Total Exergy Destruction Rate Research Articles

Process arrangement and multi-aspect study of a novel environmentally-friendly multigeneration plant relying on a geothermal-based plant combined with the goswami cycle booted by kalina and desalination cycles

In this study, a novel trigeneration system for cooling, heating, freshwater, and electricity generation, driven by geothermal energy is evaluated from thermodynamics, thermoeconomic, and environmental perspectives. To gain a better understanding of the system's performance, energy and exergy analyses are conducted, and the outcomes are compared with other studies. The proposed structure includes a single-flash geothermal plant, a water desalination unit, the Goswami power and cooling cycle, and the Kalina power cycle. This analysis is conducted using Aspen HYSYS software, and the results demonstrated that the single-flash geothermal plant has the highest irreversibility (48 %), and the major sources of irreversibility among all equipment are the heat exchangers, contributing to 68 % of the total exergy destruction rate. Additionally, it is observed from the thermodynamic analysis results that the energy and exergy efficiencies and the total unit cost of products of the proposed process are 32.28 %, 51.71 %, and 5.66 $/GJ, respectively. According to the results, the production rate of the products is cooling (24.8 m3/h), steam (27.44 m3/h), domestic hot water (209.7 m3/h), fresh water (45.02 m3/h), and electric power (16260 kW). The environmental analysis shows that the new process has zero CO2 emission and can save an annual consumption of petroleum equal to 4325160 L, and when compared to the power plants with natural gas and oil as fuel, CO2 emissions are prevented equal to 5691000 kg/year and 13804740 kg/year, respectively.

Energy and Exergy Analysis of an Ejector Expansion Transcritical Carbon Dioxide Air Conditioning System

A carbon dioxide based transcritical air conditioning system integrated with an ejector is thermodynamically modeled and the system is simulated for different ambient conditions. Throughout the analysis, the isentropic efficiency of motive nozzle, suction nozzle and diffuser is assumed as 85% while the mixing takes place at constant pressure. A step-by-step iterative procedure is adopted to obtain the pressure lift and entrainment ratio. The present thermodynamic model is validated with the experimental results available in the open literature. Results were then compared to a conventional transcritical carbon dioxide system working between the same operating conditions. Results show a significant improvement of about 21% and more in system performance compared to a conventional system working under the same operating conditions. To justify the application of an ejector as an expansion work recovery device and to identify the component level exergy destruction rate, a comprehensive exergy analysis is implemented and the results show 20% reduction in total exergy destruction rate of the system, with an ejector.

Thermo-environmental multi- investigation and ANN-based optimization of a novel heat integration criteria system integrated with a marine engine generating liquefied hydrogen

Marine transportation is a significant contributor to overall energy consumption among transportation sectors and is responsible for producing a considerable amount of greenhouse gases. A potential solution for alternative applications involves implementing combined heat integration, thereby enabling the production of additional utilities and mitigating emissions. The current work introduces an innovative heat integration process for a marine engine, focusing on implementing an optimal thermal matching technique to minimize overall irreversibility in producing liquefied hydrogen and coolant. The process incorporates an organic flash-bi-evaporator cooling cycle, a humidification dehumidification desalination, a polymer electrolyte membrane water electrolysis process, and a Claude cycle. The generated freshwater is delivered to the electrolyzer to produce gaseous hydrogen. This product and the cooling for freezing are utilized in the Claude cycle for hydrogen liquefaction. The study utilizes an advanced thermo-environmental multi-criteria investigation and optimization, considering sensitivity analysis and optimization based on artificial intelligence method. The optimization process incorporates the training and testing of artificial neural networks, NSGA-II method, and TOPSIS decision-making. The primary objective functions include exergetic efficiency and carbon dioxide emission. The findings demonstrate that the specified objectives are computed to be 0.121 and 2.67 kg/MWh, correspondingly. Besides, this condition exhibits a liquefied hydrogen flow rate of 6.44 L/h and a cooling output of 43.61 kW, showing an energy efficiency of 0.1145. Also, the total exergy destruction rate associated with the arranged structure is 124.5 kW. Furthermore, the optimum state reveals an exergoenvironmental index of 0.840 and an exergetic stability factor of 0.869.

Thermodynamic feasibility evaluation of an innovative multigeneration system using biogas dry reforming integrated with a CCHP-desalination process

This work investigates a new method for developing systems that use a creative heat integration process that provides heating, cooling, fresh water and power. Specifically, the suggested framework operates by syngas obtained through the dry reforming process of biogas. Environmental considerations and decrease in thermodynamic irreversibility are main features of suggested system. The energy, exergy-related, environmental, and thermoeconomic properties of the suggested system are evaluated after it has been simulated using the Aspen HYSYS software. Results indicate 99,775.5 kW of net power, 10,880 kW of cooling power, and 141,800 kW of heating power. Also, the multigeneration scenario exhibits energy and exergy efficiencies of 58.06 % and 36.0 %, respectively. From the exergetic point of view, total exergy destruction rate is found at 493479 kW. The results of the environmental assessment show that the structure emits 0.27 kg of carbon dioxide per kWh while it is operating in the multigeneration mode. This value is contrasted with a reduction of 34.15 % in heat generation and a decrease of 69.11 % in power generation modes. According to the economic study, when the system functions under multigeneration conditions, the total equipment cost and the levelized cost of products are obtained at 59,536,233 $ and 0.029 $/kWh.

Evaluation of the energy and exergy of a trans‐critical CO2 cycle driven by a double flash geothermal power plant

AbstractFacing the dual challenges of environmental impact and the finite nature of fossil fuels, the shift toward sustainable energy sources is imperative. Geothermal energy, a renewable and underutilized resource, offers a promising alternative. This study ventures into a novel domain, exploring the integration of trans‐critical CO2 (tCO2) cycle with a double‐flash geothermal (DFG) cycle, an area not extensively covered in existing research. This study aims to develop a recovery system that utilizes a tCO2 cycle powered by a DFG cycle. A crucial part of this study involves conducting a sensitivity analysis to evaluate the system's energy and exergy performance. This analysis focuses on understanding the impact of changes in key system design parameters, such as energy efficiency, exergy efficiency, net power output, and total exergy destruction rate, to determine the optimal values for these parameters. The results indicate that the recovery system shows a significant improvement of 22% in energy efficiency over the basic cycle. However, there is a decrease in exergy efficiency in the recovery system, which represents a 5.26% decline. As a result, this study paves the way for innovative approaches in geothermal energy use, suggesting potential breakthroughs in renewable technologies.

Simulation and comprehensive 4E study of a high-efficient CCHP arrangement utilizing geothermal energy and eco-friendly heat recovery

In recent years, geothermal energy has received significant attention as it provides a sustainable and renewable energy resource for various applications. The primary objective of this study is to manage the relative irreversibility and enhance productivity through efficient utilization of geothermal energy. The present paper establishes a high-efficiency and environmentally sustainable heat integration model in a novel configuration to be a geothermal energy source having the ability to produce power, heat, and cooling. The proposed framework consists of a Kalina cycle, two organic Rankine cycles, an ammonia Rankine cycle, a single-flash power unit, and a combined cooling and power unit. The simulation of the proposed system is implemented within the Aspen HYSYS software, with an examination of its feasibility across energy, exergy, economic, and environmental considerations. The research findings indicate that the system can generate 23250.8 kW of power, 582.1 kg/s of hot water, and 2.812 kg/s of chilled water. Therefore, the total exergy destruction rate is 14104 kW, with the Kalina cycle accounting for the majority share at 40.47 % Moreover, the energy and energy efficiencies of the suggested structure are 61.81 % and 72.52 %, respectively. The environmental analysis indicates that the entire process lacks carbon dioxide emissions. Furthermore, the economic analysis reveals that the total unit exergy cost and levelized cost of energy are determined to be 5.13 $/GJ and 0.511 $/kWh, respectively. Also, the proposed system exhibits a favorable net present value of approximately 32.16 M$. Hence, the project demonstrates profitability.

Exploring an innovative approach to hydrogen generation for fuel cell energy production by integrating a dual organic Rankine system with an absorption chiller powered by geothermal energy

This study delved into the thermodynamic optimization of a geothermal system integrated with a fuel cell unit for energy storage during peak consumption. An innovative system was devised to simultaneously produce cooling, electricity, hydrogen, and freshwater by combining an absorption chiller, reverse osmosis, PEM Electrolyzer, and two double Organic Rankine Cycles. To assess the impact of local weather conditions, case studies were conducted in the cities of Hong Kong (China), Bandar Abbas (Iran), Tepic (Mexico), and Melbourne (Australia). Computational modeling employed EES software, and optimization using Response Surface Methodology aimed to enhance system performance and minimize costs. The geothermal system was engineered to meet the electricity demands of residential households during peak consumption. The optimal results demonstrated that the proposed geothermal system, in its most efficient configuration, could achieve an exergy efficiency of 73.17 % and an energy efficiency of 25.25 % while operating at a cost rate of 74.36 $/h. An economic analysis revealed that among the system components, ORC1 unit and PEME incurred the highest costs. Additionally, the PEME, evaporator, and absorption chiller were identified as the main contributors to exergy destruction. The total exergy destruction rate of the proposed geothermal system is 1840.7 kWh and the total cost rate of the system is 51.73 $/h. Lastly, the assessment of the suggested geothermal system across the studied cities indicated that it performed most effectively in Melbourne, Australia. The results of the study of the production capacity in the four study cities showed that Melbourne has the highest production rate with a rate of 14,573 MWh, Tepic with a rate of 13,425 MWh, and Hong Kong with a rate of 13,174 MWh. The lowest annual rate with the amount of 12,784 MWh belongs to the city of Bandar Abbas. The environmental results showed that by producing 14,573 megawatts of electricity in the city of Melbourne, it is possible to expand 14 hectares of green space per year. Also, prevented the reduction of carbon dioxide emissions by 2972.8 tonsCO2/MWh at 71,349.4 $/tonsCO2. The analysis of the production power of the system showed that the electricity needs of 1533 people can be provided for one year by starting the geothermal system in Melbourne City.

Performance analysis of a dual-ejector enhanced two-stage auto-cascade refrigeration cycle for ultra-low temperature refrigeration

Auto-cascade refrigeration cycle (ARC) is a cost-effective solution for ultra-low temperature refrigeration. This paper proposes a dual-ejector enhanced two-stage auto-cascade refrigeration cycle (ETARC). In ETARC, two ejectors replace the throttle valves at the liquid phase outlet of the two gas–liquid separators in the conventional two-stage auto-cascade refrigeration cycle (CTARC). They are connected in series to recover partial expansion work in the throttling process, aiming to lift the suction pressure of the compressor. The ternary mixture component is selected and R600a/R41/R1150 is supposed to be the working fluid due to the best performance. The mass fraction ratio of the refrigerant mixture components, the quality at the inlet of two separators and the expansion ratio of the throttle valve (EPR) of the two cycles are optimized using particle swarm optimization (PSO) with respect to the maximum COP. The performances of the two cycles at optimum operating conditions are compared using energetic and exergetic methods, and the effect of the evaporation temperature and the condensation temperature on cycle performances and operating characteristics are discussed in detail. The results show that applying the two ejectors effectively improves the performance of ETARC. Compared with the CTARC at the evaporation temperature of −85℃, and the condensation temperature of 45℃, the ETARC cycle exhibits 16.07% improvement in COP, 29.43% increase in the volumetric refrigeration capacity qv, 17.17% reduction in the total exergy destruction rate. ETARC shows significant performance improvement and has a remarkable energy-saving potential.

Comprehensive energy, exergy, and economic analyses of a geothermal and flue gas-based dual-source power, hydrogen, and freshwater trigeneration system

Designing a ploy-generation system to produce various products is an effective method to improve the common power plant’s performance. Hence, the current investigation proposes a green poly-generation system driven by geothermal and flue gas. The proposed scheme consists of an organic Rankine cycle, proton exchange membrane electrolyzer, saline water desalination unit, and Allam cycle to produce power, hydrogen, and freshwater. The produced oxygen in the electrolyzer feeds the Allam cycle to perform an oxyfuel process to achieve zero CO2 emission. Per the 4E analysis, the system produces 27,720 kW net power, 931 kmol/h hydrogen, and 616.7 kmol/h freshwater. In this way, the energy and exergy efficiencies are obtained at about 16.87% and 51.65%. The total exergy destruction rate is estimated at about 78,926 kW, in which the organic Rankine cycle and its vapor generator have the highest portions among the different parts and equipment by about 69% and 18.87%. The sensitivity analysis indicates that by the CO2 recycle ratio of 60%, the highest energy and exergy efficiencies reach 19.3% and 54.33%. Furthermore, the unit cost of hydrogen and electricity productions are 0.07$/kWh and 7.24 $/GJ, which is a considerable reduction compared to similar methods.

Two-Objective Optimization of a Cogeneration System Based on a Gas Turbine Integrated with Solar-Assisted Rankine and Absorption Refrigeration Cycles

The current study investigates a cogeneration system based on a gas turbine, integrated with a Rankine cycle and an absorption refrigeration cycle, considering energy and exergy perspectives. The fuel used in the gas turbine’s combustion chamber is obtained through biomass gasification, specifically using wood as the biomass fuel. To enhance the system’s performance, solar energy is utilized to preheat the working fluid in the Rankine cycle, reducing the energy required in the heat recovery steam generator. Additionally, an absorption refrigeration cycle is incorporated to recover waste heat from exhaust gases and improve the plant’s exergy efficiency. A two-objective optimization is conducted to determine the optimal operating conditions of the proposed system, considering exergy efficiency and carbon dioxide emission index as criteria. The case study reveals that the gasifier and combustion chamber contribute the most to system irreversibility, accounting for 46.7% and 22.9% of the total exergy destruction rate, respectively. A parametric study is performed to assess the impact of compression ratio, turbine bleed steam pressure, gas turbine inlet temperature, and solar share (the ratio of energy received by solar collectors to biomass fuel input energy) on system performance. The findings demonstrate that maximum energy and exergy efficiencies of the power generation system are achieved at a pressure ratio of 10. Furthermore, a 1% reduction in the gas turbine’s compression pressure ratio can be compensated by a 9.3% increase in the solar share within the steam Rankine cycle.

Energy, exergy, and economic analyses and optimization of a deethanizer tower of a petrochemical plant

Abstract The distillation tower’s reboiler is one of the largest energy consumers in petrochemical facilities, and reducing its energy consumption is a crucial issue. This study proposes two optimal methods, namely Direct Vapor Recompression (DVR) and External Vapor Recompression (EVR), to reduce the consumption of cold and hot utilities in a petrochemical deethanizer tower. The Pars petrochemical in Iran is taken as a case study, and the proposed methods are compared with the base case using energy, exergy, and economic approaches, simulated through Aspen HYSYS software in the steady-state design conditions. Exergy analysis reveals that the EVR and DVR methods reduce the exergy destruction of the deethanizer tower by about 70.06 % and 67.29 %, respectively, compared to the base case. Moreover, the EVR method allows for complete recycling of low-pressure vapor, reducing the total exergy destruction rate from 0.871 to 0.261 GJ/tethane. The feed separation cost for the base case, DVR, and EVR are estimated to be around 28 $/kgfeed, 21.57 $/kgfeed, and 21.14 $/kgfeed, respectively. The EVR method results in reduced utility and ethane separation cost rates from 5.153 to 3.274 $/tethane and 17.64 to 15.78 $/year. Overall, the findings suggest that both DVR and EVR methods are effective in reducing the energy consumption and costs associated with deethanizer tower operations. Moreover, real-time optimization techniques can be developed to monitor and adjust the deethanizer tower’s operating parameters, such as feed flow rate, reboiler duty, and reflux ratio.

Thermodynamic analysis and optimization of a biogas-powered trigeneration system to produce power, cooling and freshwater

Despite all the efforts to reduce the consumption of fossil fuels worldwide, the majority of the global energy matrix continues to depend on them, leading to serious environmental impacts such as droughts, that heavily affect rural areas in arid and semi-arid regions. In this work, aiming to reduce environmental impacts, losses and instability associated with power lines and water scarcity, a computational model of a decentralized small-scale trigeneration system to produce power, cooling and freshwater was developed and operating conditions were optimized to maximize both Energy Utilization Factor (EUF) and exergetic efficiency. The trigeneration system consists of biogas-powered microturbines, an LiBr/H2O absorption refrigeration system and a humidification-dehumidification desalination system. The results obtained have shown that the system was able to produce 104.4 kW, 12 kW and 0.1231 kg·s−1 of power, refrigeration and freshwater mass flow rate, respectively, with an EUF of 1.024 and exergetic efficiency of 25.39%. The analysis of exergy destruction has revealed that the microturbines, particularly their combustion chambers, accounted for 78.23% of the total exergy destruction rate in the system which was 295.92 kW for the base case. Using Genetic Algorithm to maximize the EUF, it was possible to achieve a 12.12% increase in the EUF and a 16.25% increase in freshwater production when compared to the base case considered.

A novel renewable energy system designed with Mg–Cl thermochemical cycle, desalination and heat storage options

In this paper, a novel multigenerational integrated system that is able to produce five useful commodities, such as freshwater, space heating, hot water, power and hydrogen for a community, is proposed and investigated. The system uniquely covers heat storage by molten salt heat storage along with hydrogen production by magnesium-chlorine (Mg–Cl) based thermochemical cycle. Additionally, the present system has a multi-effect desalination plant to provide freshwater community needs. A solar power tower is offered due to its capability of harvesting high energy levels. The heat recovered by the solar power receiver is passed through an organic Rankine cycle (ORC) to meet the need for the high-temperature level that is required for the thermochemical cycle. The molten salt storage tanks are used to offset the mismatch between demand and supply for the necessary energy to run the system in case of the absence of solar irradiation. The suggested system is intended to leverage solar and geothermal energy sources to generate practical necessities like power, heat, and hot water for residential applications of a projected community. The system is then analyzed in detail thermodynamically in the context of exergy and energy approaches. In addition, the subsystems are analyzed parametrically to study the performance of the overall system to observe how the ambient and working conditions change the system efficiencies. The city of Vancouver in Canada is selected as the potential location where the system performance assessment is carried out accordingly. As a result of the present thermodynamic analysis, the energetic and exergetic efficiencies for the system are obtained as 45.45% and 52.32%. The total exergy destruction rate is another exergy metric to compare both versions, where the rate of 163967.39 kW exergy destruction is obtained for the overall system.

Experimental investigation of the effects of compressor types on the performance of an automobile air conditioning system using R1234yf

In this study, the performance of R1234yf as an alternative to R134a has been experimentally investigated in an experimental automobile air conditioning (AAC) system with variable (VCC) and fixed (FCC) capacity compressors. The AAC system was equipped with original components and instruments for mechanical measurements. The experiments were conducted for both types of compressors and refrigerants at various compressor speeds, air temperatures entering the evaporator and condenser and air speeds passing over them. The performance parameters of the AAC system have been evaluated by performing energy and exergy analysis based on the experimental data, and the results were presented in the form of comparative graphics. The experimental results show that the VCC compressor limits the refrigerant flow rate when the capacity control system is activated due to the decrease in the evaporator and condenser air inlet temperatures and the increase in the compressor speed. It was found that the coefficients of performance (COPs) of the R1234yf AAC system with VCC and FCC were approximately 13.6% and 20.1% lower than those of the R134a system with VCC and FCC, respectively. For both refrigerants, in the AAC system with VCC, the total exergy destruction rate per unit cooling capacity was 18.2% − 47.5% lower compared to the system with FCC. The R1234yf AAC system experiences lower exergy destruction in the evaporator and condenser compared to the R134a system, while it practices higher exergy destruction in the compressor and expansion device in comparison to the R134a system

A simulation and thermodynamic improvement of the methanol production process with economic analysis: natural gas vapor reforming and utilization of carbon capture

Abstract The current investigation proposes an efficient process to produce methanol through the natural gas vapor reforming and direct hydrogenating of CO2 that reduces CO2 emission. The proposed process includes methanol synthesis in the catalytic reactor with an injection of carbon dioxide recovered from the plant’s flue and separation of methanol by distillation. An Aspen HYSYS code analyzes the proposed plant to assess the energy, exergy, economic, and environmental performances. Also, the effect of captured CO2 flow on the methanol production, carbon efficiency, stoichiometric number of synthesized gas, and reboiler and condenser duties are investigated as a sensitivity analysis. The results indicate that the methanol production rate of 82,040 kg/h provides carbon, energy and exergy efficiencies of 85 %, 77.26 % and 77.32 %, which are higher than the similar proposed plants. Regarding exergy analysis, the total exergy destruction rate is about 238,468.21 kW, in which the reforming and burner sections contribute to the highest portions of about 47 % and 30 %. The global warming potential of the process is obtained at about 0.26 k g C O 2 , e q / k g M e O H ${\mathrm{k}\mathrm{g}}_{{\mathrm{C}\mathrm{O}}_{2,\mathrm{e}\mathrm{q}}}/{\mathrm{k}\mathrm{g}}_{\mathrm{M}\mathrm{e}\mathrm{O}\mathrm{H}}$ , which is reduced by captured CO2. The annual costs of investment and income are about 416,772,399 $ and 236,292,429 $, yielding 1.72 years payback period.

Techno-economic modeling of a novel poly-generation system based on biogas for power, hydrogen, freshwater, and ammonia production

In the current study, a new poly-generation energy system run by biogas steam reforming is proposed and assessed. To dissect the techno-economic feasibility of the offered system, energy, exergy, and sum unit cost of the products (SUCP) are considered as robust indicators for the system appraisal. Also, to acquire enhanced thermodynamic efficiencies, the system has benefited from the careful design of the biogas steam reforming unit, modified Rankine cycle, ammonia synthesis unit, hydrogen generation equipment as well as reverse osmosis unit. It is uncovered that the prepared poly-generation system is qualified to provide 687.4 kW of power, 0.9662 kg/s of freshwater, 0.15 kg/s of hydrogen, and 1.149 kg/s of ammonia. Besides, the energy and exergy efficiencies of the system have been calculated at about 18.9% and 16.9%, respectively with a total exergy destruction rate of 51020.78 kW. Also, following the results of the thermodynamic appraisals, the biogas steam reforming reactor and ammonia synthesis reactor have the highest contributions to inefficiencies happening in the system. Furthermore, from a sweeping sensitivity investigation, the optimum performance of the system appears in a biogas steam reforming reaction temperature of 1050K. Also, the SUCP decreases by about 21 $/GJ by increasing the Biogas Steam Reforming reactor pressure.

Conventional and advanced exergy and exergoeconomic analysis of a biomass gasification based SOFC/GT cogeneration system

In this paper, a small scale biomass gasification based solid oxide fuel cell/gas turbine (SOFC/GT) combined heat and power (CHP) plant is investigated by means of both conventional and advanced exergy and exergoeconomic analysis. A one-dimensional model of an internal reforming planner SOFC is employed to account for the temperature gradient within the fuel cell solid structure, which is maintained at the maximum allowable temperature gradient (150 K) under different operating conditions. Two main parameters of the gasification process, namely, air-to-steam ratio and modified equivalence ratio, are investigated, and the key parameters of the cycle exergy and exergoeconomic study are analyzed. Moreover, a multi-objective optimization procedure is applied to determine the unavoidable gasifier conditions required for the advanced exergy analysis of the system. The results of the conventional exergy and exergoeconomic analysis reveal that the highest rate of exergy destruction occurs in the gasifier, followed by the afterburner (AB) with 41.87% and 21.98%, respectively. Also, the lowest exergoeconomic factor is related to AB by 5.34%, followed by heat recovery steam generator (HRSG), gasifier, air compressor, and SOFC, which implies that the priority is to improve these components to reduce the exergy destruction cost rate. The results obtained from the advanced exergy and exergoeconomic analysis indicate that the most of the total exergy destruction rate is unavoidably in the CHP plant. The AB shows the least improvement potential in terms of reduction of the exergy destruction by almost 2% avoidable part, followed by Heat Exchanger 3 (H.X.3), gasifier, and SOFC duo to their lowest avoidable exergy destruction parts of almost 5%, 10% and 13%f respectively. Furthermore, the unavoidable part of the investment cost rate for all the components of the cogeneration plant is larger than the avoidable part, which means that it is difficult to reduce the investment cost rate of the system components. Meanwhile, the endogenous/exogenous analysis shows that the exergy destruction is completely endogenous for all components of the integrated plant, except for HRSG, GT, and HX1. Compressors and turbines have the highest potential to reduce endogenous exergy destruction. This is due to their higher avoidable endogenous exergy destruction. Reducing the investment cost rate seems difficult, as the main investment cost rate was found to be an unavoidable endogenous part for all system components. Finally, some results obtained from the advanced analysis approach are the opposite to those of the conventional method. This fact emphasizes that the results of conventional exergy analysis alone are insufficient and unreliable. For example, based on the advanced analysis perspective, the gas turbine and H.X.2 by 8.9% and 8.46% modified exergoeconomic factor, respectively, should be considered for reducing investment cost rate, while the conventional method gives opposite results.

Exergy and environmental analysis of oscillating wave energy converter hybrid with other renewable energy resources: A case study

ABSTRACT In order to evaluate the hybrid renewable configurations in diverse applications, this inquiry tries to propose a novel decision-making procedure. The open-source WEC dynamics simulator, exergetic assessment, and Hybrid Optimization Model for Electric Renewables Pro software are integrated. In this innovative method, the exergy of the component is calculated using MATLAB software. Technical analysis for the goal of rural electrification is examined in this work. Thus, several integrated energy systems are technically researched. This study deals with the exergy, environmental, and exergoenvironmental analyses of the hybrid renewable energy system, to assess its performance and environmental impact when operating on Siri Island. In the photovoltaic solar panels, wind turbines, wave energy converters, diesel generators, and batteries set up, the total exergy efficiency and exergy destruction rate were 18.4% and 7.24 106 kWh/year, respectively. Additionally, it was discovered that the wave energy converter was responsible for 5% of the total energy wasted. Photovoltaic solar panels, wind turbines, and wave energy converters all have mean annual exergy efficiencies calculated to be 11.7%, 13.1%, and 20.8%, respectively. Environmental and exergoenvironmental analyses illustrate that the off-grid scenario decreases CO2 emission by 95% compared to the on-grid scenario and utilizing diesel generators increases the exergy stability factor of the energy system. The suggested decision-making procedure can be a potent and reliable instrument for analyzing any hybrid renewable arrangement from a technological standpoint.

Indirect integration of a thermal–mechanical heat pump with a humidification-dehumidification desalination unit

Many previously developed integrated desalination and heat pump cycles have been observed to consume a significant amount of direct electricity supply, raising concerns about their cost effectiveness. To address this issue, this study has modified the performance and cost metrics of the double-effect absorption heat pump cycle combined with a humidification-dehumidification desalination system in terms of configuration. The novelties of the present study are to preheat seawater for desalination utilizing the waste heat of the absorption chiller and to design a doble-effect hybrid thermal–mechanical heat pump. Thermodynamic and thermoeconomic tools were applied to the system. The proposed cooling/desalination system was found to produce 23.23% more freshwater and 47.7% more cooling than a traditional combination. As a result, the current cogeneration unit achieved an energy utilization factor (EUF) of 6.96, which is approximately 17.89% higher than the conventional configuration. Compared to the base case, optimal steam extraction showed a significant improvement of 27.23% in exergy efficiency. Regarding cost metrics, the cost of freshwater was determined to be 2.051 $/m3. As a result, the humidifier has the highest attribution to the overall exergy destruction at 8.98 kW, which represents approximately 16.5% of the total exergy destruction rate.

Modeling and Optimization of a Solar-Driven System Coupled with Liquid Dehumidification and Absorption Refrigeration Based on Advanced Exergy and Exergoeconomic Analyses

A novel hybrid system coupled liquid dehumidification with absorption refrigeration driven by solar energy is proposed. Traditional and advanced exergy and exergoeconomic analyses of the system are conducted to ascertain the degree of irreversibility and potential improvement for each component. Based on the advanced exergy and exergoeconomic analyses, the effects of air humidity, segment temperature, and refrigeration temperature on the total exergy destruction and cost rates of the system are obtained. The total avoidable exergy destruction rate, avoidable exergy destruction cost rate, and avoidable investment cost rate of the system are selected as objective functions and optimized by using nondominated sort genetic algorithm-II. The results show that the total exergy destruction rate and the total exergy destruction cost rate reach 262.39 kW and 8.563 $/h, respectively. The generator and regenerator have higher cost rates of the irreversibility overall system, achieving the values 3.536 and 2.430 $/h, respectively. The absorber has the highest investment cost rate in the whole system. The endogenous parts of the exergy destruction and cost rates are much higher than the exogenous parts in the system. Multiobjective optimization results show that optimal values for the total avoidable exergy destruction rate and the exergy destruction cost rate are 50.99 kW and 1.60 $/h, which are 4.15 and 9.14% lower than those calculated by single-objective optimization, respectively. This study provides a potential way to utilize solar energy for dehumidification and refrigeration.