Final Presentation CO2 as potential medium for detector-cooling at CERN Members of project: Christian Brosch Andreas Maier Tamara Bubeck Persons in support: Prof. Dr. Ing. Walter Czarnetzki Dr. Ing. Friedrich Haug

Table of contents Overview of test ridge and installed components (including the cycling process) Improvements Results for the measurement (α – coefficient) Maximum error estimation Summary Prospects 03.12.2018

Overview Test ridge (schematic) 5 6 4 3 2 1 New „brick“ 03.12.2018

Assembly of ridge 03.12.2018

Cyclic process: Compression 1 2 4 3 2 State 1 2 Temperature Ti [°C] -36,7 105 Pressure pi [bar] 11,2 35 Enthalpy hi [kJ/kg] 435 556 Entropy si [kJ/kg] 2,03 2,23 Compression 03.12.2018

One-way-valve Compressor Oil separator Cyclic process: Compression 1 2 One-way-valve Compressor Oil separator 03.12.2018

Cyclic process: Compression 1 2 Data Compressor max. power absorption 3,2 kW weight: 49 kg max. high pressure: 43 bar cooling rating: 6058 W Oil separator returns ca. 98% of the exhaust oil back to compressor One-way-valve avoid back flow of oil or CO2 Pressure control valve opens at 40 bar to avoid damages 03.12.2018

Cyclic process: Condensation: 2 3 1 4 3 2 State 2 3 Temperature Ti [°C] 105 Pressure pi [bar] 35 34,6 Enthalpy hi [kJ/kg] 556 200,3 Entropy si [kJ/kg] 2,23 1,03 Condensation 03.12.2018

Condensor (secondary circuit) Cyclic process: Condensation: 2 3 Condensor (secondary circuit) Cooling medium: R404a Refrigeration capacity: 4,0-8,7 kW(adjustable) Cooling compressor: Bock HGX22P Heat exchanger: plate heat exchanger water cooled 03.12.2018

Cyclic process: Expansion 3 4 1 4 3 2 State 3 4 Temperature Ti [°C] -36,7 Pressure pi [bar] 34,6 11,2 Enthalpy hi [kJ/kg] 200,3 Entropy si [kJ/kg] 1,00 1,03 Expansion 03.12.2018

Cyclic process: Expansion 3 4 Expansion valve Coriolis mass flow meter Pre-heating 03.12.2018

Cyclic process: Expansion 3 4 Coriolis mass flow meter Expansion valve to expand CO2 gas Pre-heating (0,75 kW) to adjust the starting point of measurement in two phase area and vapor quality factor Mass Flow Accuracy in % 100 kg/h 260 kg/h 03.12.2018

Cyclic process: Evaporation 4 1 3 2 State 4 1 Temperature Ti [°C] -36,7 Pressure pi [bar] 11,2 Enthalpy hi [kJ/kg] 200,3 435 Entropy si [kJ/kg] 1,03 2,03 Evaporation 03.12.2018

Cyclic process: Evaporation 4 1 Testsection After-heating 03.12.2018

Cyclic process: Evaporation 4 1 Components of Testsection: length 5,5 meter Copper tube inner diameter 14mm outer diameter 16mm 5 heating elements each 1000 Watt 4 heating elements each 250 Watt Thermal conductive paste SI-setral-HSC/N PT100 surface sensors for measuring outside tube temperature Aluminum sheet Isolation stone wool, λ = 0,038W/(mK) at 50°C; ( Steel ≈ 50W/(mK) ) After-heating to make sure that CO2 is completely evaporated before entering the compressor 03.12.2018

Location of sensors for surface temperature OT4 OT3 OT2 OT1 03.12.2018

Measurement „bricks“ Material: AlCuMgPb Pressure sensor: SHD-U_25 transmitter 0-25 bar(Testsection) or SHD-U_40 transmitter 0-40 bar Accuracy: ± 0,5% Temperature sensor: PT100A 15/10 Accuracy:±0,1K 03.12.2018

Improvements 03.12.2018

More effective Isolation get off the aluminum tape Fix aluminum sheet to avoid heat losses 03.12.2018

Heat loss because of convection Application over all heating coils Heat convection to the copper pipe is more effective and faster 03.12.2018

Heat loss because of convection Q=α·A·(TW-TF) discrepancies caused by convection as well as small parts radiation  A total loss of 13 W 03.12.2018

New aluminum brick after pre-heating Application of pressure transmitters and fluid temperature sensors in „Aluminium bricks“ to define conditions in entrance of test-section 03.12.2018

Current measurement The heating coils were connected in three-phase Every phase gets his own current measurement , so current will be added in total Modification of cables in the switching cabinet 03.12.2018

New oil separator Two possible solutions: better oil separator 99% separation efficiency activated carbon filter  99 +% separation efficiency cost ca. 250€ cost ca. 2000€ 03.12.2018

DAQ 03.12.2018

Data acquisition 03.12.2018

Results of measurement 03.12.2018

03.12.2018

1,3 kW 2,3 kW 03.12.2018

Results for the α - coefficient q = 19,9 kW/m2 m = 85 kg/h 03.12.2018

Maximal error estimation The maximum error of heat transfer coefficient can be calculated by: Accuracy of measurement intruments: Instruments Measurand Accuracy AT20 B10 ∆U ±1,5 % PT100A 15/10 ∆T ± 0,1K  for max. heat capacity : 5,5 kW ∆α =18 % 03.12.2018

Oscillation of the system 03.12.2018

03.12.2018

Summary improvement of isolation Modification of data acquisition Oscillation of the „whole system“  insufficient cooling medium: R404a Long delivery times 03.12.2018

Prospects Decision for more efficient oil separator Extensive performance tests Development of flow visualization Measurements of flow stability according CMS constraints  Next project group starts in april 03.12.2018

Thank you for your attention Any questions left? 03.12.2018