This study presents an integrated assessment of waste heat recovery from an existing Algerian gas turbine (GT) power plant retrofitted as a Combined Heat and Power (CHP) system for District Heating (DH) applications. Unlike conventional studies that assess thermodynamic performance and heat demand separately, this work proposes an integrated framework that combines process simulation, demand estimation, and sustainability evaluation. The system is modeled using Aspen HYSYS, while the DH demand of the Aïn Beïda urban area is estimated using the degree-day method. The results demonstrate that upgrading the F’Kirina power plant to CHP mode significantly enhances overall efficiency from 33.6% to 88.1%. The integrated analysis indicates that, from an annual energy-balance perspective, the recovered waste heat is theoretically sufficient to satisfy the estimated heating demand of Aïn Beïda. Practical implementation will require dedicated studies on District Heating Network (DHN) design, thermal storage, and peak-load management. Sensitivity analysis reveals that electricity generation is strongly affected by ambient temperature, whereas heat recovery remains comparatively stable. Exergy analysis identifies the combustion chamber and Waste Heat Recovery Exchanger (WHRE) as the dominant sources of irreversibility. Furthermore, a sustainability assessment based on the Sustainability Index (SI) shows a marked improvement in exergetic performance, with SI rising from 1.46 to 1.80 after CHP integration. Environmentally, the CHP configuration reduces specific fuel consumption from 243.2 to 189.8 kg/MWh and CO 2 emissions per MWh by 29% (from 616.8 to 437 kg CO 2 /MWh). Annual avoided emissions through the substitution of conventional heating amount to 58.6 kt CO 2 /year. The proposed framework provides a comprehensive tool for evaluating CHP retrofitting strategies by linking energy production, demand profiles, and thermodynamic efficiency. These findings underscore the theoretical feasibility of CHP-based DH as a pathway to improve energy efficiency, reduce environmental impacts, and provide benchmarks to support future large-scale feasibility and infrastructure planning studies.

Energy efficiency and conservation measures are considered key solutions to foster energy transition and to reduce both energy consumption and greenhouse gas emissions, especially for the intense carbon footprint activities like in the petroleum industry. In this industry, gas flaring is considered a waste of heat and a principal source of pollution due to volatile organic compounds and greenhouse gas emissions. Gas turbine units are largely used for upstream facilities in the petroleum industry. These units are known to have low thermal efficiency and thus a high amount of the supplied fuel is not utilized and is rejected as high-temperature waste heat through exhaust hot gases. In this context, the present paper aims to assess the energy-saving potential of an organic Rankine cycle (ORC) activated by a combined gas turbine and flare waste heat recovery. The mass and energy balances as well as realistic technical specifications of the main components of the hybrid power plants form the core of the theoretical model. The simulations are performed using Aspen Hysys and typical case studies corresponding to an Algerian upstream petroleum facility are investigated. The conducted analysis highlights that the hybrid Gas Turbine-Flare gas-ORC configuration leads to a power output of 5.8 MW and a thermal efficiency of 7.41

This article presents a study of the electricity generation potential using ORC systems of the most important geothermal sites in northeastern Algeria, combining geological, thermodynamic and economic analysis. The results highlight that geothermal electricity is technically feasible with the selected indirect heat ORC geothermal plant. Such production can present an interesting economic profitability when considering the international electricity price. The best economic performance was obtained for the geothermal site of Meskhoutine leading to a depreciated payback period of 10.8 years. The electricity production cost was evaluated at 0.21$/kWh for an electricity production capacity of 498 kW. Such performance is completely breakdown when considering Algerian subsidised electricity prices. These subsidies must be revised. Otherwise, it will harm the profitability of renewable energy systems, limit their development, and constrain seriously the Algerian energy transition road map. In addition, this study highlights that the selected indirect ORC configuration presents an important internal auxiliary consumption, especially for the Air Condenser (AC) unit, and was not suitable for geothermal temperatures below 117 degrees C. Other configurations, especially hybridisation and combined heating and power production are prioritized for future investigation.

The significant increase in energy demand conjugated with the declining capacity for fossil fuel production has led to the development of polygeneration technologies (integrated simultaneous generation of electricity, cooling and heating and other energy outputs). Such technologies are projected to enhance the energy efficiency and decrease greenhouse gas emissions, particularly for industries with high carbon footprints such as the petroleum sector. The present study investigates a Combined Cooling and Power system (CCP) energy system designed for cooling, and power generation by recovering the waste heat of a combined gas turbine and flare gas system of an Algerian upstream petroleum facility. The proposed system aims to integrate an Organic Rankine Cycle (ORC) combined with an Absorption Refrigeration Cycle (ARC) to produce useful power and cooling, respectively. The energy analysis of the CCP system is implemented with the Aspen Hysys tool. The overall efficiency is improved passing from 34.6% from the basic configuration to 42.3% for the proposed new CCP configuration. This enhancement is expected to directly reduce natural gas demand and greenhouse gas emissions.

This paper presents thermo-economic analyses of upgrading an existing Algerian gas turbine power plant into a CHP system. The proposed system includes a permanent upper steam Rankine cycle combined with a flexible ORC system during the summer period or a waste heat recovery exchanger during the winter period. The results revealed an increased energy efficiency by 16.9% and 21.59% for summer and winter configurations, respectively. Additionally, an increased exergy efficiency has been observed by 15.5% for both proposed configurations compared to the simple gas cycle with a positive environmental impact in terms of carbon footprint the reduction. The economic study highlights that the proposed solution is more attractive for international market rather than the local Algerian market that is characterised by a lower energy price.

Every year, flare gas is responsible for more than 350 million tons of CO2 emissions. Aside from thermal and environmental pollution impacts, flare gas contributes to global warming and enormous economic losses. Thus, waste heat recovery due to flaring gas can be explored through Organic Rankine Cycle ORC systems for electricity production. In this context, the assessment of a toluene ORC system is proposed for a potential application in an Algerian petrochemical unit. The study focuses mainly on highlighting the potential and thermodynamic performances of the ORC application to produce electricity and potential cooling thanks to coupling an absorption chiller by recovering heat due to flaring gas. Such a solution can easily be implemented as an energy efficiency key solution. The ORC electrical production can meet the increasing demand of natural gas initially intended to be provided to a gas power plant and assures the major part of the Algerian electrical production.

Purpose Double-diffusive convection within a tri-dimensional in a horizontal annulus partially filled with a fluid-saturated porous medium is numerically investigated. The aim of this work is to understand the effects of a source of heat and solute on the fluid flow and heat and mass transfer rates. Design/methodology/approach In the formulation of the problem, the Darcy–Brinkman–Forchheimer model is adopted to the fluid flow in the porous annulus. The laminar flow regime is considered under steady state conditions. Moreover, the transport equation for continuity, momentum, energy and mass transfer are solved using the Patankar–Spalding technique. Findings Through this investigation, the predicted results for both average Nusselt and Sherwood numbers were correlated in terms of Lewis number, thermal Grashof number and buoyancy ration. A comparison was made with the published results and a good agreement was found. Originality/value The paper’s results are validated by favorable comparisons with previously published results. The results of the problem are presented in graphical forms and discussed. This paper aims to study the behavior of the flow structure and heat transfer and mass for different parameters.

We consider an ascending laminar air flow in a vertical channel formed by two parallel flat plates wetted by a thin water film and under different temperature and concentration conditions. The study includes a numerical finite volume method for the treatment of the double diffusion problem, where the analytical solution is given to the thermal diffusion. The analytical study showed that the reversed flow is observed only under some wall temperature conditions and also for certain values of Re/Gr. The reversed flow is also strongly dependent on the aspect ratio A, which is based on the cross section of the channel. Indeed, the results show than this dependence is very strong for values less than a certain critical one equal to 2.22. In the absence of the mass transfer the results showed that the evaporation rate remains null along the channel, decreases when the mass gradient is favorable and it finally vanishes at x=15. However, the evaporation rate increases in the case of an unfavorable mass gradient, to cancel at position x=20, then merges with the curve representing the forced convection. In the absence of heat transfer the evaporation rate is less important and amounts to fifty percent of the double diffusion. The results obtained by the analytical and numerical methods are compared each other and with those of a similar works and a good agreement was found.

This study is interested in the effect of an axial magnetic field imposed on incompressible flow of electrically conductive fluid between two horizontal coaxial cylinders. The imposed magnetic field is assumed uniform and constant. The effect of heat generation due to viscous dissipation is also taken into account. The inner and outer cylinders are maintained at different uniform temperatures. The movement of the fluid is due to rotation of the cylinder with a constant speed. An exact solution of the equations governing the flow was obtained in the form of Bessel functions. A finite difference implicit scheme was used in the numerical solution. The velocity and temperature distributions were obtained with and without the magnetic field. The results show that for different values of the Hartmann number, the velocity between the two cylinders decreases as the Hartmann number increases. Also, it is found that by increasing the Hartmann number, the average Nusselt number decreases. On the other hand, the Hartmann number does not affect the temperature.

This paper presents the effect of an axial magnetic field imposed on incompressible flow of electrically conductive fluid between two horizontal coaxial cylinders. The imposed magnetic field is assumed uniform and constant, we also take into account the effect of heat generation due to viscous dissipation for some cases. The inner and outer cylinders are maintained at different and uniform temperatures and concentrations. The movement of the fluid is due to the rotation of the cylinders with a constant speed. An exact solution of the governing equations for momentum and energy are obtained in the form of Bessel functions. A finite difference implicit scheme was used in the numerical solution to solve the governing equations of convection flow and mass transfer. The concentration and temperature distributions were obtained with and without the magnetic field. The results show that for different values of the Hartmann number, the concentration between the two cylinders decreases as the Hartmann number increases. Also, it is found that by increasing the Hartmann number, the local Nusselt and Sherwood numbers decreases.

This study is interested in the effect of an axial magnetic field imposed on incompressible flow of electrically conductive fluid between two horizontal coaxial cylinders. The imposed magnetic field is assumed uniform and constant. The effect of heat generation due to viscous dissipation is also taken into account. The inner and outer cylinders are maintained at different uniform temperatures and concentrations. The movement of the fluid is due to rotation of the cylinder with a constant speed. An exact solution of the governing equations for momentum and energy are obtained in the form of Bessel functions. A finite difference implicit scheme was used in the numerical solution to solve the governing equations of convection flow and mass transfer. The velocity, concentration and temperature distributions were obtained with and without the magnetic field. The results show that for different values ​​of the Hartmann number, the velocity and concentration between the two cylinders decreases as the Hartmann number increases. On the other hand, the Hartmann number does not affect the temperature. Also, it is found that by increasing the Hartmann number, the Nusselt and Sherwood numbers decreases. Key words: Rotating cylinders, viscous dissipation, heat transfer, mass transfer, magnetic field, Bessel function, finite difference.