility in NOVEC is poor 10 mg/kg at 25 oC Elizarov Ilya | 06.07.2023 | 17 Reaction without Excess of Water TM No acid is formed during water precipitation when NOVEC is cooled TM NOVEC molecule Acid H2O Separate phase equilibrium equilibrium Cooling to 0 oC H2O dissolved TM In NOVEC TM Miniscule acid concentration in NOVEC is in equilibrium with dissolved water TM Due to the decrease in water solubility in NOVEC, TM water molecules start to leave NOVEC solution forming a separate water phase into which acid can migrate. NOVEC, water and acid concentration are kept in equilibrium. Elizarov Ilya | 06.07.2023 | 18 Reaction with Excess of Water Acid is only created in presence of water excess from external source H2O from the excess of water Acid migrates into water H2O dissolved In NOVEC TM NOVEC TM molecule When excess of water is added to TM NOVEC, the equilibrium of hydrolysis reaction is broken Elizarov Ilya | 06.07.2023 | Acid Used water molecules are replaced with those from the excess of water. Acidity of water is increased. + TM More NOVEC molecules are subjected to hydrolysis 19 Acid Formation Mechanism: Conclusion Since our cooling supply system has no possibility for water to be added inside the system from an external source, no acid formation will occur in the system under any circumstances or operational modes TM The maximum acid concentration off-the-shelf NOVEC is 3 mg/kg, no more will be synthesized inside the cooling supply system The acidity of 3 mg/kg is equivalent to weight share 310-6, which is so miniscule, that it cannot case any noticeable The piping system of CO2 cooling plant is at the pressures that prevent water to enter CO2 circuit even if evaporator and desuperheater started to leak. In case of noticeable CO2 pressure loss, a controller will inform about this failure and stop the plant. This is true under assumption if the heat exchanger is leaking as well. corrosion inside the piping system As a result, measures against acid formation are not required for our cooling supply system, e.g. acid concentration monitoring, acid absorption devices Elizarov Ilya | 06.07.2023 | 20 Precipitated Water Freezing TM TM While the NOVEC temperature is reaching the nominal set-point -22,5 oC at the cooling plant, water from NOVEC will TM principate and freeze. The amount of frozen water is extremely low due to the poor solubility in NOVEC. 10 mg/kg solid water concentration is approximate equal to three snowflakes per liter The minimum solid water sediments size is 500 m Forming precipitates can be eliminated during formation process by drying and filtered The share of water content that can be extracted in liquid phase is 78% Elizarov Ilya | 06.07.2023 | 21 Eliminating Precipitated Water TM Drying NOVEC at room temperatures trying to extract dissolved in it water is ineffective with molecular sieve filter dryers (99% share of industrial refrigeration). However, molecular sieve driers are very effective for absorbing water as a separate phase. TM As a result, for an effective drying process NOVEC must be brought to 0 oC, when most of the water content precipitates as water. After most of the water is absorbed, a 15 m filtering material remaining solid water particles. No precipitations are left after the cooling plant - the piping system of the detector cannot be clogged. This method is highly reliable and, thus, does not require humidity monitoring system. Water elimination in this way naturally occurs during the system start-up. TM H2O as a separate phase (liquid) H2O as a separate TM phase (solid) TM TM Felt gasket 15 m Molecular sieve dessicant Elizarov Ilya | 07.07.2023 | 22 TM NOVEC Substitution TM 3M corporation announced that it plans to discontinue per- and polyfluoroalkyl substance (PFAS), including include TM NOVEC 649 and its variation for fire-extinguishing application TM NOVEC 1230, by the end of 2025 TM NOVEC 649 is a trademark for perfluor(2-methyl-3-pentanon) An extensive search for alternative suppliers that can provide us with industrial quantities and acceptable purity 99,9% was made After careful considerations, one company was selected, and a trial purchase of 35 kg was made (Imported outside the EU) Elizarov Ilya | 06.07.2023 | 23 Thank you for your attention Elizarov Ilya | 06.07.2023 | 24