Moharram Jafari - Academia.edu (original) (raw)

Papers by Moharram Jafari

Journal of Applied Fluid Mechanics, Sep 1, 2019

Non-circular jet is identified as an efficient passive flow-control technique that attracts many ... more Non-circular jet is identified as an efficient passive flow-control technique that attracts many research topics. The existence of twine-vortexes is the main reason for dissimilarity between circular and non-circular jets. Which also influences the production of droplets and satellites as well as the jet instability. This investigation presents instability analysis of liquid-gas interface as an applicable conception in free-jet flows. We experiment different jet geometries within a gas ambient in order to study their hydrodynamic behavior. These studies give an appropriate perception about contributing forces that play essential roles in fluid instability. We focus on varying viscosity and surface tension as our excitation techniques. These methods are vital to examine the key properties of non-circular jets such as breakup and decay length, axis-switching wavelength as well as produced droplets and satellites characteristics. First, instabilities of charged liquid jets are investigated by considering the interaction between electric and inertial forces. Also, the viscosity effect was studied for its interaction with the inertial and surface tension forces. In each case, liquid jet instability for various nozzle geometries over a specific range of jet velocity is examined. The obtained results illustrate that the geometry of nozzle has an important effect on jet instability. In addition, by increment of We number, the breakup and decay length as well as the axis-switching wavelength are raising. However, by the rise of twin-vortex number, the breakup length increases but the decay length and axis-switching wavelength decrease.

International Journal of Energy Research, Feb 27, 2021

An advanced adiabatic compressed air energy storage (AA-CAES) system can operate as a polygenerat... more An advanced adiabatic compressed air energy storage (AA-CAES) system can operate as a polygeneration system, which stores power from renewables or the grid at off-peak periods and releases power, heating load and cooling load to users at peak periods. According to the energy forms produced by AA-CAES system, it can be categorized as either a cogeneration system (producing power and heating load simultaneously) or a trigeneration system (producing power, heating load and cooling load simultaneously). In this study, a comprehensive mathematical model of polygeneration system based on AA-CAES system is established. Thermo-economic analysis and comparison of cogeneration/trigeneration system based on AA-CAES system are carried out, and the relationships between the type of AA-CAES system with the number of compression/expansion stages and parameters of the system are revealed. Multi-objective optimization considering three objective functions is used to determine the optimal design for two types of AA-CAES systems. When there are two compression stages and two expansion stages, the performance of cogeneration system is optimal, and the round trip performance coefficient RTPC, exergy efficiency η ex and annual total cost saving ratio ACSR are 0.898, 0.68 and 0.258, respectively. When there are three compression stages and one expansion stage, the performance of the trigeneration system is optimal, and RTPC, η ex and ACSR are equal to 1.057, 0.555 and 0.134, respectively. This study will provide guidelines for the design of polygeneration system based on AA-CAES system, which can be widely applied in distributed energy systems to improve the off-design performance.

Applied Energy, Dec 1, 2017

• A multi-generation system for producing power, cooling and fresh water is proposed. • The propo... more • A multi-generation system for producing power, cooling and fresh water is proposed. • The proposed system is based on the combined power and ejector refrigeration cycle. • To recover some energy, the HDH desalination unit is integrated with the top cycle. • A zeotropic mixture is selected as the working fluid in the proposed system. • Thermodynamic analysis and two scenarios of optimization are carried out.

Sustainable Energy Technologies and Assessments

Arabian Journal of Geosciences

International Communications in Heat and Mass Transfer, 2017

Jet fans are increasingly preferred over traditional ducted systems as a means of ventilating pol... more Jet fans are increasingly preferred over traditional ducted systems as a means of ventilating pollutants from large spaces such as underground car parks. The spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) -which causes novel coronavirus disease (COVID-19)- through the jet fans in the underground car parks has been considered a matter of key concern. A quantitative understanding of the propagation of respiratory droplets/particles/aerosols containing the virus is important. However, to date, studies are yet to demonstrate the viral (e.g. SARS-CoV-2) transmission in the underground car parks equipped with jet fans. In this paper, the numerical simulation has been performed to assess the effects of jet fans on the spreading of viruses inside the underground car parks.

In the current paper, heat transfer in conduction pumping of n-hexane and n-decane dielectrics (a... more In the current paper, heat transfer in conduction pumping of n-hexane and n-decane dielectrics (as working fluids) using flush electrodes is investigated by conducting experimental tests. The Study has been carried out for different fluid film thicknesses and variable applied electric voltage, and the effects of various parameters such as physical properties (ion mobility difference, density and viscosity), as well as fluid working temperature on heat transfer performance of the conduction pump have been investigated. The results show that higher ion mobility difference, as well as lower density and viscosity, increases the flow rate and heat transfer in the conduction pump, due to the improvement of the vortices formation in the vicinity of the electrodes. Moreover, it significantly increases the heat transfer in the pump by creating turbulent flow around the electrodes. On the other hand, higher operating temperatures enhance the flow rate and heat transfer due to decreasing densi...

Applied Thermal Engineering, 2019

Abstract Due to the finite nature of fossil fuels and their unsustainable function in the power p... more Abstract Due to the finite nature of fossil fuels and their unsustainable function in the power production industry, a photovoltaic combined cycle with biomass post firing and hydrogen production is proposed and assessed with conventional and enhanced (avoidable and unavoidable) exergy and exergoeconomic analyses. It is observed that increasing the compressor pressure ratio increases the CO2 discharge rate, the system exergy destruction rate, and the exergoeconomic factor of the cycle, and decreases the exergy efficiency, the natural gas flow rate, the exergy destruction cost rate and the system unit product cost. Further, the energy efficiency is optimized by adjusting the compressor pressure ratio. Increasing the area of the photovoltaic thermal system decreases the energy and exergy efficiencies and increases the unit product cost of the system. Hydrogen injection to the combustion chamber is an alternative for using the product hydrogen. This operation decreases the CO2 discharge rate, the exergy destruction rate in the combustion chamber, the system product cost and the energy efficiency. A comparison of the results of conventional and enhanced analyses shows that they have different implications about the optimization of the post combustion chamber, the heat recovery steam generator, and the pump. With conventional analyses, the post combustion chamber and the pump should be considered for investment cost decreases and the heat recovery steam generator for quality improvement. But the enhanced analyses lead to opposite conclusions.

Diamond and Related Materials, 2019

In this study, effective thermal conductivity and viscosity of multi walled carbon nanotubes wate... more In this study, effective thermal conductivity and viscosity of multi walled carbon nanotubes water based nanofluids containing multi walled carbon nanotubes with various geometrical characteristics were investigated, with volume fraction 0.05%vol. The experimental results demonstrated that thermophysical properties of the nanofluids depend on the geometrical characteristics of carbon nanotubes. The results were compared with some well-known models for thermal conductivity enhancement and relative viscosity and good conformities were observed. In this research, maximum enhancements of 36% and 5.5% were achieved for nanofluids effective thermal conductivity and dynamic viscosity respectively; these improvements were established in comparison to the base fluid at 45 ºC. In addition, the results indicate that applying processes based on the surface modification on the nanotubes and improvement in nanoparticles dispersion can lead to enhancement in thermophysical properties in the nanofluids. During the experiments, the effective procedure of nanofluids stabilization was obtained. These findings combined with obtaining a pH value near the neutral state result an improvement in heat transfer and flow characteristics of the nanofluids.

Journal of colloid and interface science, Jan 3, 2018

A controlled technique to produce a precise volume of fluid species, such as water droplets, has ... more A controlled technique to produce a precise volume of fluid species, such as water droplets, has critical importance in a variety of industrial applications. Electric field provided a well-established method to produce charged water droplets with a controlled volume. The coalescence of produced charged water droplets, however, impedes the efficiency of electric field-assisted methods. Whereas the coalescence of stationary single droplets, often charged, is overwhelmingly studied in air or vacuum, the effects of surrounding medium and approaching velocity are neglected. Systematic series of experiments and simulations were designed to address the effect of viscosity as well as approaching velocity on the coalescence of charged water droplets in viscous surrounding mediums (μ = 100 & 1000 cSt). Results suggested that increasing the electrical conductivity of water droplets with lower approaching velocity diminishes the chance of coalescence between water droplets. The higher viscosity...

International Communications in Heat and Mass Transfer, 2017

Available online xxxx This work is dedicated to finding a suitable measure to judge thermal perfo... more Available online xxxx This work is dedicated to finding a suitable measure to judge thermal performance of nanofluids. The importance of this issue arises from misleading claim of excess heat transfer of nanofluids compared to the base fluid, neglecting the hydraulic effects such as increase in pressure drop. To clarify the issue, the experimental setup with capability to create constant Reynolds number and constant pumping power is constructed. Thermal behavior of nanofluids of silicon oxide/water and aluminum oxide/water and distilled water in developing region of laminar flow regime is investigated. In this regard, the convective heat transfer coefficient within the finned tube heat exchanger is evaluated. According to the results, the concentration of nanoparticle in the base fluid will have a significant impact on the amount of deflection of these two criteria, so that by increasing the nanoparticle's concentration the difference between these two measures becomes greater.

Experimental Heat Transfer, Sep 10, 2014

ABSTRACT The influence of external electrohydrodynamic forces on natural convection from a flat p... more ABSTRACT The influence of external electrohydrodynamic forces on natural convection from a flat plate has been studied. Temperature distribution in aforementioned channel at α = 45°,90° and 150°angles in different 10, 12 and 15 kV electrostatic fields have been reviewed. Corona wind and the shape of created vortex by electrohydrodynamic were detected. The results showed that the heat transfer enhanced by increasing the electrostatic field in all angles. In presence of the field, enhancement the heat transfer of the plate at acute angles is better than obtuse ones. The optimal angle in terms of heat transfer was 45° noting heat transfer improvement by 61%.

Powder Technology, 2016

This work is devoted to find an appropriate criterion for thermal judging of nanofluidics. The im... more This work is devoted to find an appropriate criterion for thermal judging of nanofluidics. The importance of this issue arises from the possible misleading which asserts an existence of extra heat transfer for nanofluid compared to the base fluid, neglecting the hydraulic effects such as increasing the pressure drop. To clarify the issue, an experimental apparatus with ability of making fixed Reynolds number and constant pumping power was constructed and thermal behavior of silicon oxide/water nanofluid and distilled water are investigated in the turbulent regime. In this regard, heat transfer coefficient inside the finned air cooled heat exchanger is evaluated. Results are provided for different inlet temperatures and different nanofluid concentrations for two criteria of fixed Reynolds number and constant pumping power. Results show that the criterion of fixed Reynolds number between nanofluid and base fluid may lead to a misleading of extra heat transfer. Indeed we are obligated to increase the flow velocity to compensate the viscosity increment to make the constant Reynolds number. Hence, the existence of extra heat transfer would be comparatively related to growth of convection rather than nanoparticles effect. But it is confirmed that the criterion of constant pumping power does highly appear the real effect of nanoparticles on the heat transfer enhancement.

Applied Thermal Engineering, 2015

ABSTRACT Optimization of fin numbers in an external extended finned tube heat exchanger is the ma... more ABSTRACT Optimization of fin numbers in an external extended finned tube heat exchanger is the main subject of this work. For this purpose an experimental apparatus was constructed and available data such as temperature distribution along the heat exchanger surface at fixed Reynolds and different Rayleigh numbers were recorded and used as a verification tool for corresponding numerical results. Numerical results which are responsible for heat transfer rate, average fin Nusselt number and temperature distribution were reported. According to numerical results optimized fin numbers for maximum heat transfer were obtained for a given conditions. Also the rate of entropy generation has been calculated and consequences to the same results for optimum fin numbers. Finally to estimate the average fin Nusselt number, characteristic length scale S is introduced and used in new obtained correlation for current heat exchanger.

Heat Transfer-Asian Research, 2014

This is an open access article under the terms of the Creative Commons Attribution License, which... more This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Energy, 2011

In this paper, two new CO 2 cascade refrigeration cycles are proposed and analyzed. In both these... more In this paper, two new CO 2 cascade refrigeration cycles are proposed and analyzed. In both these cycles the top cycle is an ejector-expansion transcritical cycle and the bottom cycle is a sub-critical CO 2 cycle. In one of these proposed cycles the waste heat from the gas cooler is utilized to drive a supercritical CO 2 power cycle making the plant a combination of three cycles. Using the first and second laws of thermodynamics, theoretical analyses on the performance characteristics of the cycles are carried out. Also a parametric study is conducted to optimize the performance of each cycle under various operating conditions. The proposed cycles exhibit a reasonable value of COP (coefficient of performance) with a much less value of compressor discharge temperature, compared to the conventional cycles.

Journal of Applied Fluid Mechanics, Sep 1, 2019

Non-circular jet is identified as an efficient passive flow-control technique that attracts many ... more Non-circular jet is identified as an efficient passive flow-control technique that attracts many research topics. The existence of twine-vortexes is the main reason for dissimilarity between circular and non-circular jets. Which also influences the production of droplets and satellites as well as the jet instability. This investigation presents instability analysis of liquid-gas interface as an applicable conception in free-jet flows. We experiment different jet geometries within a gas ambient in order to study their hydrodynamic behavior. These studies give an appropriate perception about contributing forces that play essential roles in fluid instability. We focus on varying viscosity and surface tension as our excitation techniques. These methods are vital to examine the key properties of non-circular jets such as breakup and decay length, axis-switching wavelength as well as produced droplets and satellites characteristics. First, instabilities of charged liquid jets are investigated by considering the interaction between electric and inertial forces. Also, the viscosity effect was studied for its interaction with the inertial and surface tension forces. In each case, liquid jet instability for various nozzle geometries over a specific range of jet velocity is examined. The obtained results illustrate that the geometry of nozzle has an important effect on jet instability. In addition, by increment of We number, the breakup and decay length as well as the axis-switching wavelength are raising. However, by the rise of twin-vortex number, the breakup length increases but the decay length and axis-switching wavelength decrease.

International Journal of Energy Research, Feb 27, 2021

An advanced adiabatic compressed air energy storage (AA-CAES) system can operate as a polygenerat... more An advanced adiabatic compressed air energy storage (AA-CAES) system can operate as a polygeneration system, which stores power from renewables or the grid at off-peak periods and releases power, heating load and cooling load to users at peak periods. According to the energy forms produced by AA-CAES system, it can be categorized as either a cogeneration system (producing power and heating load simultaneously) or a trigeneration system (producing power, heating load and cooling load simultaneously). In this study, a comprehensive mathematical model of polygeneration system based on AA-CAES system is established. Thermo-economic analysis and comparison of cogeneration/trigeneration system based on AA-CAES system are carried out, and the relationships between the type of AA-CAES system with the number of compression/expansion stages and parameters of the system are revealed. Multi-objective optimization considering three objective functions is used to determine the optimal design for two types of AA-CAES systems. When there are two compression stages and two expansion stages, the performance of cogeneration system is optimal, and the round trip performance coefficient RTPC, exergy efficiency η ex and annual total cost saving ratio ACSR are 0.898, 0.68 and 0.258, respectively. When there are three compression stages and one expansion stage, the performance of the trigeneration system is optimal, and RTPC, η ex and ACSR are equal to 1.057, 0.555 and 0.134, respectively. This study will provide guidelines for the design of polygeneration system based on AA-CAES system, which can be widely applied in distributed energy systems to improve the off-design performance.

Applied Energy, Dec 1, 2017

• A multi-generation system for producing power, cooling and fresh water is proposed. • The propo... more • A multi-generation system for producing power, cooling and fresh water is proposed. • The proposed system is based on the combined power and ejector refrigeration cycle. • To recover some energy, the HDH desalination unit is integrated with the top cycle. • A zeotropic mixture is selected as the working fluid in the proposed system. • Thermodynamic analysis and two scenarios of optimization are carried out.

Sustainable Energy Technologies and Assessments

Arabian Journal of Geosciences

International Communications in Heat and Mass Transfer, 2017

Jet fans are increasingly preferred over traditional ducted systems as a means of ventilating pol... more Jet fans are increasingly preferred over traditional ducted systems as a means of ventilating pollutants from large spaces such as underground car parks. The spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) -which causes novel coronavirus disease (COVID-19)- through the jet fans in the underground car parks has been considered a matter of key concern. A quantitative understanding of the propagation of respiratory droplets/particles/aerosols containing the virus is important. However, to date, studies are yet to demonstrate the viral (e.g. SARS-CoV-2) transmission in the underground car parks equipped with jet fans. In this paper, the numerical simulation has been performed to assess the effects of jet fans on the spreading of viruses inside the underground car parks.

In the current paper, heat transfer in conduction pumping of n-hexane and n-decane dielectrics (a... more In the current paper, heat transfer in conduction pumping of n-hexane and n-decane dielectrics (as working fluids) using flush electrodes is investigated by conducting experimental tests. The Study has been carried out for different fluid film thicknesses and variable applied electric voltage, and the effects of various parameters such as physical properties (ion mobility difference, density and viscosity), as well as fluid working temperature on heat transfer performance of the conduction pump have been investigated. The results show that higher ion mobility difference, as well as lower density and viscosity, increases the flow rate and heat transfer in the conduction pump, due to the improvement of the vortices formation in the vicinity of the electrodes. Moreover, it significantly increases the heat transfer in the pump by creating turbulent flow around the electrodes. On the other hand, higher operating temperatures enhance the flow rate and heat transfer due to decreasing densi...

Applied Thermal Engineering, 2019

Abstract Due to the finite nature of fossil fuels and their unsustainable function in the power p... more Abstract Due to the finite nature of fossil fuels and their unsustainable function in the power production industry, a photovoltaic combined cycle with biomass post firing and hydrogen production is proposed and assessed with conventional and enhanced (avoidable and unavoidable) exergy and exergoeconomic analyses. It is observed that increasing the compressor pressure ratio increases the CO2 discharge rate, the system exergy destruction rate, and the exergoeconomic factor of the cycle, and decreases the exergy efficiency, the natural gas flow rate, the exergy destruction cost rate and the system unit product cost. Further, the energy efficiency is optimized by adjusting the compressor pressure ratio. Increasing the area of the photovoltaic thermal system decreases the energy and exergy efficiencies and increases the unit product cost of the system. Hydrogen injection to the combustion chamber is an alternative for using the product hydrogen. This operation decreases the CO2 discharge rate, the exergy destruction rate in the combustion chamber, the system product cost and the energy efficiency. A comparison of the results of conventional and enhanced analyses shows that they have different implications about the optimization of the post combustion chamber, the heat recovery steam generator, and the pump. With conventional analyses, the post combustion chamber and the pump should be considered for investment cost decreases and the heat recovery steam generator for quality improvement. But the enhanced analyses lead to opposite conclusions.

Diamond and Related Materials, 2019

In this study, effective thermal conductivity and viscosity of multi walled carbon nanotubes wate... more In this study, effective thermal conductivity and viscosity of multi walled carbon nanotubes water based nanofluids containing multi walled carbon nanotubes with various geometrical characteristics were investigated, with volume fraction 0.05%vol. The experimental results demonstrated that thermophysical properties of the nanofluids depend on the geometrical characteristics of carbon nanotubes. The results were compared with some well-known models for thermal conductivity enhancement and relative viscosity and good conformities were observed. In this research, maximum enhancements of 36% and 5.5% were achieved for nanofluids effective thermal conductivity and dynamic viscosity respectively; these improvements were established in comparison to the base fluid at 45 ºC. In addition, the results indicate that applying processes based on the surface modification on the nanotubes and improvement in nanoparticles dispersion can lead to enhancement in thermophysical properties in the nanofluids. During the experiments, the effective procedure of nanofluids stabilization was obtained. These findings combined with obtaining a pH value near the neutral state result an improvement in heat transfer and flow characteristics of the nanofluids.

Journal of colloid and interface science, Jan 3, 2018

A controlled technique to produce a precise volume of fluid species, such as water droplets, has ... more A controlled technique to produce a precise volume of fluid species, such as water droplets, has critical importance in a variety of industrial applications. Electric field provided a well-established method to produce charged water droplets with a controlled volume. The coalescence of produced charged water droplets, however, impedes the efficiency of electric field-assisted methods. Whereas the coalescence of stationary single droplets, often charged, is overwhelmingly studied in air or vacuum, the effects of surrounding medium and approaching velocity are neglected. Systematic series of experiments and simulations were designed to address the effect of viscosity as well as approaching velocity on the coalescence of charged water droplets in viscous surrounding mediums (μ = 100 & 1000 cSt). Results suggested that increasing the electrical conductivity of water droplets with lower approaching velocity diminishes the chance of coalescence between water droplets. The higher viscosity...

International Communications in Heat and Mass Transfer, 2017

Available online xxxx This work is dedicated to finding a suitable measure to judge thermal perfo... more Available online xxxx This work is dedicated to finding a suitable measure to judge thermal performance of nanofluids. The importance of this issue arises from misleading claim of excess heat transfer of nanofluids compared to the base fluid, neglecting the hydraulic effects such as increase in pressure drop. To clarify the issue, the experimental setup with capability to create constant Reynolds number and constant pumping power is constructed. Thermal behavior of nanofluids of silicon oxide/water and aluminum oxide/water and distilled water in developing region of laminar flow regime is investigated. In this regard, the convective heat transfer coefficient within the finned tube heat exchanger is evaluated. According to the results, the concentration of nanoparticle in the base fluid will have a significant impact on the amount of deflection of these two criteria, so that by increasing the nanoparticle's concentration the difference between these two measures becomes greater.

Experimental Heat Transfer, Sep 10, 2014

ABSTRACT The influence of external electrohydrodynamic forces on natural convection from a flat p... more ABSTRACT The influence of external electrohydrodynamic forces on natural convection from a flat plate has been studied. Temperature distribution in aforementioned channel at α = 45°,90° and 150°angles in different 10, 12 and 15 kV electrostatic fields have been reviewed. Corona wind and the shape of created vortex by electrohydrodynamic were detected. The results showed that the heat transfer enhanced by increasing the electrostatic field in all angles. In presence of the field, enhancement the heat transfer of the plate at acute angles is better than obtuse ones. The optimal angle in terms of heat transfer was 45° noting heat transfer improvement by 61%.

Powder Technology, 2016

This work is devoted to find an appropriate criterion for thermal judging of nanofluidics. The im... more This work is devoted to find an appropriate criterion for thermal judging of nanofluidics. The importance of this issue arises from the possible misleading which asserts an existence of extra heat transfer for nanofluid compared to the base fluid, neglecting the hydraulic effects such as increasing the pressure drop. To clarify the issue, an experimental apparatus with ability of making fixed Reynolds number and constant pumping power was constructed and thermal behavior of silicon oxide/water nanofluid and distilled water are investigated in the turbulent regime. In this regard, heat transfer coefficient inside the finned air cooled heat exchanger is evaluated. Results are provided for different inlet temperatures and different nanofluid concentrations for two criteria of fixed Reynolds number and constant pumping power. Results show that the criterion of fixed Reynolds number between nanofluid and base fluid may lead to a misleading of extra heat transfer. Indeed we are obligated to increase the flow velocity to compensate the viscosity increment to make the constant Reynolds number. Hence, the existence of extra heat transfer would be comparatively related to growth of convection rather than nanoparticles effect. But it is confirmed that the criterion of constant pumping power does highly appear the real effect of nanoparticles on the heat transfer enhancement.

Applied Thermal Engineering, 2015

ABSTRACT Optimization of fin numbers in an external extended finned tube heat exchanger is the ma... more ABSTRACT Optimization of fin numbers in an external extended finned tube heat exchanger is the main subject of this work. For this purpose an experimental apparatus was constructed and available data such as temperature distribution along the heat exchanger surface at fixed Reynolds and different Rayleigh numbers were recorded and used as a verification tool for corresponding numerical results. Numerical results which are responsible for heat transfer rate, average fin Nusselt number and temperature distribution were reported. According to numerical results optimized fin numbers for maximum heat transfer were obtained for a given conditions. Also the rate of entropy generation has been calculated and consequences to the same results for optimum fin numbers. Finally to estimate the average fin Nusselt number, characteristic length scale S is introduced and used in new obtained correlation for current heat exchanger.

Heat Transfer-Asian Research, 2014

This is an open access article under the terms of the Creative Commons Attribution License, which... more This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Energy, 2011

In this paper, two new CO 2 cascade refrigeration cycles are proposed and analyzed. In both these... more In this paper, two new CO 2 cascade refrigeration cycles are proposed and analyzed. In both these cycles the top cycle is an ejector-expansion transcritical cycle and the bottom cycle is a sub-critical CO 2 cycle. In one of these proposed cycles the waste heat from the gas cooler is utilized to drive a supercritical CO 2 power cycle making the plant a combination of three cycles. Using the first and second laws of thermodynamics, theoretical analyses on the performance characteristics of the cycles are carried out. Also a parametric study is conducted to optimize the performance of each cycle under various operating conditions. The proposed cycles exhibit a reasonable value of COP (coefficient of performance) with a much less value of compressor discharge temperature, compared to the conventional cycles.