Saidur Rahman | University of Malaya, Malaysia (original) (raw)

Papers by Saidur Rahman

In this research, overall performance of a shell and tube heat exchanger operated with Al2O3–W, S... more In this research, overall performance of a shell and tube heat exchanger operated with Al2O3–W, SiO2–W, and ZnO–W nanofluids were experimentally investigated. Al2O3–W and SiO2–W nanofluids were prepared without using any surfactant. The polyvinylpyrrolidone (PVP) surfactant was used to stabilize
ZnO–W and Fe3O4–W nanofluids. Photo capturing method was used to justify the stability. However, Fe3O4–W nanofluid has not been stabilized by PVP so it was not considered for further analysis. Highest convective heat transfer coefficient (hfT), overall heat transfer coefficient (Uo), and actual heat
transfer (qfT) have been observed for ZnO–W and lowest effectiveness (e), hfT, Uo and qfT have been found
for SiO2–W. Approximately, 50%, 15%, and 9% enhancement in hfT have been found for ZnO–W, Al2O3–W, and SiO2–W nanofluids, respectively. About 35%, 26%, and 12% improvement of Uo were observed accordingly
for using the above-mentioned nanofluids and qfT also improved around 51%, 32%, and 26%, respectively
compared to water. Experimentally, in case 1 (at constant shell side fluid flow of 4 lpm with
different tube side fluid flow from 2 to 8 lpm), highest performance can be attained at 6 lpm using 0.3 vol.% of ZnO–W (with PVP) nanofluid. Likewise, highest performance reached at 7 lpm using 0.5 vol.% of Al2O3–W and SiO2–W. In case 2 (at the constant tube side fluid flow of 4 lpm with different shell side fluid flow from 2 to 8 lpm), highest performance can be achieved at 8 lpm for all nanofluids. However, overall performance of the shell and tube heat exchanger can be improved about 35% by using ZnO–W (with PVP) nanofluids.

A large number of populations of the world live in rural or remote areas those are geographically... more A large number of populations of the world live in rural or remote areas those are geographically isolated. Power supply and uninterrupted fuel transportation to produce electrical power for these remote areas poses a great challenge. Using renewable energy in hybrid energy system might be a pathway to solve this problem. Malaysia is a large hilly land with the gift of renewable energy resources. There is a good chance to utilize these renewable resources to produce electrical power and to limit the dependency on the fossil fuel as well as reduce the carbon emissions. In this perspective, a research is carried out to analyze the performance of a solar-wind-diesel-battery hybrid energy system for a remote area named “KLIA Sepang station” in the state of Selangor, Malaysia. In this study, a 56 kW hybrid energy system has been proposed that is capable to support more than 50 households and 6 shops in that area. Real time field data of solar radiation and wind speed is used for the simulation and optimization of operations using “Homer” renewable energy software. The proposed system can reduce CO2
emission by about 16 tons per year compared to diesel generator only. In the same time the Cost of energy (COE) of the optimized system is USD 5.126 /kWh.The proposed hybrid energy system might be applicable for other parts of the world where the climate conditions are similar.

Engineering e-Transaction, Dec 31, 2011

Nanorefrigerant is one kind of nanofluids that have better heat transfer performance than traditi... more Nanorefrigerant is one kind of nanofluids that have better heat transfer performance than traditional refrigerants. Recently, some researches have been done about nanorefrigerants, which are mostly related to thermal conductivity of these fluids. Pressure drop is an important phenomenon for refrigeration system. Pumping power is closely related to it. In this paper, the effects of pressure drop for 0–5 volumes % of TiO2–R123 nanorerfrigerants have been theoretically studied. The experimental conditions include: mass fluxes from 100 to 200 kgm-2s-1, vapor qualities from 0.2 to 0.7, temperature at 25oC and atmospheric pressure. Based on the analysis it is found that pressure drop augmented significantly with the increase of volume concentrations. Therefore, low volume concentration of nanorefrigerant can improve the performance of a refrigeration system.

International Journal of Mechanical and Materials Engineering, Aug 31, 2012

Nanorefrigerant is one kind of nanofluids. It is the mixture of nanoparticles with refrigerants. ... more Nanorefrigerant is one kind of nanofluids. It is the mixture of nanoparticles with refrigerants. It has better heat transfer performance than traditional refrigerants. Recently, some researches have been done about nanorefrigerants. Most of them are related to thermal conductivity of these fluids. Viscosity also deserves as much consideration as thermal conductivity. Pumping power and pressure drop depends on viscosity. In this paper, the volumetric and temperature effects over viscosity of R123-TiO2 nanorefrigerants have been studied for 5 to 20ºC temperature and up to 2 vol. %. The effect of pressure drop with the increase of viscosity has also been investigated. Based on the analysis it is found that viscosity of nanorefrigerant increased accordingly with the increase of nanoparticle volume concentrations and decreases with the increment of temperature. Furthermore, pressure drop augmented significantly with the intensification of volume concentrations and vapor quality. Therefore, low volume concentrations of nanorefrigerant are suggested for better performance of a refrigeration system.

Continuous need for the optimum conversion efficiency of polymer electrolyte membrane fuel cell (... more Continuous need for the optimum conversion efficiency of polymer electrolyte
membrane fuel cell (PEMFC) operation has triggered varieties of advancements,
namely in the thermal management engineering scope. Excellent heat dissipation is
correlated with higher performance of a fuel cell, thus increasing its conversion
efficiency. This study reveals the potential advancement in thermal engineering of a fuel
cell cooling system with respect to nanofluid technology. Nanofluids are seen as a
potential evolution of nanotechnology hybridization with the fuel cell serving as a
cooling medium. The available literature on the thermophysical properties of potential
nanofluids, especially on the electrical conductivity property, has been discussed. The
lack of electrical conductivity data for various nanofluids in open literature was another
challenge in the application of nanofluids in fuel cells. Unlike in any other thermal
management system, a nanofluid in a fuel cell is dealt with using a thermoelectrically
active environment. The main challenge in nanofluid adoption in fuel cells was the
formulation of a suitable nanofluid coolant with heat transfer enhancement, as compared
to its base fluid, but still complying with the strict limits of electrical conductivity as
low as 2 S/cm and several other restrictions discussed by the researchers. It is
concluded that a nanofluid in PEMFC is advantageous in terms of both heat transfer and
simplification of the cooling system through radiator size reduction and potential
elimination of the deionizer as compared to the current PEMFC cooling system.
However, there are challenges that need to be well addressed, especially in the electrical
conductivity requirement

International Journal of Mechanical and Materials Engineering (IJMME), 2010

Mixed convection heat transfers in a two-dimensional trapezoidal cavity with constant heat flux a... more Mixed convection heat transfers in a two-dimensional trapezoidal cavity with constant heat flux at the heated bottom wall while the isothermal moving top wall in the horizontal direction has been studied numerically. Control Volume based finite volume method (FVM) has been used to discretize the governing differential equations. The pressure- velocity coupling in the governing equations is achieved by using the well known SIMPLE method for numerical computations. A second order upwind differencing scheme is to be used for the formulation of the coefficients in the finite-volume equations. All computations are to be done for a range of Richardson number, Ri from 0.1 to 10 and the aspect ratio, A are to be changed from 0.5 to 2 for a fluid having Prandtl number equal to 0.71 (air). First the optimum configuration of the trapezoidal cavity has been obtained by changing the inclination angle, γ of the side walls. Then the effect of Richardson number, aspect ratio, and Rotation angle, Φ (30°, 45° and 60°) of the optimum trapezoidal cavity has been studied by changing the desired parameter. Results have been presented in the form of streamline and isotherm plots as well as the variation of the Nusselt number at the heat source surface under different conditions. The results shows that with increasing Ri, the heat transfer rate increases as natural convection dominates. The rotational angle of the trapezoidal cavity and the direction of the lid motion affect the heat transfer rate significantly. Optimum heat transfer rate is obtained at aiding flow condition having higher values of Ri.

International Journal of Renewable Energy Research, 2011

A numerical model is presented for the simulation of double-diffusive natural convection in a tri... more A numerical model is presented for the simulation of double-diffusive natural convection in a triangular solar collector. This design is encountered in greenhouse solar stills where vertical temperature and concentration gradients between the saline water and transparent cover induce flows in a confined space. This phenomenon plays an important function in the water distillation process and in the biological comfort. In this double-diffusion problem, the ratio Br of the relative magnitude thermal and compositional buoyancy and Rayleigh numbers are key parameters. Finite element technique is used to solve the governing equations. Numerical results are presented for the effect of the abovementioned parameters on local heat and mass transfer rate. In addition, results for the average heat and mass transfer rate are offered and discussed for the mentioned parametric conditions. Some interesting results are found in this investigation.

Clean Technologies and Environmental Policy, 2012

Industrial sector is the largest user of energy in India and many parts of the world. More than ... more Industrial sector is the largest user of energy in
India and many parts of the world. More than half of the
total energy is used in industries to operate various energyusing
machineries. Energy conservation is a cost-effective
approach in any energy optimization program that can be
implemented in industrial activities. Energy-intensive
industries in developing economies offer significant
energy-saving potential owing to the technology gap as
well as lower operating efficiency. A detailed energy flow
analysis was conducted in a paper carton manufacturing
unit in India to quantify the energy-saving potential. The
study revealed that the compressed air leakage is responsible
for about 50% of the total energy loss. The specific
electrical and thermal energy consumption was estimated
and found to be 91.85 kWh/ton and 1,619 MJ/ton of biomass,
respectively. Annual energy saving potential was

World renewable energy congress, 2000

Household electrical appliances consume a significant amount of electricity in the domestic secto... more Household electrical appliances consume a significant amount of electricity in the domestic sector of Malaysia and as such, have become a target for efficiency improvement. Like other developing countries in Southeast Asia, Malaysia is experiencing a dramatic growth in the number of household electrical appliances usage and it will be higher in the future. This paper attempts to identify energy saving possibilities by implementing energy efficiency standards for selected household appliances. As such, efficiency improvement on these appliances will give a significant impact on future electricity consumption in the country.

TENCON 2000. Proceedings, 2000

This is a summarized previous works on energy efficiency standards and labels for household elec... more This is a summarized previous works on energy
efficiency standards and labels for household electrical
appliances. It concerns mostly about international situation
and other country experience about energy efficiency
standard in residential sector. The possibilities of
implementation of standards and labels for various
household electrical appliances in Malaysia are also
discussed. From the international review and other country
experience shown that; there are many advantages for
Malaysia to implement the standards and labels for
household electrical appliances.

TENCON 2000. Proceedings, 2000

An experiment was conducted to investigate the effect of temperature, door opening, thermostat ... more An experiment was conducted to
investigate the effect of temperature, door opening,
thermostat setting position, relative humidity, and loading
on energy consumption of a household refrigerator-freezer.
Our investigation reveals that temperature has the greatest
effect on energy consumption followed by loading. Next
greatest effect are due to door opening and thermostat
setting position. Relative humidity has minimal effect on
energy consumption. With the experimental data, a
multiple regression equation has been developed to
investigate their combine effect.

2000 TENCON Proceedings, 2000

This is a summarized previous works on energy efficiency standards and labels for household elect... more This is a summarized previous works on energy efficiency standards and labels for household electrical appliances. It concerns mostly about international situation and other country experience about energy efficiency standard in residential sector. The possibilities of implementation of standards and labels for various household electrical appliances in Malaysia are also discussed. From the international review and other country experience shown that; there are many advantages for Malaysia to implement the standards and labels for household electrical appliances.

2000 TENCON Proceedings, 2000

An experiment was conducted to investigate the effect of temperature, door opening, thermostat se... more An experiment was conducted to investigate the effect of temperature, door opening, thermostat setting position, relative humidity, and loading on energy consumption of a household refrigerator-freezer. Our investigation reveals that temperature has the greatest effect on energy consumption followed by loading. Next greatest effect are due to door opening and thermostat setting position. Relative humidity has minimal effect on energy consumption. With the experimental data, a multiple regression equation has been developed to investigate their combine effect.

Energy conversion and management, 2001

This study attempts to predict the environmental impact of implementing an energy efficiency stan... more This study attempts to predict the environmental impact of implementing an energy efficiency standard for room air conditioners in Malaysia. The ownership of room air conditioners has increased tremendously in this country. At present, there are about 528,792 room air conditioners in Malaysian households. In the year 2020, it will be about 1,511,276. The potential carbon dioxide reduction is based on the predicted electricity savings from implementing a minimum energy efficiency standard for room air conditioners. The electricity savings are calculated based on the predicted electricity consumption by a single air conditioner in the Malaysian household. The replacement of less efficient units of this appliance is reflected in reduced electricity consumption and emissions from power plants. The energy efficiency provisions of this regulation and agreement provide targets to save money, energy and, most importantly, to protect the environment.

ASEAN Journal on Science and Technology for Development, 2001

Energy Conversion and Management, 2001

This study attempts to predict the environmental impact of implementing an energy efficiency stan... more This study attempts to predict the environmental impact of implementing an energy efficiency standard for room air conditioners in Malaysia. The ownership of room air conditioners has increased tremendously in this country. At present, there are about 528,792 room air conditioners in Malaysian households. In the year 2020, it will be about 1,511,276. The potential carbon dioxide reduction is based on the predicted electricity savings from implementing a minimum energy efficiency standard for room air conditioners. The electricity savings are calculated based on the predicted electricity consumption by a single air conditioner in the Malaysian household. The replacement of less efficient units of this appliance is reflected in reduced electricity consumption and emissions from power plants. The energy efficiency provisions of this regulation and agreement provide targets to save money, energy and, most importantly, to protect the environment.

Energy, 2001

ISO 8187, ISO 8561, and ISO 7371 are the relevant test standards for household refrigerating appl... more ISO 8187, ISO 8561, and ISO 7371 are the relevant test standards for household refrigerating appliances. This paper presents the possibility of introducing ISO household refrigerator-freezer test standards in Malaysia. An experiment was conducted to investigate the effect of room temperature, door opening, thermostat setting position, relative humidity, and loading on energy consumption of a household refrigerator-freezer. With the experimental data, a multiple regression equation is developed to investigate their combined effect. Finally, energy consumption according to the regression equation with optimum setting conditions is compared with ISO standard test conditions, Our comparison reveals that ISO refrigerator-freezer test standards are applicable with respect to Malaysian climatic conditions and usage patterns.

International journal of power & energy systems, 2002

Air conditioners are one of the major energy-consuming appliances in the Malaysian domestic secto... more Air conditioners are one of the major energy-consuming appliances in the Malaysian domestic sector. According to a load survey, air conditioners account for around 8.3% of the total residential electricity consumption in Malaysia. To reduce the energy consumption in this sector, Malaysia Energy Center is considering implementing minimum energy efficiency standards for room air conditioners sometime in the coming year. The first step towards adopting energy efficiency standards is to create a test procedure for rating and testing this appliance. An energy test procedure is the technical foundation for all energy efficiency standards, energy labels, and other related programs. As room air conditioners are a climate-dependent appliance, the climatic condition for a particular country or region is an important determinant in developing the test conditions. Therefore, before setting the test conditions, the requirements for a specific country and region must be clarified. This article is an analysis of the applicability of ISO 5151 nonducted air conditioner test conditions, based on the climatic conditions in Malaysia. International adoption of ISO 5151 by several countries is also discussed. There is a trend towards international harmonization of appliance test standards; this work can be considered as support to that end.

Energy Conversion and Management, 2002

Because of changing fossil fuel prices, sources and environmental consciousness, Malaysian utilit... more Because of changing fossil fuel prices, sources and environmental consciousness, Malaysian utilities have been forced to change the type of energy sources to generate electricity. This new policy of electricity generation companies will change fuel use gradually from 70% gas, 15% coal, 10% hydro and 5% petroleum in the year 2000 to 40% gas, 30% hydro, 29% coal and only 1% petroleum in the year or 2020. These changes tend to reduce CO2 emission. This study attempts to predict the potential CO2 reduction due to these changes. The calculation is based on CO2 emission for unit electricity generated and the changing type of fuel percentages for electricity generation in Malaysia. The study found that the substitution will reduce CO2 emission from power plants in this country.

Energy Conversion and Management, 2002

Refrigerator-freezers energy consumption is greatly affected by room temperature, door opening an... more Refrigerator-freezers energy consumption is greatly affected by room temperature, door opening and
thermostat setting position. Two frost free household refrigerator freezers of the same capacity were tested
in the laboratory to determine the sensitivity of their energy consumption to various usage conditions. The
experiments were conducted to investigate the effect of single variables, such as temperature, thermostat
setting positions and door opening, and their combined effect on energy consumption. Our investigation
reveals that room temperature has the higher effect on energy consumption, followed by door opening.
Thermostat setting position has the lower effect on energy consumption. More detailed tests were performed
under different room temperature, thermostat setting position and door opening conditions. With
the experimental results, a first order mathematical model has been developed to investigate their combined
effect on energy consumption. The test results are discussed and presented.

In this research, overall performance of a shell and tube heat exchanger operated with Al2O3–W, S... more In this research, overall performance of a shell and tube heat exchanger operated with Al2O3–W, SiO2–W, and ZnO–W nanofluids were experimentally investigated. Al2O3–W and SiO2–W nanofluids were prepared without using any surfactant. The polyvinylpyrrolidone (PVP) surfactant was used to stabilize
ZnO–W and Fe3O4–W nanofluids. Photo capturing method was used to justify the stability. However, Fe3O4–W nanofluid has not been stabilized by PVP so it was not considered for further analysis. Highest convective heat transfer coefficient (hfT), overall heat transfer coefficient (Uo), and actual heat
transfer (qfT) have been observed for ZnO–W and lowest effectiveness (e), hfT, Uo and qfT have been found
for SiO2–W. Approximately, 50%, 15%, and 9% enhancement in hfT have been found for ZnO–W, Al2O3–W, and SiO2–W nanofluids, respectively. About 35%, 26%, and 12% improvement of Uo were observed accordingly
for using the above-mentioned nanofluids and qfT also improved around 51%, 32%, and 26%, respectively
compared to water. Experimentally, in case 1 (at constant shell side fluid flow of 4 lpm with
different tube side fluid flow from 2 to 8 lpm), highest performance can be attained at 6 lpm using 0.3 vol.% of ZnO–W (with PVP) nanofluid. Likewise, highest performance reached at 7 lpm using 0.5 vol.% of Al2O3–W and SiO2–W. In case 2 (at the constant tube side fluid flow of 4 lpm with different shell side fluid flow from 2 to 8 lpm), highest performance can be achieved at 8 lpm for all nanofluids. However, overall performance of the shell and tube heat exchanger can be improved about 35% by using ZnO–W (with PVP) nanofluids.

A large number of populations of the world live in rural or remote areas those are geographically... more A large number of populations of the world live in rural or remote areas those are geographically isolated. Power supply and uninterrupted fuel transportation to produce electrical power for these remote areas poses a great challenge. Using renewable energy in hybrid energy system might be a pathway to solve this problem. Malaysia is a large hilly land with the gift of renewable energy resources. There is a good chance to utilize these renewable resources to produce electrical power and to limit the dependency on the fossil fuel as well as reduce the carbon emissions. In this perspective, a research is carried out to analyze the performance of a solar-wind-diesel-battery hybrid energy system for a remote area named “KLIA Sepang station” in the state of Selangor, Malaysia. In this study, a 56 kW hybrid energy system has been proposed that is capable to support more than 50 households and 6 shops in that area. Real time field data of solar radiation and wind speed is used for the simulation and optimization of operations using “Homer” renewable energy software. The proposed system can reduce CO2
emission by about 16 tons per year compared to diesel generator only. In the same time the Cost of energy (COE) of the optimized system is USD 5.126 /kWh.The proposed hybrid energy system might be applicable for other parts of the world where the climate conditions are similar.

Engineering e-Transaction, Dec 31, 2011

Nanorefrigerant is one kind of nanofluids that have better heat transfer performance than traditi... more Nanorefrigerant is one kind of nanofluids that have better heat transfer performance than traditional refrigerants. Recently, some researches have been done about nanorefrigerants, which are mostly related to thermal conductivity of these fluids. Pressure drop is an important phenomenon for refrigeration system. Pumping power is closely related to it. In this paper, the effects of pressure drop for 0–5 volumes % of TiO2–R123 nanorerfrigerants have been theoretically studied. The experimental conditions include: mass fluxes from 100 to 200 kgm-2s-1, vapor qualities from 0.2 to 0.7, temperature at 25oC and atmospheric pressure. Based on the analysis it is found that pressure drop augmented significantly with the increase of volume concentrations. Therefore, low volume concentration of nanorefrigerant can improve the performance of a refrigeration system.

International Journal of Mechanical and Materials Engineering, Aug 31, 2012

Nanorefrigerant is one kind of nanofluids. It is the mixture of nanoparticles with refrigerants. ... more Nanorefrigerant is one kind of nanofluids. It is the mixture of nanoparticles with refrigerants. It has better heat transfer performance than traditional refrigerants. Recently, some researches have been done about nanorefrigerants. Most of them are related to thermal conductivity of these fluids. Viscosity also deserves as much consideration as thermal conductivity. Pumping power and pressure drop depends on viscosity. In this paper, the volumetric and temperature effects over viscosity of R123-TiO2 nanorefrigerants have been studied for 5 to 20ºC temperature and up to 2 vol. %. The effect of pressure drop with the increase of viscosity has also been investigated. Based on the analysis it is found that viscosity of nanorefrigerant increased accordingly with the increase of nanoparticle volume concentrations and decreases with the increment of temperature. Furthermore, pressure drop augmented significantly with the intensification of volume concentrations and vapor quality. Therefore, low volume concentrations of nanorefrigerant are suggested for better performance of a refrigeration system.

Continuous need for the optimum conversion efficiency of polymer electrolyte membrane fuel cell (... more Continuous need for the optimum conversion efficiency of polymer electrolyte
membrane fuel cell (PEMFC) operation has triggered varieties of advancements,
namely in the thermal management engineering scope. Excellent heat dissipation is
correlated with higher performance of a fuel cell, thus increasing its conversion
efficiency. This study reveals the potential advancement in thermal engineering of a fuel
cell cooling system with respect to nanofluid technology. Nanofluids are seen as a
potential evolution of nanotechnology hybridization with the fuel cell serving as a
cooling medium. The available literature on the thermophysical properties of potential
nanofluids, especially on the electrical conductivity property, has been discussed. The
lack of electrical conductivity data for various nanofluids in open literature was another
challenge in the application of nanofluids in fuel cells. Unlike in any other thermal
management system, a nanofluid in a fuel cell is dealt with using a thermoelectrically
active environment. The main challenge in nanofluid adoption in fuel cells was the
formulation of a suitable nanofluid coolant with heat transfer enhancement, as compared
to its base fluid, but still complying with the strict limits of electrical conductivity as
low as 2 S/cm and several other restrictions discussed by the researchers. It is
concluded that a nanofluid in PEMFC is advantageous in terms of both heat transfer and
simplification of the cooling system through radiator size reduction and potential
elimination of the deionizer as compared to the current PEMFC cooling system.
However, there are challenges that need to be well addressed, especially in the electrical
conductivity requirement

International Journal of Mechanical and Materials Engineering (IJMME), 2010

Mixed convection heat transfers in a two-dimensional trapezoidal cavity with constant heat flux a... more Mixed convection heat transfers in a two-dimensional trapezoidal cavity with constant heat flux at the heated bottom wall while the isothermal moving top wall in the horizontal direction has been studied numerically. Control Volume based finite volume method (FVM) has been used to discretize the governing differential equations. The pressure- velocity coupling in the governing equations is achieved by using the well known SIMPLE method for numerical computations. A second order upwind differencing scheme is to be used for the formulation of the coefficients in the finite-volume equations. All computations are to be done for a range of Richardson number, Ri from 0.1 to 10 and the aspect ratio, A are to be changed from 0.5 to 2 for a fluid having Prandtl number equal to 0.71 (air). First the optimum configuration of the trapezoidal cavity has been obtained by changing the inclination angle, γ of the side walls. Then the effect of Richardson number, aspect ratio, and Rotation angle, Φ (30°, 45° and 60°) of the optimum trapezoidal cavity has been studied by changing the desired parameter. Results have been presented in the form of streamline and isotherm plots as well as the variation of the Nusselt number at the heat source surface under different conditions. The results shows that with increasing Ri, the heat transfer rate increases as natural convection dominates. The rotational angle of the trapezoidal cavity and the direction of the lid motion affect the heat transfer rate significantly. Optimum heat transfer rate is obtained at aiding flow condition having higher values of Ri.

International Journal of Renewable Energy Research, 2011

A numerical model is presented for the simulation of double-diffusive natural convection in a tri... more A numerical model is presented for the simulation of double-diffusive natural convection in a triangular solar collector. This design is encountered in greenhouse solar stills where vertical temperature and concentration gradients between the saline water and transparent cover induce flows in a confined space. This phenomenon plays an important function in the water distillation process and in the biological comfort. In this double-diffusion problem, the ratio Br of the relative magnitude thermal and compositional buoyancy and Rayleigh numbers are key parameters. Finite element technique is used to solve the governing equations. Numerical results are presented for the effect of the abovementioned parameters on local heat and mass transfer rate. In addition, results for the average heat and mass transfer rate are offered and discussed for the mentioned parametric conditions. Some interesting results are found in this investigation.

Clean Technologies and Environmental Policy, 2012

Industrial sector is the largest user of energy in India and many parts of the world. More than ... more Industrial sector is the largest user of energy in
India and many parts of the world. More than half of the
total energy is used in industries to operate various energyusing
machineries. Energy conservation is a cost-effective
approach in any energy optimization program that can be
implemented in industrial activities. Energy-intensive
industries in developing economies offer significant
energy-saving potential owing to the technology gap as
well as lower operating efficiency. A detailed energy flow
analysis was conducted in a paper carton manufacturing
unit in India to quantify the energy-saving potential. The
study revealed that the compressed air leakage is responsible
for about 50% of the total energy loss. The specific
electrical and thermal energy consumption was estimated
and found to be 91.85 kWh/ton and 1,619 MJ/ton of biomass,
respectively. Annual energy saving potential was

World renewable energy congress, 2000

Household electrical appliances consume a significant amount of electricity in the domestic secto... more Household electrical appliances consume a significant amount of electricity in the domestic sector of Malaysia and as such, have become a target for efficiency improvement. Like other developing countries in Southeast Asia, Malaysia is experiencing a dramatic growth in the number of household electrical appliances usage and it will be higher in the future. This paper attempts to identify energy saving possibilities by implementing energy efficiency standards for selected household appliances. As such, efficiency improvement on these appliances will give a significant impact on future electricity consumption in the country.

TENCON 2000. Proceedings, 2000

This is a summarized previous works on energy efficiency standards and labels for household elec... more This is a summarized previous works on energy
efficiency standards and labels for household electrical
appliances. It concerns mostly about international situation
and other country experience about energy efficiency
standard in residential sector. The possibilities of
implementation of standards and labels for various
household electrical appliances in Malaysia are also
discussed. From the international review and other country
experience shown that; there are many advantages for
Malaysia to implement the standards and labels for
household electrical appliances.

TENCON 2000. Proceedings, 2000

An experiment was conducted to investigate the effect of temperature, door opening, thermostat ... more An experiment was conducted to
investigate the effect of temperature, door opening,
thermostat setting position, relative humidity, and loading
on energy consumption of a household refrigerator-freezer.
Our investigation reveals that temperature has the greatest
effect on energy consumption followed by loading. Next
greatest effect are due to door opening and thermostat
setting position. Relative humidity has minimal effect on
energy consumption. With the experimental data, a
multiple regression equation has been developed to
investigate their combine effect.

2000 TENCON Proceedings, 2000

This is a summarized previous works on energy efficiency standards and labels for household elect... more This is a summarized previous works on energy efficiency standards and labels for household electrical appliances. It concerns mostly about international situation and other country experience about energy efficiency standard in residential sector. The possibilities of implementation of standards and labels for various household electrical appliances in Malaysia are also discussed. From the international review and other country experience shown that; there are many advantages for Malaysia to implement the standards and labels for household electrical appliances.

2000 TENCON Proceedings, 2000

An experiment was conducted to investigate the effect of temperature, door opening, thermostat se... more An experiment was conducted to investigate the effect of temperature, door opening, thermostat setting position, relative humidity, and loading on energy consumption of a household refrigerator-freezer. Our investigation reveals that temperature has the greatest effect on energy consumption followed by loading. Next greatest effect are due to door opening and thermostat setting position. Relative humidity has minimal effect on energy consumption. With the experimental data, a multiple regression equation has been developed to investigate their combine effect.

Energy conversion and management, 2001

This study attempts to predict the environmental impact of implementing an energy efficiency stan... more This study attempts to predict the environmental impact of implementing an energy efficiency standard for room air conditioners in Malaysia. The ownership of room air conditioners has increased tremendously in this country. At present, there are about 528,792 room air conditioners in Malaysian households. In the year 2020, it will be about 1,511,276. The potential carbon dioxide reduction is based on the predicted electricity savings from implementing a minimum energy efficiency standard for room air conditioners. The electricity savings are calculated based on the predicted electricity consumption by a single air conditioner in the Malaysian household. The replacement of less efficient units of this appliance is reflected in reduced electricity consumption and emissions from power plants. The energy efficiency provisions of this regulation and agreement provide targets to save money, energy and, most importantly, to protect the environment.

ASEAN Journal on Science and Technology for Development, 2001

Energy Conversion and Management, 2001

This study attempts to predict the environmental impact of implementing an energy efficiency stan... more This study attempts to predict the environmental impact of implementing an energy efficiency standard for room air conditioners in Malaysia. The ownership of room air conditioners has increased tremendously in this country. At present, there are about 528,792 room air conditioners in Malaysian households. In the year 2020, it will be about 1,511,276. The potential carbon dioxide reduction is based on the predicted electricity savings from implementing a minimum energy efficiency standard for room air conditioners. The electricity savings are calculated based on the predicted electricity consumption by a single air conditioner in the Malaysian household. The replacement of less efficient units of this appliance is reflected in reduced electricity consumption and emissions from power plants. The energy efficiency provisions of this regulation and agreement provide targets to save money, energy and, most importantly, to protect the environment.

Energy, 2001

ISO 8187, ISO 8561, and ISO 7371 are the relevant test standards for household refrigerating appl... more ISO 8187, ISO 8561, and ISO 7371 are the relevant test standards for household refrigerating appliances. This paper presents the possibility of introducing ISO household refrigerator-freezer test standards in Malaysia. An experiment was conducted to investigate the effect of room temperature, door opening, thermostat setting position, relative humidity, and loading on energy consumption of a household refrigerator-freezer. With the experimental data, a multiple regression equation is developed to investigate their combined effect. Finally, energy consumption according to the regression equation with optimum setting conditions is compared with ISO standard test conditions, Our comparison reveals that ISO refrigerator-freezer test standards are applicable with respect to Malaysian climatic conditions and usage patterns.

International journal of power & energy systems, 2002

Air conditioners are one of the major energy-consuming appliances in the Malaysian domestic secto... more Air conditioners are one of the major energy-consuming appliances in the Malaysian domestic sector. According to a load survey, air conditioners account for around 8.3% of the total residential electricity consumption in Malaysia. To reduce the energy consumption in this sector, Malaysia Energy Center is considering implementing minimum energy efficiency standards for room air conditioners sometime in the coming year. The first step towards adopting energy efficiency standards is to create a test procedure for rating and testing this appliance. An energy test procedure is the technical foundation for all energy efficiency standards, energy labels, and other related programs. As room air conditioners are a climate-dependent appliance, the climatic condition for a particular country or region is an important determinant in developing the test conditions. Therefore, before setting the test conditions, the requirements for a specific country and region must be clarified. This article is an analysis of the applicability of ISO 5151 nonducted air conditioner test conditions, based on the climatic conditions in Malaysia. International adoption of ISO 5151 by several countries is also discussed. There is a trend towards international harmonization of appliance test standards; this work can be considered as support to that end.

Energy Conversion and Management, 2002

Because of changing fossil fuel prices, sources and environmental consciousness, Malaysian utilit... more Because of changing fossil fuel prices, sources and environmental consciousness, Malaysian utilities have been forced to change the type of energy sources to generate electricity. This new policy of electricity generation companies will change fuel use gradually from 70% gas, 15% coal, 10% hydro and 5% petroleum in the year 2000 to 40% gas, 30% hydro, 29% coal and only 1% petroleum in the year or 2020. These changes tend to reduce CO2 emission. This study attempts to predict the potential CO2 reduction due to these changes. The calculation is based on CO2 emission for unit electricity generated and the changing type of fuel percentages for electricity generation in Malaysia. The study found that the substitution will reduce CO2 emission from power plants in this country.

Energy Conversion and Management, 2002

Refrigerator-freezers energy consumption is greatly affected by room temperature, door opening an... more Refrigerator-freezers energy consumption is greatly affected by room temperature, door opening and
thermostat setting position. Two frost free household refrigerator freezers of the same capacity were tested
in the laboratory to determine the sensitivity of their energy consumption to various usage conditions. The
experiments were conducted to investigate the effect of single variables, such as temperature, thermostat
setting positions and door opening, and their combined effect on energy consumption. Our investigation
reveals that room temperature has the higher effect on energy consumption, followed by door opening.
Thermostat setting position has the lower effect on energy consumption. More detailed tests were performed
under different room temperature, thermostat setting position and door opening conditions. With
the experimental results, a first order mathematical model has been developed to investigate their combined
effect on energy consumption. The test results are discussed and presented.