full scale thermosyphon design parameters and technical description
DESCRIPTION
Full Scale Thermosyphon Design Parameters and Technical Description . Jose Botelho Direito EN/CV/DC. Outline. Design specifications Thermodynamic cycle Power requirement and power consumption Pipe sizing and insulation Condenser/Tank design. Thermosyphon Design Specification. P out. - PowerPoint PPT PresentationTRANSCRIPT
4th Thermosyphon Workshop 1
Full Scale Thermosyphon Design Parameters
and Technical Description
Jose Botelho DireitoEN/CV/DC
19 November, 2010
4th Thermosyphon Workshop 2
Outline
• Design specifications• Thermodynamic cycle• Power requirement and power consumption• Pipe sizing and insulation• Condenser/Tank design
19 November, 2010
4th Thermosyphon Workshop 3
Thermosyphon Design Specification
19 November, 2010
Parameter Actual Plant Thermosyphon Design Specification
Flow of C3F8 at full power 1.1 kg/s (1) 1.2 kg/s
Liquid pressure at the supply distribution lines (plant side) 15 bara 15 bara (Height required = 95 m)
Temperature at the supply rack 20°C 20°C
Nominal pressure of the C3F8 at the return rack (plant side) 0.8 bara 0.5 bara (Psat=0.31 bara;Tsat=-60°C)
Temperature at the return rack 20°C 20°CMaximum operating pressure PN25 PN40(1) Read from the plant flow meter.
Evaporative /Thermosyphon
Return Rack
Supply RackPin Tin
Pout
4th Thermosyphon Workshop 4
Thermosyphon Basic Scheme
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4th Thermosyphon Workshop 5
Thermodynamic Cycle
19 November, 2010
12/10/2010 60kW Thermosyphon 6
AB
C
DE
F G H I
JK
LM N O
PI‘
4th Thermosyphon Workshop 6
Cooling and Electrical Power
19 November, 2010
Operation Line0
Description Component Power [kW] Power Type
Point A to B Cooling of the Return vapour Sub-Cooling HX 35 Passive component
Point B to C Return line Return pipe (+) 4 Passive component
Point C to D Condensation Tank Condensation 165 -
Point D to E Sub-Cooling Tank sub-cooling 5.5 -
Point C to E Condensing + Sub-cooling Condenser/Tank (-) 170 Chiller Power
Point E to F Supply line Supply pipe (+) 4 Passive component
Point F to G Heating up to the dew point Electrical Heater (-) 13 Electrical
Point G to H Heating the liquid using the return vapour
Heat Exchanger 35 Passive component
Point H to I Heating to room temperature Electrical Heater (-) 51 Electrical
Point I’ to A Evaporation and super heating Dummy Load (-) 107(1)/22(2)/0(3) Electrical
(1) During the commissioning period only.(2) Start up.(3) Running trough the detector.
4th Thermosyphon Workshop 7
Pipe Sizing and Insulation• Supply Pipe:
– Minimize pressure drop -> Larger diameter.– Minimize liquid volume and cost of pipes and installation -> Smaller diameter.
• Return Pipe: – Minimize pressure drop
• A high pressure drop can force us to decrease saturation pressure, increasing the Chiller cost!– Minimize cost of pipes and installation
• Insulation:– Minimize heat pick up on the return line.
• taking into account the external wall temperature of the Insulation.– Maximize heat pick up on the supply line.
• Tanking into account the external wall temperature of the insulation.
19 November, 2010
4th Thermosyphon Workshop 8
Pipe Sizing and Insulation: Supply• Pipe Size and Insulation Supply:
– DN50; ΔPfriction=55mbar– Insulation Thickness: 40mm; ΔTmax/100m=1.8K
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0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
0 5 10 15 20 25 30 35 40 45
dT/ 10m [K]
h air [W/m2.K]
DN50 Liquid line; HTCC3F8=329W/m2.K
Ins. Thick 20 mmIns. Thick 30 mmIns. Thick 40 mm
-30
-25
-20
-15
-10
-5
0
5
10
15
20
25
0 5 10 15 20 25Twall Out [°C]
h air [W/m2.K]
DN50 Liquid line; HTCC3F8=329W/m2.K
Ins. Thick 40 mmIns. Thick 30 mmIns. Thick 20 mm
4th Thermosyphon Workshop 9
Pipe Sizing and Insulation: Return• Pipe Size and Insulation Return:
– DN200; ΔPfriction=25mbar; ΔPheight=35mbar (independent from the pipe)– Insulation Thickness: 40mm; ΔTmax/100m=3.5K
19 November, 2010
0.0
0.1
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0.5
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0.7
0 5 10 15 20 25 30 35 40 45
dT/ 10m [K]
h air [W/m2.K]
DN200 Vapour line; HTCC3F8=42W/m2.K
Ins. Thick 20 mmIns. Thick 30 mmIns. Thick 40 mm
-5
0
5
10
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25
30
0 5 10 15 20 25
Twall Out [°C]
h air [W/m2.K]
DN200 Vapour line; HTCC3F8=42W/m2.K
Ins. Thick 40 mmIns. Thick 30 mmIns. Thick 20 mm
4th Thermosyphon Workshop 10
Condenser/Tank Design• Total Cooling Power: 170kW (164.5kW of
condensation + 5.5kW of sub-cooling).
• Required flow of C6F14: 40kg/s (ΔT=5K)
– The pressure drop would be too high using only one coolant coil (standard size of ≈16mm ID).
– The solution is the use of a Shell and Tube Heat Exchanger.
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4th Thermosyphon Workshop 11
Condenser Design
19 November, 2010
Finned External Surface
Smooth Internal Surface
• First Approach* on the Condenser Design:
• HTC on Condensing side: 12 kW/m2.K• HTC on Brine side: 1.1 kW/m2.K• Overall HTC: 253 W/m2.K• Required surface area of heat exchange: 93 m2
• Required number of tubes: 225 (with 3m length; 0.208 m2/m of external finned surface area)• Number of tubes: 253 (12% over surface)• Number of loops: 42• Number of tube passes: 4• Velocity of C6F14: 2.6m/s (Copper alloy needed)• Pressure drop: 1.9 bar
C3F8 vapour inlet (x3)
C3F8 liquid outlet (x3)To liquid tank
3 m
Φ 0.8m
* Calculations will be verified by Claudio Zilio (Padova University)and by the manufacture company.
4th Thermosyphon Workshop 12
Tank Design• Total required mass of Liquid: 2750kg
– Liquid side: 1565 kg– Vapour side: 644kg– Compensation for leaks: 540kg (3kg/day; 180days)
• Maximum volume: 2.15m3 (@32°C)
• Minimum volume: 1.6m3 (@-65°C)
• Approximate recommended total volume of the Tank: 2.5m3
• The possibility of joining the Condenser and the Tank is being studied.
19 November, 2010
4th Thermosyphon Workshop 13
Thermosyphon P&ID
19 November, 2010