There are 1 NTU research institute and 1 laboratory in the Clean Energy Group:

• Energy Research Institute @ NTU (Erian)
• Fuel Cell Lab (N3-B2a-02a)

Research Projects

Fuel Cell Range Extender for Electric Boats
Reformed methanol is used as the source of hydrogen for HT-PEMFC stack with maximum power output of 5-kW. It is meant for extending the travel range of electric boats.

Principal Investigator: Professor Chan Siew Hwa

Facile Preparation of high-Platinum Loading Catalysts by Microwave-Assisted Continuous Flow Reduction
This project aims to develop catalysts such as platinum with average diameter of less than 2 nm. It is also meant for scaling up the process for mass production of precious metal based catalysts.

Principal Investigator: Professor Chan Siew Hwa

Power Generation in Chlor-Alkali Plants Using Hydrogen Fuel Cells
Hugh amount of hydrogen with high purity is discharged from chlor-alkali plants as a byproduct. Unfortunately, it cannot be fed directly to H2-PEMFC as tracer amount of chlorine as low as 1 ppm would poison the Pt catalyst in the electrode. This project is meant to develop chloride-ions tolerant catalyst for such application.

Principal Investigator: Professor Chan Siew Hwa

Membrane-based Absorption Air-conditioning and Dehumidification System Using Renewable Energy or Waste Heat
We have developed a LDAC and dehumidification to improve the efficiency of air-conditioning system employing membrane technology. The membrane based sorption reactor maximizes the area for water vapour transfer and minimizes conductive heat transfer. 

Principal Investigator: Associate Professor Anutosh Chakraborty

Development of A Coupled Simulation Methodology for Offshore Wind Turbines
This EDB-IPP project with Lloyd’s Register GTC is to analyse the various unsteady aerodynamic phenomena by means of higher order methods such as direct rotor modelling, actuator disc modelling and free vortex wake models, and using these analyses to develop an accurate and reliable analytical tool for floating offshore wind turbines aerodynamics using unsteady blade element momentum method (uBEM). 

Principal Investigator: Associate Professor Ng Yin Kwee, Eddie

Optimal Structural Design of Wind Energy System
This EDB-IPP project with DNV-GL & NTNU is to conduct design modeling, dynamic analysis and structural optimization of compliant structure in offshore wind application. We perform parametric study on concept against offshore wind environmental design drivers and design parameters.
Ref: “Offshore Wind Turbine Jacket Substructure - A Comparison Study between Four-Legged and Three-Legged Designs”, (2014), J. of Ocean and Wind Energy, 1(2): 74-81. 

Principal Investigator: Associate Professor Ng Yin Kwee, Eddie

Integrated Wave Loads Analysis of Offshore Wind Turbine Platform Under Special and Complex Conditions
Offshore floating wind technology is one of the key research and development directions in the wind energy sector. This EDB-DNV & NREL project aims to build and validate a FAST model of the SWAY prototype downwind floating wind turbine with open sea data. Refs.: “Building and Calibration of a FAST Model of the Sway Prototype Floating Wind Turbine”, (2013), 2nd International Conference on Renewable Energy Research and Applications, ICRERA-2013, Paper ID:291. 978-1-4799-1464-7/13/©2013 IEEE. 

Principal Investigator: Associate Professor Ng Yin Kwee, Eddie

Improvement of BEM Analysis to Incorporate Stall Delay Effect of NREL phase VI Turbine
We developed hybrid wake modelling by coupling BEM and RANS for near wake regions and LES for far wake regions. Detached Eddy Simulation is used to couple between RANS and DES. BEM method computes the aerodynamic properties of the aerofoil sections along the blade span. A new BEM model with the local radius effect for aerofoil characteristics (other than as a function of Reynolds number and angle of attack only) is proposed. Implementation of the new model showed a good agreement with aerofoil characteristics distribution along the blade span. MATLAB code was developed for both BEM and Inverse BEM analysis.

Principal Investigator: Associate Professor Ng Yin Kwee, Eddie

Simulation of Sustainable Energy for Building Energy Efficiency
The present research work aims to analyze and optimize the thermal performance of ventilated roofs in tropical climate, and minimize the heat flux transferred across the roofs with different inclination angles and geometries, materials as well as ventilation modes, via (1) a field experiment and modeling analysis for the thermal performance of a flat roof subjected to the tropical climate in Singapore; (2) development of a novel model with experimental validation for the fast and accurate estimation of the heat flux transferred across the naturally-ventilated inclined roof with finite/infinite width-to-height ratios; and (3) the theoretical and experimental studies of the thermal performance of forced-ventilated roofs. 

Principal Investigator: Associate Professor Li Hua

Simulation of Sustainable Energy for Fuel Cell System
The present research work aims to develop various novel reduced models for the cell and stack equipped with parallel plain flow channels to significantly reduce computational cost with desired numerical accuracy, while capturing both the average properties and the variability of the dependent variables in the 3D model. The model reduction is performed based on full 3D cell model for conservation of mass, momentum, species, charge and energy, and is validated with experiments. 

Principal Investigator: Associate Professor Li Hua

Optimal Structural Design of Wind Energy System
Structural design optimization is applied to offshore wind support structures under aero and hydro-dynamic loads, to minimize mass/costs subject to extreme and fatigue load constraints.

Principal Investigator: Associate Professor Tai Kang

LNG Cold Energy Recovery for Assisted Air Liquefaction
The proposed project focusses on:

• To optimize the small scale air liquefaction processes
• Analyze the thermodynamic interaction between the system components, recovery of low grade heat, high grade cold energy storage and optimization of sub-components
• Assess the techno-economic potential of the proposed air liquefiers

There are 6 laboratories under the Thermo-Fluid Group:

• Fluid Mechanics Lab (N3-B2b-03) 
• Water Tunnel (N3.1A-B4-10a)
• Thermal & Fluids Lab (N3-B2c-06) 
• Heat Transfer Lab (N3-B2a-01) 
• Energy Systems Lab (N3.1A-B4-01) 
• Sembcorp Marine Lab (N2-B5c-02) 

Research Projects

The quad generation plant uses saline water as refrigerant and produces chilled water (7 to 12 ^oC) and cooling water for process cooling and air conditioning purposes. The fresh water is collected at the condenser. The plant is environmentally benign. 

Principal Investigator: Associate Professor Anutosh Chakraborty

Gas storage employing Metal organic Frameworks (MOFs)
We have performed an extensive study on synthesis, characterization and property evaluation of MIL-101(Cr, Fe) metal-organic framework (MOF) for CH₄ adsorption under LNG-ANG coupling conditions. MIL-101(Cr) exhibits high CH₄ delivery capacity at 298 K. 

Principal Investigator: Associate Professor Anutosh Chakraborty

Renewable Energy Based Cooling Systems
We have demonstrated that the low grade heat source can be used to generate cooling either by chemical (sorption) or physical (ejector) methods. In these systems, the driving heat source could be provided by either a solar collector array or low temperature waste heat source. 

Principal Investigator: Associate Professor Anutosh Chakraborty

Design and flow investigations of miniature centrifugal pumps
We have developed a miniature centrifugal pump and investigate the effects of geometrical parameters on the pump performances. This project will enhance our understanding of the performance of miniature devices for heat transfer, pharmaceutical and biomedical applications.

Principal Investigator: Associate Professor Chan Weng Kong

Slip modeling in microdevices
We have developed theoretical models to examine the discontinuous profiles across fluid-solid interfaces in micro and nano fluid systems. An adsorption model that is applicable for both gases and liquids was proposed to account for the temperature jump and velocity slip and temperature jump.

Principal Investigator: Associate Professor Chan Weng Kong

Development of activated carbons prepared from pistachio-nut shells.
Activated carbons were prepared from pistachio-nut shells by a two-step physical method. The effects of the preparation variables on the activated carbon pore structure were studied, followed by the optimization of these operating parameters. It was found that the activation temperature and dwell time are the important parameters that affect the characteristics of the activated carbons obtained. The effects of CO2 flow rate and heating rate during activation were also studied. Under the experimental conditions used, the optimum conditions to prepare activated carbons with high surface area and pore volume were identified. The microstructure of the activated carbons prepared was examined by scanning electron microscopy while the Fourier transform infrared spectra showed the changes in the surface functional groups produced during the different preparation stages.

Principal Investigator: Professor Lua Aik Chong

Preparation of activated carbons from oil-palm-shell chars by microwave-induced carbon dioxide activation.
A novel method of preparing activated carbons from oil-palm-shell chars by microwave-induced CO2 reaction was studied. The effects of processing parameters (gas flow rate, input microwave power and exposure time to microwave energy) and the presence of CuO receptors on the characteristics of the activated carbons were investigated in order to determine and optimise the control parameters for the process. Experimental results showed that it was feasible to prepare activated carbons with high density and predominant microporosity from oil-palm-shell chars by microwave heating. These activated carbons are to be used as gas-phase adsorbents. CO2 gas flow rate, input microwave power and exposure time were found to be important processing parameters that would significantly affect the quality of the final products. Adding CuO receptors to the char samples increased the surface temperature and significantly reduced the processing time.

Principal Investigator: Professor Lua Aik Chong

Hydrogen production by methane decomposition using Ni-Cu alloy nano-particle catalysts.
A series of Ni-Cu alloy particles with different atomic ratios of Ni/Cu were prepared by the thermal decomposition of fibrous Ni-Cu oxalate precursors in methane atmosphere. The resulting porous aggregates of Ni-Cu alloy particles showed promising catalytic activities for methane decomposition at temperatures of 700 and 750°C. A Ni-Cu alloy catalyst with 62.5% nickel content was able to achieve the highest methane conversion of about 82% at a reaction temperature of 750 °C. The addition of the right amount of copper led to the formation of alloy particles with small crystalline and particle sizes. Unlike the supported catalysts, the self-regulating system of the unsupported catalysts led to the formation of isometric, round catalyst particles which showed stable catalytic activity even at 750 °C. The frequent appearance in the supported catalyst system of liquid-like Ni-Cu catalyst at temperatures above 700 °C was suppressed in the unsupported Ni-Cu alloy catalyst system.

Principal Investigator: Professor Lua Aik Chong

Preparation and characterization of polyimide-silica composite membranes and their derived carbon-silica composite membranes for gas separation.
Polyimide (PI)-silica composite membranes and their derived carbon-silica composite membranes were prepared for gas separation. The polyimide-silica composite membranes were prepared using the sol-gel technique, in which the polyimide matrix was synthesized by the condensation of pyromellitic dianhydride (PMDA) and 4,4'-oxydianiline (ODA) while the inorganic phase was prepared by the in situ hydrolysis of tetraethyl orthosilica (TEOS) and a silane coupling agent, (3-aminopropyl)triehtoxysilane (APTES). The derived carbon-silica composite membranes were prepared by the pyrolysis of the polyimide-silica composite membranes at 900 degrees C under vacuum. The gas (He, CO2, N-2 and O-2) permeabilities of the polyimide-silica composite membranes and carbon-silica composite membranes were investigated. With the introduction of the silica, there was no significant enhancement of the gas separation in the resulting polyimide-silica composite membranes over the polyimide membrane. However, the derived carbon-silica composite membranes exhibited better gas separation properties. The C-SiO2 28% composite membrane produced the highest permeances of 1042.18, 991.21, 296.03 and 155.26 GPU for He, CO2, O-2 and N-2, respectively, which were 21.61, 137.67, 103.15 and 150.74 times, respectively, of those of the pure carbon membrane. The C-SiO2 11% composite membrane produced the highest selectivities of 37.57, 36.61 and 7.09 for He/N-2, CO2/N-2 and O-2/N-2, respectively, which had surpassed the Robeson's upper bound for these gas pairs.

Principal Investigator: Professor Lua Aik Chong

Coupled CFD and Depth Integrated Modelling of Marine Structures
The focus point of this EDB-DHI-IPP project is to improve on the correlation between the wave and depth-averaged properties obtained from DHI’s MIKE-21 and flow properties that are required as boundary conditions for the Navier-Stokes solver. The emphasis will be on the handling of the transitions between near-field and far-field in a logical manner, transiting from the far to the near-field. 

Principal Investigator: Associate Professor Ng Yin Kwee, Eddie

Computational Fluid Dynamics Study of C-130 External Aerodynamics Flow Field
To perform CFD investigative study with MINDEF-USAFA-RSAF for the external aerodynamic flow field in the vicinity of a military cargo airplane (e.g. C130H) during airdrop of supplies and hardware in order to assess aerodynamic interference effects on the trajectories of the airdrop. We apply 6 degree of motion freedom to the extraction parachute/cargo pallet to determine the actual trajectory rather than specifying the motion. 

Principal Investigator: Associate Professor Ng Yin Kwee, Eddie

Probability Model for Ignition of Gas Ingested by a Gas Turbine
This EDB-IPP-ERIAN project with Lloyd’s Register GTC is to build a probability model for ignition of flammable gas ingested by a gas turbine engine computationally and validated experimentally. It aims to improve the comprehensiveness of the Quantitative Risk Analysis in the Norwegian oil and gas sector and other areas where gas turbine engines operate close to other equipment and gas sources. 

Principal Investigator: Associate Professor Ng Yin Kwee, Eddie

Modelling and Prediction of Blockage Effects on the Operation of Tidal Turbines
We presents a series of studies performed to gain a better understanding of the effects of channel blockage on the performance and wake recovery of tidal turbines. Implementation of analytical models for the prediction of the operation of a turbine under blocked conditions is also explored, and guidelines for implementation are given where appropriate.

Principal Investigator: Associate Professor Ng Yin Kwee, Eddie

CFD (Computational Fluid Dynamics) Study of Ship-to-Bank Interaction
Ship-to-bank interaction is a complex physical phenomenon that involves not only in the asymmetric pressure field near banks or channels but also shallow water effect. Traditionally many experimental studies were carried out in this field. As numerical method is getting popular, there were various computational approaches as well. In this study, flow around a container ship in confined water is investigated with the open source CFD toolbox, OpenFOAM. Computations with several bank arrangements and different settings are performed. The OpenFOAM results are also compared to experiment results for validation.

Principal Investigator: Associate Professor Ng Yin Kwee, Eddie

Novel Refrigeration Compressors - Expander-compressor unit
We have developed a novel highly energy efficient expander–compressor unit called cross vane expander compressor (CVEC) which significantly improves energy efficiency of refrigeration systems. This new invention recovers the expansion energy to reduce the net energy input into the refrigeration systems without noticeable cost increase. Such a design is best suited for high pressure differential refrigeration systems such as those when using CO2 as the refrigerant. 

Principal Investigator: Professor Ooi Kim Tiow

Enhanced Microchannel Heat Transfer in Macro Geometry
Microchannels are known to have very high heat transfer effects, but it comes with a high manufacturing cost and large pressure drop. In this project, the microchannel heat transfer effects are duplicated in macro channels thus solving the cost issues and at the same time lower the significant pressure drop.

Principal Investigator: Professor Ooi Kim Tiow

Metabolite profiling of malaria parasites by means of magnetic resonance imaging/spectroscopy
We developed a malaria diagnosis technique which combined microfluidics separation of malaria infected red blood cells (iRBCs) with magnetic resonance relaxometry (MRR) system. The iRBCs are separated from the uninfected healthy red blood cells (hRBCs) through a phenomenon known as margination. 

Principal Investigator: Associate Professor Marcos

Characteristics of Swimming microorganisms in Flow
We developed a model to investigate the effects of shear flow on the shape of 2D propulsion flagellum, as well as hydrodynamic parameter of a single-flagellated microorganism such as sperm. The analytical results showed that under certain conditions, the shear flow could help the swimmer to swim faster. 

Principal Investigator: Associate Professor Marcos

Bubble dynamics with actuation in microfluidic chamber
This project, funded by Singapore Ministry of Education, is to carry out a fundamental study on bubble dynamics, including bubble formation, growth, coalescence and motion, in a microfluidic chamber under actuations.

Principal Investigator: Associate Professor Huang Xiaoyang

Nucleate boiling on flexible micro-structured surfaces
In this project we study the heat and mass transfer during the nucleating boiling process on heated surfaces fabricated with flexible pillars. We aim to find the relation between the heat transfer rate and the pillar characteristics such as physical and thermal properties. The results from this project will help enhancing the performance of current cooling systems.

Principal Investigator: Associate Professor Tran Anh Tuan

Micro-pillar array actuators for micro-fluidic functions
The main objective of this project is to develop an understanding of the hydrodynamics and mixing performance in micro-channels with embedded actuated micro-pillars. This understanding will then be used and implemented for various practical applications such as active mixing, and micro-pump.

Principal Investigator: Associate Professor Tran Anh Tuan

Evaporative Spray Cooling for High Power System
High power electronic devices have now reached extreme cooling requirements that cannot be met by enhanced convection cooling technology. The operating characteristics required for such cooling system would be to reject high heat load per unit area at close to the ambient temperature. We first characterized the spray atomization as well as the heat transfer performance of pressure swirl nozzles in spray cooling. Thereafter, we developed and tested a high-power (16 kW), large-area (size of a 6U card), and multi-nozzle spray cooled system. The application of high heat flux removal ( > 400 W/cm²) was achieved by applying multi miniaturized jet-swirl nozzles for a small heated surface area of 2 cm².

Principal Investigator: Associate Professor Wong Teck Neng

Oil-Gas Multiphase Flow
In literatures, research efforts on multiphase flow have been heavily towards gas-Newtonian liquid. In the oil and process industries, non-Newtonian liquids, especially pseudo-plastic liquids are encountered frequently through pipelines over long distance. A good understanding of the basic flow mechanism involved non-Newtonian liquid-gas flow is essential to economic design of equipment and processes. This project develops theoretical models to investigate the effects of non-Newtonian liquid on two-phase pressure gradient and liquid holdup; the proposed models were validated with the published experimental data.

Principal Investigator: Associate Professor Wong Teck Neng

Chilled Ceiling Air-Conditioning System for Tropical Climates
In collaboration with industry partner to develop new generation of passive chilled ceiling air conditioning system that provide comfort and energy-efficient cooling in tropical climate 

Principal Investigator: Associate Professor Wan Man Pun

High Performance Cool Roof Coating for Green Buildings
In collaboration with A*STAR and industry partner to investigate the heat transfer and aging mechanisms of cool roof coating. Develop new generation of high anti-dirt and anti-algal performance cool coatings. 

Principal Investigator: Associate Professor Wan Man Pun

Novel Electrokinetic Power Generation via Forward Osmosis
We have proposed a new power generation method for harvesting renewable energy from salinity gradient that is available from seawater, brackish water and concentrated brine discharged from desalination plants. The principle of the proposed method encompasses forward osmosis (FO) and electrokinetic (FK) phenomena. Our preliminary results show that the FO-EK technique can produce electrical voltages in the same order of magnitude as those produced by one typical fuel cell unit. The projected power density based on our experimental results is comparable to those generated by pressure-retarded osmosis (PRO) and reverse electrodialysis (RED) technologies. We are working on modeling and scalability development.

Principal Investigator: Professor Yang Chun, Charles

Thermophoresis of Micro- and Nano-Particles
The main objective of the present project is to carry out both theoretical and experimental studies to directly address several fundamental issues related to thermophoresis. Experimentally, we propose a microfluidic technique as a new experimental tool to directly visualize and characterize the dynamic behavior of both micro and nano-sized particles under various physicochemical conditions. Meanwhile, new theoretical modeling and analysis of theremophoresis by using both analytical and numerical approaches are carried out.

Principal Investigator: Professor Yang Chun, Charles

Electrokinetic Flow of Non-Newtonian Fluids
This topic is of high relevance for electrokinetically-driven microfluidic and nanofluidic systems which are routinely used to process and analyze non-Newtonian fluids, such as biofluids, polymeric solutions and colloidal suspensions. Our current research focuses on fundamental understanding and characterization of the electrokinetic flow of non-Newtonian fluids.

Principal Investigator: Professor Yang Chun, Charles

Microfluidic Separation of Live and Dead Cells in Continuous Flow
We are developing polymer micro flow cytometer with applications in environmental monitoring. Flow cytometry is a technique for counting, examining and sorting biological cells and particles suspended in a liquid stream. Our proposed micro flow cytometry will highlight the following features: (i) alignment of cells via hydrodynamic focusing, (ii) separation of live and dead cells via dielectrophoresis, and (iii) on-chip counting.

Principal Investigator: Professor Yang Chun, Charles

Induced-Charge Electrokinetic (ICEK) Flow and its Applications
Induced-charge electrokinetics deals with a new group of non-linear electrokinetic phenomena. The project aims at theoretical advancement of nonlinear ICEK flows and exploration of their applications in micro/nano fluidics. In particular, we are working on derivation of generalized electric boundary conditions, dynamic characteristics of the charging of electric double layers and the associated induced flows around polarizable dielectrics, implementation of ICEK phenomena to nanofluidics, and the use of ICEK flow for particle manipulations.

Principal Investigator: Professor Yang Chun, Charles

Characterization of Thermoplasmonic Heat Transfer in Liquids
This project is to fundamentally study thermoplasmonics with emphasis on ensemble effects. Thermoplasmonics refers to a new phenomenon involving the resistive heat-loss in nano-sized metallic particles under light illumination due to their enhanced absorption capabilities. We are carrying out both experimental investigation and theoretical analysis to characterize thermoplasmonic heat transfer with exploring applications in energy utilization and storage.

Principal Investigator: Professor Yang Chun, Charles

Nano/micro fluids
The understanding of how flow behaves on a solid surface is an unsolved problem in science and engineering. Modelling fluid flows past the surface required some assumptions about the flow boundary condition on the solid interface. One of the simplest boundary conditions is a no-slip condition, which dictates that fluid particles close to the surface do not move. Although this no-slip boundary condition as an engineering approximation has been remarkably successful in reproducing the characteristics of many types of flow, there exist situations in which it does not always hold in reality and leads to singular or unrealistic behaviors.

Principal Investigator: Associate Professor Shu Jian Jun

Thermal Energy Storage for Low Grade Waste Heat Recovery
The proposed project focusses on:

• Formulation, encapsulation and characterization of materials for thermal storage 
• Heat exchanger design, heat transfer and fluid flow analysis of thermal energy storage charge/discharge cycle