Development of a cooling system for geothermal borehole probes

Transcription

1 Development of a for geothermal borehole Benedict Holbein National Research Center of the Helmholtz Association application range open tasks Structure of presentation Why the system is needed How the system works What the system misses applications challenge benefit concept process components problems next steps cooperation experiments Benedict Holbein development of a for geothermal borehole

2 application range possible applications Why the system is needed applications challenge benefit interesting requests - long operation times - many operations at frequent intervalls - little amount of maintenance between operations Benedict Holbein development of a for geothermal borehole application range application example Why the system is needed applications challenge benefit interesting requests - long operation times with different modules - hot environments protection for electronics required Benedict Holbein development of a for geothermal borehole

3 application range challenges and benefits depth environment / operation borehole borehole >5 km > 600 bar > 200 C borehole media corrosive thermal water cooling system Why the system is needed applications challenge benefit borehole diameter cool room < 81/2inch < 70 C Benedict Holbein development of a for geothermal borehole application range challenges and benefits cooling system - no time limitations for operations - operations also in very hot boreholes - standard electronics usable - heat protected measurement advices Why the system is needed applications challenge benefit Benedict Holbein development of a for geothermal borehole

4 The Components (I) depth environment / operation borehole >5 km > 600 bar refrigerant evaporation cooling process acetone ~ 57 C boundary conditions borehole > 200 C borehole media corrosive thermal water borehole diameter cool room < 81/2inch < 70 C max. working sourrounding media condensing max. diameter inside max. diameter outside ~ 230 C corrosive ~ 40 bar 110 mm 170 mm environmental operational Benedict Holbein development of a for geothermal borehole concept of the condenser borehole refrigerant aligned process conduct heat conduction expansion valve M motor compressor insulation vacuum MLI evaporator components robust materials cool room custom-built engineering modular design Benedict Holbein development of a for geothermal borehole

5 prototype refrigerant aligned process conduct heat conduction insulation vacuum MLI components robust materials custom-built engineering modular design Benedict Holbein development of a for geothermal borehole The sub-processes: acetone evaporation (4 1) compression (1* -2) ~ 56,5 C ~ 1 bar isobar isothermal ~ 230 C ~ 40 bar polytropic condensation (2* -3*) expansion (3 4) ~ 215 C ~ 40 bar -39 bar -140 C isobar isothermal isenthalpic heat flow mass flow refrigerating capacity: after C. Clapeyron = h h percentage of liquid phase specific volume superheated differential specific volume subcooled Benedict Holbein development of a for geothermal borehole evaporation entropy1 / 4 enthalpy 1 / 4

6 The insulation Multi Layer (MLI) radial heat input from outside heat radiation heat conduction heat convection Teflon (PTFE) minimal heat input from outside axial Multi Layer vacuum solid insulation vacuum PTFE ceramic wool Benedict Holbein development of a for geothermal borehole The Components (I) actual evaporator: -resistant: 1 bar (i)// 1 bar (o) max. diameter: 110 mm mounting surface for electronic maximal heat conduction surface high heat transfer coefficient * wounduptube heatexchanger * copper * d/l: 110/1400 mm * max. refigerating capacity: 110 W main components evaporator condenser compressor expansion valve refrigerant max. inside inside acetone ~ 1bar newevaporator: max. inside ~ 60 C * grooved plate heat exchanger * copper * d/l: 110/900 mm * max. refigerating capacity: 190 W *straight tube heat exchanger *nickel base alloy * d/l: 170/2000 mm sourrounding media max. outer max. outer air ~ 1 bar ~ 70 C max. diameter 110 mm Benedict Holbein development of a for geothermal borehole

7 The Components (II) condenser: -resistant: 40 bar (i)// 600 bar (o) max. diameter: 170 mm corrosion-resistant maximal heat conduction surface high heat transfer coefficient *straight tube heat exchanger *material: Inconel 600; Nicofer 721 & * d/l: 170/2000 mm main components evaporator condenser compressor expansion valve refrigerant max. inside outside acetone ~ 40bar compressor: -resistant: 40 bar (i)// 600 bar (o) compression ratio: 1/40 max. diameter: 170 mm corrosion-resistant acetone gas-resistant low power input *piston compressor *gaskets: PTFE; PCTFE; PVDF & * d/l: 170/1200 mm max. inside sourrounding media max. outer max. outer ~ 230 C corrosive water ~ 600 bar ~ 200 C max. diameter 170 mm Benedict Holbein development of a for geothermal borehole experiments(i) experiments heat transfer sub-processes test set-up thermocouples inside cool room heating jacket outside insulation heating up from outside: > 200 C vacuum insidebarrier: < 5 E-4 mbar Benedict Holbein development of a for geothermal borehole

8 experiments(ii) [ C] profil with acetone time [min] evaporation experiments heat transfer sub-processes evaporation test set-up thermocouples inside cool room heating jacket outside insulation evaporator heating up from outside: > 200 C vacuum insidebarrier: < 5E-4 mbar liquid acetone in evaporator: ~ 700 ml!.#$%& '' acetone filled in Benedict Holbein development of a for geothermal borehole experiments(iii) experiments heat transfer sub-processes test set-up thermocouples inside cool room heating jacket outside heating up from outside: > 200 C vacuum insidebarrier: < 5E-4 mbar liquid acetone in evaporator: ~ 700 ml internal heat input: 20 Watt insufficient heat transfer between loads and acetone insulation evaporator acetone filled in loads Benedict Holbein development of a for geothermal borehole

9 experiments(iva) simulation of heat transfer improvement with CPU-fan on theloadboard significant improvement caused by acceleration of air experiments heat transfer sub-processes test set-up thermocouples inside cool room heating jacket outside insulation evaporator acetone filled in loads fan Benedict Holbein development of a for geothermal borehole experiments(ivb) experiments heat transfer sub-processes heating up from outside: > 200 C vacuum inside barrier: < 0.5 E-4 mbar liquid acetone in evaporator: ~ 700 ml internal heat input: 20 Watt slight improvement but load s still to high test set-up thermocouples inside cool room heating jacket outside insulation evaporator acetone filled in loads fan Benedict Holbein development of a for geothermal borehole

10 open tasks open questions materials gaskets + joints for compressor delivery times and batch grindability vs. shape complex heat transfer thermodynamics process control refrigerants ressources What the system misses problems next steps cooperation cooperation Benedict Holbein development of a for geothermal borehole open tasks components- tests optimized condenser optimized evaporator prototype What the system misses problems missing components new evaporator condensator lab compressor expansion valve missing resources laboratory equipment future experiments evaporation v.2 condensation compression heat exchange v.2 expansion complete next steps cooperation Benedict Holbein development of a for geothermal borehole

11 open tasks 2-stage system What the system misses problems activecoolingin ~400 C environment 2 stages concept 2nd refrigerant dodecane next steps cooperation condenserofstage1 insidecool roomofstage2 condenser of first stage = evaporator of 2nd stage 2nd refrigerant for other boundary conditions required 2nd complete at higher level Benedict Holbein development of a for geothermal borehole application range open tasks conclusion An active for borehole would be a great advance The concept for works There sstill a lotofwork to do Benedict Holbein development of a for geothermal borehole

12 ende Prof. Max Mustermann - Title cooling system The insulation(i) Multi Layer (MLI) heat radiation Quelle: Entwicklung eines Kühlsystems für eine Geothermie Bohrlochsonde. Masterarbeit HS Karlsruhe und ENSMM Besançon, 2010 Polytetrafluoroethylene(PTFE) heat transfer ptfe thickness thickness heat conduction radial axial Multi Layer vacuum solid insulation PTFE ceramic wool Quelle: Entwicklung eines Kühlsystems für eine Geothermie Bohrlochsonde. Masterarbeit HS Karlsruhe und ENSMM Besançon, Benedict Holbein development of a for geothermal borehole

13 cooling system The insulation(ii) Vacuum heat convection radial Multi Layer vacuum axial solid insulation PTFE vacuum experiment: heating jacket around housing: 200 C vacuum inside barrier: < 0.5 E-4 mbar ceramic wool Benedict Holbein development of a for geothermal borehole open tasks prototype What the system misses problems next steps cooperation preparation constrution of components Testing optimization ready for operation prototype Benedict Holbein development of a for geothermal borehole

14 contact information web: mail: flyer: summarized information to take away Benedict Holbein development of a for geothermal borehole open tasks time table 2013 sub-process experiments construction of missing components realisation of in laboratory A What the system misses next steps problems 2014 completion of test construction of prototype firstfieldtest??? A cooperation Benedict Holbein development of a for geothermal borehole