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The presented paper focuses on renewable energy-assisted electricity, hydrogen, and cold energy production. Solar energy is used as the energy source in the study. The organic Rankine cycle (ORC) is used for electricity generation, a proton exchange membrane electrolyzer (PEMe) for hydrogen production, and an ejector refrigeration system for cold energy production. The study is based on the exergy concept and examines thermo-economic and thermo-environmental analyses. The exergy efficiency of each equipment in the system is calculated from a holistic perspective. Considering the energy consumption values of the equipment in the whole system, the cost required for hydrogen production is calculated as 1.086 $/kg. Additionally, the exergy efficiency of the whole system is found to be 2.082 %. • Thermodynamic analysis of the solar-based hydrogen production system. • The exergy efficiency of the whole system is found as 2.082 %. • The cost of green hydrogen production is found as 1086 $/kg. [ABSTRACT FROM AUTHOR]

A solar-powered combined cooling, heating, and power (CCHP) plant integrated with a water electrolysis unit is investigated in terms of energy, exergy, and exergo-economic (3E) assessments. A comprehensive parametric study and optimization is conducted following the thermodynamic and exergo-economic assessment of the proposed system to evaluate the key performance parameters of the system for efficiency and economic factors. This system employs a heliostat field and a receiver tower by taking advantage of thermal energy from the sun and produces a continuous energy supply with an integrated phase-change material (PCM) tank to store the heat. In addition, a supercritical CO2 Rankine cycle (RC), an ejector refrigeration cooling (ERC) system, and a PEM water electrolyzer are coupled to produce cooling, heating, power, and hydrogen. Thermodynamic analysis indicates that the system exergy efficiency and energy efficiency are improved to 33.50 % and 40.61 % , respectively, while the total cost rate is 2875.74   U S D / h and the total product cost per exergy unit is 25.65   U S D / G J . Additionally, the system produces a net generated power, heating load, and cooling load of 11.70 , 13.92 , and 2.60   M W , respectively, and a hydrogen production rate of 12.95 g / s . A two-objective optimization approach utilizing a non-dominated sorting genetic algorithm (NSGA) was performed, demonstrating that the system's ideal design point offers a cost rate of 1263.35   U S D / h and an exergetic efficiency of 34.17 % . [ABSTRACT FROM AUTHOR]

In this study, the organic Rankine cycle (ORC) and hybrid absorption recompression cycle have been modified by the addition of turbine bleeding with regeneration and ejector, making it a unique solar-powered trigeneration system. With this modification, the useful electric power increases by 65 kW due to increased mass flowrate and overall efficiency nearly by 0.7%, and this difference grows as direct normal irradiation (DNI) rises. After identifying these improvements, a parametric study was conducted to determine the optimum value of these operating variables, such as direct normal irradiation, condenser pressure, turbine inlet temperature, and pressure ratio based on the desired outputs and efficiencies of the proposed modified systems. The results indicate that the proposed system is capable of simultaneously generating 315.3 kW of electric power, 1588 kW of heating output, and 501.6 kW of cooling at energy and exergy efficiencies of 80.8% and 25.36%, respectively. Further, in terms of energy one could conclude that only 19.2% of total available energy is getting wasted, but in reality, around 75% of the work potential of the input exergy is getting wasted. The maximum exergy is lost at the solar collector and destructed at heat recovery vapor generator (HRVG), hence requiring careful design to improve their performance. Lastly, an economic analysis of the proposed system has also been conducted, and the payback period is found to be 2.33 years, which ensures its economic viability. [ABSTRACT FROM AUTHOR]

The Organic Rankine Cycle (ORC) is one of the most promising systems to recover the waste heat sourced from internal combustion engines. In this study, thermodynamic, economic and environmental analyses of the scavenge air cooling water-driven Waste Heat Recovery System (WHRS) based on the organic Rankine cycle are conducted for a dual-fuel marine engine integrated with exhaust gas recirculation (EGR) system. Zero ozone-depleting and low global warming potential working fluids; R245fa, R236ea from hydrofluorocarbons, R600a, R601a from hydrocarbons, R1234ze and R1234yf from hydrofluoroolefins are selected for the low-grade WHRS. In addition to the thermal analyses, the mass and volume of the system along with the safety factors of the working fluids are evaluated to judge the physical applicability of the system for ships. Thermo-economic performances of the fluids are analyzed, optimized and compared under various engine loads, Tier II and Tier III modes to reveal the effects of different engine operating conditions on the parameters. According to the results, scavenge air has a significant amount of waste heat at medium and heavy loads and switching the engine mode remarkably affects the performance of the WHRS. R601a shows the best thermo-economic performance, however, considering the applicability of the system R236ea is the most suitable working fluid for the ORC WHRS. The overall thermal efficiency of the power generation system can be increased by about 2.8%. [ABSTRACT FROM AUTHOR]

As a competitive new energy storage technology, the thermally integrated pumped thermal electricity storage (TI-PTES) system has received much attention. In this work, two TI-PTES systems are constructed: the RHP-BORC system, which consists of a heat pump cycle (HP) with a regenerator and a basic organic Rankine cycle (BORC), and the RHP-EOFC system, which consists of a HP with a regenerator and an organic flash cycle with ejectors. Meanwhile, R1233zd(E) and Cis-butene are selected to form R1233zd(E)/R1233zd(E) (denoting the working fluid used in the charge and discharge cycles, respectively), R1233zd(E)/Cis-butene, Cis-butene/Cis-butene, and Cis-butene/R1233zd(E) groups. Thermodynamic and economic analyses as well as multi-objective optimization are performed for both systems. The results indicate that for the two systems with different working fluid groups, different parameters have distinct effects on the system performance, and the thermodynamic and economic performance of the RHP-BORC system is better than those of the RHP-EOFC system. For the RHP-BORC system, with the variations of thermal storage temperature, evaporation temperature of heat pump and pinch point temperature difference, the values of different performance metrics of the system with different working fluid groups are close respectively, such as power-to-power efficiency, energy storage density and annual emission reduction. For the RHP-EOFC system under different parameter conditions, when the system uses R1233zd(E)/Cis-butene and Cis-butene/Cis-butene, the performance is better. From the results of the multi-objective optimization, the optimal working fluid group of the RHP-BORC and RHP-EOFC systems are Cis-butene/Cis-butene and R1233zd(E)/Cis-butene, and the values of the power-to-power efficiency and the levelized cost of storage under the optimal solution conditions are 75.76 %, 0.234 $·kWh−1, and 84.31 %, 0.227 $·kWh−1, respectively. The results of the exergy destruction analysis under the optimal solution conditions show that the largest exergy destruction in the RHP-BORC and RHP-EOFC systems are in the condenser (480 kW) and compressor (1275 kW) of the HP cycle. This work expands the configuration of the TI-PTES system, showing promising development prospects. It also provides theoretical support for the further advancement of the TI-PTES system and offers valuable guidance for the design of such systems.

A novel tri-generation system powered by geothermal energy is assessed from exergo-economic and thermodynamic perspectives. The proposed system consists of a geothermal single flash cycle, an ORC with the OFOH and the IHE, a HDH desalination system, and a double-effect absorption refrigeration system. This system aims to produce power, cooling load, and the freshwater. The design parameters effects such as geothermal inlet temperature, the flash chamber inlet pressure, HPG temperature difference, and steamturbine outlet pressure on the main indicators, including exergy efficiency, cooling load, total product unit cost, and produced freshwater mass flow rate. Moreover, the multi-objective optimization is applied using machine learning method and Grey wolf algorithm to optimize the total product unit cost, the net generated power rate, and the exergy efficiency. Under base design conditions, the total product unit cost and the exergy efficiency are 77.8 $/GJ and 44.2%, respectively. Moreover, the results for the exergy efficiency, the total product unit cost, and the net generated power rate of the system under multi-objective optimization are 54%, 62.5 $/GJ, and 180 kW. Among all elements of the current system, TEG1 has the greatest rate of the exergy destruction, which is 94.02 kW. Additionally, the rate of the overall system exergy destruction is 221.72 kW. [ABSTRACT FROM AUTHOR]

The following research compared some energy, exergetic and thermo-economic indicators of a supercritical CO2 simple Brayton cycle integrated with a simple organic Rankine cycle (SORC), and a regenerative organic Rankine cycle (RORC). A thermodynamic model was developed to determine the net power, thermal efficiency, the fuel consumption, and the exergy destruction of all the components of the system. Also, a thermo-economic model was developed to determine some economic indicators such as the levelized cost of energy (LCOE), the payback period (PBP) and specific investment cost (SIC). A sensitivity analysis was carried out to study the influence of the primary turbine inlet temperature (TIT), the high-pressure in the compressor (PHigh), the evaporator pinch point temperature difference (PPT), and the pressure ratio (Pr) on the indicators performance. Three different working fluids were selected in this study: acetone, toluene and cyclohexane. The results showed that cyclohexane had the best energy performance giving an efficiency of 48.02% for the RORC system. Besides, it presented the best thermo-economic results for the LCOE (0.26 USD/kWh), SIC (2626.75 USD/kWh), and a PBP (11.2 years). Finally, a multi-objective optimization was developed based on energy, exergy and thermo-economic performance parameters as objective functions to obtain a technical and economic feasible solution able to implement them in industrial applications.

A solar-powered combined cooling, heating, and power (CCHP) plant integrated with a water electrolysis unit is investigated in terms of energy, exergy, and exergo-economic (3E) assessments. A comprehensive parametric study and optimization is conducted following the thermodynamic and exergo-economic assessment of the proposed system to evaluate the key performance parameters of the system for efficiency and economic factors. This system employs a heliostat field and a receiver tower by taking advantage of thermal energy from the sun and produces a continuous energy supply with an integrated phase-change material (PCM) tank to store the heat. In addition, a supercritical CO2 Rankine cycle (RC), an ejector refrigeration cooling (ERC) system, and a PEM water electrolyzer are coupled to produce cooling, heating, power, and hydrogen. Thermodynamic analysis indicates that the system exergy efficiency and energy efficiency are improved to 33.50% and 40.61%, respectively, while the total cost rate is 2875.74 USD/h and the total product cost per exergy unit is 25.65 USD/GJ. Additionally, the system produces a net generated power, heating load, and cooling load of 11.70, 13.92, and 2.60 MW, respectively, and a hydrogen production rate of 12.95 g/s. A two-objective optimization approach utilizing a non-dominated sorting genetic algorithm (NSGA) was performed, demonstrating that the system’s ideal design point offers a cost rate of 1263.35 USD/h and an exergetic efficiency of 34.17%.

Abstract In this paper, an improved thermo‐economic diagnosis model based on the structural theory of thermo‐economics combined with advanced exergy analysis is proposed in a combined cycle fault diagnosis model. Diagnosis model simulation of a 590 MW combined cycle unit is implemented by EBSILON Professional in terms of advanced exergy analysis method. The characteristic fault value (CFV) required for diagnosis is quantitatively presented and precisely located in the diagnosis model. The results show that with 3% performance deterioration fault of the compressor, gas turbine and intermediate pressure cylinder of the turbine, gas turbine failure leads to three times fuel consumption to the unit compared to the compressor. In contrast, multiple fault diagnosis results show that the fault value generated by each component under multiple faults is not a simple superposition of a single fault. The impact of some component faults is partially offset or increased. However, the increased fuel consumption of the whole unit under multiple faults or malfunctions must be greater than the sum of the increased fuel consumption under a single fault. CFV can effectively perform precise positioning and quantitative analysis on single and multiple fault scenarios of the combined cycle unit. In addition, CFV has strong sensitivity and changes linearly with the performance deterioration of the components, which paves the way for a reliable approach for early‐stage warning and diagnosis.

In this paper, an improved thermo‐economic diagnosis model based on the structural theory of thermo‐economics combined with advanced exergy analysis is proposed in a combined cycle fault diagnosis model. Diagnosis model simulation of a 590 MW combined cycle unit is implemented by EBSILON Professional in terms of advanced exergy analysis method. The characteristic fault value (CFV) required for diagnosis is quantitatively presented and precisely located in the diagnosis model. The results show that with 3% performance deterioration fault of the compressor, gas turbine and intermediate pressure cylinder of the turbine, gas turbine failure leads to three times fuel consumption to the unit compared to the compressor. In contrast, multiple fault diagnosis results show that the fault value generated by each component under multiple faults is not a simple superposition of a single fault. The impact of some component faults is partially offset or increased. However, the increased fuel consumption of the whole unit under multiple faults or malfunctions must be greater than the sum of the increased fuel consumption under a single fault. CFV can effectively perform precise positioning and quantitative analysis on single and multiple fault scenarios of the combined cycle unit. In addition, CFV has strong sensitivity and changes linearly with the performance deterioration of the components, which paves the way for a reliable approach for early‐stage warning and diagnosis. [ABSTRACT FROM AUTHOR]

The use of solar energy is considered a potential strategy for the production of electrical energy through thermal heat sources. This article portrays a study framed to be energetic, economic, and environmental fields. This study was carried out in two thermal configurations: the Regenerative Rankine Cycle (RORC) and the Simple Organic Rankine Cycle (SORC), which use solar energy to supply electrical power to a building. The thermodynamic and economic models were proposed for each subsystem of the thermal process, allowing hourly simulations to know the economic indicators such as the payback period (PBP), the levelized cost of energy (LCOE), the specific investment cost (SIC), and the initial investment cost (CInv). The effect of operational variables such as the pressure ratio (rp), the evaporator pinch point temperature (Ap), the condensation pinch point temperature (Tcond), and the solar collector area (Ac) on the Relative Annual Benefit (RAB) were studied. Finally, the Particle Swarm Optimization (PSO) algorithm was implemented to optimize the economic indicators and the environmental impact of the thermal configurations. Results showed that the RORC configuration presented a better performance in terms of generation, purchase, and hourly sale of energy. However, in terms of RAB, the SORC (39,833 USD/year) showed better results in contrast to the RORC (39,604 USD/year) for an evaporator pinch point temperature of 35 °C. Finally, the application of the PSO optimization algorithm allowed the reduction of the LCOE (11.64%), SIC (11.67%), and PBP (11.81%) thermo-economic indicators from the base condition for the SORC, and the reductions obtained in the RORC were LCOE (18.11%), SIC (10.67%), and PBP (11.11%). However, the decrease in environmental Impact for both systems was less than 1% as a consequence of the high contribution of thermal oil in the construction phase of the system.

• A solar energy pumped thermal electricity storage system is established. • Parameter analysis is conducted and compared for system with five working fluids. • The multi-objective optimization for system is executed by genetic algorithm. • The optimal solutions are determined for the system using the five working fluids. • Life cycle assessment under optimal solutions for the system are performed. The applications of renewable energy sources are an effective way to reduce carbon emissions. However, its intermittent nature presents challenges for large-scale application. Energy storage technology shows great potential in addressing this issue. Thermally integrated pumped thermal electricity storage systems are a promising technology for power storage due to its outstanding role in integrating renewable energy sources. In this work, the pumped thermal electricity storage system incorporates solar energy, utilizing five different working fluids: R1233zd(E), R1336mzz(Z), R123, Pentane, and R245ca. Comparative analyses of the thermodynamic and economic performance of the system under the five working fluid conditions were conducted, followed by multi-objective optimization using genetic algorithm. Additionally, under optimal solution conditions, life cycle assessment analyses are conducted for the system that employs the five working fluids. The results indicate that the performance indexes of the system under different parameter conditions show the variation rule of either increasing or decreasing, and the variation trend of the same performance indexes is basically coincident for different industrial materials. The results of multi-objective optimization show that the power-to-power efficiency of the system has an obvious competitive relationship with environmental impact load and Levelized Cost of Storage, and the larger the value of power-to-power efficiency is, the larger the values of environmental impact load and Levelized Cost of Storage are. Under the optimal solution conditions, the life cycle assessment analysis shows that for the five environmental impact potentials, the percentage of environmental impact potentials is higher in the construction and operation phases, while the environmental impact load has the maximum (4.09 × 10−5 mPE) and minimum (3.94 × 10−5 mPE) values when the system uses Pentane and R1336mzz (Z), respectively. This work can provide a valuable reference for the study of TI-PTES in terms of environmental impact. [ABSTRACT FROM AUTHOR]

Three novel geothermal-based organic Rankine cycle (ORC) systems are proposed to enhance the efficiency and for waste heat recovery purpose. The proposed systems are modeled based on a basic ORC system (concept 1), an ORC system with an internal heat exchanger (concept 2), and a regenerative ORC system (concept 3). Accordingly, two thermoelectric generators (TEG) are introduced into the systems to exploit the waste heat of the system. The condenser is replaced with a TEG unit while the other TEG unit is used to recover the waste heat of the reinjected geothermal fluid. A comprehensive numerical investigation is conducted to compare the proposed systems from the thermodynamic and thermo-economic points of view. Furthermore, the most favorable proposed system is considered for optimization purposes and multi-objective optimization using the genetic algorithm is performed. Accordingly, a Pareto frontier is extracted consisting of the optimal solutions along with the scatter distribution of the critical parameters. The results indicate that the third proposed concept holds the highest exergy and energy efficiency among the studied systems. Also, the concept concludes the highest power output from the employed TEG units. The results further show that the first concept has the lowest associated cost with the system and the smallest payback period and at the same time higher net power generation. At the baseline of the systems, the exergy efficiencies are 59.39%, 57.92%, and 60.27%, and the total product costs are 25.8 $/GJ, 28.79 $/GJ, and 31.27 $/GJ for the first, the second, and the third proposed concepts, respectively. Results of the multi-objective optimization of the third concept reveal that the superheater temperature difference should be kept at higher values while the optimal range of the figure of merit is between 0.9 to 1.6. The proposed systems can be designed practically to exploit the geothermal heat source and recover the waste heat of the system.

In the current article, a novel geothermal-biomass-powered multi-generation plant was introduced and probed through thermo-economic-environmental aspects plus multi-criteria optimization. To produce various outcomes, like electricity, heating, cooling, as well as hydrogen and freshwater, the plant took advantage of the Rankine cycle, a dual-effect absorption refrigeration unit, a proton exchange membrane water electrolyzer, and a biomass combustor. The plant's environmental consequences were reviewed based on NOx and CO 2 emitting to mark the environmental advantages of burning municipal solid waste as biomass rather than coal. Owing to the investigation, the plant provided 31.68 MW direct power, 39.85 MW heating, 126.36 MW cooling, 23.3 m3/h freshwaters, and 88.12 kg/h hydrogen, besides 58.54% and 16.45% calculated as plant energetic and exergetic efficiencies. By applying the SPECO approach, the total product cost rate was attained at 1.629 $/s. As well, this plant had an exergo-environmental impact factor of 0.9. Moreover, a parametric study was brought out to comprehend the consequences of chief parameter changes. Eventually, a multi-criteria optimization was employed for the plant for the enhancement of the techno-economic operations. In the optimum status, the total cost rate of the product and exergetic efficiency of 1.57 $/s and 17.26% were attainable. [ABSTRACT FROM AUTHOR]

• A comparative study of three cases for tabular solar still was carried out. • Enhanced tabular solar still with air injection, nanocoating and nanofluid was studied. • An energy, exergy, and economic analyses for the system were conducted. • The advanced tabular solar still distillate production cost per liter was 0.032$. • The advanced tabular solar still productivity has a 79.88 % increase over classic still. Nowadays, due to freshwater scarcity intensifying, researchers are actively seeking to improve solar desalination, a technology with immense potential, but there are still limitations in production capacity. This study investigated the integration of various additives in tubular solar still (TSS) at three configurations. In Case I, a V-corrugated basin and an air parabolic trough collector (PTC) equipped with evacuated tubes were integrated. Then, with the same attachments, CuO nanocoating was applied to the basin surface in Case II, aiming to enhance heat absorption. Finally, in Case III, CuO nanofluid was used in the presence of all previous enhancers. The system was studied during summer days with weather parameters having average ranges (minimum – peak) of 32.5–37.5 °C (ambient temperature), 318.5–1000 W/m2 (solar radiation), and 1.1–2.3 m/s (wind speed). The results were very acceptable and competitive. All modified configurations of the advanced TSS (ATSS) significantly increased distillate production compared to the classic TSS (CTSS), with a range of 49.84–79.88 %. Case III stood out as the most successful configuration, achieving outstanding gains in both energy and exergy efficiencies. Compared to the CTSS, Case III boasted an impressive 83.69 % improvement in energy efficiency and a staggering 242.45 % increase in exergy efficiency. This refers to a system that not only produces more desalinated water but also does so with significantly less wasted energy, making it a more environmentally sustainable solution. Case III also offered a good economic advantage with a 13.51 % cost reduction compared to CTSS. [ABSTRACT FROM AUTHOR]

The solar-energy sector is growing fast and expected to continue. Inclined solar still (ISS) is one of the promising techniques used in the solar desalination field. Adding a single-axis solar tracking system to the ISS will increase its yield and efficiency. Consequently, the total device cost will be increased. Does it worth? To answer this question, an experimental investigation of the ISS without and with a single-axis solar tracking system was conducted and evaluated. Thermo-economic analysis was developed and evaluated. Results showed that adding a single-axis solar tracking to the inclined solar still increased its productivity and efficiency by 26% and 25.4%, respectively, with an increase in the system total cost by 39.2%. The payback period of the extra cost due to adding the solar tracking system is estimated in the range between 0.9 and 1.1 years. Thus, using a solar tracking for inclined solar still is thermally and economically beneficial due to the increase of the device performance and the reduction of the required land area by almost 26% to produce the same freshwater amount which means a lot of money-saving. [ABSTRACT FROM AUTHOR]

Many academics have spent decades trying to identify the right settings and approaches to minimize its drawback. The behavior of the absorber was evaluated using a parametric analysis. A multi-objective Genetic Algorithm was used to improve the shape of PCM. For finding capacity of fluid, ANSYS model is used. To examine vaporescence and moisture content, CFD is used for generating the capacity of fluid and assorted different phase flux version. Exergoeconomic review and improvement, thermal distribution transfer in an absorber, changes in designing parameters are all covered in this study for reductions of yearly running costs and thermal efficiency destruction. There was also a discussion about the Vapour Absorption Refrigeration System's advancements.

To quicken the process for high global warming potential (GWP) working fluid replacement for organic Rankine cycle (ORC) systems, a thermo-economic evaluation of low GWP fluid R1233zd(E) as an R245fa alternative has been performed in comparison with other natural fluids n-Pentane, Isopentane, and Isobutane for geothermal applications. The heat source water mass flow rate remains constant and 5 K pinch point is set for both evaporator side and condenser side. All working fluids have a close net thermal efficiency within 2%. Increasing the heat source from 120 °C to 160 °C gives a more than 20% efficiency rise. The low critical temperature of Isobutane limits its application for 160 °C heat source. R1233zd(E) displays a close mass flow rate (within 2%) from R245fa and others exhibit more than 40% flow rate reduction. The component level performance has also been investigated in this study. All alternatives exhibit a lower evaporator side (evaporator and preheater) heat transfer area than baseline R245fa, and a slightly higher condenser side (condenser and desuperheater) heat transfer area. For turbine performance, R245fa displays the highest volume flow ratio, indicating a significant change of the rotor blade height should be made between the inlet and outlet point for the expansion process. R1233zd(E) displays ∼10% increase for turbine size parameter from baseline, n-Pentane shows ∼22% rise, Isopentane exhibits ∼11% rise, while Isobutane presents 32% decrease, respectively. In general, R1233zd(E) only exhibits ∼2.3% higher specific investment cost than R245fa, while n-Pentane and Isopentane exhibit more than 15% cost rise. Thus, from the thermo-economic scale with an extended application range, R1233zd(E) exhibits a better overall performance index when compared with other R245fa alternatives and can be serviced as promising candidate to replace R245fa. [ABSTRACT FROM AUTHOR]

Hybridisation, using an alternative heat source besides solar power, as a back-up unit can be a promising solution for the deployment of Compound Parabolic Concentrator (CPC) technology in low-temperature (100–150°C) industrial applications. In this research, a new integration of a non-evacuated CPC collector with a back-up system was studied for performance optimisation where a thermo-economic evaluation was carried out to investigate the viability of the proposed model for industrial deployment. In operational assessment, the effects of different operating modes as the manipulation of oil mass flow rate and controlling temperature and their interaction on collector efficiency and thermal behaviour were analysed. Results revealed that the maximum collector efficiency reaches about 72% suggesting improvements compared to the similar works. The hybrid mode operation was also evaluated as accurate and instantaneous proportionally to the weather changes. In addition, thermo-economic assessments identified the optimum adjustment based on the minimum payback period.

The increasing urbanization and population growth that humanity has undergone in the last century constitutes a real challenge for our ecosystem and our economic model. Energy needs and consumption of natural resources like water continue to increase year after year. One of the possible solutions is seawater desalination using renewable energies. This study presents exergy and thermo-economic analyses of different multi-effect distillation (MED) configurations. Our systems are powered by thermal energy produced in solar concentration units at parabolic trough collector. Therminol VP-1 oil is used as a heat transfer fluid for indirect steam generation through the solar field and the evaporator heat exchanger. The comparisons made relate to a nominal production of 350 m³/d of distilled product. The results reveal that for the MED-PF (parallel/crossfeed) configuration, the total price of water is 1.44 $/m³ which is less expensive than the other configurations, MED-FFH (forward feed configuration with feedwater heaters), MED-BF (backward feed) and MED-FF (forward feed) of approximately –21.9%, –21.4% and –42.6%. In addition, the specific energy consumption (STPC, kWh/m³) of a MED-PF configuration is significantly better with more than 74% of energy saving. Moreover, its performance becomes better if we increase the number of effects to more than 12 effects. [ABSTRACT FROM AUTHOR]

Ground source heat pump, due to high coefficient of performance (COP) and use of low-temperature thermal energy source, is one of the best technologies to use renewable energy resources. In this work, at first, a geothermal heat pump for heating with an economizer is simulated, and then the effects of the variations in different parameters such as evaporator pressure, condensation pressure, and intermediate pressure on heat pump and total COP and exergy efficiency are analyzed. Initially, the thermodynamic simulation of the system is performed for different working fluids (R134a, R-12, R152a, R1234yf, and R1234ze(E)) in the EES software programming environment. The COP and exergy efficiency are calculated for different working fluids and obtained optimal values. The best overall coefficient of performance of the system is related to fluid R134a with a value of 3.663 and the best overall exergy efficiency of the system is related to fluid R1234ze(E) with a value of 0.5517. The lowest PCEU value is for fluid R152a with 0.01247$ per kilowatt. It can be concluded that by reducing the evaporator pressure of the cycle, the cost of producing an energy unit will be cheaper and by reducing the middle pressure of the cycle, the cost of producing an energy unit will be more expensive.

Geothermal energy is a characteristic of widely distributed, high capacity factor, high reliability, and lower environmental impact potential values. And it will play an important role in achieving the goal of carbon neutral carbon peak. Nonetheless, geothermal energy presents its own particular challenges, i.e., the high investment cost and long payback period. The binary flashing cycle (BFC) system is proved to be a promising power generation technology due to the efficient and full utilization of a low-grade heat source. While the economic performance still needs further evaluation, in the present study, the thermo-economic comparison between organic Rankine cycle (ORC) and the BFC for geothermal energy has been investigated. R245fa has been chosen as the working fluid. Considering the thermodynamic and economic performance simutaneously, several evaluation indicators were selected including thermal efficiency, exergy efficiency, net power output per ton geothermal water, heat exchanger area, and heat recovery efficiency, and the system modeling and comparison were presented. The simulation results reveal that the BFC system obtains 32% more net power output than the ORC system under the working conditions investigated. The heat recovery efficiency of the BFC is 1.96 times as much as that of the ORC, which indicates that the BFC can realize the full utilization of low-grade energy. And more heat exchanger areas are required in the BFC system. What is more, the preliminary discussion of the economic feasibility of BFC system applied in the FengShun geothermal power plant is presented. The payback period of the BFC is just 6.0 years under the generation pressure of 600 kPa. It is indicated that the BFC system has obvious economic benefits, especially in a nonflowing geothermal well.

A thermo-economic assessment of a hybrid concentrated photovoltaic–thermoelectric power generator (CPV–TEG) is performed based on the first law of thermodynamics and principles of costing. This study aims at estimating the optimum water-cooled CPV–TEG design parameters that yield the maximum overall performance. The influence of key parameters (such as direct normal irradiance (DNI), geometric concentration, thermoelectric figure of merit, temperature ratio of thermoelectric junction and heat sink thermal resistance) and their significance on the performance and cost of the system is examined. A performance measure known as the overall performance index (OPI) is used to evaluate the optimum design of the CPV–TEG system operating within the limits of allowable cell temperatures. OPI can incorporate several performance indicators that are crucial for performance estimation of a hybrid system by using a mass coefficient for each indicator based on its priority in the overall system performance. OPI accounts for three performance indicators of the CPV–TEG system, namely: energy efficiency, cost of the solar receiver (COSR) and levelized cost of energy (LCOE). The variation of the OPI provides an indication of the performance of the hybrid system under different design parameters and the selection of the appropriate design of the system to be at a point where the OPI is a maximum. Two scenarios are considered such that different mass coefficients are assigned to the performance indicators when evaluating the system performance. In the first scenario (performance case), energy efficiency is given the highest priority while for the second scenario (economic case), the cost of the solar receiver (CPV–TEG system) is given more emphasis. Optimization is performed for the water-cooled CPV–TEG design such that the PV temperature is kept below the maximum allowable cell temperature of 100 °C. LCOE of 0.0392 $ kWh−1 was obtained with an optimum OPI of 94.7% for the economic case. [ABSTRACT FROM AUTHOR]

Bitumite is widely used in coal-fired power plants. However, due to its high volatile content, the temperature of primary air to coal mills is limited to a lower value because of its high risk of spontaneous combustion. The method to reduce primary air temperature by mixing with cold air leads to irreversible loss and reduces the power generation efficiency of the power plant. To address the issue, a novel flue gas waste heat recovery system integrated with the bypass flue and outside primary air preheater for bitumite-fired power plants was suggested. The thermo- and techno-economic analysis models of the waste heat recovery system were developed, and the design parameters were optimized to maximize profit. The thermo-economic analysis shows that the exergy efficiency of the waste heat recovery system can reach 49.8 %, and the coal consumption rate can be reduced by 4.75 g (kW h)−1 by integrating the optimal waste heat recovery system. The techno-economic analysis shows that the net present value of the power plant during ten years can reach 10.6 M$, and the discounted payback period is 0.6 years. The novel waste heat recovery system can effectively improve the thermo- and techno-economic performance of bitumite-fired power plants. • A novel waste heat recovery system is suggested for bitumite-fired power plants. • The bypass flue and outside primary air preheater are used to heat primary air. • The exergy efficiency of the waste heat recovery system can reach 49.8 %. • The coal consumption rate is reduced by 4.75 g (kW h)−1 by recovering waste heat. • The net present value of the power plant during ten years can reach 10.6 M$. [ABSTRACT FROM AUTHOR]

[Display omitted] • Green hydrogen production from biomass waste heat with PEME was investigated from a thermo-enviro-economic point of view. • In the ORC unit of the 'Biomass waste heat - SRC - ORC – PEME' combined system, four different layouts (basic, regenerative, recuperative, regenerative with recuperator) and two different organic fluids (R245fa and R152a) were investigated. • The maximum hydrogen production was 93.81 tons per year, at which point the LCOH was 1.74 $/kg. • With CO2 emission reduction, a carbon gain of 37,527 $ was obtained. In this study, thermodynamic, thermo-economic and enviro-economic analyses of green hydrogen production with biomass waste heat-Steam Rankine Cycle (SRC)-Organic Rankine Cycle (ORC)-Proton Exchange Membrane electrolyzer (PEME) combined system were carried out. After the high-temperature biomass waste heat is used in the SRC unit, the mid-low temperature waste heat released is used in the ORC unit, which is more suitable for these temperatures, to generate electricity. Hydrogen production was investigated by transferring the power generated in the SRC and ORC unit to the PEME unit. Eight different configurations were created by using two organic fluids (R245fa-dry and R152a-wet) in four different layouts of the ORC unit. These layout are basic, regenerative, recuperative, regenerative with recuperator. The effect of turbine inlet temperature variation on system efficiency and hydrogen production rate at different evaporation pressure/critical pressure (Pe/Pcr) ratios in the ORC unit was determined. After determining the maximum hydrogen production point in each configuration, thermo-economic and enviro-economic analysis was performed. With the thermo-economic analysis, the payback period of the system, specific investment cost (SIC-$/kW) and levelized cost of hydrogen (LCOH-$/kg) were determined. For this, the amount of hydrogen produced per year, purchase equipment and other costs (installation, structural, contingencies, etc.) were taken into consideration. Finally, an enviro-economic analysis was carried out to determine the amount of CO2 reduction and the corresponding carbon credit gain (CCG-$). As a result of the study, the best performance was obtained in Conf-4a (Biomass waste heat-SRC-Regenerative recuperator ORC with R245fa-PEME). The amount of hydrogen produced per year, LCOH and CCG were 93.81 tons, 1.74 $/kg and 37,527 $, respectively. [ABSTRACT FROM AUTHOR]

The single-basin solar still is one of the effective ways of desalinating the seawater at an affordable price. But, the productivity of solar still is low and many kinds of research are under progress to enhance the yield. In this regard, a single-basin solar still with a solid staggered pin finned absorber inserted into a paraffin wax bed is developed to investigate the yield enhancement. This investigation is carried out by varying the seawater depths of the absorber basin from 2 to 4 cm in the developed solar still. The obtained results are compared with conventional solar still without fins and PCM bed. It is observed that the yield obtained in the developed solar still with 2-cm depth is having greater productivity when compared to other cases of seawater depths (3 cm and 4 cm). The yield of modified solar still and conventional solar still at 2-cm water depth is 3750 mL/m2 and 3017 mL/m2 respectively. It is also observed that thermal efficiency of the developed single-basin solar still is increased by 12.23%, 22.66% and 24.26% respectively compared to the conventional solar still for the seawater depths of 4 cm, 3 cm and 2 cm. In addition to that, it is observed from the economic analysis, the cost per litre potable water produced from modified solar still and conventional solar still is ₹ 2.1 and ₹ 2.25 respectively. Also, the environmental analysis is carried out to analyse the carbon credit from the developed single-basin solar still and found that the carbon credit gained from modified still and conventional solar still is $ 172.8 and $ 137.9 respectively. Based on this investigation, it is observed that the developed single-basin solar still with solid staggered pin finned absorber inserted into paraffin wax bed can be effectively used for the drinking water production to overcome the water scarcity. [ABSTRACT FROM AUTHOR]

Summary: The major intention of this study is to reduce the total expenditure of a vapor absorption cooling system (VACS) by developing an optimization model with an alternative working pair LiCl‐H2O and compares it with the traditional LiBr‐H2O system. Considering the cooling capacity of 50 kW, two working pairs were to compare parametrically at various operating conditions. The model comprises of three parts, viz. a thermodynamic model for the estimation of coefficient of performance, exergetic efficiency, and availability destruction of system components; an economic model for computing expenditure flow rate and capital investing expenditure rate; and the minimization of the total expenditure using genetic algorithm. The parametric study suggests that a LiCl‐H2O system performs better from both thermodynamic and expenditure‐effective aspects under all working conditions involved in this study. Especially, a low generator temperature produces a noticeable difference. The present global optimization technique assesses the optimal operating temperatures of generator, absorber, condenser, and evaporator. An optimal operating condition provides a system with a 1.20% of decrement in total expenditure rate and 5.39% of reduction in total capital investing expenditure rate using LiCl‐H2O solutions with respect to LiBr‐H2O solutions. Finally, results derived from this study may assist to designers to choose an alternative working fluid for enhancing the performance of VACS. [ABSTRACT FROM AUTHOR]

Absorption refrigeration cycle is considered a vital option for thermal cooling processes. Designing new systems is needed to meet the increasing communities' demands of space cooling. This should be given more attention especially with the increasing conventional fossil fuel energy costs and CO2 emission. This work presents the thermo-economic analysis to compare between different solar absorption cooling system configurations. The proposed system combines a solar field, flashing tank and absorption chiller: two types of absorption cycle H2O-LiBr and NH3-H2O have been compared to each other by parabolic trough collectors and evacuated tube collectors under the same operating conditions. A case study of 200 TR total cooling load is also presented. Results reveal that parabolic trough collector combined with H2O-LiBr (PTC/H2O-LiBr) gives lower design aspects and minimum rates of hourly costs (5.2 $/h) followed by ETC/H2O-LiBr configuration (5.6 $/h). H2O-LiBr gives lower thermo-economic product cost (0.14 $/GJ) compared to the NH3-H2O (0.16 $/GJ). The absorption refrigeration cycle coefficient of performance ranged between 0.5 and 0.9. [ABSTRACT FROM AUTHOR]

The suitability of organic Rankine cycle (ORC) technology for the conversion of low- and medium-grade heat sources to useful power has established this as a promising option in geothermal power-generation applications. Despite extensive research in this field, most of which has focused on parametric analyses and thermodynamic performance evaluations, there is still a lack of understanding concerning the comparative performance of different plant configurations from both thermodynamic and economic perspectives. This study seeks to investigate the thermo-economic performance of subcritical and transcritical geothermal ORC power-plants, while considering a range of working fluids and the use of superheating and/or recuperation. A specific case study based on the exploitation of a medium-temperature geothermal heat source (180 °C, 40 kg/s) is conducted. Multi-objective optimization is performed to maximize the power/exergy efficiency (i.e., resource use) and to minimize the payback period. Different optimized configurations are compared and the influence on system performance of superheating, recuperation, and subcritical vs. transcritical operation are evaluated. The results reveal that superheating is preferable for working fluids with low critical temperatures, but hinders the performance of fluids whose critical temperature is higher. Recuperation is not attractive under most operating conditions, since the thermodynamic performance improvement and cooling water saving cannot compensate the cost associated with the installation of the additional heat exchanger. Finally, transcritical ORC systems are favored thanks to the better thermal match between the heat source and the working fluid in these configurations. A more generalized geothermal heat source is then considered to explore the optimal configuration over a range of heat sources, which indicates that non-recuperated transcritical-cycle systems with working fluids whose critical temperature is close to the heat-source temperature are generally favorable.

Hybridisation, using an alternative heat source besides solar power, as a back-up unit can be a promising solution for the deployment of Compound Parabolic Concentrator (CPC) technology in low-temperature (100–150°C) industrial applications. In this research, a new integration of a non-evacuated CPC collector with a back-up system was studied for performance optimisation where a thermo-economic evaluation was carried out to investigate the viability of the proposed model for industrial deployment. In operational assessment, the effects of different operating modes as the manipulation of oil mass flow rate and controlling temperature and their interaction on collector efficiency and thermal behaviour were analysed. Results revealed that the maximum collector efficiency reaches about 72% suggesting improvements compared to the similar works. The hybrid mode operation was also evaluated as accurate and instantaneous proportionally to the weather changes. In addition, thermo-economic assessments identified the optimum adjustment based on the minimum payback period. [ABSTRACT FROM AUTHOR]

Cement plants have the potential points to waste heat recovery. The method studied in this paper is based on the use of air quenching chamber (AQC) and suspension preheater (SP) Boilers which are installed at the output of the clean cooler and preheating stage respectively in Cement Plant. Due to the low temperature of the existed gases, three different fluids, water, R123 and R245fa are used as the working fluids and are evaluated in a similar cycle in terms of energy, exergy and the optimum parameters selection based on genetic algorithm. The results of this study showed that fluid R123 with optimized parameters leads to a 4% increase the total exergy loss and also will increase the production power from 5 MW to 9 MW. That is while in the case of water production power is increased from 4.8 to 5 MW is optimal state. Also the Results showed that the cost of produced electricity and exergy efficiency are lower in the case of organic fluid application in comparison with water as working fluid. [ABSTRACT FROM AUTHOR]

The current research deals with thermodynamic and economic analyses and optimization of a geothermal system integrated with organic Rankine flash cycle (ORFC) and a polymer electrolyte membrane fuel cell (PEM-FC). A thermodynamic model for ORFC and PEM-FC is developed to investigate employing the PEM-FC in a combined geothermal ORFC. A comparative study is carried out to determine the effect of applying PEM-FC in a geothermal based ORFC. The validation of PEM-FC simulation with experimental data from the literature shows a good agreement. The results of numerical modeling indicate that using the rejected heat in the PEM-FC instead of the low-temperature geothermal source can increase the net output power from 254.9 kW to 1628.9 kW and the exergy efficiency from 23.77% to 36.19%, in the case of R123 as working fluid for the ORC system. Furthermore, using the PEM-FC imposes 9.07 US$/h cost rate to the system. Additionally the parametric study shows that the net output power and the total cost rate of the system are two major objective functions for the optimization. Thus, a multi-objective genetic algorithm is applied to determine the optimal values of design parameters with respect to some practical constraints. The results of the multi-criteria optimization represent that the optimum value of decision variables with considered objective functions are T 1 = 116 °C , r f l a s h = 0.55 , P F C = 230 kPa , and P 4 = 1208.4 kPa. Image 1 • Thermodynamic conceptualization of the geothermal energy integrated with a PEM-FC. • R123 regarding the cost rate and exergy efficiency is the best working fluid. • Exergy efficiency of the integrated system with employing PEM-FC increase 18.68%. • In the optimum state of the Geo/ORFC-FC system, the net output work is 1571.1 kW. • In the optimum state of the Geo/ORFC-FC system, the total cost rate is 10.51 US$/h. [ABSTRACT FROM AUTHOR]

• A thermo-economic multi-objective model is proposed for HEN design with compression. • The model is formulated as an enhanced superstructure-based MINLP model. • The superstructure simultaneously allows heat integration and compressor placement. • The presented model can effectively synthesize sub- and above-ambient HEN. • Our model can successfully cope with HEN design with multi-stream compression. Two significant forms of energy widely used in chemical industries are heat and work related to temperature and pressure manipulation. Since complex relationship exists in these strongly interacting properties (heat, work, temperature, pressure), it is essential to investigate work and heat integration as a whole. In this paper, an enhanced stage-wise superstructure is proposed that involves simultaneous optimization of compressor placement and heat integration for each pressure-changing sub-stream in stages. It explicitly considers non-isothermal mixing in each stage and enables the optimized selection of pre-coolers, end-heaters as well as end-coolers to adjust temperature requirements. A novel thermo-economic multi-objective mixed-integer nonlinear programming (MINLP) model is formulated to synthesize sub and above-ambient heat exchanger networks between constant-pressure streams and pressure-changing streams with multi-stream compression. The new model aims to achieve the optimal balance between thermodynamic and economic performances, with the objective of minimizing exergy consumption and total annual cost (TAC), respectively. Three case studies are conducted, where the results illustrate the well-known trade-off between thermodynamic and economic objective that is a decrease of 12.6%, 7.6%, 23.8% in TAC, while exergy consumption is increased by 14.8%, 12.8%, 4%. The Pareto curve is plotted for decision-makers to determine the optimal alternatives in terms of process requirement. [ABSTRACT FROM AUTHOR]

The present work focused on the comparative analysis of organic Rankine cycle (ORC) operated with nanoparticles. The effect of CuO and Al2O 3 nanoparticles synthesized with water and circulated within heat exchangers are examined. Thermal efficiency and levelized energy cost (LEC) of the nanofluid based ORC are evaluated simultaneously in the present work. The optimization problem of ORC is formed and solved using heat transfer search algorithm. Operating parameters of the nanofluid based ORC such as pinch point temperature difference of heat exchangers, evaporation pressure, the mass flow rate of refrigerant, and concentration of nanoparticles are investigated in the optimization study. Further, the effect of turbine ratio, heat source temperature, and mass flow rate of heat source fluid on CuO and Al 2O 3 based ORC is explored and discussed. It was observed that a total variation of 35.2% was obtained at the cost of 3.5% variation in LEC between extreme design points. The maximum thermal efficiency of 19.3% and 19.32% can be obtained with CuO and Al 2O 3 with 2.616 and 2.62 $/kWh, respectively. Comparative results reveal that CuO based ORC shows dominance in terms of economic performance over Al 2O 3 based ORC for any given value of the thermal efficiency. [ABSTRACT FROM AUTHOR]

Forced circulation crystallizer is one of the main contributors in Zero Liquid Discharge wastewater treatment processes. This technology enables the extraction of pure water from wastewater and separates impurities in the form of crystals. In the present study, a fast one-dimensional (nodal) model with high accuracy is introduced to predict the dynamic performance of the crystallization process in an FC crystallizer. Besides, to design and optimize a crystallizer, the parameters affecting the system performance should be evaluated from thermodynamic and economic perspectives. For this purpose, the developed model is used to investigate the crystallizer thermo-economic performance. Results show that the performance of the crystallizer system has the most significant sensitivity to varying the inlet feed concentration, suspension concentration, and rotational speed of the circulation pump. Increasing the suspension concentration reduces the mean diameter of output crystals. Also, increasing the pump rotational speed by about two times decreases the mean size of output crystals by approximately 41.39 %. From an economic point of view, increasing the heat input has a significant effect on the reduction of the dynamic payback period. Also, increasing the inlet feed concentration by 36 % leads to a 7.84 % increase in the internal rate of return. • A fast one-dimensional model with high accuracy is introduced. • Thermo-economic performance of FC crystallizer is investigated. • The results of zero- and one-dimensional modeling are highly close to each other. • Mixing zone has significant role in the crystallization process. • Increasing the inlet feed concentration by 36 % leads to a 7.84 % increase in the IRR. [ABSTRACT FROM AUTHOR]

• The performance of a single slope distiller was improved via a 250 W heat pump. • The evaporator was utilized to boost the condensation rate and supply space cooling. • The vapor extraction speed and condenser subcooling were experimentally optimized. • A daily yield of 10.263 L/m2 was obtained, exhibiting an improvement ratio of 158.5%. • A freshwater price of 0.0136 $/L was achieved. Developing conventional solar stills has been given a wide interest being a solution for the water shortage and world energy crises because of simplicity and low energy consumption. As a contribution to these innovation efforts, a 250 W heat pump unit was integrated with a single-slope solar distiller to provide two functions: heating the basin water (by a part of the heat pump condenser) and cooling effect for the extracted vapor from the distiller cavity (via the heat pump evaporator). The other part of the heat pump condenser is subcooled in a separate container via water. The effects of extracted vapor speeds (by varying the fan speed) and different subcooling container temperatures were studied to select the best performance for the modified distiller. The vapor speed tests included 4 variable speeds from 9.33 to 17 m/s. The selected vapor speed was 14 m/s due to its higher corresponding daily cumulative yield of about 10.14 L/m2, which means a 152.63% increasing ratio than that of the reference distiller. Additionally, at a subcooling temperature range of 45 – 50 °C, the enhancement ratio increased to 158.5% with a daily water productivity of 10.263 L/m2. The thermo-economic performance was also assessed. From the thermal performance point of view, augmentation ratios of 89.18% and 33.57% were obtained for energy and exergy efficiencies, respectively. Also, for the economic part, the results showed that the freshwater price was 0.0136$/L (for the modified device), which exhibits a reduction of 8.1% than that of the conventional distiller. [ABSTRACT FROM AUTHOR]

The thermal energy conversion of natural gas (NG) using appropriate configuration cycles represents one of the best nonrenewable energy resources because of its high heating value and low environmental effects. The natural gas can be converted to liquefied natural gas (LNG), via the liquefaction process, which is used as a heat source and sink in various multigeneration cycles. In this paper, a new configuration cycle is proposed using LNG as a heat source and heat sink. This new proposed cycle includes the CO2 cycle, the organic Rankine cycle (ORC), a heater, a cooler, an NaClO plant, and reverse osmosis. This cycle generates electrical power, heating and cooling energy, potable water (PW), hydrogen, and salt all at the same time. For this purpose, one computer program is provided in an engineering equation solver for energy, exergy, and thermo-economic analyses. The results for each subsystem are validated by previous researches in this field. This system produces 10.53 GWh electrical energy, 276.4 GWh cooling energy, 1783 GWh heating energy, 17,280 m3 potable water, 739.56 tons of hydrogen, and 383.78 tons of salt in a year. The proposed system energy efficiency is 54.3%, while the exergy efficiency is equal to 13.1%. The economic evaluation showed that the payback period, the simple payback period, the net present value, and internal rate of return are equal to 7.9 years, 6.9 years, 908.9 million USD, and 0.138, respectively.

Absorption refrigeration cycle is considered a vital option for thermal cooling processes. Designing new systems is needed to meet the increasing communities’ demands of space cooling. This should be given more attention especially with the increasing conventional fossil fuel energy costs and CO2 emission. This work presents the thermo-economic analysis to compare between different solar absorption cooling system configurations. The proposed system combines a solar field, flashing tank and absorption chiller: two types of absorption cycle H2O-LiBr and NH3-H2O have been compared to each other by parabolic trough collectors and evacuated tube collectors under the same operating conditions. A case study of 200 TR total cooling load is also presented. Results reveal that parabolic trough collector combined with H2O-LiBr (PTC/H2O-LiBr) gives lower design aspects and minimum rates of hourly costs (5.2 $/h) followed by ETC/H2O-LiBr configuration (5.6 $/h). H2O-LiBr gives lower thermo-economic product cost (0.14 $/GJ) compared to the NH3-H2O (0.16 $/GJ). The absorption refrigeration cycle coefficient of performance ranged between 0.5 and 0.9.

In this study, thermo-economic optimization of single-pass SAHs (solar air heaters) with obstacles of arcuate shape has been carried out. The research is conducted in order to compare the exergy efficiency of three different types of flat plate SAHs. Also, using NSGA-II (non-dominated sorting genetic algorithm) influencing factors were optimized. The SAHs were two different arcuate obstacles (type II and type III), and the other one had no obstacles (type I). All heater types with single and double glass cover were evaluated. The results showed that the heater with double glass cover and the obstacles (type III) had the highest function in both economic and exergetic aspects. Based on the NSGA-II results, collector with flow rate, area and the outlet temperature of 0.017 kg s−1, 2.6 m2 and 78 °C, respectively, had the best performance. [ABSTRACT FROM AUTHOR]

The applications of multi-evaporator and low temperature refrigeration systems are growing rapidly, highlighting the necessity of developing new configurations that can be economically and environmentally attractive. In this study, a hybrid dual-evaporator absorption refrigeration system for refrigerating and freezing applications is proposed and evaluated from thermodynamic, economic, and environmental viewpoints. In the proposed system, two compressors were employed between the evaporators and absorbers to increase the absorbers pressure to a higher level. The detailed parametric study results demonstrated that only employing a compressor between the higher temperature evaporator and absorber is beneficial improving the coefficient of performance (COP) significantly. However, the economic results showed that the compressor should be implemented carefully because in most design and operating conditions, the required capital and operating costs outweigh the COP improvement. Under specified design conditions, integrating the second compressor with a pressure ratio of 2.5 significantly increased the COP from 0.404 to 0.624 while it caused an increase in the unit production cost of cooling (UPCC) from $0.211/ton-hr to $0.228/ton-hr. The use of flue gas as a heat input was found to have excellent potential to improve the economic and environmental performance of the system. A detailed comparison with a dual-temperature transcritical carbon dioxide refrigeration cycle from the literature demonstrated that, under similar conditions, the system of this study has a substantially lower UPCC than the system in the literature ($0.211/ton-hr and $0.110/ton-hr for the steam and waste heat driven systems against $0.457/ton-hr). Overall, the proposed system (with and without the compressor) of this study showed an excellent potential for dual-temperature refrigeration applications. • A new hybrid dual-evaporator absorption refrigeration system is proposed. • Detailed thermodynamic and economic analysis is conducted to evaluate the system. • Combining a compressor is economical only at certain conditions. • Developing the new system is more economical than a system from the literature. • Proposed system shows an excellent potential for dual-temperature applications. [ABSTRACT FROM AUTHOR]

• A novel trigeneration system is proposed to recover diesel engine waste heat. • ORC has been combined with absorption-compression cooling and power system. • Thermo-economic analysis and parametric study have been carried out. • Applying screw expander improves the total exergy performance. • Applying compressor causes total performance to decrease. A novel trigeneration system consisting of organic Rankine cycle (ORC) and absorption-compression cooling and power system (ACCPS) is proposed to recover diesel engine waste heat. A compressor is used between evaporator and absorber in ACCPS. Moreover, a screw expander is applied in ACCPS to increase power generation and domestic hot water (DHW) is prepared by DHW heat exchanger (HX) in ORC. Exergoeconomic analysis using the specific exergy costing (SPECO) method is implemented for system assessment. Base case and parametric analysis as well as the effects of using expander and compressor in ACCPS on total performance of the system are examined. The results show that the best thermo-economic performance of the system is achieved when ORC condensation temperature and generator outlet temperature have respectively the lowest (85 °C) and the highest (80 °C) values. It is difficult to select the proper ORC evaporation temperature, because the lower this temperature is, the higher net power output is obtained while higher ORC evaporation temperature leads to less total cost rate and more total energy efficiency of system. Moreover, system exergy efficiency has an optimum point versus variation of ORC evaporation temperature. By increasing expander inlet steam quality, ACCPS coefficient of performance (COP) and total energy efficiency of system decrease; however, due to increase in net power output and system exergy efficiency respectively equal to 18.23% and 3%, total system performance improves from exergy viewpoint. By utilizing a compressor in ACCPS and increasing its pressure ratio, the performance of ACCPS improves from energy viewpoint; however, system thermo-economic performance decreases. [ABSTRACT FROM AUTHOR]

• Comparative analysis of NH 3 /CO 2 and C 3 H 8 /CO 2 cascade refrigerating system is investigated. • Total annual cost and exergy destruction of system are considered for the comparative analysis. • Optimization problem of cascade refrigerating system is developed and solved. • Investigate the effect of operating parameters on the performance of cascade system. • Investigate the sensitivity of design variables on the performance of cascade system. A cascade refrigeration system operating with CO 2 in the low temperature circuit and NH 3 as well as C 3 H 8 in the high temperature circuit are investigated for the thermo-economic optimization. Optimization results are used for the comparative analysis of both the refrigerant pairs (NH 3 /CO 2 vs. C 3 H 8 /CO 2). Optimization problem is formulated to minimize the total annual cost and exergy destruction of the system, and solved using a heat transfer search algorithm. Four operating parameters such as evaporator temperature, condenser temperature, condensing temperature of the low temperature circuit, and cascade temperature difference are investigated for the optimization. An application example of cascade refrigeration system is presented. Results are obtained in the form of Pareto-optimal points. Comparative results reveal that C 3 H 8 /CO 2 pair offered 5.33% lower cost and 6.42% higher exergy destruction compared to NH 3 /CO 2 pair. The effect of design variables and its sensitivity to the performance of cascade system are also presented and discussed. [ABSTRACT FROM AUTHOR]

Highlights • Thermo-economic analysis of a hybrid solar-conventional energy supply system has been conducted. • Numerical simulation of a direct parabolic trough solar collector was done. • A mathematical model to describe zero liquid discharge process was proposed. • Sensitivity analysis of hybrid design was performed to manage the supplied energy cost. Abstract In this paper, thermo-economic evaluation of hybrid solar-conventional energy supply in a zero liquid discharge plant has been conducted. The zero liquid discharge plant includes a brine concentrator and a crystallizer. Brine concentrator and crystallizer utilize falling film and forced circulation evaporators respectively. The plant was studied thermo-economically in capital of Iran, Tehran city weather conditions. The plant performance and economics were investigated in four design (winter, spring, summer and autumn design) conditions based on the seasonal weather data and compared with the conventional energy supply system. It was concluded that the design proposed based on average weather conditions shows no economic advantage over the conventional design; due to accounting for financial aids and subsides for the fuel cost at 0.05 $/m3, affecting the steam and water costs. However, a parametric study demonstrated that if the financial aids associated with the fuel are disregarded, it will have a pronounced effect on the cost of steam and produced water. [ABSTRACT FROM AUTHOR]

Highlights • Three configurations using nanofluid based PTSC are compared and optimized. • Four organic fluids are used in ORC in which toluene has the best performance. • Optimization results show that pure oil should be used in PTSC. • Configurations 1 & 2 perform relatively similar at the optimal point. • Configuration 3 has the weakest performance at the optimal point. Abstract The main goal of this study is to compare thermo-economic performance of three configurations of power generation system driven by solar heat source in which nanofluid based PTSC is used. Configuration 1 presents simple steam Rankine cycle (SRC) and configuration 2 and 3 show combined SRC with organic Rankine cycle (ORC) in two different conditions. In second configuration, ORC absorbs heat from SRC condenser and in third one, ORC absorbs heat in ORC evaporator from remain heat of SRC evaporator exiting nanofluid. The effects of various parameters such as concentration of nanoparticles, SRC evaporation temperature and SRC condensation temperature are investigated on output parameters and each configuration is optimized by using 4 different organic fluids (R113, n-hexane, cyclohexane, toluene) in ORC. After parametric analysis and performance comparison in base case, components performance and comparison of various configurations are examined at optimal point. Comparison of applying organic fluids in ORC related to configurations 2 and 3 shows that toluene has the best performance. Nanoparticles concentration for all 3 configurations is equal to zero at the selected optimal point and configurations 1 and 2 have relatively similar thermo-economic performance. Configuration 3 has the most net power output (4293 kW); however, it has the weakest thermo-economic performance due to the highest total cost rate (1434 $/h) and less energy and exergy efficiencies. [ABSTRACT FROM AUTHOR]

First generation ethanol (1G) contributes to the majority of the ethanol produced worldwide, predominantly centered on corn and sugarcane. Nevertheless, several issues are regularly highlighted concerning the long-term sustainability of this technology, including its intensive water and land use, potential contamination of soils through the distillation residues, as well as the balance between fuel and food crops. Accordingly, in this study, a process design approach for biomass to ethanol production (1G ethanol technology) from sugarcane was performed by using Aspen Plusr software, based on the autonomous distillery (AUT, ethanol production) and the annexed plant (ANX, joint ethanol and sugar production) configurations. In addition, a performance comparison in respect to the exergy efficiency and the irreversibility as quality indicators of the conversion processes is carried out to identify potential improvements in the production facilities. Hence, the shortcomings of the techno-economic assessment of ethanol production can be overcome by using exergy efficiency as a suitable indicator for process performance. Moreover, the technical/sustainability aspects related to the process design of the sugarcane biorefineries are discussed in light of the renewability exergy index (λ). In general, the ANX plant has a saving in the process irreversibility rate of about 6 %, whereas the average unitary exergy cost is 10% lower (AUEC= 2.41 kJ/kJ), in contrast to the AUT distillery. Moreover, a techno-economic analysis was carried out to assess the annexed plant and the autonomous distillery systems, considering the estimated capital expenditure. The results indicated that the ANX biorefinery has higher capex than the AUT distillery. It is noted that the higher investments are associated with sugarcane reception, ethanol production (juice extraction) and the combined heat and power sub-systems. Concerning system performance, the ANX plant presented a better overall exergy efficiency, with 41.39 %. Although this multi-criteria analysis is applied to 1G ethanol technology; it may be well-matched for various biorefineries/bioprocesses as a methodology to support decision-making as concerns potential improvement, well ahead of detailed process design. [ABSTRACT FROM AUTHOR]

Waste heat recovery systems, which make use of waste sources for their input energy, have considerable importance in industry since they utilize streams, which will be disposed to nature if not employed. Ship’s engines are one of the places, where a large amount of energy is wasted in different forms. In the present article, the idea of making use of these loss streams and consequently producing useful power in the outlet is proposed in the form of two systems. In the first system, the only stream of exhaust gases is utilized, while in the second system, the jacket cooling water is used together with the engine exhaust gases. Screening in the working fluids is conducted in order to select appropriate fluids, which have suitable characteristics in the physical, safety, and environmental aspects. The analyses indicate that using R600a presents the highest net power output, which reaches to the value of about 575 kW at the most. Comparison of the two introduced systems shows that preheating the working fluid by the jacket cooling water makes the better operation of the system and the power output is increased up to about 31-58% in different fluids. The lowest payback period in the systems is achieved through the use of R600a as the working fluid, which is about 3.48 year in the second system. [ABSTRACT FROM AUTHOR]

Abstract The India's annual milk and ghee production are approximately estimated as 160 MT and 1.72 MT respectively. India has the largest production of Ghee in the dairy Industry worldwide. Ghee consumption in India is 28% annually after fluid milk i.e. 44% due to high consumer demand. The butter churner, butter melter, ghee boiler and ghee clarifier are the key subunits of ghee production plant. The dairy industry is characterised by high energy consumption for production of Ghee and Butter in the country. The thermo-economic analysis and thermodynamic derivatives calculated in this study. The value of the universal exergy efficiency and specific exergy destruction of the plant was found as 34.21% and 438.61 kJ/kg respectively. The cost rate of exergy destruction for the entire plant was calculated as 3270.68 R/H; 39% of which was contributed by boiler for ghee production (ghee boiler). The highest value of percentage relative cost difference was associated with butter melter (97.29%) followed by butter churner (96.73%). The thermo-economic factor butter churner (8.00%) and ghee boiler (1.09%) revealed that impact of capital investment was more influential in former while exergetic degradation appeared to be more noticeable in latter. Highlights • Exergy Efficiency of the plant was performed in this work. • Thermo-economic analysis of ghee production plant studied on actual plant data. • The Specific Exergy Destruction of plant ascertained to be 438.61 kJ/kg. • The Specific Exergy Improvement Potential of plant estimated as 314.26 kJ/kg. • Total plant operating cost and specific manufacturing cost of Ghee is calculated. [ABSTRACT FROM AUTHOR]

Abstract We examine the economic viability of three multi-effect distillation (MED) based processes against the MED as a benchmark, when they are driven by low grade heat. We model and compare the Boosted MED (BMED), Flash Boosted MED (FBMED) and Distributed Boosted MED (DBMED) processes with the MED in terms of waste heat performance ratio, specific capex and opex. All three new configurations generate significantly higher productions than MED with higher capex and opex investment. We provide the corresponding cash-flow analyses using such financial metrics as the Net Present Value (NPV) and Internal Rate of Return (IRR). This study leads to the conclusion that the DBMED process is the superior scenario up to an interest rate of 12.5% at 65 °C heat source supply temperature which then drops to 8.4% at 90 °C heat source supply temperature. Also, the analysis shows for the high interest rates (above 8.4% at 90 °C), MED has higher NPV compared to other MED based processes. Graphical abstract The distributed boosted multi-effect distillation (DBMED) powered with low grade heat resources has been compared against MED, Boosted MED (BMED) and Flash Boosted MED (FBMED) in both technical and economic aspects. Unlabelled Image Highlights • The distributed multi-effect distillation process is the best process for waste heat. • At 65 °C heat source temperature, this process is superior up to 12.5% discount rate. • At 90 °C heat source temperature, this process is superior up to 8.4% discount rate. • Beyond these discount rates, conventional process with lower capex is more viable. [ABSTRACT FROM AUTHOR]

Micro-CHP systems are designed to reduce energy consumption in the present era. In this study, micro-CHP systems with a solar-powered Stirling engine are designed for use in similar buildings in three different climates of Iran. These solar systems are highly dependent on weather conditions in different cities. Modeling and optimizing to reduce costs, the economic dimension of the system, increasing energy storage and reducing the amount of emissions, especially CO2, have been achieved and acceptable results have been obtained. [ABSTRACT FROM AUTHOR]