Distributed 2-stage RTBC LH 2 Pipeline Cryocooler System Design LEI ZHOU MMAE UCF.
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Transcript of Distributed 2-stage RTBC LH 2 Pipeline Cryocooler System Design LEI ZHOU MMAE UCF.
Distributed 2-stage RTBC LH2 Pipeline Cryocooler System Design
LEI ZHOU
MMAE
UCF
Basic features of LH2 Cryocooler
For prechilling/cooling of the transportation pipeline of liquid HydrogenCapable of removing heat at 19KDistributed mid-size cryocoolers are the best solution for the long LH2 pipeline
Distributed RTBC cryocooler
Reverse Turbo-Brayton cryocooler has higher efficiency than JT cryocoolerWith oil-free design, Turbo-compressor/expander has high reliability Distributed mid-size cryocoolers can be– Easy installable and manageable– Expandable– Redundant– Efficient
Cryocooler cooling power analysis
How much cooling power needed to chill down a How much cooling power needed to chill down a 50-ft-long-pipe in 24 hours50-ft-long-pipe in 24 hours
Q=1908 kJ /ft
Q C D th 310 19( )
P=Q*50/24*3600=1104W
How much heat should be removed?How much heat should be removed?The Invar LH2 pipeline should be chilled down from 310K to 19K. Size: 10-inch diameter D, 8 mm pipe wall thickness th (estimated)
2-stage RTBC: — a way to reduce chilling time
Chill down with top cycle to 80K Switch the top cycle flow to cool the bottom cycle, use bottom cycle to chill down to 19KTotal time: 7.4 hr
Chill down with the both stages simultaneously to 19KTotal time: 24.2 hr
2-stage RTBC cryocooler
Flowswitch
Top cycle
Inter-heat exchanger / bottom cycle
Cooling load interface
2-stage RTBC cryocooler:—working mode1
CLI temperature: 80K
Cooling power: 9.95 kW ; Cooling time: 2.2 hr
Cooling load interface
Flowswitch
Top cycle
Inter-heat exchanger / bottom cycle
2-stage RTBC cryocooler:—working mode2
CLI temperature: 19K
Cooling power: 1.1 kW ; Cooling time: 5.2 hr
Flowswitch
Top cycle
Inter-heat exchanger / bottom cycle
Cooling load interface
System configuration
Recuperator
DC Power Supply
Motor/ 2 Stage intercooled compressor
Intercooler
Qrej
Motor/ 2 Stage intercooled compressor
Recuperator
Turboalternator
Qrej
Turbo expander/brake
Load Interface
DC Reg-ulator/ Power Su
pply
External HX
Thermodynamical schematic design
System Optimization
System requirements: – Cooling temperature: 19K– Cooling power: 1100 W– Working temperature: 310 K
Optimizable parameters: – Bottom Cycle pressure ratio: Pr
COP vs. Pr
Ti=80K
Spec. of Components
Bottom cycle:– Compressor: centrifugal 2-stage intercooled, Pr=3– Motor: 15 kW, efficiency>=0.85– Heat regenerator: 0.96 effectiveness, 11.7 kW– Turbine: turbo-expander with gas brake, 1.5 kW
Top cycle:– Compressor: centrifugal 2-stage intercooled, Pr=2.42– Motor: 85 kW, efficiency>=0.85– Heat regenerator: 0.987 effectiveness, 121 kW– Turbine: turbo-expander with generator, 11.2 kW
Conclusions
With system optimization, the proposed system can have a COP around 0.01 W/WCooling power analysis shows that the cryocooler system is a mid-size system which is capable of chill down a 50-ft transfer line to 19K in about 8 hours