Exergoeconomic Evaluation Research Articles

Thermodynamic and exergo-economic evaluation of biomass-to-X system combined the chemical looping gasification and proton exchange membrane fuel cell

The resource utilization of biomass is of great significance to the adjustment of energy structure. The syngas produced by biomass gasification can be used for power generation and production of green chemical raw materials. In this paper, a biomass-to-X (BtX) system based on the chemical looping gasification and high temperature proton exchange membrane fuel cell (PEMFC) is proposed to produce methanol, electricity, heating and cooling. The heat produced by the BtX system is harnessed for the regeneration of the carbon capture solution, as well as to drive both the organic Rankine cycle and the double-effect absorption chiller, enabling cascade utilization of the energy. The thermodynamic and exergo-economic models are carried out to evaluate system performance. The relationship between the material, energy and cost flow from biomass to products is analyzed. Finally, the influence of key parameters on system performance is studied. The results show that the energy efficiency of the BtX system is 54.0 % and the exergy efficiency is 35.4 %. The yield rate of methanol with 99.2 wt% purity is 6.48 tons/h. The cost of equipment, propanol and biomass accounts for 34.9 %, 28.9 % and 28.1 % of the total investment cost, respectively, while the cost of the PEMFC stack represents 50.4 % of the equipment costs. The unit exergy cost of the electricity and methanol are 0.068 $/kWh and 0.049 $/kWh, respectively. The methanol, carbon capture and cooling costs are most sensitive to the change in the propanol cost, followed by the biomass cost. For every 0.05 increase in the hydrogen fraction to methanol production, the electricity decreases by 3.1 MW and the methanol yield increases by 0.23 kg/s.

An efficient biogas-base tri-generation of power, heating and cooling integrating inverted Brayton and ejector transcritical CO2 cycles: exergoeconomic evaluation

An efficient biogas-base tri-generation of power, heating and cooling integrating inverted Brayton and ejector transcritical CO2 cycles: exergoeconomic evaluation

Optimizing small-scale power generation: Exergetic and exergoeconomic evaluation of an integrated gasification system for sacha inchi residues

Biomass is the primary non-fossil energy source, especially in regions such as Central and South America, and holds immense potential for non-fossil energy. Utilizing waste biomass, mainly through gasification for syngas production, offers environmental advantages over direct combustion for electricity and heating. The sacha inchi seed shell (SIS), currently discarded, presents an untapped biomass resource. Hence, the significance of this work lies in assessing the gasification potential of SIS for decentralized power generation, targeting rural off-grid areas. Detailed modeling of mass, energy, and exergy flows was used to establish a self-sustaining 35 kW sacha inchi processing plant using Aspen Plus software. The best operational condition was identified at an equivalence ratio of 0.25, achieving 100 % carbon conversion efficiency and 73.5 % cold gas efficiency with a lower heating value of 6.126 MJ/kg. Exergetic analysis highlights heat exchangers and the power generator as the least efficient components (0.214 % to 27.85 %), contrasting with superior efficiencies in the gasifier, compressor, and cyclone (82.85 %, 85.5 %, and 96.13 %, respectively). Exergoeconomic assessment reveals an energy cost of 10.25 USD/GJ, notably lower than Colombian energy costs for equivalent power needs.

Exergo-economic approach for comprehensive evaluation of the performance of industrial-scale milk and coffee beverage process lines

This study aimed to perform comprehensive analyses of the performance of the industrial-scale production of three different beverages (whole milk, black coffee, and milk coffee) in carton aseptic and glass bottle packaging process lines from raw material to the secondary packed final product by using innovative exergo-economic approach to promote a detailed data for a sustainable, performance-efficient production and economy in beverage industry. System performance efficiencies (energy and exergy) for the whole of production lines and individual processing steps were determined, and the exergo-economic performance of the industrial productions of three different beverages was compared. The maximum overall exergy efficiencies for glass bottle and carton aseptic packaging lines were as 52.57 % and 55.90 %, respectively, in whole milk production whereas the minimum overall exergy efficiencies were for these lines were 47.39 % and 48.67 %, respectively, for milk coffee production. For whole milk, the process steps having the minimum exergy efficiency were the filling step in carton aseptic (23.14 %±1.25) and the seperation step (26.90 %±1.09) in glass bottle packaging lines. For black coffee and milk coffee productions, the process step with the highest improvement potential was the homogenization/deaeration step for both carton aseptic and glass bottle packaging lines. The highest exergy destruction costs were obtained for the milk coffee; 72.52±0.03$/MJ for carton aseptic package and 63.82±1.85$/MJ for glass bottle. The most cost-efficient process was determined to be the black coffee in the carton aseptic packaging line due to the minimum product cost rate (89.71±2.39 $/MJ). It is thought that this study contributes valuable information on the approach of the comparing the performance of different production lines using exergo-economic evaluation.

Energy, exergy, and exergoeconomic (3E) evaluation of a hybrid multigeneration system based on a solar tower

This study focuses on analyzing a multigeneration system that integrates conventional energy systems with renewable energy sources to boost efficiency and decrease the use of fossil fuels. The aim is to find a financially viable and low-carbon solution for sustainable development. The performance of the proposed multigeneration system, which can simultaneously supply fresh water, hydrogen, heating, and cooling, is evaluated by analysis. The energy, exergy, and economic analyses in this assessment all use thermodynamic equations. In addition, the effects of different variables on the operating results of the hybrid system were examined and the economic viability of the power plant was assessed by calculating the net present value (NPV). The results of the analysis show that this system can supply 47.297 MW of electrical power, 8.287 MW of heating power, 11.222 MW of cooling power, 2.49 kg/s of fresh water, and 18.06 kg/h of hydrogen. The use of renewable solar energy leads to a 26.47 % reduction in fuel consumption and an annual reduction in CO2 emissions of 18,230 tons. The calculation results in a total system cost rate of 9299 USD/hour and a unit price of cogeneration of 34.5 USD/GJ. At the end of the 20-year lifespan of the power plant, a payback period (PP) of 2 years and 11 months was expected, which corresponds to a net profit of USD 200 million at present value.

Exergoeconomic evaluation and optimization of a solar-powered polygeneration system producing freshwater, electricity, hydrogen, and cooling

This study presents a comprehensive exergoeconomic assessment and optimization of a pioneering solar-powered polygeneration system designed for simultaneous production of electricity, cooling, freshwater, and hydrogen, aiming to fill the gap in knowledge about such a polygeneration system. The study employs an advanced methodology to evaluate future improvement methods, considering the system's performance and economic viability. The Specific Exergy Costing (SPECO) method is used for exergoeconomic analysis, and the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) is preferred to reveal Multiple Criteria Decision Analysis (MCDA) for optimization.As an important conclusion, it is recognized that system modifications should reduce the financing cost while simultaneously increasing the system's lifespan and annual operational time. The most expensive components of the system are the PTC, ORC, and electrolyzer, which are responsible for 51%, 23%, and 18% of the total cost of energy destruction, respectively. Thus, purchase price reduction and improvement in the efficiencies of these units are crucial. Also, considering the exergoeconomic factor (fc) values calculated for the system components, it is necessary to increase the efficiency of the compressor and electrolyzer, which have fc values of 37.37% and 32.1%, respectively, even if it results in higher capital expenditures. Additionally, it should be preferred to reduce the capital costs of the other system components, which have higher fc values in the range of 46.68% and 52.47%, without reducing their efficiencies significantly.

Exergoeconomic evaluation and multi-objective optimization of a novel geothermal-driven zero-emission system for cooling, electricity, and hydrogen production: capable of working with low-temperature resources

Geothermal energy is an abundant natural resource in many regions around the world. However, in some areas, the temperature of the geothermal energy resource is too low to be efficiently harvested. Organic Rankine cycles (ORCs) are known for recovering heat from low-temperature resources and generating electricity. Furthermore, half-effect absorption chillers (HEACs) are designed to produce cooling with low-temperature resources. This study proposes a novel configuration that utilizes an ORC for electricity generation, a HEAC for cooling production, and a PEM electrolysis system to produce hydrogen. The power section consists of two turbines, one driven by the vapor produced from the geothermal flow expansion, which powers the PEM section, while the other turbine in the ORC is used to drive pumps and electricity production. First, the system is thermoeconomically analyzed for an initial set of inputs. Then, various parameters are analyzed to determine their influences on system performance. The analyses reveal that the system can work with geothermal source temperatures as low as 80 °C, but the exergy and energy (thermal) efficiencies decrease to around 17% under the base settings. Furthermore, the system is capable of working with resource temperatures up to 170 °C. Ten parameters are found to affect the system’s efficiency and effectiveness. To optimize the system, the Non-dominated Sorting Genetic Algorithm II (NSGA-II) is implemented to find the optimum conditions. The objective functions are exergy efficiency and unit polygeneration cost (UPGC), which can conflict. The optimization shows that the exergy efficiency of the system can reach 48% in the optimal conditions (for a heat source temperature of 112 °C and a mass flow rate of geothermal fluid of 44 kg/s), with a hydrogen production rate of 1.1 kg/h.

Thermodynamic, exergoeconomic evaluation and optimization of S–N2O/t-N2O nuclear power cycle for the construction of the lunar base

With the continuous development of deep space exploration, many planetary exploration schemes and development plans regard the construction of planetary bases as an essential goal, especially the exploration of the Moon. Supercritical and transcritical nitrous oxide (N2O) cycles are compact, low-cost, efficient, and lightweight for nuclear reactors to supply power to the bases on other planets. This paper presents the thermodynamic, exergoeconomic, and mass analyses of a combined cycle consisting of a supercritical N2O recompression Brayton cycle and a transcritical N2O cycle (S–N2O/t-N2O). It is shown that under the optimal conditions, the combined thermal efficiency and exergy efficiency are 45.52 % and 60.13 %, respectively. Based on the exergy analysis, the exergy destruction mainly occurs in the reactor and main compressor. A sensitivity study shows that the split ratio, pressure ratio in the supercritical N2O cycle, main compressor inlet pressure, turbine2 inlet temperature, and turbine2 inlet pressure have significant effects on the net output work, thermal efficiency, specific mass, and levelized cost of electricity. Furthermore, multi-objective optimizations are considered to obtain the Pareto frontier solutions for different multi-objectives, and the optimal design condition is found. These findings could improve the power cycle performance for the construction of the Lunar Base.

Solar powered cascade system for sustainable deep-freezing and power generation - exergoeconomic evaluation and multi-objective optimization for tropical regions

The global initiative to decarbonize the refrigeration sector aims to provide cooling energy while reducing CO2 emissions. In India, the majority of urban industrial refrigeration systems are powered by fossil fuel based electricity, which increases consumption of fossil fuel and it contributes to global warming. To address this issue, two unique solar thermal operated cooling configurations, the Simple Cascade System (SCS) and the Recuperative Cascade System (RCS), were designed to fulfil urban industrial cooling energy demands. The surplus electricity generated by these systems is transferred to the on-site grid. Ethane, n-butane, and R1233zd(E) were selected as working fluids due to their low global warming potential (GWP). Among them, the RCS system with R1233zd(E) demonstrated the highest energy and exergy performance, benefiting from its superior thermodynamic properties and effective utilization of internal heat. In New Delhi, the R1233zd(E) operated RCS system achieved the highest cooling and electricity outputs at 54 kW and 20 kW, respectively. Although the R1233zd(E) operated RCS system incurred higher costs, the performance improvement outweighed the increase in cost. To assess the system sustainability in terms of exergy utilisation, a new indicator sustainability index (SI) was developed and established with values of 1.1. Increasing the evaporator temperature enhanced the system performance but also raised total plant cost, while raising the system condenser temperature had the opposite effect. The multi-objective optimization assessment for RCS configuration indicated an optimal objective value of an energy utilization ratio (EUR) of 0.16, an exergy efficiency of 8.7 %, and a capital cost of 20 $/h.

Assessment of a sustainable multigeneration system integrating supercritical CO2 Brayton cycle and LNG regasification: Thermodynamic and exergoeconomic evaluation

This study proposes a cost-effective multigeneration system that integrates a supercritical carbon dioxide (sCO2) power cycle with a liquefied natural gas (LNG) regasification process. The system aims to deliver electricity, cooling, heating, and hydrogen simultaneously. Utilizing the temperature difference between the sCO2 cycle and the LNG thermal sink, an ammonia-water-based absorption refrigeration cycle (ARC) recovers waste heat from the sCO2 power cycle, producing cooling. The elevated ammonia concentration at the ARC's condenser outlet is leveraged by a heat pump system for heating production. Concurrently, cold energy from LNG is used to recover latent heat from the condenser and heat rejected from the sCO2 power cycle, providing inputs for additional electrical power through an NG turbine. The system incorporates a PEM electrolyzer (PEME) for hydrogen production. A comprehensive examination, including energy, exergy, and exergoeconomic analyses, evaluates system performance. A sensitivity analysis illustrates the impacts of key parameters. In the baseline scenario, the system achieves energy and exergy efficiencies of 62.79% and 54.89%, with a low product unit cost of 11.35 ($/GJ). The system demonstrates substantial net power output (259.184 MW), cooling capacity (88.938 MW), heating capacity (2.839 MW), and hydrogen production (391.68 kg/h). This robust performance, coupled with cost-effectiveness, positions the proposed system as a versatile and impactful solution for sustainable and environmentally friendly energy applications.

Assessment of a combined heating and power system based on compressed air energy storage and reversible solid oxide cell: Energy, exergy, and exergoeconomic evaluation

The electricity grid with high-penetration renewable energy sources has urged us to seek means to solve the mismatching between electricity supply and demand. Energy storage technology could accomplish the energy conversion process between different periods to achieve the efficient and stable utilization of renewable energy sources. In this paper, a hybrid energy storage system based on compressed air energy storage and reversible solid oxidation fuel cell (rSOC) is proposed. During the charging process, the rSOC operates in electrolysis cell (EC) mode to achieve the energy storage by converting the compression heat to chemical fuels. During the discharging process, the cell operates in fuel cell mode for electricity production and the gas turbine is conducted to recover the waste heat from cell. To evaluate the comprehensive performance of the proposed system, the energy, exergy, and exergoeconomic studies are conducted in this paper. Under the design condition, the results indicated that the proposed system is capable of generating 300.36 kW of electricity and 106.28 kW of heating; in the meantime, the energy efficiency, exergy efficiency, and total cost per unit exergy of product are 73.80%, 55.70%, and 216.78 $/MWh, respectively. The parametric analysis indicates that the increase in pressure ratio of air compressor, steam utilization factor of rSOC stack under EC mode and current density of the rSOC stack under EC mode reduce exergy efficiency and total cost per unit exergy of product simultaneously, while the increment of operating pressure of rSOC stack under FC mode enhances the exergy efficiency and decreases total cost per unit exergy of product. The multi-objective optimization is carried out to improve the comprehensive performance of the proposed system, and the results expressed that the best optimal solution has the exergy efficiency and total cost per unit exergy of product of 65.85% and 187.05 $/MWh, respectively. Compared to the basic operating condition, the improvement of the proposed system has led to the maximum enhancement of 20.32% in exergy efficiency and 18.60% in total cost per unit exergy of product.

An Exergoeconomic Evaluation of an Innovative Polygeneration System Using a Solar-Driven Rankine Cycle Integrated with the Al-Qayyara Gas Turbine Power Plant and the Absorption Refrigeration Cycle

This study aims to develop, evaluate, and improve a polygeneration system that combines solar and Brayton cycle technologies and focuses on the sequential integration of heat. In this configuration, the exhaust gases from the Al-Qayyarah gas turbine power plant and the parabolic trough collector (PTC) array generate steam through a high recovery steam generation process. An absorption refrigeration system also supplies the Brayton circuit with low-temperature air. This process is evaluated from a 3E perspective, which includes exergy, energy, and exergoeconomic analyses for two different configurations. These configurations are integrated solar combined cycle (ISCC) with and without absorption systems (ISCC and ISCC-ARC). In addition, a comprehensive analysis was carried out to assess the impact of critical factors on the output generated, the unit cost of the products, and the exergy and energy efficiency for each configuration. The results revealed that the power produced by the ISCC-ARC and ISCC systems is 580.6 MW and 547.4 MW, respectively. Accordingly, the total energy and exergy efficiencies for the ISCC-ARC are 51.15% and 49.4%, respectively, while for the ISCC system, they are 50.89% and 49.14%, respectively. According to the results, the total specific costs for the ISCC-ARC system increased from 69.09 $/MWh in June to 79.05 $/MWh in December. ISCC’s total specific costs also fluctuate throughout the year, from 72.56 $/MWh in June to 78.73 $/MWh in December.

Exergoeconomic evaluation of fuel production from rice husk residue through the pyrolysis process

Some agro-industrial wastes are currently untreated, resulting in an increase in greenhouse gas emissions. Therefore, in relation to the pollution generated by fossil fuels, the study of the obtained fuels from agro-industrial and forestry residues has been promoted. Rice is a basic product for several families in the world, and its residue is a component that has enormous potential in Colombia due to its consumption. The objective of the present study is to conduct an exergoeconomic evaluation of the production of fuel from rice husks as agro-industrial waste by means of the slow and fast pyrolysis process. Using simulators like Aspen Plus, the simulation of the two processes was carried up, implementing a rigorous kinetic model. The yield values were validated with data from the literature, obtaining values of 42.3% and 41.4% for slow and fast pyrolysis, respectively, for pyrolytic oil. The total investment cost of the process is 2146.45 kUSD. According to the thermodynamic parameters of the simulator, an exergy analysis was conducted for the two processes. Overall exergy percentages of 73.84% and 78.19% were obtained for the slow and fast pyrolysis, respectively. The economic and exergy analysis was coupled to implement a specific exergy costing. The exergoeconomics factors obtained values of 72.21% and 76.78%, for the slow and fast pyrolysis reactors, respectively. The contribution of the present research is related to the rigorous kinetic model, in addition to its implementation in slow pyrolysis, involved in the exergoeconomic study of biomass pyrolysis processes.

Exergoeconomic Evaluation of a Cogeneration System Driven by a Natural Gas and Biomass Co-Firing Gas Turbine Combined with a Steam Rankine Cycle, Organic Rankine Cycle, and Absorption Chiller

Considering energy conversion efficiency, pollution emissions, and economic benefits, combining biomass with fossil fuels in power generation facilities is a viable approach to address prevailing energy deficits and environmental challenges. This research aimed to investigate the thermodynamic and exergoeconomic performance of a novel power and cooling cogeneration system based on a natural gas–biomass dual fuel gas turbine (DFGT). In this system, a steam Rankine cycle (SRC), a single-effect absorption chiller (SEAC), and an organic Rankine cycle (ORC) are employed as bottoming cycles for the waste heat cascade utilization of the DFGT. The effects of main operating parameters on the performance criteria are examined, and multi-objective optimization is accomplished with a genetic algorithm using exergy efficiency and the sum unit cost of the product (SUCP) as the objective functions. The results demonstrate the higher energy utilization efficiency of the proposed system with the thermal and exergy efficiencies of 75.69% and 41.76%, respectively, while the SUCP is 13.37 $/GJ. The exergy analysis reveals that the combustion chamber takes the largest proportion of the exergy destruction rate. The parametric analysis shows that the thermal and exergy efficiencies, as well as the SUCP, rise with the increase in the gas turbine inlet temperature or with the decrease in the preheated air temperature. Higher exergy efficiency and lower SUCP could be obtained by increasing the SRC turbine inlet pressure or decreasing the SRC condensation temperature. Finally, optimization results indicate that the system with an optimum solution yields 0.3% higher exergy efficiency and 2.8% lower SUCP compared with the base case.

Thermodynamic and exergoeconomic evaluation of coal and biomass co-gasification as solid oxide fuel cell feed coupled with supercritical carbon dioxide and organic Rankine cycle

Coal-biomass cogeneration technology can not only diversify energy supply, but improve the combustion characteristics of coal and enhance system performance. This work developed a power generation system for co-gasification of coal and biomass to supply solid oxide fuel cell, and coupled with a dual system of supercritical carbon dioxide cycle and organic Rankine cycle to achieve energy cascade utilization. A comprehensive thermodynamic analysis was conducted to evaluate and optimize this system more intuitively. Constrained optimization algorithms elucidated the optimal parameters, identifying an oxygen-to-fuel mass ratio of 0.48 and a steam-to-fuel ratio of 0.18. These conditions led to a higher gasification temperature and optimal syngas yield. And sensitivity analysis on three biomass types confirms that dry and carbon-rich biomass is ideal for system doping. With a 20% doping amount, the system achieves 59.18% maximum thermal efficiency and 2.43 kg/MWh net carbon emission, outperforming the single fuel cell system by 11.14% and 4.79% respectively. The discount rate has the greatest impact on system costs in economic analysis, with a 30% fluctuation causing system costs to vary by about 14.31%. In addition, the exergy and exergoeconomic analyses identify cost formation, propose efficiency measures, and enhance cost-effectiveness.

Exergetic and exergoeconomic evaluation of an SOFC-Engine-ORC hybrid power generation system with methanol for ship application

The SOFC-Engine hybrid system is considered suitable as a marine power system due to its impressive attributes, including high efficiency and effective adaptability to variable loads. Combined with the ORC system and methanol fuel, the system's efficiency and carbon reduction can be taken to the next level. This study introduces a novel solid oxide fuel cell (SOFC)-Engine-Organic Rankine cycle (ORC) hybrid power generation system that operates on methanol. Rigorous assessments were conducted utilizing energy analysis, exergetic analysis, and exergoeconomic analysis. These evaluations aimed to pinpoint precise strategies for enhancing system efficiency while curbing expenses. The results show that the power generation efficiency of the hybrid system is 61.86%, and the exergy efficiency was 58.06%. Notably, the air preheater and engine emerge as components causing substantial exergy losses. Through exergoeconomic analysis, the exergy cost distribution across all system parts was unveiled. The reformer's exergoeconomic factor registers the highest at 77.62%. Consequently, mitigating the exergy cost associated with the reformer holds paramount importance in augmenting overall system revenue. Remarkably, the engine incurs the highest cost of exergy destruction at 10.134 $/h. Overall, this research offers pivotal insights for optimizing component performance and driving cost reductions.

Optimizing the Cooling System of High-Speed Train Environmental Wind Tunnels Using the Gene-Directed Change Genetic Algorithm.

Environmental wind tunnels play a crucial role in the research and development of high-speed railways. However, constructing and operating these wind tunnels requires significant resources, especially with respect to the cooling system, which serves as a vital subsystem. The cooling system utilizes an air compression refrigeration cycle and consists of multiple components. The efficient operation of these components, along with the adoption of appropriate strategies, greatly enhances the efficiency of the wind tunnel refrigeration system. Despite this, the existing methods for evaluating the refrigeration system do not fully capture the energy consumption of an air compression refrigeration system during practical use. To address this issue and effectively evaluate the wind tunnel refrigeration system, we propose using an exergoeconomic evaluation coefficient with experimental cycles to establish the system. This method incorporates the use of frequency coefficients and related parameters. By employing the newly developed evaluation coefficient as an objective function, we utilize the adaptive value-sharing congestion genetic algorithm to optimize the wind tunnel for high-speed trains. Furthermore, we compare the advantages and disadvantages of different optimization schemes. Traditional optimization methods prove inefficient because of the system's numerous variables and the presence of multiple peaks in the objective function. Inspired by the biogenetic breeding method, we introduce an optimization approach based on a specific gene mutation. This innovative method significantly reduces optimization time and improves efficiency by approximately 17%.

Towards an environmentally friendly power and hydrogen co-generation system: Integration of solar-based sorption enhanced gasification with in-situ CO2 capture and liquefaction process

The sorption-enhanced gasification systems, which integrate the gasification process with an in-situ CO2 capture system, have emerged as environmentally friendly solutions. This study proposes an innovative solar-based SEG system aimed at co-generating power and hydrogen while ensuring environmental sustainability. The suggested system comprises municipal solid waste gasification, in-situ calcium looping CO2 capture process, steam and humid air gas turbine secondary power cycles, and a CO2 liquefaction system. Comprehensive analysis including energy, exergy, and exergoeconomic evaluations are conducted to assess the overall system performance. The annual electrical energy efficiency of the system is calculated to be 11.9%, resulting in a net electrical power generation of 19.48 MW. The annual total energy efficiency is determined to be 54.8%. To convert the captured CO2 into a liquid form, a dual-pressure Linde-Hampson cycle with a coefficient of performance of 1.9 is employed. Among the system components, the carbonator reactor exhibits the highest exergy efficiency at 88.7%, while the sorption-enhanced gasifier, calciner, and combustion chamber show relatively higher exergy destruction. The heliostat field is identified as the most expensive component in the SEG system. The levelized cost of electricity (LCOE) for the produced electricity is calculated to be 60.1$/MWh.

Exergoeconomic evaluation of an organic Rankine cycle integrated with a compression refrigeration to select the best working fluid for waste heat recovery application: a case study of Isfahan, Iran

Exergoeconomic evaluation of an organic Rankine cycle integrated with a compression refrigeration to select the best working fluid for waste heat recovery application: a case study of Isfahan, Iran

Investigation of a novel near-zero emission poly-generation system based on biomass gasification and SOFC: A thermodynamic and exergoeconomic evaluation

SOFC poly-generation system exhibits the potential for clean and efficient conversion, but few studies have been conducted on the comparative analysis of the combined cooling, heating and power considering CO2 capture and condensate recovery. This study investigates a novel near-zero emission poly-generation system based on biomass gasification and SOFC employing different biomass fuels. This combined system adopting oxy-fuel combustion instead of traditional pre-combustion makes the flue gas easier to achieve a concentrated CO2 stream, thereby the system structure is simplified and the purity of captured CO2 is improved. The results reveal that the larch wood is the preferred fuel for the proposed system and the corresponding overall efficiency, exergy efficiency and unit cost of products achieve 80.17%, 29.12% and 20.49 $/GJ, respectively. The exergy analysis demonstrates that the exergy destruction mainly occurs in gasifier and turbine. The exergoeconomic analysis indicates that SOFC possesses a greater exergoeconomic factor of 85.12%. The parametric analysis shows that increasing gasifier temperature (Tgas), SOFC temperature difference (ΔT) and current density (j) decreases overall efficiency. The higher Tgas results in a higher unit cost (ct), whereas ct is more economic as ΔT increases. Besides, as j changing, ct of various biomass-based systems exists an optimal value.