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This study investigates carbon black (CB) production challenges, including high energy usage and waste of heat sources, by proposing a waste heat energy recovery concept to increase the sustainability of this energy‐intensive and environmentally impactful process. The research involves a novel integration of a steam power plant (STP) with an industrial CB plant (CBP) using Aspen Plus simulation software. Comparative exergetic performance analyses of the system were conducted with this tool, while the Engineering Equation Solver (EES) was used to evaluate the exergoeconomic modelling of the plant. Additionally, environmental sustainability indicators were determined. The integrated plant system delivered CB capacity of 1817 kg/s, converted 98.03% of CB feedstocks with a purification value of 99.25% and produced 195 MW of electricity, significantly improving plant efficiency. The overall energy and exergy efficiencies for the integrated system are computed as 98.75% and 80.40%, respectively, with the STP contributing to the overall plant improvement. About 50% of the produced exergy was destroyed, with the CB combustor accounting for 48% of the combined plant exergetic destruction. Despite a substantial waste–exergy ratio from CBP, the integration of the STP increased the system’s exergetic sustainability index (ESI) by 18%. The exergoeconomic analysis highlighted the highest cost of destruction in the combustor and evaluated the evaporator as the least exergoeconomic factor driver. Components with potential exergetic and cost destruction improvements were identified. In conclusion, integrating power generation units with CB production plants can markedly reduce thermal heat waste in the CBP and enhance integrated plant environmental performance.

Waste heat recovery systems are proposed to be an environmentally benign and a cost-effective application for efficiency improvement of energy conversion systems. In this research, three different subsystems—gas turbine cycle, steam Rankine cycle, and a coupled organic Rankine cycle–vapor compression refrigeration—are integrated to obtain a high-efficiency layout from technical, economic, and environmental viewpoints. The whole system is simulated and analyzed with regard to energy, exergy, and exergoeconomic models. Furthermore, a sensitivity analysis is made to enable a better understanding of the effect of design parameters on the final performance of the total system. Based upon a parametric study, R602 demonstrates advantageous features such as higher thermal efficiency and improved exergetic efficiency in the ORC–VCR subsystem. Overall, analyses show that the proposed integrated system obtains the total energy and exergy efficiencies of 46.1% and 40.57%, respectively. Moreover, it has been illustrated that the overall structure is able to provide a 3810 kW net output power and a 303.8 kW cooling load. Besides, exergoeconomic evaluation depicts an exergy cost of 49.84 ( $ GJ−1) and an exergy cost rate of 826.4 ($h−1).

The paper aims to investigate the fuel and system options for a floating power plant (FPP) considering economic performance and the decarbonization goals of the International Maritime Organization. Various case studies have been assessed using a reference FPP, encompassing the instant and future retrofitting scenarios. The ready-to-use scenarios involve alternative fuel and organic Rankine cycle-based waste heat recovery system usage. Nuclear energy systems have been evaluated within the reference FPP since they are suitable candidates for achieving zero-carbon objectives and providing low-cost electricity. A simulation framework created in Python has calculated the fuel consumption regarding the power requirement and organized the approaches used in the study. An environmental model comparing the systems has been built to calculate upstream and operational emissions. The cost projection model for 2030 and 2050 has assessed the economic performance. Technique for Order of Preference by Similarity (TOPSIS) one of the multi-criteria decision-making approaches has ranked the systems considering the outcomes of economic and environmental models over the years. Findings demonstrate that the current fuel usage scenario of the FPP is not suitable both environmentally and economically. The other emissions can be near zero and greenhouse gases can be decreased by up to 15.95% using alternative fuels. Nuclear energy is a strong candidate to meet the 2050 targets, but its viability is largely based on economic performance.

Most primary energy sources, such as the fossil fuels of oil, coal, and natural gas, produce waste heat. Recycling of this unused thermal energy is necessary in order to increase the efficiency of usage. Thermoelectric (TE) conversion technologies, by which waste heat is directly converted into electricity, have been extensively studied, and the development of these technologies has continued. TE power-generation has attracted significant attention for use in self-powered wireless sensors, which are important for our increasingly sophisticated information society. For the middle-temperature range (i.e., 600–900 K), with applications such as automobiles, intensive studies of high-performance TE materials have been conducted. In this study, we review our recent experimental and theoretical studies on alkaline-earth silicide Mg2Si TE materials, which consist of nontoxic abundant earth elements. We demonstrate improvements in TE performance brought about by lightly doping Mg2Si with isoelectronic impurities. Furthermore, we examine the electrode formation and material coatings. Finally, we simulate the exhaust heat requirements for the practical application of TE generators.

Turbo compounding is one of the ways to recover wasted energy in the exhaust. This paper presents the effectiveness of series and parallel turbo compounding on a turbocharged diesel engine. A power turbine is coupled to the exhaust manifold, either in series or in parallel with the turbocharger, to recover waste heat energy. The effectiveness and working range of both configurations are presented in this paper. The engine in the current study is a 6 cylinder, 13 L diesel engine. Both the configurations were modeled with one dimensional simulation software. The current study found that series and parallel turbo compounding could improve average brake specific fuel consumption (BSFC) by 1.9% and 2.5%, respectively. When the power turbine is mechanically connected to the engine, it could increase the average engine power by 1.2% for the series configuration and 2.5% for the parallel configuration.

In recent decades, there has been an increasing trend toward the technical development of efficient energy system assessment tools owing to the growing energy demand and subsequent greenhouse gas emissions. Accordingly, in this paper, a comprehensive emergy-based exergoeconomic (emergoeconomic) method has been developed to study the biomass combustion waste heat recovery organic Rankine cycle (BCWHR-ORC), taking into account thermodynamics, economics, and sustainability aspects. To this end, the system was formulated in Engineering Equation Solver (EES) software, and then the exergy, exergoeconomic, and emergoeconomic analyses were conducted accordingly. The exergy analysis results revealed that the evaporator unit with 55.05 kilowatts and the turbine with 89.57% had the highest exergy destruction rate and exergy efficiency, respectively. Based on the exergoeconomic analysis, the cost per exergy unit (c), and the cost rate (C˙) of the output power of the system were calculated to be 24.13 USD/GJ and 14.19 USD/h, respectively. Next, by applying the emergoeconomic approach, the monetary emergy content of the system components and the flows were calculated to evaluate the system’s sustainability. Accordingly, the turbine was found to have the highest monetary emergy rate of capital investment, equal to 5.43×1012 sej/h, and an output power monetary emergy of 4.77×104 sej/J. Finally, a sensitivity analysis was performed to investigate the system’s overall performance characteristics from an exergoeconomic perspective, regarding the changes in the transformation coefficients (specific monetary emergy).

Absorption heat transformers (AHTs) are a promising technology for industrial waste heat recovery, enhancing energy efficiency and sustainability. However, achieving quick start-up and stable operation remains challenging due to complex thermal interdependencies and limited understanding of transient dynamics. This study proposes a methodology to reduce AHT stabilization time by identifying critical thermal variables in transient-state conditions. The approach combines correlation and significance analyses to determine variables most influential on output temperatures across main components, such as heat source/cooling water temperatures, pressures, mass flow rates, and solution concentrations. The methodology was tested using experimental data from a 2-kW AHT prototype, supported by an artificial neural network (AHT-ANN) model to simulate stabilization time reductions. Results identified three critical transient variables: desorber heating water input temperature, condenser cooling water input temperature, and system low pressure. Strategic management of these parameters reduced start-up stabilization time by up to 36.1%. Additionally, the model’s coefficient of performance aligned closely with experimental values (discrepancies < 0.0625), validating its accuracy and consistency with baseline energy metrics. This methodology offers a practical framework to minimize start-up delays in AHT systems while maintaining adaptability across configurations and operating conditions. By advancing insights into transient behavior, the study paves the way for improved operational efficiency and broader industrial adoption of AHTs in waste heat recovery.

Ceramic membrane condensers that are used for water and waste heat recovery from flue gas have the dual effects of saving water resources and improving energy efficiency. However, most ceramic membrane condensers use water as the cooling medium, which can obtain a higher water recovery flux, but the waste heat temperature is lower, which is difficult to use. This paper proposes to use the secondary boiler air as the cooling medium, build a ceramic membrane condenser with negative pressure air to recover water and waste heat from the flue gas, and analyze the transfer characteristics of flue gas water and waste heat in the membrane condenser. Based on the experimental results, it is technically feasible for the ceramic membrane condenser to use negative pressure air as the cooling medium. The flue gas temperature has the most obvious influence on the water and heat transfer characteristics. The waste heat recovery is dominated by latent heat of water vapor, accounting for 80% or above. The negative pressure air outlet temperature of the ceramic membrane condenser can reach 50.5 °C, and it is in a supersaturated state. The research content of this article provides a new idea for the water and waste heat recovery from flue gas.

(1) Background: the shipping industry forced ships to adopt new energy-saving technologies to improve energy efficiency. With the timing modulation for the marine low-speed diesel engine S-CO2 Brayton cycle, the waste heat recovery system is optimized to improve fuel economy. (2) Methods: with the 6EX340EF marine low-speed diesel engine established in AVL Cruise M and verified by the bench test data, the model of the S-CO2 Recompression Brayton Cycle (SCRBC) system for the low-speed engine flue gas waste heat recovery was developed in EBSILON, and verified by SANDIA experimental data. On this basis, the effects of injection timing and valve timing parameters on the comprehensive performance of the main engine and the waste heat recovery system were investigated. By optimizing the timing modulation parameters through multi-objective genetic algorithm (MOGA) and evaluating the flue gas waste heat recovery from the perspective of thermodynamic performance and emission reduction, the research on the performance modulation method of the S-CO2 Brayton Cycle for flue gas waste heat in marine low-speed engines has been completed. (3) Results: the SCRBC with waste heat modulation will further increase the total power and efficiency, which in turn brings about a reduction in the fuel consumption rate. The efficiency of the SCRBC system with the addition of waste heat modulation increases by 2.28%, 1.04% and 2.07% at 50%, 75% and 100%, respectively. After adding the residual heat modulation, the maximum annual CO2 emission reduction of 748.51 × 103 kg·a−1 occurred at 50% load; with the exergy analysis, the cooler has the largest system exergy loss of 165 kW, with the exergy loss efficiency of 2.06% under 100% load. (4) Conclusions: the research on the performance modulation method of S-CO2 Brayton cycle for flue gas waste heat in the marine low-speed engine has been completed, which further improves the efficiency of the system and can be extended to other engines.

The maritime industry will continue to see increasing regulatory requirements to reduce carbon emissions from ships’ operations. Improving the energy efficiency of ships with waste heat recovery systems based on the organic Rankine cycle (ORC) is an attractive way to meet these tightening requirements. The operational profile of a ship has a huge influence on the feasibility of installing ORC onboard as it affects the waste heat source profile from the diesel engines. However, to date, scant attention has been paid to examining the effects that the operational profile has on the marine application of ORC as it is both difficult and expensive to obtain. The present paper aims to describe a methodology that can overcome this problem by developing a generic ship speed profile that defines the ship’s operational profile. This speed profile works together with a fit-for-purpose diesel engine waste heat model to derive a waste heat source profile that is used as the input to a thermoeconomic analysis that can justify the installation of ORC. The proposed methodology allows for an objective comparison of the feasibility of ORC subjected to variations in the operational profile. Furthermore, the optimum ORC design can be identified to meet payback time expectations of different shipowners.