Simultaneous Power Generation Research Articles

Numerical examination of exergy performance of a hybrid solar system equipped with a sheet-and-sinusoidal tube collector: Developing a predictive function using artificial neural network

Integrating cooling systems with photovoltaic-thermal (PVT) collectors has the potential to mitigate the exergy consumption in the building sector due to their capability for simultaneous power and thermal energy generation. The simultaneous utilization of nanofluid and geometry modification resulted in a synergetic enhancement in the performance of PVTs and thereby reducing their sizes and costs. In addition, there is still a lack of high accurate predictive model for the estimation of the performance of PVTs at a given Re number and nanofluid concentration ratio to be used in engineering design for the further product commercialization. To this end, the current numerical study investigates the exergy electricity, thermal, and overall exergies of a building-integrated photovoltaic thermal (BIPVT) solar collector with Al2O3/water coolant. The increase in nanoparticle concentration (ω) from 0 % to 1 % increased the useful thermal exergy and overall exergy efficiency (Exu,t/ Υov) by 0.3999 %/0.0497 %, 1.3959 %/0.2598 %, and 0.7489 %/0.1771 % at Re numbers of 500, 1000, and 1500, respectively, while Exu,t/ Υov exhibited a reducing trend at Re = 2000; 0.3928 %/0.1056 % decrease. In addition, the increase in ω from 0 % to 1 % caused the useful electricity and electrical exergy (Exu,e/ Υe) to be diminished by 0.0060 %/0.0025 % at Res 500 and 1000, and to be escalated by 0.0113 %/0.0055 % at Res of 1500 and 2000. Meanwhile, the Re augmentation, from 500 to 2000, improved the Exu,t, Exe, Υe, and Υov by 60 %, 1.26 %, 1.26 %, and 17.50 %, respectively, at different ω s. In addition, two functions were developed and proposed by applying a group method of data handling-type neural network (GMDH-ANN) to forecast the value of Υov based on two input values (Re and ω). The results showed high accuracy of the proposed model with MSE, EMSE, and R2 of 0.0138, 0.1143, and 0.99785, respectively.

WITHDRAWN: Integration of an O2 transport membrane and a biomass-fueled SCO2 cycle for liquid CO2/freshwater/power production: ANN-based optimization and techno-economic evaluation

This research presents a sustainable approach leveraging biomass as a renewable energy source and separation technology to produce liquid carbon dioxide for the food industry, alongside power and freshwater. The proposed system comprises five key sections. The biomass gasification section produces pure oxygen as a gasification agent using an oxygen transport membrane. The power generation section employs supercritical carbon dioxide oxy-fuel, enabling simultaneous power generation and carbon dioxide separation and purification. The freshwater production department uses a Multi-Stage Flash unit for desalination, drawing heat from the power generation cycle. The oxygen production section, based on oxygen transport membrane technology, supplies oxygen for the power generation cycle. The liquefaction section, utilizing the Claude cycle, facilitates carbon dioxide storage and transportation. The proposed system underwent rigorous techno-economic analysis and was further explored through multi-objective optimization based on artificial intelligence, aiming to minimize liquid carbon dioxide production costs and maximize net power output. Under pre-optimized conditions, the system exhibited a net power of 850 kW and a carbon dioxide price of $0.6/kg. Optimization results revealed a 12-year payback period, with a minimum carbon dioxide price of $0.51/kg and a maximum net power of 1692 kW. Comparative analysis under minimum carbon dioxide price conditions showed a 15% decrease in liquid carbon dioxide price and an 89% decrease in net power compared to pre-optimized conditions. Conversely, comparing the system's maximum net power after optimization to pre-optimized conditions demonstrated a 17% increase in liquid carbon dioxide price and a remarkable 99% increase in net power, highlighting substantial economic benefits.

2D covalent organic framework/reduced graphene oxide hybrid hydrogel for simultaneous power generation and organic contamination degradation in microbial fuel cell

Microbial fuel cells (MFCs) are promising devices that convert chemical energy into electrical energy via extracellular electron transfer between bacteria and electrodes. However, inefficient extracellular electron transfers and bacteria/electrode interactions often limit their performance. Herein, we demonstrate a hybrid hydrogel assembled by a 2D covalent organic framework (COF) and reduced graphene oxide (rGO) nanosheets as anode materials for MFCs. The 2D COF nanosheets effectively prevent the stacking of rGO nanosheets, resulting in the hybrid hydrogel with a high specific surface area (313.2 m2/g), abundant mesopores and macropores, and high electrical conductivity (492 S/m). The COF material also brings many quinone groups as redox mediators to facilitate electron transfer between bacteria and electrodes. The COF/rGO hybrid hydrogel enhances the growth of Shewanella decolorationis S12 cells, even under the influence of different organic dyes. Dense biofilms are formed on the hybrid hydrogel's surface and inside its macropores, further improving extracellular electron transfers. Assembled MFCs using COF/rGO anodes deliver a maximum power density of 905.1 mW/m2 and can operate for 600 h. They also enable simultaneous power generation and fast organic contamination degradation in electrolytes. This work shows the potential of using 2D nanoarchitectures to promote high-performance MFCs.

Thermodynamic feasibility and multiobjective optimization of a closed Brayton cycle-based clean cogeneration system

The present research has analyzed the energy and exergy of a combined system of simultaneous power generation and cooling. To provide a comprehensive data sheet of this system, the system has been investigated in the temperature range of 300–800 °C, and 6 working fluids, including air, carbon dioxide, nitrogen, argon, xenon, and helium, have been investigated. The parameters affecting the performance of the system, namely the compressor inlet pressure, the compressor pressure ratio, and the intermediation pressure ratio were investigated. The power produced by the Brayton cycle at a pressure ratio of 5.2 is the highest due to the increase in compressor power consumption and turbine power generation. The results of the parametric study showed that the exergy efficiency of the system has the maximum value at the pressure ratio of 4.73. The results of the parametric study showed that increasing the pressure of the compressor does not have a significant effect on the electricity consumption and the temperature of the working fluid due to the constant pressure ratio. The input energy to the heat exchanger of the absorption chiller decreases with the increase in the Brayton cycle pressure ratio, and as a result, the cooling created by the chiller also decreases. In this method, three objective functions of exergy efficiency, energy efficiency, and total production power are considered as objective functions. The most optimal value of intermediation pressure ratio was obtained after the optimization process of 1.389. Also, the most optimal value of the pressure ratio of high-pressure and low-pressure turbines was reported as 2.563 and 1.845, respectively.

Efficient energy generation and thermal storage in a photovoltaic thermal system partially covered by solar cells and integrated with organic phase change materials

To address the limitations of conventional photovoltaic thermal systems (i.e., low thermal power, thermal exergy, and heat transfer fluid outlet temperature), this study proposes a photovoltaic thermal system with a solar thermal collector enhancer (PVT-STE), incorporating phase change materials for simultaneous electricity and thermal power generation and thermal energy storage. The system consists of a water based solar collector with a partially covered absorber plate utilizing photovoltaic cells, while each component is equipped with a thermal storage enclosure filled with phase change materials. The primary objectives of this research encompass the evaluation of the proposed system's performance and the identification of appropriate phase change materials for each component. To gain comprehensive insight into the effects of employing and selecting appropriate phase change materials, the study investigates various configurations under both hot and cold weather conditions of Shanghai, China. Water serves as the heat transfer fluid under real-world operational conditions. The numerical results indicate that, for the given conditions, optimal phase change material selection entails using higher melting temperatures (e.g., RT42) in the STE component and lower melting temperatures (e.g., RT31) in the PVT component. Employing the optimal phase change materials for each component, the system can store 3234 and 1802 kJ/m2 of thermal energy during the charging process in July and November, respectively. Moreover, the proposed system generates almost 1.8 and 2 times more thermal energy per square meter in July and November, respectively, compared to a standalone photovoltaic thermal system coupled with a phase change material.

Utilisation of Renewable Electricity to Produce Synthetic Methane

This study demonstrates the production of synthetic methane or synthetic natural gas via methanation of carbon dioxide (CO2), which could replace natural gas. For the power-to-methane (P2M) process, a simulation of two-stage methanation with simultaneous power generation was carried out in Aspen Plus. The process is based on an assumed production capacity of 1 t/h of synthetic methane and is also capable of simultaneous methanation of CO2 and biogas. The biogas flow rate was estimated from industry data. When co-methanation is carried out, it is possible to produce up to 1.3 t/h of synthetic methane. After the production of synthetic methane, compression of the product was added to the process scheme, followed by dehydration. The dehydration of the synthetic methane was carried out via dynamic simulation in Aspen Adsorption. The steady-state operation was determined. The final dehydrated product contained on average only about 4.85 × 10−4 mol.% water (H2O) and the methane (CH4) contents were above 97 mol.%, providing a composition suitable for injection into the pipelines of many European countries.

Simultaneous power generation and heat recovery within a novel thermosyphon heat pipe: An experimental study and correlation development

The unique concept of generating electricity from a thermosyphon heat pipe (THP) utilizing an oscillating magnet in the adiabatic section was successfully examined experimentally. Generating electrical power while the THP operates is a revolutionary approach to improving its performance. In this regard, an energy harvesting module, including a magnet, was designed, built, and installed into the adiabatic section of the THP. The investigation was performed for four filling ratios ranging from 10 to 40%, while water served as the working fluid. In addition, the effect of variation of heat input on the performance of both THP and oscillating magnet thermosyphon heat pipe (OM-THP) was studied. Results demonstrated a negligible difference between the thermal resistances of OM-THP and THP before dry-out. The presence of the oscillating magnet causes dry-out to occur sooner; however, OM-THP still has electrical power generation during stable operation in the range of 50–125 W of heat inputs. According to the results, raising the filling ratio delays the drying of OM-THP. At 20% filling ratio and 100 W heat input, the highest average peak-to-peak open circuit voltage was 1 V. Besides, new correlations are presented to predict the induced voltage and thermal performance of the THP and OM-THP. The proposed correlations can predict the thermal resistances of THP and OM-THP, and the induced voltage of OM-THP with RSQ values of 0.91, 0.79, and 0.94, respectively.

Protonic Ceramic Electrochemical Cells with Dry Reforming of Methane for Electricity Generation, Chemicals Manufacturing, and Greenhouse Gas Mitigation

The massive exploration and utilization of fossil fuels for power generation and chemicals manufacturing have contributed to worldwide economic growth. However, these activities lead to significant greenhouse gas (GHG) emissions, which primarily include CO2 and CH4. The technologies, which intensify power generation with chemicals production from CO2 and CH4, will reduce the carbon footprint and address associated challenges. Dry reforming of methane (DRM, CH4 + CO2→ 2CO + 2H2) in electrochemical devices, which converts both CO2 and CH4 to a mixture of CO and H2 (i.e., syngas), and electricity, could be leveraged to achieve simultaneous power generation, chemicals manufacturing, and GHG mitigation. In this talk, we will present our novel protonic ceramic electrochemical cells (PCECs) for achieving this objective. The current PCECs with internal DRM suffer from poor performance, high operating temperature, and short durable operation, which is mainly ascribed to the lack of highly active and coking tolerant DRM catalysts that could be chemically and physically compatible with PCECs. This talk with present an oxide-supported in-situ exsolved Ni-Ru catalyst, which has been carefully designed and computationally validated as a highly active and coking-tolerant DRM catalyst. This DRM catalyst significantly enhances the catalytic activity and coking tolerance, which consequently lowers the operating temperatures of PCECs, with excellent fuel cell performance durability demonstrated. An exceptional peak power density of 0.94, 0.65, and 0.30 W cm-2 has been attained at 650 °C, 600 °C, and 550 °C, respectively, setting a record of PCECs for DRM.

Evaluation of Multi-Utility Models with Municipal Solid Waste Combustion as the Primary Source under Specific Geographical and Operating Conditions

Developments in waste incineration technology in terms of efficient fuel preparation, combustion, and emissions reduction, as well as the growing needs of the community in terms of electricity, water, and air conditioning loads, are the prime motive for this study. This study presents a novel approach, in which three models of the fluidized bed combustion of municipal waste for simultaneous power generation, freshwater production, and district cooling are analyzed for their energy and exergy performance. The three simultaneously evaluated utility models are different configurations of a fluidized bed combustion system with Rankine cycle power generation, cooling with a vapor absorption refrigeration system, and fresh water production using multiple effect desalination. The output from the turbine, cooling system, and desalination system is determined using the Engineering Equations Solver for different boiler operating pressures. Energy and exergy analysis data for different pressures are used to identify the best configuration. Two variants of the absorption cooling system, namely, single effect and double effect, are considered. The variants of the multiple-effect desalination are the three-stage and five-stage methods. Input parameters used in this study are municipal solid waste generation and composition data collected for an urban community in an arid climate zone with high demand for electric power, cooling, and fresh water. Model 2, which contains two turbines with the reheating and cooling systems connected to a high-pressure turbine and water desalination connected to a low-pressure turbine, gave the best overall performance. Significant savings in terms of the replacement of conventional energy were observed from these waste conversion plants with greater benefits in arid weather conditions. The results obtained by different models under different operating criteria constitute a guideline for municipal planners for the selection of appropriate waste utilization technology, as well as the appropriate operations.

Perovskite-Derived Bismuth with I- and Cs+ Dual Modification for High-Efficiency CO2 -to-Formate Electrosynthesis and Al-CO2 Batteries.

Bi-based materials are one of the most promising candidates for electrochemical CO2 reduction reaction (CO2 RR) to formate; however, the majority of them still suffer from low current density and stability that essentially constrain their potential applications at the industrial scale. Surface modification represents an effective approach to modulate the electrode microenvironment and the relative binding strength of key intermediates. Herein, it isdemonstrated that the surface comodification with halides and alkali metal ions from the conversion of Bi-based halide perovskite nanocrystals is a viable strategy to boost the CO2 RR performance of Bi for formate electrosynthesis. Cs3 Bi2 I9 nanocrystals are prepared by a hot-injection method. The as-prepared products feature well-defined hexagonal shape and uniform size distribution. When used as the precatalyst, Cs3 Bi2 I9 nanocrystals are converted to Cs+ and I- comodified Bi. The resultant catalyst exhibits high formate Faradaic efficiency close to 100%, and remarkable partial current density up to 44mA cm-2 in an H-cell and up to 276 mA cm-2 in a flow cell. Moreover, Cs3 Bi2 I9 is used as the cathode catalyst and paired with an Al anode in an Al-CO2 battery for simultaneous CO2 valorization and power generation.

Numerical analysis of solar ventilated façade integrated thermoelectric energy harvesting panel for simultaneous building thermal insulation and power generation

Although coupled thermal and power analysis has been conducted on many existing solar ventilated façade system, there is still a challenge and considerable problem on the synergistic enhancement of power generation and thermal insulation using solar energy. Motivated by this, this study proposed a novel solar ventilated façade integrated thermoelectric energy harvesting panel (SVF-TEHP) using computational fluid dynamics (CFD) simulation to produce renewable electricity and augment thermal resistance by implementing solar active thermoelectric power generation and passive ventilation strategies. Firstly, a coupled simulation model jointly with heat transfer process, energy and exergy analysis were presented to explore the effect of key parameters on thermal insulation performance and electrical performance of the SVF-TEHP, such as solar intensity, channel height, channel width and length of thermoelectric arm. Furthermore, a comparison of the system performance of SVF-TEHP, solar ventilated façade (SVF) wall and conventional wall (CW) was made from the viewpoint of building cooling and solar thermoelectric generation. Finally, the economic payback period, carbon emissions and solar utilization limit were addressed to predict the application potential and challenge of the SVF-TEHP as functional enclosure structure for building energy saving. The comparisons of SVF-TEHP, SVF and CW show that interior wall temperature can be decreased by 8.5 K and 16.5 K for solar intensity of 900 W/m2, and the output power of SVF-TEHP can reach 0.37 mW. Alternatively, the detailed analysis performed that there is a positive correlation between power generation and thermal insulation performance and the shortest payback period of this system can reaches less than 1 year. This paper will provide a lot of useful information for understanding thermal insulation and energy conversion of solar buildings.

Janus carbon nitride membrane for robust and enhanced nanofluidic power generation from wastewater

Nanofluidic membranes have shown great promise in harvesting osmotic power. Yet, previous studies extensively focused on osmotic energy released by the mixing of seawater and river water, while there exist many other osmotic energy sources, such as the mixing of wastewater with other water. However, harvesting the osmotic power of wastewater is highly challenging because it requires the membranes to have environmental remediation capabilities to avoid pollution and biofouling, which has not been satisfied by previous nanofluidic materials. In this work, we demonstrate that a Janus carbon nitride membrane can be used for simultaneous power generation and water purification. The Janus structure of the membrane generates asymmetric band structure and therefore a built-in electric field, facilitating electron-hole separation. As a result, the membrane shows strong photocatalytic capability, which efficiently degrades organic pollutants and kills microorganisms. In particular, the built-in electric field also facilitates ionic transport, significantly promoting the osmotic power density up to 30 W/m2 under simulated sunlight illumination. The power generation performance can be robustly kept with or without the presence of pollutants. This study will shed light on the development of multi-functional power generation materials for the comprehensive utilization of industrial wastewater as well as domestic sewage.

Research on Dual-Functional Properties of an Asymmetric Piezoelectric Metamaterial Beam for Simultaneous Vibration Reduction and Power Generation

Research on Dual-Functional Properties of an Asymmetric Piezoelectric Metamaterial Beam for Simultaneous Vibration Reduction and Power Generation

Process-intensified protonic ceramic fuel cells for power generation, chemical production, and greenhouse gas mitigation

•Simultaneous power generation, chemical production, and greenhouse gas mitigation •Sm0.2Ce0.7Ni0.1Ru0.05O2-δ catalyst was designed for dry reforming of methane •Extensive studies were performed to probe the synergistic impacts of Ni and Ru •At 650°C, the DRM-PCFC attained a peak power density of 0.94 W cm−2 Here, we present protonic ceramic fuel cells (PCFCs) that achieve the internal dry reforming of methane (DRM) at 550°C–650°C to simultaneously generate power, produce syngas or hydrogen as chemical building blocks, and to mitigate two harmful greenhouse gases. We developed an oxide-supported in situ exsolved Ni-Ru catalyst (Sm0.2Ce0.7Ni0.1Ru0.05O2-δ, i.e., SDC-Ni-Ru). The in situ exsolved Ru clusters favor the CO2 activation step, while the Ni clusters promote the CH4 activation. The synergy between Ni and Ru clusters simultaneously improves the CH4 and CO2 activation, enhancing the DRM activity. Additionally, we discovered that the Ru clusters alter the DRM pathway, favoring the formation of monodentate carbonate species, which subsequently accelerates the oxidization of −CH∗ species on Ni clusters and improves the coking tolerance. The PCFCs equipped with this SDC-Ni-Ru internal DRM catalyst attain exceptional and durable power densities using a mixture of CH4 and CO2 as the fuel, setting a record for DRM-PCFCs. Here, we present protonic ceramic fuel cells (PCFCs) that achieve the internal dry reforming of methane (DRM) at 550°C–650°C to simultaneously generate power, produce syngas or hydrogen as chemical building blocks, and to mitigate two harmful greenhouse gases. We developed an oxide-supported in situ exsolved Ni-Ru catalyst (Sm0.2Ce0.7Ni0.1Ru0.05O2-δ, i.e., SDC-Ni-Ru). The in situ exsolved Ru clusters favor the CO2 activation step, while the Ni clusters promote the CH4 activation. The synergy between Ni and Ru clusters simultaneously improves the CH4 and CO2 activation, enhancing the DRM activity. Additionally, we discovered that the Ru clusters alter the DRM pathway, favoring the formation of monodentate carbonate species, which subsequently accelerates the oxidization of −CH∗ species on Ni clusters and improves the coking tolerance. The PCFCs equipped with this SDC-Ni-Ru internal DRM catalyst attain exceptional and durable power densities using a mixture of CH4 and CO2 as the fuel, setting a record for DRM-PCFCs.

Recovery of transition metal ions with simultaneous power generation by reverse electrodialysis

Renewable energy processes based on salinity gradient differences possess spreading interests as an alternative to energy production methods based on fossil fuels. The reverse electrodialysis (RED) process is used for energy production by mixing seawater and river water. In the proposed solution, the spent battery effluent is applied as a high-concentrated solution for the first time, generating a potential difference in the RED stack. The high-selective cation exchange membrane for cobalt transportation in the RED system was a demanding barrier controlling the separation behaviour. The initial research confirmed the energy production ability from mixing high concentrated (HC) solution of Co2+, Li+ and Ni2+ nitrates and low concentrated (LC) solution containing chloric acid. The maximum extracted energy was estimated at 0.44 W/m2 with an energy efficiency of 45.5%. The presented method is a promising candidate for dealing with battery waste management and converting it into a valuable product such as cobalt salts with the potential for power harvesting.

Techno-Economic Analysis of a Hybrid System with Carbon Capture for Simultaneous Power Generation and Coal-to-Hydrogen Conversion

Under the growing pressure of decarbonization across industrial sectors, power plants face great challenges in reducing carbon emissions. To improve energy efficiency and reduce the carbon emissions of thermal power plants, a hybrid system with carbon capture for simultaneous power generation and coal-to-hydrogen is proposed, which features comprehensive consideration of the energy demands of power plants and coal-to-hydrogen units. In the proposed system, the reduction of energy demand is realized by heat exchanger network synthesis (HENs) of the internal streams, and a carbon capture unit is then integrated for further reduction of carbon emissions. The techno-economic feasibility of the integrated system is analyzed and discussed by using energy consumption, economics, and emission reduction as major performance indexes. The results show that energy integration saves 108.2 MW of heat, while nearly 90% of carbon emissions are reduced for the system. When comparing the total energy consumption of the subsystems and a stand-alone carbon capture unit, the consumption for cooling and heating utilities in the integrated system is reduced by 8.81 and 9.11%, respectively. In addition, the total overnight cost and the annual operation cost using the proposed integrated system are reduced by 8.51 and 22.69%, respectively, and the cost of hydrogen production decreases by 5.99%. The economics of the integrated system is significantly affected by the market prices of coal and hydrogen. The integrated system has significant advantages in reducing energy consumption and carbon emissions with higher economic performance, which can provide guidance for the low-carbon transition of coal-fired power plants.

Isopropanol and styrene removal from aqueous solutions and simultaneous power generation using microbial fuel cells with encapsulated deoxygenated anodes

The deoxidizing packing material (DPM) in a microbial fuel cell (MFC) was improved by adding a deoxidizing agent (DA) to its surface to form DPMDA-out, causing the DA effectively to consume dissolved oxygen in the anode tank. The removal efficiencies by MFC using DPMDA-out of isopropanol and styrene were 8.72–30.5 % and 2.50–15.7 % greater than the removal efficiencies by adding DA to the interior of the DPM to form DPMDA-in, respectively. This results suggest that MFC processes hydrophilic isopropanol more easily than hydrophobic styrene. The maximum voltage outputs of a DPMDA-out-based MFC for isopropanol and styrene are 1.08 and 1.16 times those of a DPMDA-in-based MFC and the power densities are 1.31 and 1.57 times as large, respectively. Even though the removal efficiency of styrene (15.7 %) in the modified MFC is less than that of isopropanol (30.5 %), the electricity production by the MFC with styrene as its substrate exceeds that by the MFC with isopropanol. A kinetic analysis revealed that the effectiveness of improving the anode material was more easily reflected by the reaction rate constant (k) of isopropanol. The improved DPMDA-out enhances the removal efficiency of targeted pollutants and the production of power by the MFC.

Simultaneous Phosphate Removal and Power Generation by the Aluminum–Air Fuel Cell for Energy Self-Sufficient Electrocoagulation

A self-powered electrocoagulation system with a single-chamber aluminum–air fuel cell was employed for phosphate removal in this study. Electricity production and aluminum hydroxides in solution were also investigated. When the NaCl concentration increased from 2 mmol/L to 10 mmol/L, the phosphate removal increased from 86.9% to 97.8% in 60 min. An electrolyte composed of 10 mmol/L of NaCl was shown to obtain a maximum power density generation of 265.7 mW/m2. When the initial solution pH ranged from 5.0 to 9.0, 98.5% phosphate removal and a maximum power density of 338.1 mW/m2 were obtained at pH 6.0. Phosphate was mainly removed by aluminum hydroxide adsorption. These results demonstrate that the aluminum–air fuel cell can be applied as electricity-producing electrocoagulation equipment. Aluminum–air fuel cells provide an alternative method to meet the goal of carbon neutrality in wastewater treatment compared with traditional energy-consuming electrocoagulation systems.

Conceptual design and simulation of a stand-alone Wind/PEM fuel Cell/Hydrogen storage energy system for off-grid regions, a case study in Kuhin, Iran

In recent years the necessity of reducing environmental impacts and increasing flexibility in the energy sector has led to a growth in the penetration of renewable energy sources and the shift from centralized production to distributed production. This study aims to investigate the separation of the Kuhin, Qazvin region from the national grid network. In this case, two prominent scenarios are designed and proposed: the simultaneous power generation of wind turbine and proton-exchange membrane fuel cell (PEMFC) (first scenario) and fuel cell-hydrogen energy storage (second scenario). Algorithm optimization is employed to reach the best solution in the MATLAB environment to obtain the most efficient configuration of the hybrid systems. Accordingly, the proposed PEMFC is modeled and simulated using COMSOL software via the computational fluid dynamics methods. The results obtained from the optimization show that the desired PEMFC power plant suitable for the first scenario has a power capacity of 160 kW, generating electricity at $0.6452 per kWh and a present capital of $4,466,099. In the second scenario, the results show a power capacity of 168 kW at $0.7237 per kWh requiring a capital cost of $5,029,397.

The Economic and Environmental Evaluations of Combined Heat and Power Systems in Buildings with Different Contexts: A Systematic Review

Cogeneration systems—also known as combined heat and power systems—form a promising technology for the simultaneous generation of power and thermal energy while consuming a single source of fuel at a site. A number of prior studies have examined the cogeneration systems used in residential, commercial, and industrial buildings. However, a systematic review of the economic and environmental evaluations of the system is not found in the literature. The present study aims to address this research gap by reviewing the most relevant studies on the cogeneration systems applied to buildings in different contexts (e.g., residential, commercial, and industrial) and provides systematic evaluation approaches from economic and environmental perspectives. Results show that the cogeneration system can significantly reduce energy consumption, operating costs, carbon dioxide equivalent emissions, and positive performance on other relevant parameters. The present study provides extensive evidence to show that the cogeneration system is simultaneously economically profitable and environmentally friendly in various application contexts. To achieve the maximum benefits from cogeneration systems, several practical suggestions are provided for their successful installation and implementation in real-life situations.