nanofluid additive for heat exchanger (he) imran syakir mohamad combicat, um

NANOFLUID ADDITIVE FOR HEAT EXCHANGER (HE)

Imran Syakir Mohamad

COMBICAT, UM

2

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%)

3

Info (OYL Air-Cooled Mini Chiller)

4

Info (OYL Air-Cooled Mini Chiller)

5

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

6

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

7

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

9

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.

12

12

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





Optimization

Achieved

CNT+ Standard Portable Water

Nanofluid


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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Modified CNT

Sonication


Dispersant


Achieved

Achieved

Achieved

Achieved

Achieved

CNT Weight Loading

Temperature

Viscosity






Optimization

Achieved


Nanofluid


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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Modified CNT

Sonication


Dispersant


Achieved

Achieved

Achieved

Achieved

Achieved

CNT Weight Loading

Temperature

Viscosity






Optimization

Achieved


Nanofluid


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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Modified CNT

Sonication


Dispersant


Achieved

Achieved

Achieved

Achieved

Achieved

CNT Weight Loading

Temperature

Viscosity






Optimization

Achieved


Nanofluid


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


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

20

Thank you

21

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

22

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

nanofluid additive for heat exchanger (he) imran syakir mohamad combicat, um

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