|
EBTS
About Us
Contact Us
Facilities
Air-conditioning
Lab
Energy Conversion
Lab
Thermal Process Lab
People
Faculty
Staff
Students
Research Areas
Energy Systems
Energy
and Power MEMS
Bio-Thermal Systems
Electronic
Packaging
|
|
CHOU Siaw Kiang
(S. K. Chou)
Professor
Dr-Ing., D.E.A.(ENSAM),
B.Eng.(Sing); FASHRAE, FIES
Dept of Mechanical Engineering,
Faculty of Engineering,
Engineering Block EA,
#
04-12,
9 Engineering Drive
1,
Singapore
117576
Tel:(65) 6516 -2215
Fax: (65) 6779-1459
Email: skchou@nus.edu.sg
Executive Director
Energy Studies Institute (ESI) http://www.esi.nus.edu.sg
National University of Singapore
29 Heng Mui Terrace, Block A, #10-01,
Singapore 119620
Tel: (65) 6516-2000
Email: esicsk@nus.edu.sg
Curriculum
Vitae
|
.JPG) |
|
Other Associations
Deputy President, Institution of Engineers, Singapore
Chairman, Management Board, IES Academy
http://www.ies.org.sg
Associate Editor, Applied Energy
http://ees.elsevier.com/apen/
Chairman, International Editorial Board, Asian Journal of Energy and Environment
http://www.asian-energy-journal.info/
International Conference on Applied Energy, 21-23 April 2010, Singapore: http://www.icae2010.org
International Conference on Applied Energy, 16-18 May 2011, Perugia, Italy: http://www.icae2011.org
International Conference on Applied Energy, ICAE2012, 5-8 July 2012, Suzhou, China:
http://www.applied-energy.org/
|
|
Selected Publications
Yang, W.M., Chou, S.K., Shu, C., Xue, H., and Li, Z.W. "Development of a micro thermophotovoltaic system", Applied Physics Letters, Vol 81. no. 27, 5255-5257 (2002).
Chou, S. K. and Chua, K.J. "On the Study of the drying behavior of a heat-sensitive biomaterial undergoing stepwise-varying temperature schemes". Industrial and Engineering Chemistry Research, 42, 4939-4952 (2003).
Li, Z.W., Chou, S.K., Shu C., and Yang W.M. “Predicting the temperature of a premixed flame in a microcombustor”. Journal of Applied Physics , 96 (6), 3524-3530 (2004).
Chua, K.J., Ho J.C., Chou S.K. and Islam M.R. “On the study of the temperature distribution within a human eye subjected to a laser source”. International Communications in Heat and Mass Transfer, 32, 1057-1065 (2005).
Li, Z.W., Chou, S.K., Shu, C., and Yang, W.M. “Entropy generation during microcombustion”. Journal of Applied Physics , 97, 084914/8 (2005).
Yang W.M., Chou, S.K., Shu, C., Li, Z.W., Xue, H., “Study of catalytic combustion and its effect on microthermophotovoltaic power generators”. Journal of Physics D: Applied Physics, 38, 4252-4255 (2005).
Chua, K.J., Chou, S.K., and Ho, J.C. “An analytical study on the thermal effects of cryosurgery on selective cell destruction”. Journal of Biomechanics, 40, 100-116 (2007).
Zhang, K.L., Chou, S.K., and Ang, S.S. “Investigation on the ignition of a MEMS solid propellant microthruster before propellant combustion”. Journal of Micromechanics and Microengineering, 17, 322-332 (2007).
Li, J., Chou, S.K., Li, Z.W., and Yang, W.M. “A comparative study of H2-air premixed flame in micro combustors with different physical and boundary conditions”, Combustion Theory and Modelling, 12, 325-347 (2008).
Li, J., Chou, S.K., Li, Z.W., and Yang, W.M. “Characterization of wall temperature and radiation power through cylindrical dump micro-combustors”, Combustion and Flame, 156, 1587-1593 (2009).
Chua, K.J. and Chou, S.K. “Energy performance of residential buildings in Singapore”, Energy, 35, 667-678 (2010).
Li, J., Chou, S.K., Li, Z.W., and Yang, W.M. “Experimental investigation of porous media combustion in a planar micro-combustor”, Fuel, 89, 708-715 (2010).
Chua, K.J., Chou, S.K., and Yang, W.M. “Advances heat pump systems: a review”, Applied Energy, 87, 3611-3624 (2010).
Chou, S.K., Yang, W.M., Chua, K.J., Li, J. and Zhang, K.L. “Development of micro power generators: a review”, Applied Energy (accepted for publication). |
|
Current Research Areas and Activities
Micro
Thermophotovoltaic (TPV) Power Generation
The purpose of this research is to develop a novel micro power generator based on the use of photovoltaic (PV) cells to convert heat radiation into electricity. The micro thermophotovoltaic (TPV) system comprises a micro combustor-emitter, a filter and a PV cell array. The fuel-air mixture is burned in the micro combustor, which acts as an emitter of a steady stream of high energy photons. Electricity is produced when photons of sufficient energy greater than the bandgap of the PV cells impinge on the surface of PV cell array. The filter is designed to allow the transmission of photons having energy greater than the bandgap of the PV cells. At the same time, the filter will reflect photons with energy lower than the bandgap back to the emitter, thereby improving the efficiency of the micro-TPV power generator.
A prototype micro-TPV power generator has been developed
and tested at the NUS Department of Mechanical Engineering. The system is
able to deliver an electrical power output of 3 W in a package of a few cm3.
On-going work includes:
(i) studying the fundamentals of combustion and heat transfer in the micro-scale;
(ii) developing new filters so as to recycle most of the photons with energy lower than the bandgap of the PV cells, and, at the same time, transport almost all the photons with energy greater than the bandgap;
(iii) developing selective emitters which can exhibit a high emittance in the spectral range usable for the PV cells and a low emittance elsewhere; and
(iv) developing high efficiency and low bandgap PV cells so as to maximize the output power density and efficiency.
Furthermore, the radiation efficiency of the micro combustor will need to be improved by employing heat recuperation and catalytic combustion. It is expected that a prototype micro TPV power generator with an efficiency of up to 10%, and being able to deliver an electrical power of about 10 W in a package in the order of cm 3, is achievable.
More: micro
TPV, microscale
combustion
Energy Performance of Buildings
The Overall Thermal Transfer Value (OTTV), as a means of determining the rate of heat transmission into the building through its envelope, has been used as a mandatory energy standard in Singapore since 1979. In line with the need to introduce performance-based energy standards and in recognition of the value of applying the OTTV parameter in energy estimation, work at the NUS Department of Mechanical Engineering was directed at deriving a more accurate OTTV equation to predict the envelope heat gain. The result of that study is the Envelope Thermal Transfer Value (ETTV) equation. In 2004, the Building and Construction Authority (BCA) adopted the ETTV equation as the new energy standard for air-conditioned buildings. By early 2005, all building envelope designs are required to comply with the prescribed value of 50 W/m2 for the ETTV.
Recently completed work at the ME Department, funded by the Singapore Building and Construction Authority, includes: (i) effect of the ETTV on the energy consumption of an air-conditioned non-residential building; (ii) evaluating the significance of further reductions in the ETTV and the quantitative energy efficiency gains that can be achieved; (iii) evaluating the potential application of the building envelope criterion on residential air-conditioned buildings; and (iv) developing engineering tools to facilitate energy calculations and compliance of energy standards. In September 2007, we devised a new envelope thermal transfer parameter called Residential Envelope Transmittance Value (RETV) for residential buildings. The prescribed compliance value is now set at 25 W/m2.
Both the ETTV and RETV are key compliance criteria in the Green Mark certification scheme. On-going work covers algorithms for energy estimation, life-cycle analysis of clean energy alternatives, upgrading of the Building Energy STandard (BEST) code for ETTV, RETV and energy performance calculations, and a building energy rating system.
Cryo-Surgery and Cryo-Probe Development
Cryosurgery, sometimes referred to as cryotherapy or cryoablation, is a surgical technique that employs freezing at cryogenic temperatures to destroy undesirable tumour cells. The technique involves placing the cooled tip of a cryo-probe on or into the tissues to be destroyed. Principal research objectives include building an accurate thermal model for temperature distribution calculations, studying various protocol parameters so as to maximize the destruction of tumour tissues within a defined spatial domain, and studying the efficacy of different cryoprobe performance in terms of physical dimensions, shape and number of probes employed in administrating cell destruction within tumour tissues.
Solid Propellant Micro-Thrusters
Micro-spacecraft is one of many applications of MEMS technology. The cheap, reliable and versatile clusters of micro-spacecraft have more advantages than a conventional spacecraft in terms of fabrication, launch and operation. In a micro-spacecraft, a micro-propulsion system is required for high-accuracy station keeping, altitude control, gravitation compensation and orbit adjustment. The solid propellant micro-thruster is a relatively new class of micro-propulsion system and it is easier and cheaper to fabricate. Total complexity of the system is minimized due to the fact that it does not require any pumps and valves. Integrated with MEMS technology, the solid propellant micro-thruster has great potential for application in micro-spacecraft and micro air vehicles in general. More recently, attention is placed on the use of micro-thrusters in biomedical and health care.
Micro Direct Methanol Fuel Cell
The purpose of this work is to develop a micro direct methanol fuel cell (DMFC), which can significantly extend the operating time in comparison with batteries. The micro DMFC uses liquid methanol as fuel and consists of a series of membrane exchange assemblies, gaskets, current collectors and a fuel reservoir. The micro DMFC does not have any pumps or moving parts and the delivery of methanol and air is realized entirely by natural convection. The system is intended for use as a power source of portable electronic devices such as cell phones, audio-video equipment and lap-top computers.
A prototype micro-DMFC has been assembled and tested at the NUS Department of Mechanical Engineering. The system is able to deliver 100 mW electricity with a 5 cm2 membrane at near room temperature.
On-going work includes:
(i) studying the fundamentals of
heat and mass transport in micro channels;
(ii) improving the chemical kinetics of the electrodes; and
(iii) developing composite and pore-filling poly membranes
so as to decrease methanol crossover through the membrane; and
A prototype micro DMFC with an efficiency of up to 40%, and
being able to deliver an electrical power of 100 mW-10 W, is achievable.
More: micro
DMFC
|
|
