J Direito ENCVDC 06072009 1 Thermosyphon Workshop Gravitydriven Cooling Concept Natural circulation of the fluid Condensation temperaturepressure must lower than evaporation temperaturepressure ID: 286541
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Slide1
Thermosiphon pre-design
J. Direito (EN/CV/DC)
06/07/2009
1
Thermosyphon WorkshopSlide2
Gravity-driven Cooling Concept
Natural circulation of the fluid:Condensation temperature/pressure must lower than evaporation temperature/pressureNo working components in the main circuitLess probability of occurrence of leaks No significant vibrations on the system
Low maintenance operations
Access to refrigeration units at the surfaceNo limit for the Evaporation Temperature:Suction pressure of the compressors is not a limit anymore -> possibility of reaching lower evaporation temperatures
06/07/2009
2
Thermosyphon WorkshopSlide3
Preliminary design and parameters
A-B : CondensationB-C : Hydrostatic dPC-D : Heat ExchangerD-E : Pressure RegulationE-F : Sub-CoolingF-G : Capillary ExpansionG-H : EvaporationH-I : Heater
I-A : Back-Pressure regulation
B
C
D
E
G
H
I
A
F
Thermodynamic Cycle Example for C3F8 with Sub-Cooling
06/07/2009
3
Thermosyphon WorkshopSlide4
Preliminary design and parameters
SURFACE
CAVERN
100 m
06/07/2009
4
Thermosyphon Workshop
Design by A.
MorauxSlide5
B
C
D
E
G
H
I
A
F
Preliminary design and parameters
A-B :
Condensation
–
dh
=
h
(at
T
condensation
) –
h
(at
T
return
lines
)
Definition of the Condensation Power
B-C :
Hydrostatic
–
dP
>
P
transfer
lines
(
T
transfer
lines
)
–
P
return
lines
(
T
return
lines
)
Definition of minimum height
C-D :
Heat Exchanger
–
dh
=
h
(at T
in
) –
h
(
T
supply
lines
)
Definition of HX power
D-E :
Pressure Regulation
– Pressure Regulator
Cv
Regulation of mass flow
E-F :
Sub-Cooling
–
dh
=
h
(
T
evap
at
T
cond
) – h (Xin)Definition of HX Power for sub-coolingF-G : Capillary pressure drop – dP = Ppressure regulator – Pevaporation Definition of capillary length G-H : Evaporation – dP stave Definition of dP at the staveH-I : Heater – dh = h (Xout) – h (Ttransfer lines) Definition of Heater powerI-A : Back-Pressure regulation – Pressure Regulator CvRegulation of Evaporation Temperature
06/07/2009
5
Thermosyphon WorkshopSlide6
Preliminary design and parameters
Application example for the IBL detector and Distribution Racks at USA 15:Required mass flow = 36g/sEvaporation temperature = -40CSupply and return lines Temperature = 20CAltitude difference ≈ 100mDefinition of the main components:
Minimum height O.K.: 16 bar > dP (
Pcond = 7.57 bar ; Pevap = 0.87 bar)
liquid line = DN25 -> dP= 16 bar ; Vapor line = DN50 -> dP = 90 mbar
Condensation Temperature < -42.5 C (Pcond
< 0.87 bar – 90mbar)Condenser Power > 5.94kW (dh
= 165kJ/kg; m = 36g/s)
Heat Exchanger Power > 1.44kW (dh = 40kJ/kg; m = 36 g/s)
06/07/2009
6
Thermosyphon Workshop