nanofluid additive for heat exchanger (he) imran syakir mohamad combicat, um
TRANSCRIPT
NANOFLUID ADDITIVE FOR HEAT EXCHANGER (HE)
Imran Syakir Mohamad
COMBICAT, UM
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Objectives
To design a nanofluid formulation using the proprietary CNT-based additive for OYL mini chiller which will improve heat transfer efficiency by 1oC (current: T=5oC, target: T=6oC), thus allowing to:-
• Scale down heat exchanger system
• Increase energy efficiency (10%)
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Info (OYL Air-Cooled Mini Chiller)
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Info (OYL Air-Cooled Mini Chiller)
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Schematic Diagram: Test Rig
P: Diff. PressureF: Flow meter : Thermometer
SSR
Chiller
SSR
P
F
F
PID
PID
UUT: Unit under testPID: Proportional Integral Derivative controllerSSR: Heater controller
UUTBPHE
Hot side(Vary Flow)
Cold side(Fixed Flow)
Stainless Steel Tank
Pump
Stainless Steel Tank
Pump
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Specification of BPHE
The specifications of the BPHE used is as follows:
Model:
SWEP B25-26
Effective Length, Leff = Lv (m) 0.479
Effective channel width, Lw (m) 0.117
Number of plates 26
Number of Passes, Np (single pass) 1
Number of channels per pass, Ncp 13
Plate pitch, p (mm) 2.34
Plate thickness, t (mm) 0.4
Channel Spacing, b (m) (b = p - t) 0.00194
Port Diameter, Dp (m) 0.024
Surface enlargement factor 1.2(assumed)
Hydralic Diameter, Dh = 2b/1.2 (m) 0.003233
Single channel flow area = b*Lw (m^2) 0.000227
Chevron angle, b 70 deg.
Lp Lv
Lw
Lh
2b
Dp
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Water CNT-Water
Entering water temp
12oC 12oC
Leaving water temp 7oC 6oC
∆T 5oC 6oC
Fluid flow rate 2m3/hr 2m3/hr
Cooling capacity 11.61kW 13.93kW
Power input 4.56kW 4.625kW
% Energy efficiency 254.6% 301.3%
Power:
Compressor 3970W 3970W
Waterpump 350W 385W
fanmotor 270W 270W
Total 4590W 4625W
Comparison Data
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Scope of WorkThis project would be divided into five sub-phases (Phase I-V).
Phase I: Review heat-exchanger fluid technology and IP landscape.
Phase II: Develop additive for nanofluid a) Selection of suitable primary additive b) Formulation of nanofluid c) Screening Test: Thermal conductivity d) Heat transport property evaluation
Phase III: Process Simulationa) Process simulationb) Target optimization
Phase IV: Optimization of HE nanofluid formulation a) Conceptual engineering design for pilot plant b) Establish pilot plant c) Reproducibility
Phase V: Field test
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Project Flow Diagram
Flow Chart 1: Summary of Research Project
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Possible Primary Additive
• CNT• Spherical nanocarbon• Non-abrasion metal oxide
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CNT Development Route
Washing(removes impurities;
eg: Al, Si, Fe, K)
Washing(removes impurities;
eg: Al, Si, Fe, K)
Catalyst Development
Catalyst Development
Nanocarbon Growth
(Thermal-CVD)
Nanocarbon Growth
(Thermal-CVD)
CharacterizationCharacterization
• Monometallic (Iron, Ni)
• Monometallic (Iron, Ni)
• Compositional analysis (EDX,XRF)• Morphology/Structure analysis
(SEM, HRTEM)• Texture/Surface Area analysis
(BET)• Mechanical & Electrical Properties
Analysis
• Compositional analysis (EDX,XRF)• Morphology/Structure analysis
(SEM, HRTEM)• Texture/Surface Area analysis
(BET)• Mechanical & Electrical Properties
Analysis
• Carbon source (C2H4)
• Carrier gas (H2, N2)
• Carbon source (C2H4)
• Carrier gas (H2, N2)
Substrate (NC100)
Substrate (NC100)
TreatmentTreatmentImpregnationImpregnation
CNTCNT
CNT After TreatmentCNT After Treatment
Nanofluid FormulationNanofluid
Formulation
• treat with 5M HNO3, T=30oC, 24 hr
• wash with deionized water, dried T=200oC, 2 hr
• treat with 5M HNO3, T=30oC, 24 hr
• wash with deionized water, dried T=200oC, 2 hr
• Cat. + acetic acid• under ultrasonic, 30
min, 25oC (water bath)
• aging 12 hr, 45oC
• Cat. + acetic acid• under ultrasonic, 30
min, 25oC (water bath)
• aging 12 hr, 45oC
• Use acid treatment (HCl) to remove catalyst & amorphous C.
• Use acid treatment (HCl) to remove catalyst & amorphous C.
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Parameter concerned
NC100 AC
Pretreatment
Catalyst Precursor
Achieved
Cat. Weight Ratio
Achieved
Growth Parameter
Impregnation
Temperature
Gas Loading Ratio
Growth Time
Characterization
Achieved
Modified CNT
End
Characterization
Achieved
Characterization
Achieved
Optimization
Achieved
No
No
No
No
No
No
Yes
Yes
Yes
Yes
Yes
Yes
Bulk Preparation of CNT
Synthesis
Precursor (Fe)
A B
Wt % Cat.
1 3 5
UTP Parameter
% H2 loading
5% 10% 20%
Red. Temp (oC)
600 650 700
Growth Time (min)
60 90 120
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Criteria of CNT modification
• High purity of nanofiber/nanotube• Special modified surface charges to avoid
agglomeration• Functionality (oxygen-containing functional
group)
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Other Potential Additive
• Soot• ZnO• CuO• MoO
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Formulation of Nanofluid
Modified CNT
Sonication
Nanofluid FormulationDistilled Water
Dispersant
Dispersant Concentration
Achieved
Achieved
Achieved
Achieved
Achieved
CNT Weight Loading
Temperature
Viscosity
Testing & Measurement
Testing & Measurement
Testing & Measurement
Testing & Measurement
Testing & Measurement
Optimization
Achieved
CNT+ Standard Portable Water
Nanofluid
Testing & Measurement
Yes
Yes
Yes
Yes
Yes
Yes
No
No
No
No
No
No
End
To re-entangle the modified CNT
2 types of dispersant will be chosen:Purpose: To prepare a stable dispersion of CNT in liquid form.Criteria of dispersant: able to disperse CNT and stable for 24hr
Main Substance: CNT, Distilled water and Dispersant
Parameter concerned
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Formulation of Nanofluid
Modified CNT
Sonication
Nanofluid FormulationDistilled Water
Dispersant
Dispersant Concentration
Achieved
Achieved
Achieved
Achieved
Achieved
CNT Weight Loading
Temperature
Viscosity
Testing & Measurement
Testing & Measurement
Testing & Measurement
Testing & Measurement
Testing & Measurement
Optimization
Achieved
CNT+ Standard Portable Water
Nanofluid
Testing & Measurement
Yes
Yes
Yes
Yes
Yes
Yes
No
No
No
No
No
No
End
3 different weight percent3 different concentration3 different temperatureHigh to low shear rate
Parameter
Wt % CNT
D E F
Nanofluid Temp
G H I
Wt % Dispersant
A B C
Viscosity
High Low
pH
J LK
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Formulation of Nanofluid
Modified CNT
Sonication
Nanofluid FormulationDistilled Water
Dispersant
Dispersant Concentration
Achieved
Achieved
Achieved
Achieved
Achieved
CNT Weight Loading
Temperature
Viscosity
Testing & Measurement
Testing & Measurement
Testing & Measurement
Testing & Measurement
Testing & Measurement
Optimization
Achieved
CNT+ Standard Portable Water
Nanofluid
Testing & Measurement
Yes
Yes
Yes
Yes
Yes
Yes
No
No
No
No
No
No
End
Testing and measurement• Heat transfer coefficient• Thermal conductivity• Dispersion of CNT• Stability
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Formulation of Nanofluid
Modified CNT
Sonication
Nanofluid FormulationDistilled Water
Dispersant
Dispersant Concentration
Achieved
Achieved
Achieved
Achieved
Achieved
CNT Weight Loading
Temperature
Viscosity
Testing & Measurement
Testing & Measurement
Testing & Measurement
Testing & Measurement
Testing & Measurement
Optimization
Achieved
CNT+ Standard Portable Water
Nanofluid
Testing & Measurement
Yes
Yes
Yes
Yes
Yes
Yes
No
No
No
No
No
No
End
To optimize nanofluid formulation best method using standard portable water.
Testing and measurement• Heat transfer coefficient• Thermal conductivity• Dispersion of CNT• Stability
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Optimization of HE Nanofluid Formulation
CNT & Nanofluid Formulation
Reproducibility
Fluid dynamics and Heat Transfer Test
Achieved
Achieved
Achieved
Stability
Sample scale up & Performance Repeatability
Testing & Measurement
Optimized nanofluid ready for field test
End
Yes
Yes
Yes
No
No
No
• Scale up of CNT• Scale up of HE Nanofluid Formulation• Performance repeatability
• Performance stability for 100 hours• Corrosion
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Thank you
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Info
HE System (water)Entering water temp = 12oCLeaving water temp = 7oC∆T = 5oCWater flow rate=2m3/hrCooling capacity = 11.61kWPower input=4.56kW% Energy efficiency= 11.61/4.56x100%=254.6%
Power: Compressor=3970W (Fixed)Waterpump=350W (depend on viscosity of fluid) fan motor=270W(Fixed)Total=4590W
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Info
HE System(CNT+water)Entering water temp = 12oCLeaving water temp = 6oC (expected)∆T = 6oCCooling capacity = 13.93kWPower input=4.625kW% Energy efficiency= 13.93/4.625x100%=301.3%
Power: Compressor=3970W (Fixed)Waterpump=385W (depend on viscosity of fluid) fan motor=270W(Fixed)Total=4625W
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Apendix: Preparation of Nanofluids
The process could possible to be proceeding as:
Step 1: Sonicating CNT sample with a known weight in an ultrasonic bath
Step 2: Dispersing the sonicated CNTs into a present amount of distilled water containing suitable dispersant
Step 3: Treating the mixture with high shear homogenizer for 30 minutes.
Parameters concerned: Solution: distilled water, SYABAS Dispersant: Gum Arabic and Sodium Laurate Dispersant Concentration: 0.1wt% - 0.5wt% CNT Concentration: 0.1wt% - 5wt% Nanofluids Temperature: 25oC – 35oC Nanofluid Viscocity: High - slow shear rate