Search Results (101)

Shifting towards electrified industrial energy systems is pivotal for meeting global decarbonization objectives, especially since process heat is a significant contributor to greenhouse gas emissions in the industrial sector. This review examines the changing role of heat exchanger networks (HENs) within electrified process industries, where electricity-driven technologies, including electric heaters, steam boilers, heat pumps, mechanical vapour recompression, and organic Rankine cycles, are increasingly supplanting traditional fossil-fuel-based utilities. The analysis identifies key challenges associated with multi-utility integration, multi-pinch configurations, and low-grade heat utilisation that influence HEN design, retrofitting, and optimisation efforts. A comparative evaluation of various methodological frameworks, including mathematical programming, insights-based methods, and hybrid approaches, is presented, highlighting their relevance to the specific constraints and opportunities of electrified systems. Case studies from the chemicals, food processing, and cement sectors demonstrate the practicality and advantages of employing electrified heat exchanger networks (HENs), particularly in terms of energy efficiency, emissions reduction, and enhanced operational flexibility. The review concludes that effective strategies for the design of HENs are crucial in industrial electrification, facilitating increases in efficiency, reductions in emissions, and improvements in economic feasibility, especially when they are integrated with renewable energy sources and advanced control systems. Future initiatives must focus on harmonising technical advances with system-level resilience and economic sustainability considerations. Full article

A thermodynamic integrated process assessment and experimental evaluation of the conversion of woody biomass to H₂ using chemical looping approaches were explored in this work. Both a two- and three-reactor approach were evaluated for effectiveness with a CaFe₂O₄ oxygen carrier (OC). Experimental test campaigns consisted of semi-batch operations where a single reactor was loaded with a batch charge of the OC and fuel. Multi-reactor approaches were experimentally simulated by switching the gas atmosphere around the batch charge of the OC. The experiments showed that woody biomass was capable of reducing CaFe₂O₄, enabling the production of H₂ from steam oxidation. High steam conversion rates to H₂ of >75% were demonstrated. Reduced CaFe₂O₄ catalyzed tar cracking, multi-cycle tests showed stable reactivity, and sub-pilot-scale tests showed improved reactivity and H₂ yield, accompanied by improved attrition resistance after over 30 cycles. The three-reactor configuration showed the highest potential for H₂ yield between the case studies, while the two-reactor configuration had the lowest auxiliary feed requirement. Both approaches showed increased yields and lower utilities than the baseline steam gasification technology. Full article

China’s offshore heavy oil resources are abundant but underutilized. Circulating steam stimulation enhances production while increasing casing failure risks in thermal recovery wells. Accurately assessing casing performance after repeated thermal cycles is crucial for ensuring wellbore integrity. This paper presents tensile and creep experiments on TP110H casing under cyclic temperatures. The temperature distribution within the “casing-cement sheath-stratum” system is derived using heat transfer theory. Stress and displacement equations are established based on thick-walled cylinder theory and thermo-elasticity. Thermal coupling analysis assesses casing stress in straight, inclined, and sidetrack well sections. Key factors, including steam injection pressure, in situ stress, cement modulus, and prestress, are analyzed for their effects on cumulative strain below the packer. Strain-based methods evaluate casing safety. Results show that under thermal cycling at 350 °C, after 16 cycles, the casing’s elastic modulus, yield strength, and tensile strength decrease by 15.3%, 13.1%, and 10.1%, respectively, while the creep rate increases by 16.0%. Above the packer, the casing remains safe, but the lower section may be at risk. Using low-elasticity cement, higher steam injection pressure, and prestressing can help improve casing performance. This study provides guidance on enhancing casing safety and optimizing steam stimulation parameters. Full article

Background: In the cardio-respiratory rehabilitation field, thermal medicine represents an interesting complementary therapy approach. It can aid in complex medical contexts characterized by cardio-respiratory deficiency, functional limitation, and pain determined by the invasiveness of pharmacological and surgical treatments in combination with limited post-surgical physical activity. Methods: We investigated the evolution of cardio-respiratory and functional performances following the application of the Integrated Thermal Care (ITC) protocol in 11 mastectomized/quadrantectomized women (mean age of 54 years). The ITC protocol consisted of hydroponic treatments, steam inhalations treatment, hydrokinesitherapy, and manual treatments. Patients were assessed before and after a cycle of 1 h long treatment sessions, which were performed 5 days a week for 4 weeks. The outcomes were measured through the following scales and tests: Piper Fatigue Scale (PIPER), 6-Minute Walking Test (6MWT), Five Times Sit-to-Stand (5STS), Range of Arm Motion (ROM), Disability of the Arm–Shoulder–Hand Scale (DASH), and Numeric Pain Rating Scale (NPRS). Results: We found appreciable improvements in cardio-respiratory efficiency and in pain perception exemplified by a reduction of PIPER, 5STS, DASH, and NPRS values together with an increase in 6MWT and ROM values. Conclusions: We conclude that ITC is a promising rehabilitative tool to enhance cardio-respiratory and functional performance and reduce pain after mastectomy/quadrantectomy. Full article

With the increase in the amount of new energy in new power systems, the response speed of power demand changes in combined cycle gas turbines (CCGTs) is facing new challenges. This paper studies an integrated operation strategy for the coupled molten salt energy storage of CCGT systems, and analyzes the system through simulation calculation. The advantages of the coupled system are determined by comparing the electrical output regulation capability, thermoelectric ratio, gas consumption rate, and peaking capacity ratio. In addition, using stored energy to maintain the temperature of the heat recovery steam generator (HRSG) can shorten the system’s restart time, improve the unit’s operating efficiency, and reduce the start-up cost. Our findings can be used as a reference for accelerating the performance improvement of CCGT systems, which is also crucial in technologies for waste heat recovery, molten salt energy storage technology, and promoting the sustainable development of energy systems. Full article

The global push for clean hydrogen production has identified nuclear energy, particularly high-temperature gas-cooled reactors (HTGRs), as a promising solution due to their ability to provide high-temperature heat. This study conducted a techno-economic analysis of hydrogen production in Saudi Arabia using the pebble bed modular reactor (HTR-PM), focusing on two methods: high-temperature steam electrolysis (HTSE) and the sulfur–iodine (SI) thermochemical cycle. The Hydrogen Economic Evaluation Program (HEEP) was used to assess the economic viability of both methods, considering key production factors such as the discount rate, nuclear power plant (NPP) capital cost, and hydrogen plant efficiency. The results show that the SI cycle achieves a lower levelized cost of hydrogen (LCOH) at USD 1.22/kg H₂ compared to HTSE at USD 1.47/kg H₂, primarily due to higher thermal efficiency. Nonetheless, HTSE offers simpler system integration. Sensitivity analysis reveals that variations in the discount rate and NPP capital costs significantly impact both production methods, while hydrogen plant efficiency is crucial in determining overall economics. The findings contribute to the broader discourse on sustainable hydrogen production technologies by highlighting the potential of nuclear-driven methods to meet global decarbonization goals. The paper concludes that the HTR-PM offers a viable pathway for large-scale hydrogen production in Saudi Arabia, aligning with the Vision 2030 objectives. Full article

Steam thermal power plants represent important energy production systems. Within the energy mix, these could allow flexible generation and the use of hybrid systems by integrating renewables. The optimum design solution and parameters allow higher energy efficiency and lower environmental impact. This paper analyzes single reheat supercritical steam power plants design solutions using a genetic heuristic algorithm. A multi-objective optimization was made to find the Pareto frontier that allows the maximization of the thermal cycle net efficiency and minimization of the specific investment in the power plant equipment. The Pareto population was split and analyzed depending on the total number of preheaters. The mean values and the standard deviations were found for the objective functions and main parameters. For the thermal cycle schemes with eight preheaters, the average optimal thermal cycle efficiency is (48.09 ± 0.16)%. Adding a preheater increases the average optimal thermal cycle efficiency by 0.64%, but also increases the average optimum specific investments by 7%. It emphasized the importance of choosing a proper ratio between the reheating and the main steam pressure. Schemes with eight and nine preheaters have an average optimum value of 0.178 ± 0.021 and 0.220 ± 0.011, respectively. The results comply with data from the literature. Full article

This study investigates strategies to empower Cape Verdean mathematics teachers in adopting Science, Technology, Engineering, Arts, and Mathematics (STEAM) methodologies, focusing on mathematics education. Using an interactive, reflective continuous professional development (CPD) model—including teaching simulations, classroom practice, and structured reflection—qualitative research was conducted via thematic analysis of published data over two project-training cycles. In the first cycle, 27 teachers participated, with 24 later acting as trainers in the second cycle, which involved 44 non-higher education teachers. The project, a collaboration between institutions in Cape Verde, Portugal, and Austria, was guided by Rogers’ Diffusion of Innovations theory and the Technological Pedagogical Content Knowledge (TPACK) framework. GeoGebra software was employed to support STEAM adoption. Results indicate significant advancements in teachers’ technological and pedagogical skills, leading to improved student engagement and understanding. However, challenges remain, especially in integrating STEAM across disciplines due to limited resources and a lack of systemic CPD. The study concludes that sustained support is essential for fully embedding STEAM in Cape Verde’s education system. Full article

The energy transition towards renewable energy sources is vital for handling climate change, air pollution, and health-related problems. However, fossil fuels are still used worldwide as the main source for electricity generation. This work aims to contribute to the energy transition by exploring the best options for integrating a solar field within a combined cycle power plant. Different integration positions at the gas and steam cycles for the solar field were studied and compared under several operating conditions using a thermodynamic model implemented in MATLAB R2024a. Fuel-saving and power-boosting (flowrate and parameter boosting) strategies were studied. The results revealed that, for a maximum fuel savings of 7.97%, the best option was to integrate the field into the steam cycle before the economizer stage. With an integrated solar thermal power of 3 MW, carbon dioxide emissions from fuel combustion were reduced to 8.3 g/kWh. On the other hand, to maximize power plant generation, the best option was to integrate the field before the superheater, increasing power generation by 24.2% for a solar thermal power of 4 MW. To conclude, guidelines to select the best integration option depending on the desired outcome are provided. Full article

Today, most of the world’s electric energy is generated by burning hydrocarbon fuels, which causes significant emissions of harmful substances into the atmosphere by thermal power plants. In world practice, flue gas cleaning systems for removing nitrogen oxides, sulfur, and ash are successfully used at power facilities but reducing carbon dioxide emissions at thermal power plants is still difficult for technical and economic reasons. Thus, the introduction of carbon dioxide capture systems at modern power plants is accompanied by a decrease in net efficiency by 8–12%, which determines the high relevance of developing methods for increasing the energy efficiency of modern environmentally friendly power units. This paper presents the results of the development and study of the process flow charts of binary and trinary combined-cycle gas turbines with minimal emissions of harmful substances into the atmosphere. This research revealed that the net efficiency rate of a binary CCGT with integrated post-combustion technology capture is 39.10%; for a binary CCGT with integrated pre-combustion technology capture it is 40.26%; a trinary CCGT with integrated post-combustion technology capture is 40.35%; and for a trinary combined-cycle gas turbine with integrated pre-combustion technology capture it is 41.62%. The highest efficiency of a trinary CCGT with integrated pre-combustion technology capture is due to a reduction in the energy costs for carbon dioxide capture by 5.67 MW—compared to combined-cycle plants with integrated post-combustion technology capture—as well as an increase in the efficiency of the steam–water circuit of the combined-cycle plant by 3.09% relative to binary cycles. Full article

The increasing environmental challenges posed by the widespread use of fossil fuels and the fluctuating nature of renewable energy have driven the need for more efficient and sustainable energy solutions. Current research is actively exploring hybrid energy systems as a means to address these issues. One such area of focus is the integration of Organic Rankine Cycles (ORCs) with gas and steam turbines, utilizing both natural gas (NG) and solar parabolic trough collectors (PTCs) as energy sources. This study examines the performance of a hybrid system implemented in Kirkuk, Iraq, a region known for its substantial solar radiation. Previous research has shown that hybrid systems can effectively enhance energy conversion efficiency and reduce environmental impacts, but there is still a need to assess the specific benefits of such systems in different geographical and operational contexts. The analysis reveals a thermal efficiency of 59.32% and an exergy efficiency of 57.28%. The exergoeconomic analysis highlights the optimal energy cost at USD 71.93/MWh when the compressor pressure ratio is set to 8 bar. The environmental assessment demonstrates a significant reduction in ${\mathrm{C}\mathrm{O}}_2$/emissions, with a carbon footprint of 316.3 kg ${\mathrm{C}\mathrm{O}}_2$/MWh at higher compressor pressure ratios. These results suggest that integrating solar energy with natural gas can substantially improve electricity generation while being both cost-effective and environmentally sustainable. Full article

As natural gas-fired combined cycle (NGCC) power plants continue to constitute a crucial part of the global energy landscape, their carbon dioxide (CO₂) emissions pose a significant challenge to climate goals. This paper evaluates the feasibility of implementing post-combustion carbon capture, storage, and utilization (CCSU) technologies in NGCC power plants for end-of-pipe decarbonization in Uzbekistan. This study simulates and models a 450 MW NGCC power plant block, a first-generation, technically proven solvent—MEA-based CO₂ absorption plant—and CO₂ compression and pipeline transportation to nearby oil reservoirs to evaluate the technical, economic, and environmental aspects of CCSU integration. Parametric sensitivity analysis is employed to minimize energy consumption in the regeneration process. The economic analysis evaluates the levelized cost of electricity (LCOE) on the basis of capital expenses (CAPEX) and operational expenses (OPEX). The results indicate that CCSU integration can significantly reduce CO₂ emissions by more than 1.05 million tonnes annually at a 90% capture rate, although it impacts plant efficiency, which decreases from 55.8% to 46.8% because of the significant amount of low-pressure steam extraction for solvent regeneration at 3.97 GJ/tonne CO₂ and multi-stage CO₂ compression for pipeline transportation and subsequent storage. Moreover, the CO₂ capture, compression, and transportation costs are almost 61 USD per tonne, with an equivalent LCOE increase of approximately 45% from the base case. This paper concludes that while CCSU integration offers a promising path for the decarbonization of NGCC plants in Uzbekistan in the near- and mid-term, its implementation requires massive investments due to the large scale of these plants. Full article

Growing environmental concerns have driven the installation of renewable systems. Meanwhile, the continuous decline in the levelized cost of energy (LCOE), alongside the decreasing cost of photovoltaics (PVs), is compelling the power sector to accurately forecast the performance of energy plants to maximize plant profitability. This paper presents a comprehensive analysis and optimization of a hybrid power generation system for a remote community in the Middle East and North Africa (MENA) region, with a 10 MW peak power demand. The goal is to achieve 90 percent of annual load coverage from renewable energy. This study introduces a novel comparison between three different configurations: (i) concentrated solar power (parabolic troughs + thermal energy storage + steam Rankine cycle); (ii) fully electric (PVs + wind + batteries); and (iii) an energy mix that combines both solutions. The research demonstrates that the hybrid mix achieves the lowest levelized cost of energy (LCOE) at 0.1364 USD/kWh through the use of advanced transient simulation and load-following control strategies. The single-technology solutions were found to be oversized, resulting in higher costs and overproduction. This paper also explores a reduction in the economic scenario and provides insights into cost-effective renewable systems for isolated communities. The new minimum cost of 0.1153 USD/kWh underscores the importance of integrating CSP and PV technologies to meet the very stringent conditions of high renewable penetration and improved grid stability. Full article

This paper presents reduced-order modeling of thermal power dispatch (TPD) from a pressurized water reactor (PWR) for providing heat to nearby heat consuming industrial processes that seek to take advantage of nuclear heat to reduce carbon emissions. The reactor model includes the neutronics of the reactor core, thermal–hydraulics of the primary coolant cycle, and a three-lump model of the steam generator (SG). The secondary coolant cycle is represented with quasi-steady state mass and energy balance equations. The secondary cycle consists of a steam extraction system, high-pressure and low-pressure turbines, moisture separator and reheater, high-pressure and low-pressure feedwater heaters, deaerator, feedwater and condensate pumps, and a condenser. The steam produced by the SG is distributed between the turbines and the extraction steam line (XSL) that delivers steam to nearby industrial processes, such as production of clean hydrogen. The reduced-order simulator is verified by comparing predictions with results from separate validated steady-state and transient full-scope PWR simulators for TPD levels between 0% and 70% of the rated reactor power. All simulators indicate that the flow rate of steam in the main steam line and turbine systems decrease with increasing TPD, which causes a reduction in PWR electric power generation. The results are analyzed to assess the impact of TPD on system efficiency and feedwater flow control. Due to the simplicity of the proposed reduced-order model, it can be scaled to represent a PWR of any size with a few parametric changes. In the future, the proposed reduced-order model will be integrated into a power system model in a digital real-time simulator (DRTS) and physical hardware-in-the-loop simulations. Full article

In the current context of the energy transition, Integrated Solar Combined Cycle (ISCC) power plants are an alternative that are able to reduce carbon emissions from combined cycle (CC) power plants. In addition, the coupling to an energy storage system based on molten salts benefits hybridization, allowing the energy surplus to be to stored to cover peaks in energy demand. Because it is a recent technology, the determination of the optimal injection points for the solar-generated steam into the combined cycle is a critical issue. In this work, a thermodynamic model of a hybrid natural gas and solar thermal CC power plant has been developed using Thermoflex to analyze the integration effects in terms of efficiency and power. For all the steam injection candidate positions, the effects of ‘power boosting’ and ‘fuel saving’ operation modes have been simulated, considering operation conditions that are compatible with the useful range of molten salts. The results show that injection of steam at the high-pressure line before the steam turbine increases the cycle’s gross efficiency with respect to the reference case, estimating a reduction of carbon emissions of 6696 kg/h in the ‘fuel saving’ mode and an increase in gross power of 14.4 MW in the ‘power boosting’ mode. Hence, adapting current combined cycles for hybridization with solar power is a viable solution in the transition period towards more sustainable energy sources. Full article