Exergy Production Research Articles

A comparative analysis of ozone disinfection mainstream processes in wastewater treatment plants: Exergy and exergoeconomic viewpoints

Dielectric barrier discharge (DBD) and proton exchange membrane (PEM) electrolysis are widely recognized techniques for ozone disinfection. DBD, when using air, emits nitrogen oxides, posing environmental concerns, while an oxygen source elevates costs. Although PEM electrolysis can produce hydrogen and higher ozone concentrations, it demands greater energy and operational expenses. However, comparative assessments of their exergy efficiency and economic viability have been lacking. This study contrasted two ozone disinfection designs for secondary effluent from wastewater treatment plants using exergy and exergoeconomic analyses. The findings revealed that PEM electrolysis showed a higher total exergy efficiency (44.77%) when including hydrogen production, compared to DBD’s 33.16%. However, PEM also exhibited higher exergy destruction (746.6kW) versus DBD (317.0kW), mainly attributed to the ozone generator. Exergoeconomic analysis indicated that the unit product exergy cost of treated water for DBD was 2.62 times higher than for PEM. Considering the economic benefits of hydrogen production, PEM’s net cost is 83.39 USD/h, slightly higher than DBD’s 63.34 USD/h. Notably, the relative cost differences of ozone generators and exhaust gas treatment highlight the potential for optimizing economic benefits. Sensitivity analysis underscored the impact of interest rates and electricity prices. Overall, PEM electrolysis presents a promising alternative for ozone disinfection in wastewater treatment plants, offering higher exergy efficiency and potential economic benefits, especially with hydrogen production. The higher exergy destruction in PEM suggests room for further optimization, particularly in the ozone generator.

A Thermodynamic Comparison of Exergy Production from Sugarcane and Photovoltaic Modules in the Context of Brazilian Energy Transition

This article applies the exergy analysis to the production and use of sugarcane, considering a model published in the literature. In this way, we compute incident solar irradiation, carbohydrate production, water consumption, and the production of stalks and straws. Following the production estimate, we analyze a biorefinery production cycle, from solar irradiation to the biorefinery products on an exergy basis, from birth to production of sugar, electrical energy, and ethanol. The calculated sugarcane production values are 80.7 tons per hectare for a 52-week cycle. As a result, the average exergy efficiency of sugarcane is 4.99%, reaching peaks of 8.3%. When considering only the useful exergy generated in the production of stalks and straw, an annual yield of 17.86 kWh/m2 represents an overall exergy efficiency of 1.31%. Considering the energy conversion processes in the biorefinery, the exergy efficiency from the radiation to the products from the biorefinery was 0.38%. The photovoltaic modules already have a well-established application in the country, though they need to increase their insertion over time, whereby the panels exhibit an average exergy efficiency of 31.6%, resulting in an annual electrical energy production of 255.84 kWh/m2. The results show that photovoltaic modules are a more efficient alternative than sugarcane regarding exergy land use. In conclusion, this study briefly discusses the use of sugarcane and photovoltaic modules in the context of Brazil’s energy transition towards a reduced dependence on fossil fuels, based on the fact that sugarcane already has a low carbon footprint for transportation using ethanol, with supply from more than 40,000 stations, and a similar or lower carbon footprint than electrical vehicles used across the country.

Performance analysis of a modified solar assisted ejection-compression heat pump cycle for drying application

In this paper, a modified solar assisted ejection-compression heat pump cycle (SEHPC) is proposed for drying application. Based on the basic ejection-compression heat pump cycle (BEHPC), an auxiliary flash tank and an internal heat exchanger are introduced to improve its heating performances. The introduction of flash tank can improve the heat absorption in evaporator and increase the volumetric heating capacity in condenser, which eventually reduce the throttling losses and enhance the performance of the SEHPC. The performances of the modified cycle with refrigerant R1234yf are analyzed and compared to those of basic cycle by developing the thermodynamic models based on the energy, exergy and economic analysis. Moreover, the main parameters, including evaporation temperature, condensation temperature, generation temperature, ejector back pressure, and the solar radiation intensity, are selected as variables for research. The theoretical results indicate that compared to BEHPC, the mechanical coefficient of heating performance COPw, the thermal coefficient of heating performance COPt, the volumetric heating capacity qhv and the exergy efficiency ηex of SEHPC are increased by 5.2%, 8.4%, 17.1%, and 8.0%, respectively, under a specified working condition. Furthermore, the SEHPC outperforms BEHPC under all given working conditions, especially at high condensation temperature and high generation temperature. The economic analysis results show that the cost per unit of exergy production by SEHPC is 6% lower than that of BEHPC. Additionally, the maximum exergy destruction occurred in the solar collector, which means great optimization potential in solar collector. This study demonstrates that SEHPC has practical performance improvement potential for heat pump drying application.

Exergetic, economic and exergy-based sustainability analysis of a power generation system with CO2 capture and methanol production

This study proposes a new biomass-based Combined Heat and Power (CHP)/renewable methanol production through captured carbon dioxide. A liquid organic hydrogen carrier (LOHC) stores and releases hydrogen. Literature review shows that LOHC has been integrated into such a system for the first time. The exergetic, exergoeconomic, and economic performance are researched. On average, results show that the exergetic efficiency of the system is 6.6 %. Depletion ratio (DR) is the depletion rate of the exergy source given to the system, which is desired to have low values. The sustainability index (SI) is the DR's reverse, representing the required exergy source per exergy destruction (exergy depletion). High values of this index indicate less exergy source consumed in the system. Exergetic ecological index (EECI) compares the useful products or depleted exergy per consumed exergy source destruction. The negative value of EECI means that the depletion of the exergy source is more significant than the product exergy and vice versa. The exergy-based sustainability indices, including DR, SI, and EECI, are found as 0.934, 1.071, and −0.868, respectively. Exergoeconomic analysis reveals that the exergy destruction rate at the system's capital cost (REX) value is 0.087×102. Heat Recovery Steam Generator (HRSG), gasifier, and Heat Exchanger 1 (HE1) are obtained as 5.153×10−2 (kW/€), 1.707×10−2 (kW/€), 3.094×10−2 (kW/€) respectively. The payback period and the REX are 14.56 years and 0.087×10−2 (kW/€), respectively; it seems long for an engineering application, but these technologies are relatively new, and their costs might decrease soon. Exergy destruction or lost power per capita, which means depleted investment, costs much less than 1. Although the thermodynamic values of the system seem low because irreversibilities occurred in chemical reactions, CO2 saved and produced methanol and cannot be ignored in terms of its environmental and economic benefits, considering CO2 taxes and the methanol economy.

Exergy-water nexus of a multi-energy complementary trigeneration system with different fuel mixture ratios

Complex coupling relationships of energy, exergy and water streams in multi-energy complementary systems due to different characteristics of energy flows are necessarily revealed to determine the intensities of downstream products. This paper proposes a multi-energy complementary trigeneration system driven by biomass, solar energy, and natural gas to generate cooling, heating, and power products. An exergy-water analysis approach, considering energy levels of streams, is adopted to determine the exergy and water footprint intensities per unit energy products. A life cycle assessment method is used to calculate the water footprint of biomass and natural gas as the primary energy sources. The relationship between the exergy and water footprint intensity of the system equipment and output products is presented and discussed with the mixture ratios of natural gas and biomass product gas. Furthermore, the cumulative exergy and water footprint intensity of products are analyzed under different system working conditions, such as mixture ratio of biomass and natural gas and the solar irradiance. When the same mixture volume gas fuels drive the trigeneration system, the overall exergy efficiency is 25.38 % while the efficiency including the upstream cumulative exergy destruction is only 21.93 %. The unit water footprint intensities of power and cooling products based on exergy measurement are 7.12 kg/kWh and 36.32 kg/kWh, respectively. The exergy-water footprint sensitivity of biomass and natural gas on system product intensities are implemented to consider the uncertain variables. When the mixture ratio increases from 0 to 1, the cumulative exergy destruction of system power is declined by 35.62 % under the uncertain ranges of ±50 %. Also, its water footprint is declined by 91.62 %. The proposed model provides an effective tool to reveal the exergy-water nexus and determine the intensities of multi-energy products.

Exergoeconomic assessment of a multi-section solar distiller coupled with solar air heater: Optimization and economic viability

This study focuses on optimizing the solar distiller and provides a foundation for future research and development in solar distillation technologies. This paper does an exergoeconomic analysis of a multi-section solar distiller (MS-SS) system that is combined with a solar air heater (SAH). Therefore, its objective is to determine the most effective operational and design parameters while taking into account the system's lifespan and interest rate. This will offer significant knowledge for improving the MS-SS. Key parameters examined in the study include exergoeconomic indicators, exergy production factor (EPF), exergy-based loss rate, exergy efficiency, and water cost. Variations in exergy loss rate across different seasons were observed, with implications for system efficiency. The exergoeconomic analysis demonstrates the impact of interest rates on the system's economic viability, with corresponding effects on water costs. The key findings suggest varying daily output and exergy efficiency, with the lowest values recorded in winter and the highest in summer. Summer demonstrates superior output exergy, averaging of 145 × 103 Wh per month. In the normal case of output salinity between 0 and 500 ppm, the cost was reduced by 96.7 %, and by 96.3 % in the case of four interior sections. Water cost reduction is also observable at the same output salinity, with 54.1 % at 0 ppm and 62.4 % at 200 ppm between number of interior sections = 0 and 4.

A process flow of an air separation unit with an energy storage function: Utilizing distillation potential to absorb energy storage air and its performance

The integration of liquid air energy storage (LAES) and air separation units (ASUs) can improve the operation economy of ASUs due to their matching at refrigeration temperature. A process flow of an ASU with energy storage utilizing the distillation potential of the ASU to absorb the released air due to storing energy (i.e., the energy storage air) is proposed. Its novelty is thus: the ASU can be used to absorb the energy storage air to maximize the air utilization and improve the energy efficiency of the integrated system. It can be simulated using Aspen Plus software. Based on the simulated data, an optimal process flow is determined by analyzing the effect of a reduction in discharge of energy storage air on the distillation conditions of the ASU, and its energy efficiency analysis and economic evaluation are conducted. When the discharge of energy storage air is reduced by 50 % during energy storage and the stored liquid air is directly recovered into the ASU during energy release, a proposed process flow with largest absorption for energy storage air could be obtained. Its product exergy efficiencies for energy storage and release are 37.80 % and 37.57 %, respectively. The overall exergy efficiency of the LAES and the electrical round-trip efficiency of the proposed system are both 67.48 %, the electricity cost saving ratio is 6.43 %, and the payback period of the LAES is 2.4 years. The investment in an air booster accounts for the largest proportion of the overall cost (being some 49.3 % of the total investment required for such a LAES system). After the proposed system is applied throughout the industry, carbon dioxide emissions can be decreased by 15.12–26.76 Mt/year on the grid side.

Thermodynamic, environmental, and exergoeconomic analysis of multi-ejector expansion transcritical CO2 supermarket refrigeration cycles in different climate regions of Türkiye

Restrictions on high-GWP refrigerants have made the use of transcritical CO2 refrigeration systems widespread. Using transcritical booster refrigeration cycle in warm climates is unsatisfactory due to its high energy consumption. This paper presents theoretical analysis and performance comparison of three different transcritical CO2 supermarket refrigeration cycle configurations with ejector expansion in Türkiye, which has different climatic regions. Bin-hour data were derived using hourly dry-bulb temperature values for provinces from 7 different regions in Türkiye. The applicability of multi-ejectors to each modeled cycle was also investigated. Annual energy consumption and environmental impact reductions of up to 17% were obtained using ejector expansion cycle compared to booster cycle. Ejector expansion cycles achieved higher performance than booster cycle up to 46% in terms of exergy efficiency at investigated ambient temperatures. Unit product exergy costs of the ejector cycles were found up to 28% lower than booster cycle.

Comprehensive analysis and optimization for a novel combined heating and power system based on self-condensing transcritical CO2 Rankine cycle driven by geothermal energy from thermodynamic, exergoeconomic and exergoenvironmental aspects

In this paper, a novel combined heating and power (CHP) system is proposed to realize full-scale utilization of geothermal energy and efficient multi-generation, which not only performs preferable overall performance than previous homogeneous system, but also offers an effective energy cascade utilization approach for self-condensing transcritical CO2 (TCO2) Rankine cycle. Based on the established mathematical models, the performance comparison is conducted for proving the superiority of the novel CHP system. Then, an overall performance analysis is implemented to reveal the combined effects for six key parameters on system thermodynamic, exergoeconomic and exergoenvironmental performances. Furthermore, multi-objective optimization considering system overall performance is conducted. The results show that for the novel CHP system, the largest relative improvement rate of system exergy efficiency (ηexg) and declining rate of total unit product exergy cost (cP,total) versus the previous CHP system are 15.03 % and 18.89 %, respectively. The final optimization results of ηexg, cP,total and total unit product exergy environmental impact (bP,total) are determined as 51.10 %, 14.12 $/GJ and 9.00 mPts/GJ, respectively. This paper fulfills an elaborate performance analysis and optimization for the novel CHP system, which fills the research gap of efficient and promising CHP system based on self-condensing TCO2 Rankine cycle.

4E assessment of ejector-enhanced R290 heat pump cycle with a sub-cooler for cold region applications

Currently, the worldwide implementation of the Montreal Protocol has accelerated the development of low GWP refrigerants. R290 as an alternative refrigerant with low GWP has great advantages over R134a for heat pump applications. However, the use of expansion valve throttling in the heat pump cycle has a large irreversible loss. Therefore, an ejector-enhanced sub-cooler vapor injection heat pump cycle (ESVIC) with R290 for water heating is proposed in this paper to improve the energy efficiency by applying ejector. The thermodynamic models are established based on the 4E (energy, exergy, economic and environmental) analysis to compare its performance with the basic ejector-enhanced heat pump cycle (BEEC) and the sub-cooler vapor injection heat pump cycle (SVIC). The energy analysis results show that compared with the BEEC and SVIC, the volumetric heating capacity of the ESVIC is improved by 42.0 % and 21.2 %, and the heating coefficient of performance (COPh) of the ESVIC is improved by 27.6 % and 5.3 %, respectively. The exergy analysis results indicate that in BEEC, SVIC and ESVIC the exergy destruction of the expansion valves is 0.3 %, 13.5 % and 0.8 %, respectively. It is indicated that the adoption of ejector can significantly decrease the exergy destruction of expansion valves. Moreover, the environmental analysis results reveal that the carbon emissions of ESVIC is 21.5 % and 5.0 % lower than those of BEEC and SVIC, respectively. Besides, for the ESVIC system, the carbon emissions of the life cycle climate performance when using R290 are 9.9 % lower than that of using R134a, indicating that the R290 is a potential substitute for R134a in heat pump applications. The economic analysis results demonstrate that the unit exergy production costs of ESVIC is 21.6 % and 5.1 % lower than BEEC and SVIC, respectively.

Tri-generation design and analysis of methanol-reforming high-temperature fuel cell based on double-effect absorption cooling power cycle

The methanol-reforming based high-temperature proton exchange membrane fuel cells is promising in both stationary and mobile applications, due to the trade-off between the efficiency and durability. However, challenges arise in the system integration due to the coupling of various-grade heat flows. Additionally, the exiting waste heat recovery systems face thermal-electric coupling issues, leading to limited flexibility in the energy supply. To this end, a thermally coupled tri-generation system based on methanol-reforming high-temperature proton exchange membrane fuel cell and double-effect absorption cooling power cycle is proposed. The cooling oil cycle absorbs heat from the fuel cell stack and burner, supplying heat for the preheaters, methanol reformer and double-effect absorption cooling power cycle. The cooling and power outputs of the double-effect absorption cooling power cycle are flexibly adjusted by varying the vapor split ratio. The mathematical models are developed and validated, based on which the exergy, exergoeconomic, economic and environmental performances are investigated. Under the design conditions, the tri-generation system yields net power, cooling, and hot water of 102.8 kW, 64.75 kW, and 43.83 kW, respectively, with exergy efficiency of 39.0% and unit exergoeconomic cost of product exergy of 65.09 $/GJ. The economic and environmental analyses indicate that, compared to the conventional system, a 54.2% reduction in carbon dioxide emissions is achieved, and the payback periods stand at 4.0, 5.6 and 9.0 years for the methanol prices of 0.40, 0.45 and 0.50 $/kg, respectively.

Extended exergy analysis of a novel integrated absorptional cooling system design without utilization of generator for economical and robust provision of higher cooling demands

The focus of this study is on designing a novel system for the provision of high-capacity cooling and heating loads (4000 kW) with the utilization of absorption technology to increase economic viability and COP value of existing cooling plants via lower-grade waste heat sources (70 °C-90 °C). To achieve this aim, in the novel system, an integration including the LiBr-water solution based absorptional heat transformer (AHT), and absorptional cooling cycle (ACC), and flat plate solar collector (FPSC) systems was proposed. In the integration, the utilization of the generator in the cooling cycle was avoided with the interaction of the high-temperature LiBr-water solution (120 °C-150 °C) from the AHT system and ACC system evaporator. In this way, both the additional cost of the boiler and heat source and the enhancement of economic viability and COP value were achieved. Energy, economic, traditional, and extended exergy, sustainability, and environmental analyses were implemented in this novel system. The COP value for the cooling system was determined to be 3.10 from energy analysis. This result forms a significant indicator for achieving of the main focus of the current study with the proposed novel system. The annual heating and cooling duty generations with this novel system were computed as 52.37 GWh and 52.40 GWh, respectively. In the context of economically comparing the proposed system to other plants with similar scale that already exist, the initial overall expenditure, yearly operational expenses, and the time it takes to recover the investment for the proposed system were set at $4.56 million, $3.12 million, and 1.75 years, respectively. It is worth noting, though, that these figures fall within the range of $6–8 million, $5–7 million, and 5–10 years, respectively, for the currently operational plants. This result indicated that the proposed system provides a robust alternative to the existing cooling-heating cogeneration systems in terms of main output generation and is more economically viable. Also, the novel system gained annually US$3.89 million in energy costs. The conventional exergy analysis results were summarized by forming an exergy flow and loss diagram, namely, the Grassmann diagram. In addition, in this current study, the novel extended exergy flow diagram indicating extended exergy content components, energy carriers of the proposed system, and exergy product rate streams was also proposed and drawn for the proposed system.

WITHDRAWN: Energetic and Exergetic Performance Improvement of a Solar Flat Plate Collector Working with Nanofluid

For maximum heat absorption by solar collectors, the use of a suitable fluid is very important. For this purpose, the energy analysis and maximum exergy use of the fluid are needed. Therefore, in this research, a nanofluid has been used in the flat plate collectors for maximum heat absorption. The effect of using nanofluid (Molybdenum disulfide nanoparticles) in a flat plate collector was evaluated by energy and exergy production. In this regard, a simulation was developed based on mathematical modeling in Ansys Fluent software. In this study, the flat plate collector was modeled while considering environmental parameters. To analyze the performance of the solar collector, two different mass flow rates were considered, and the effects of mass flow rate on different characteristics were investigated. In addition, solar collector evaluation for different nanoparticle shapes (i.e., Spherical, Square Pyramid, Hexagonal Prism, and Pentagonal Prism) was discussed. Based on the obtained results and according to the evaluation criteria of the thermal–hydraulic science in a volume fraction of ϕ = 5 % for a mass flow rate with ṁ=1kg/s, pentagonal prism nanoparticles were deemed the best model among different forms of nanoparticles, and their value was approximately 1.489. The flow with a mass flow rate of 0.75 kg/s upon adding spherical or pentagonal nanoparticles to the base fluid had no effect in terms of improving energy efficiency. Meanwhile, for a flow with a ṁ=1kg/s, we used a volume fraction of 2 % to 5 %.The present study and the observed results can be a suitable guide for improving the performance of flat plate solar collectors based on nanofluids.

Exergy-efficient sustainable production of diesel additive in infrared energized continuous flow rotating real reactor: Optimization, heterogeneous kinetics, and life cycle analyses

An exploratory expedited synthesis of a diesel additive viz., glycerol monooleate (GMO) was investigated for the first time in a novel energy-efficient infrared-energized continuous flow rotating catalytic fixed bed real reactor (IR-RFBR). Under statistically derived optimum condition maximum 98 ± 0.5 % per pass GMO selectivity was obtained. Using kinetic data from a rotating batch reactor under equivalent conditions, an inclusive non-catalytic and heterogeneous-catalytic kinetic model (R2=0.99) was developed. The IR-RFBR’s performance was evaluated using the derived kinetic model and accounting for axial dispersion (Pećlet Number: 70.15).Comparative exergy and exergo-economic analyses were performed on rotating and non-rotating IR-fixed bed reactors. In terms of lower product exergy cost (4.69 $/kJ), the IR-RFBR outperformed its non-rotating counterpart (11.85$/kJ) due to a 22 % higher GMO yield at reduced residence time (3.2 min). Furthermore, IR-RFBR manifested greater exergoeconomic efficiency (91 %) than conventionally heated RFBR (CRFBR, 69 %, 7.67 $/kJ). Life cycle analyses for IR-RFBR confirmed significant reductions in environmental impact categories such as global warming, fossil depletion, and human toxicity potentials by ∼ 88 %, ∼84.3 %, and ∼ 83 %, respectively, when compared to IR-non-rotating and CRFBR. Thus, the developed process for glycerol based diesel additive synthesis ensures more glycerol utilization in a sustainable and economic pathway.

Python-based energy and exergy analysis for efficient evaluation of steam turbine performance

Gas and Steam Power Plant (PLTGU) is a thermal power plant that has been in use since 1901. Over time, the energy and exergy analysis of PLTGU must be a fast analysis and takes very little time. This study aims to analyze the energy and exergy of one of the PLTGU components, namely the steam turbine using the python programming language, so that the analysis can be carried out quickly. As a theoretical basis to be able to carry out energy and exergy analysis of PLTGU steam turbines. The objects analyzed are: system input energy, isentropic efficiency, turbine work, energy loss rate, turbine energy efficiency, system exergy, fuel and product exergy, exergy destruction rate, and exergy efficiency. In carrying out the analysis, the theory used is the laws of thermodynamics 1 and 2. The results of the analysis are carried out according to the adopted theory, the isentropic efficiency of the steam turbine is in the range of to , the exergy of the system will always be greater than the energy of the system, the exergy of fuel is greater than product exergy, and the exergy efficiency of steam turbines is above . It can be concluded from this research, that the steam turbine can still be operated for the next few years.

Comprehensive performance assessment and multi-objective optimization of a new combined cooling, heating and power system with CO2 working fluid

In order to utilize the medium-and-low grade energy sources more efficiently, a new combined cooling, heating and power system using CO2 working fluid is proposed in this paper. The system is coupled by supercritical CO2 Brayton cycle and transcritical CO2 refrigeration cycle, and is characterized by the clever arrangement of some heat exchangers which could recover overall waste heat to generate useful heating capacity. Firstly detailed mathematical models are established to investigate the thermodynamic and exergoeconomic performance of the system. Under the preliminary design conditions with 170 °C heat source, the system could achieve values of 115.49%, 41.37% and 16.84$‧GJ−1 in thermal efficiency, exergy efficiency, and cost of unit product exergy respectively. Then comprehensive parameter analysis are conducted and reveal that within some certain ranges, the decrease of turbine inlet pressure and the increase of turbine inlet temperature, turbine outlet pressure, evaporation pressure and ratio of CO2 mass flow rates would lead to higher exergy efficiency and lower unit product exergy cost. Afterwards multi-objective optimizations performed under two operation modes demonstrate the everlasting high-efficiency of the system at different modes. Finally a performance comparison with a similar system in the literature further proves the superiority of the proposed system.

A comprehensive assessment of a new hybrid combined marine engine using alternative fuel blends

Large cargo that cannot be moved worldwide by air or rail transportation is typically conveyed via marine transportation, which relies on fossil fuels and contributes to global emissions. However, a more cost-effective solution is to utilize eco-friendly fuels to reduce carbon emissions. The design of a new hybridized powering system using environmentally friendly hydrogen-based fuel blends is investigated. This paper presents a new hybrid combined marine engine, which involves an internal combustion engine paired with a hybrid solid oxide fuel cell and gas turbine. The exergy, exergoeconomic, and exergoenvironmental analyses are conducted on this proposed engine. It is found that the average net power is about 27 MW with an increase of 30% and the energy and exergy efficiencies are 31% and 41%, respectively. In addition, the average exergetic efficiency based on fuel and product principle is 60%. This new marine engine has 228 $/h Levelized cost rate and 1109 mPt/h environmental rate. Finally, the average overall specific product exergy cost and environment are 64 $/GJ and 22 mPt/MJ, respectively. Also, carbon emissions are significantly reduced by 35%–61%, depending on the fuel blend. Comparing five fuel blends, the methane and hydrogen fuel blend is the most economical and has the least impact on the environment, and the second option is the ethanol blend.

Economic and environmental impact assessments of a newly designed energy system for marine applications

Marine transportation via the world's oceans is a critical way to convey goods and fuels between continents that cannot be performed cost-effectively by any other means. However, big ships heavily rely on fossil fuels, aggravating global carbon emissions. A key resolution to this dilemma is to employ clean fuels to reduce carbon emissions. This research paper introduces a new hybrid compound marine engine comprising a gas turbine, a solid oxide fuel cell, and a steam Rankine cycle. Three types of analyses, such as exergy, exergoeconomic, and exergoenvironmental analyses, are conducted on this proposed engine. It is found that the engine can produce a power of 15.5 MW, which is more than 48% compared to the traditional marine engine power, and the engine performance has up to 61% energy efficiency and 43% exergy efficiency. However, the exergetic efficiency of this engine based on fuel and product principal is 60%, which is more than 17% compared to its exergy efficiency. This engine has a 218 $/h Levelized cost rate and 139 mPt/h environmental rate. Finally, the average overall specific product exergy cost and environment are obtained to be 59 $/GJ and 20 mPt/MJ. By comparing five fuel blends, methane and hydrogen are the most economical and have the least impact on the environment; the second option is ethanol blend.

Experimental study on double effect solar distiller using bioactivity nanoparticles with analysis of thermo-economic and enviro-economical

Potable water is crucial in today's society, which is resolving the freshwater issue. In this work, the progress of direction in a basin area inner heat transmission mode with a Double Effect Solar Distiller (DESD), which is approaching the temperature mechanisms (parameters) for the Laplacian method using builds coated basin areas with a TiO2/Jackfruit peel with silver balls (TJPSB) blend is done. To create green TiO2 nanoparticles from eco-friendly bleaching chemicals and jackfruit peel, a green nanoscale approach has been developed. The TiO2/Jackfruit peels (TJP) (0.1%, 0.2%, and 0.3%), along with the performance of silver color balls, are used to build and verify the DESD. The TJP materials studies were supported by the surface morphology analysis of chemical compounds with functional energy absorption additions. A typical particle magnitude of jackfruit peel has 40–60 nm, giving a zeta potential value. Images taken using a scanning electron microscope (SEM) presented an absorbent structure with 85% crystallinity in the X-ray powder diffraction (XRD) measurements. The TJPSB by the DESD outcomes as of 9.00 a.m. to 5.00 p.m. focuses on 0.1%, 0.2%, and 0.3% by layer yields of approximately 4.800 L/m2, 5.560 L/m2, then 6.120 L/m2, individually. More vibration basin regions that benefit from TJPSB's average productivity of 50.55% and 8.790 L/m2/d attracted to focus on 0.3% with a performance of DESD. TJPSB initially presents further manipulative applications of solar desalination process ingredients. Maximum access to the energy, exergy productivity of DESD consequences is 41% and 5.63%, individually. Based on water depth of 0.8 cm, TJPN is discovered in 20% of cases. Overall DESD efficiency is 7.35 kg m2 per day at 12 h of 30% TJPN observation and 0.8 cm of water depth. An economic analysis of DESD was found with a cost of concentration that portable water (per liter) and assessed approximately 0.0726$ by reimbursement term of 14 months. The average thermo-enviro-economics analysis of DESD was found to be 3.35 (exergy), and 4.71% (Energy).

Exergoeconomic analysis of solar photovoltaic power plants: Case study in differents tropicals zone (Maroua and Douala) in Cameroon

The present work highlights the exergoeconomic analysis of photovoltaic (PV) systems. It consists in carrying out an exergy and economic balance of these systems to evaluate the energy losses at all levels of the production chain. For this purpose, a 11,52 kWp power plant with storage installed at Maroua Airport (tropical dry region) and a 1,25 MWp grid connect plant at Douala Airport (tropical humid region) are considered. The meteorological data and the cells' temperature which highly affect the PV performances are directly measured on site. The estimated useful exergy production of electricity is about 1585.68 kWh/kWp/yr in Maroua PV plant and 1452.75 kWh/yr in Douala PV plant. The losses are respectively evaluated to be 142.76 kWh/kWp/yr in Maroua and 37.6 kWh/kWp/yr in Douala. The performance of each plan is evaluated using the exergy matrix concept. The results obtained give an exergy payback time value of 6.19 years for the Maroua plant, which is higher than the exergy return time of the Douala plant, which is 5.25 years due to losses related to storage system, the cost per kilowatt-hour of useful electrical energy produced is 0.130 UDS for the Maroua plant and 0.002 USD for the Douala plant. The cost of exergy losses per kWp/yr is estimated at 19.163 USD for the Maroua plant, and 0.065 USD for the Douala plant. Thus, the exergy losses are higher for solar PV systems installed in the Sahelian regions of the country, and even higher for systems with storage. Based on this analysis, it appears that the PV plant installed in the dry tropical zone is more efficient, while the one installed in the humid tropical zone has a better production cost. Fortunately, these climatic regions are favorable for the implementation of PV plants.