Combined Power Research Articles

A novel configuration optimization approach for IES considering exergy-degradation and non-energy costs of equipment

Improving the exergy utilization and economic performance is the core goal for the configuration optimization of the integrated energy system (IES). Achieving such a goal requires accurate evaluation of the exergy efficiency and economy. However, IES is a multisource heterogeneous and strongly coupled system. The development of reasonable exergy efficiency-economy characteristic evaluation indicators is a complex issue that limits its application in IES configuration. This article proposes a novel IES configuration optimization approach based on the concept of the equipment exergyeconomic cost coefficient. The exergyeconomic cost coefficient consists of the exergy-degradation and non-energy costs, which can quantitatively characterize the exergy efficiency and economy of the IES under a unified benchmark. A mechanism model for the equipment exergyeconomic cost coefficient, output of various equipment and total exergyeconomic cost is established. Furthermore, exergy flow attribute classification method is proposed to obtain the equipment exergyeconomic cost coefficient in the IES. The proposed method is verified in a real-world study case located in Yancheng, China. Compared to the conventional configuration method, the capacity of the renewable energy and combined heat and power generation (CHP) are enhanced, while the capacity of purchased electricity and electric boiler (EB) are reduced. It can obtain the minimum total exergyeconomic cost (TEC) for the IES. This study offers a new direction for the optimal configuration of IES.

Heat Energy Utilization of a Double-Flash Geothermal Source Efficiently for Heating/Electricity Supply through Particle Swarm Optimization Method

The principal aim of this article is to optimize the thermal and electrical efficiency of a geothermal combined heat and power system through metaheuristic particle swarm optimization (PSO) method. The objective of this research is to conduct a thorough analysis of the incorporation of metaheuristic PSO technique, with a specific emphasis on the potential advantages and obstacles associated with the utilization of metaheuristic approaches in improving the effectiveness of geothermal energy systems. The utilization of a double-flash geothermal system in conjunction with a transcritical carbon dioxide Rankine cycle is utilized for the co-generation of electricity and thermal energy. The research utilized a PSO method to enhance power generation, heating capacity, and overall system efficiency. The PSO algorithm was employed to determine the optimum operational parameters for a pressure level of 820 kPa and a pressure ratio of 1.59, leading to the maximization of power output to 2591.4 kW The PSO algorithm effectively identified the optimal operational parameters as a pressure of 820 kPa and a pressure ratio of 1.59, resulting in the achievement of a peak power output of 2591.4 kW. The methodology has determined that a pressure of 916.4 kPa and a pressure ratio of 1.5 represent the optimal parameters for achieving a maximum heating capacity of 12329.1 kW.

Probing the physics of star formation (ProPStar)

Context. Turbulence is a key component of molecular cloud structure. It is usually described by a cascade of energy down to the dissipation scale. The power spectrum for subsonic incompressible turbulence is ∝k−5/3, while for supersonic turbulence it is ∝k−2. Aims. We determine the power spectrum in an actively star-forming molecular cloud, from parsec scales down to the expected magnetohydrodynamic (MHD) wave cutoff (dissipation scale). Methods. We analyzed observations of the nearby NGC 1333 star-forming region in three different tracers to cover the different scales from ∼10 pc down to 20 mpc. The largest scales are covered with the low-density gas tracer 13CO (1–0) obtained with a single dish, the intermediate scales are covered with single-dish observations of the C18O (3–2) line, while the smallest scales are covered in H13CO+ (1–0) and HNC (1–0) with a combination of NOEMA interferometer and IRAM 30m single-dish observations. The complementarity of these observations enables us to generate a combined power spectrum covering more than two orders of magnitude in spatial scale. Results. We derive the power spectrum in an active star-forming region spanning more than 2 decades of spatial scales. The power spectrum of the intensity maps shows a single power-law behavior, with an exponent of 2.9 ± 0.1 and no evidence of dissipation. Moreover, there is evidence that the power spectrum of the ions to have more power at smaller scales than the neutrals, which is opposite to the theoretical expectations. Conclusions. We show new possibilities for studying the dissipation of energy at small scales in star-forming regions provided by interferometric observations.

ARCHITECTURAL AND CIRCUIT MODEL OF NAVIGATION DEVICE FOR ULTRA-LIGHT LAUNCH VEHICLE

The paper considered the architectural and circuitry model of a navigation device for an ultra-lightweight launch vehicle designed to improve the accuracy and reliability of positioning and orientation in flight conditions. The study utilized modern approaches to the integration of global navigation satellite system (GNSS) and inertial navigation system (INS) to achieve high accuracy and stability of the system. The key components of the device including UM980 module, LSM6DSV32X inertial measurement module, STM32 F7 series microcontroller, E220-400T30S radio module, LMR50410XDBVR converter based power supply and RS422 interface were described in detail. The UM980 module, including SAW and LNA filter blocks, demonstrated the ability to efficiently process incoming RF signals. The NebulasIV main function block combined GNSS BB, GNSS RF, interfaces and power management unit (PMU) modules, supporting multiple communication interfaces such as UART, SPI and I²C, as well as RTK and PPS signals. The study analyzed the integration and accuracy aspects of the module in navigation systems. The signal processing scheme of the inertial navigation system module was also presented, including digital filters, free-fall and activity/inactivity detection functions, and interfaces for data communication. User bias functions and filter modes are considered to ensure the accuracy and stability of the navigation device. The work lays the groundwork for further improvements in navigation technology, especially in the context of increasing availability and accuracy for small scale space launches.

Coordinated control algorithm of hydrogen production-battery based hybrid energy storage system for suppressing fluctuation of PV power

Photovoltaic (PV) power generation has issues of volatility and intermittency. Currently, PV plants are generally equipped with 10% rated capacity lithium-ion (Li) battery energy storage systems in China, who often fail to suppress fluctuation in the output power of PV plants effectively and meet the grid-connected standard. The hybrid energy storage system (HESS) combining with hydrogen production and Li battery system can produce hydrogen by water electrolysis during the peak period of PV power generation, effectively improving PV utilization efficiency, while smoothing PV power fluctuation and improving grid connection electricity quality. Firstly, models of the solid oxide electrolysis cell (SOEC) and alkaline electrolysis cell (AEC) systems for hydrogen production, and Li battery energy storage system are established, and the transient response characteristics of each system are analyzed. Secondly, an adaptive wavelet packet decomposition (AWPD) method for PV power signal decomposition is proposed based on the wavelet packet decomposition (WPD) method. Thirdly, a capacity configuration method for HESS are proposed based on the APWD method. Fourthly, a coordinated control strategy for HESS is proposed with the transient response characteristics of different energy storage systems and the state of charge for Li battery system. Finally, the proposed method is validated through simulation experiments based on the actual power data of the PV plant. The results show that the developed methods can effectively utilize partial PV power generation to produce hydrogen, improve PV utilization, and the combined output power of PV plant and HESS can fulfill the grid-connected standard.

Hydrogen vs. conventional sector-coupling residential energy systems: An economic and environmental comparison based on multi-objective design optimization

Planning residential energy systems faces economic, environmental, and technical challenges, necessitating cost-effective and environmentally friendly solutions. Hydrogen technologies in districts have recently gained interest. However, their economic and environmental potential relative to conventional technologies remains largely unexplored. Therefore, we quantitatively compared the impacts of designing hydrogen-based and conventional sector-coupling systems on total costs and CO2 emissions.We developed a multi-objective optimization model for the design and operation of generation and storage units, aiming to minimize total costs and CO2 emissions. We created three energy system configurations for an exemplary German district, each involving photovoltaics, heat storage, and batteries, while varying the main heat supplier. The first configuration includes a gas combined heat and power unit, the second features a heat pump, and the third incorporates a fuel cell, an electrolyzer, and hydrogen storage.Our comparison of the Pareto fronts revealed that the hydrogen system’s cost is 83% higher than the gas-based system and 33% higher than the heat-pump-based system. Environmentally, the hydrogen system emits 11% less than the gas-based system but 47% more than the heat-pump-based system. In conclusion, hydrogen units offer environmental benefits through improved photovoltaic utilization but perform poorly economically due to high investment and operating costs.

Model-based evaluation of ammonia energy storage concepts at high technological readiness level

Ammonia is a promising carbon-free energy carrier since it can be stored as a liquid at mild conditions and its production process from hydrogen and nitrogen is established and efficient. Several Ammonia-to-Power concepts have been proposed in the literature, many of which employ not-yet-mature electrochemical technologies. We model the charging and discharging phases of three ammonia energy storage concepts in Aspen Plus seeking a compromise between efficient concepts and mature technologies. In the charging phase, ammonia is produced via the Haber–Bosch process using hydrogen from low-temperature water electrolysis for all the considered concepts. For the discharging phase, three ammonia conversion processes are modeled: (i) ammonia is thermally decomposed into nitrogen and hydrogen by using thermal energy from storage, and hydrogen is converted into electricity in a fuel cell; (ii) ammonia is thermally decomposed by using heat generated through the combustion of a fraction of the ammonia stream, and the produced hydrogen is supplied to a fuel cell; (iii) ammonia is used as a fuel in a combined power cycle. We compare these concepts with respect to roundtrip efficiency and levelized cost of electricity. The roundtrip efficiency and the levelized cost of electricity of the modeled concepts are ca. 30–34 % and 0.28–0.31 €kWh−1 (for an electricity purchase price of 0.03 €kWh−1). Concept (i) has both the highest roundtrip efficiency and the lowest levelized cost of electricity. We identify the process bottlenecks via an exergy analysis.

JWST MIRI Detections of Hα and [O iii] and a Direct Metallicity Measurement of the z = 10.17 Lensed Galaxy MACS0647−JD

JWST spectroscopy has revolutionized our understanding of galaxies in the early Universe. Covering wavelengths up to 5.3 μm, NIRSpec can detect rest-frame optical Hα emission lines out to z = 7 and [O iii] to z = 9.5. Observing these lines in more distant galaxies requires longer wavelength spectroscopy with MIRI. Here we present MIRI Medium Resolution Spectrograph integral field unit observations of the lensed galaxy merger MACS0647–JD at z = 10.165. With exposure times of 4.2 hr in each of two bands (SHORT and LONG), we detect Hα at 9σ, [O iii] λ5008 at 11σ, and [O iii] λ4960 at 3σ. Combined with previously reported NIRSpec spectroscopy that yielded seven emission lines including the auroral line [O iii] λ4363, we present the first direct metallicity measurement of a z > 10 galaxy: 12+log(O/H)=7.79±0.09 , or 0.13−0.03+0.02Z⊙ . This is similar to galaxies at z ∼ 4–9 with direct metallicity measurements, though higher than expected given the high specific star formation rate log(sSFR/yr−1) = −7.4 ± 0.3. We further constrain the ionization parameter log(U) = −1.9 ± 0.1, ionizing photon production efficiency log(ξ ion) = 25.3 ± 0.1, and SFR = 5.0 ± 0.6 M ⊙ yr−1 within the past 10 Myr. These observations demonstrate the combined power of JWST NIRSpec and MIRI for studying galaxies in the first 500 million years.

Population data for 12 X-STRs loci in Malaysian Malay and Chinese populations

The utilization of X-chromosome short tandem repeats (X-STRs) for human identification particularly in resolving complex kinship cases has been advocated. Since, forensic statistical parameters vary among different populations, and because the X-STRs population data representing the diverse population of Peninsular Malaysia remain unavailable, the specific attempt reported here for the Malays (n = 224) and Chinese (n = 201) populations appears forensically relevant to support the evidential value of the 12 X-STRs markers for human identification in Malaysia. Results derived from the Qiagen Investigator® Argus X-12 kit revealed that DXS10135 as the most polymorphic locus with high genetic diversity, polymorphic information content, heterozygosity as well as power of exclusion. Based on allele frequencies, the combined power of discrimination as well as the mean exclusion chance (MECKrüger, MECKishida, MECDesmarais and MECDesmaraisDuo) values for the Malays and Chinese were individually ≥0.999995532964908. As for the combined power of discrimination as well as the mean exclusion chance (MECKrüger, MECKishida, MECDesmarais and MECDesmaraisDuo) calculated based on haplotype frequencies, the values were ≥0.9999986410567 for the Malays and Chinese populations. In addition, results from the genetic distance, neighbor-joining phylogenetic tree and principal component analysis revealed close biogeographical distributions of the studied populations with other South East Asian populations. Hence, the utilization of the X-STRs data for identifying individuals among the Malays and Chinese populations in Peninsular Malaysia for forensic application appears as highly supported.

Economic Analyses of a New Power and Cooling System at Low Temperature Applications

Recent research suggests that the implementation of more efficient combined cooling and power systems, which enable the cogeneration of electricity and cooling, can enhance the efficiency of hybrid plants. The present investigation is motivated by finding that, in the literature review on combined power and cooling systems, there is very limited information on the coupling of the organic Rankine cycle (ORC) and the ejector refrigeration cycle (ERC) with low sink temperatures. A suggested approach to do this involves using hot exhaust gas and waste heat engines to power an ORC hybrid system. To enhance the ORC–ERC system's performance, three heater configurations use waste heat from the ORC turbine exhaust, ejector, and engine waste heat to heat the working fluid. Renewable energy sources are the primary focus of most current research initiatives. The present research focuses on unique ORC and ERC systems, considered as combined power and cooling systems, with the goal of improving exergy performance at low temperatures. The suggested ORC–ERC can generate energy destruction of 69.85 kW at a source temperature of 155 °C, with an exergetic efficiency of 76.9% at the turbine. Setting the entrainment ratio at 0.5 results in a total sum unit cost of products (SUCP) of 465 $/kW‐h for the ORC–ERC. Furthermore, the 37.83% exergy destruction ratio introduces heat exchanger 2 (HE2) as the primary cause of the suggested ORC–ERC's irreversibility. A detailed parametric study reveals that altering the hot source temperature and entrainment ratio improves the system's SUCP. The current examination at high sink temperatures may be expanded to an advanced exergoenvironmental investigation.

Determining optimal component configurations for flexible biogas plants based on power prices of 2020–2022 and the legislation framework in Germany

The aim of this study is to find optimal component configurations for flexible biogas plants considering electricity prices in Germany, for maximum annuities considering costs and revenues. Cases for solely power-price driven operation and cogeneration-led operation were investigated for electricity prices in 2020, 2021, and 2022 in hourly resolution.Additional revenue from flexible operation increases as price volatility increased from 2020 to 2022. Interestingly, the choice of capacity for the combined heat and power unit (CHPU) is determined by the expected service life of the CHPU. Irrespective of electricity market signals, power quotients (PQ) of at least PQ = 4 avoid reinvestment for the CHPU within 20 years.Another result is that the the optimality region for CHPU capacity flattens for 2022 and shift to capacities above PQ = 4. Thus, high price volatility will allow plant operators to amortise even larger CHPUs, which could stimulate the installation of peak load by flexible biogas plants. Considering the day-ahead market can provide clear recommendations for optimal component configurations.The presented Smart-Force-Optimisation (SFO) combines a prefiltering of schedules matching given constraints and a brute force optimisation to the filtered subset. Thus, SFO has an improved performance comparing to bare brute force approaches.

Dynamic simulation and optimal design of a combined cold and power system with 10 MW compressed air energy storage and integrated refrigeration

A combined cold and power system with 10 MW compressed air energy storage and integrated refrigeration (CCR) is proposed. In traditional 10 MW compressed air energy storage (CAES) system, outlet pressure of air tank is throttled to a low pressure by throttling device. In CCR system, the throttling device is replaced by a piston turbine to achieve control of pressure and mass flow. Meanwhile, pressure potential energy of compressed air is converted to mechanical work, which is used to drive refrigeration subsystem. The dynamic mathematic model of proposed CCR system is built up. According to energy and exergy analysis of the whole dynamic process, it is confirmed that the proposed model obeys the first and second laws of thermodynamics. The optimal solution for T23 and γAC are calculated to be 259.6896 K and 1.2335, respectively. The Pareto frontier of multi-objective optimization of energy and exergy efficiencies are conducted. Energy efficiency of proposed CCR system is higher than that of CAES system by at least 32.8 %. The electrical efficiency of proposed CCR system is also higher than that of CAES system. It suggests that the pressure potential energy wasted in the throttle process is well utilized by the piston turbine in CCR system.

A computational study on square and helical magnetohydrodynamic generators including applications to a combined power cycle

A computational study on square and helical magnetohydrodynamic generators including applications to a combined power cycle

The effect of smart transformers on the optimal management of a microgrid

This study examines the impact of smart transformers on the optimal management of microgrids within a combined heat and power framework. Utilizing a Genetic Algorithm for optimization, the research identifies optimal settings for control variables and resource capacities. The integration of smart transformers significantly enhances performance, improving voltage profiles and reducing electrical losses, while minimizing costs and pollution levels.Key gaps in existing literature include insufficient exploration of smart transformers' advantages and a lack of holistic approaches that integrate technical and economic objectives. This study proposes a comprehensive optimization framework that simultaneously addresses multiple goals, such as reducing power losses and environmental impacts.The contributions include the innovative application of smart transformers for accurate control of active power flow and the development of a robust optimization strategy. Comparative analyses with other techniques, such as Particle Swarm Optimization and Interior Point Method, demonstrate the superior performance of the Genetic Algorithm approach in achieving optimal microgrid management.

Liquid biopsy in prostate cancer: A novel dual biomarker analysis approach integrating circulating tumor cells and circulating tumor DNA data.

This study aimed to explore the potential of liquid biopsy as a diagnostic tool by integrating two key biomarkers, Circulating Tumor Cells (CTCs) and Circulating Tumor DNA (ctDNA), and to enhance the detection fidelity of prostate cancer. A dual biomarker analysis approach was employed to synergize the sensitivities of CTCs and ctDNA. Various genetic mutations of ctDNA and tissues were scrutinized, investigating their prevalence, co-existence, and mutual exclusivity. The findings uncovered a more intricate mutation landscape than previously anticipated, indicating a complex interplay between cellular and genetic aberrations in prostate cancer. Through harnessing the combined power of CTCs and ctDNA, our dual biomarker approach provides a more comprehensive understanding of prostate cancer genetics. This has the potential to revolutionize early detection and guide personalized therapeutic interventions.

An innovative bio-inspired Aquila technique for efficient solution of combined power and heat economic dispatch problem

In the field of power systems, the optimization challenge of combined heat and power units economic dispatch (CHPUED) holds immense importance. This study presents an improved Aquila optimization technique (IAQT) that effectively tackles the CHPUED. The primary objective of the enhanced IAQT model is to minimize the overall cost of power generation in CHP systems while satisfying demand and operational constraints. However, to achieve more accurate cost estimations and avoid suboptimal solutions, it is crucial to consider transmission losses in the optimization model. By incorporating transmission losses, the IAQT algorithm can allocate power generation resources more effectively, leading to improved system efficiency and reduced operational costs. The proposed IAQT algorithm addresses the limitations of the standard AQT and introduces novel features to enhance its search capabilities. One key limitation of the standard AQT is its heavy reliance on the best solution found during optimization. To overcome this drawback, the enhanced IAQT model eliminates the dependency on the best solution and enables a more thorough exploration of the search space. Moreover, the algorithm incorporates specific limitations and constraints for each dimension of the newly generated solutions, ensuring their feasibility and validity. The standard AQT and proposed IAQT are tested on CEC 20 benchmark functions. Moreover, the proposed approach is extensively evaluated through experimentation and testing on various scenarios, including 7–48-unit and large 96-unit systems with/without losses. Furthermore, the overall costs for the 7 unit-system are considered including the reserve constraint. The results exhibit the remarkable performance and efficiency of the enhanced IAQT model, outperforming the standard version and several previously reported results. This validation underscores the significant contribution of the study in addressing the CHPUED and highlights its potential for real-world applications.

ESTUDIO DE DIFERENTES ALTERNATIVAS DE FUNCIONAMIENTO DE LOS GRUPOS EN LAS CENTRALES ELÉCTRICAS DE CANARIAS

Island electricity systems aim to adapt to the environmental expectations established by the European framework. For this reason, it is necessary to increase efforts to increase the penetration of renewables and optimize energy production. An extensive preliminary research study has been carried out on the current production system, its variables and its conditioning factors, with which a series of operating alternatives have been obtained that will optimize the energy production system through combustion technology (non-renewables) and combine them with the production of energy through renewable sources. renewables, complying both in dynamic response, security, scaling and integration with such systems, in terms of efficiency and power. The reduction of greenhouse gas emissions and the penetration of these renewable energies in the island's electricity systems will be increased. As has been proven in the research background, the usually established combination of power producing equipment is not the best to reduce pollution, and there are other possible combinations with better results. The study methodology followed leads to take measures based on: a) changing the type of fuel in the equipment that allows it, b) using the combination of less pollutant producing equipment with response capacity and c) considering the integration and incorporation of the pumped hydroelectric electric storage plant (PHES) "Chira-Soria" into Gran Canaria's electrical system. The different measures contribute to the improvement in the reduction of greenhouse gases (GHG) in a convincing way. Keywords: Isolated power system, Generation expansion planning, Energy transition, Insular electrical systems (IES), Energy policy, Canary Islands, Renewable energy, Pumped hydroelectric storage plant (PHES).

Data Tells the Truth: A Knowledge Distillation Method for Genomic Survival Analysis by Handling Censoring

Survival analysis is a critical tool for cancer research, yet handling censored data remains challenging due to supervision bias and inaccurate hazard estimates. To address these issues, we propose a simple but effective method termed KD, which employs knowledge distillation using uncensored data to rectify the supervision bias in censored data. This approach leverages the combined power of both rectified censored data and uncensored data to improve survival prediction accuracy. Remarkably, our KD method not only effectively harnesses censored data but also better reflects clinical reality, demonstrating its immense value in survival analysis. We applied our KD method to 19 target cancer sites using The Cancer Genome Atlas (TCGA) dataset. Our results consistently outperform traditional machine learning and deep learning-based methods across both target cancer sites and independent cancer cohorts. More importantly, our data-driven approach enables the model to extract hidden information from censored data, leading to conclusions that align more closely with clinical knowledge and scenarios. This validation of our KD method’s effectiveness highlights the substantial value of rational censored data usage, providing valuable insights for cancer research and clinical decisions. All data and codes are freely available at: https://datatellstruth.github.io/.

Performance analysis of multi turbines and SOFC combined power generation system for hypersonic vehicles

Scramjets are one of the most promising propulsion systems for hypersonic vehicles, but their application in vehicles with long-endurance is limited by electricity supply issue. This study proposes a combined power generation system based on solid oxide fuel cells and turbines for efficient power generation and energy cascade utilization. A lumped parameter model coupling proposed system and scramjet is developed for performance evaluation. Results indicate that in the process of energy cascade utilization, more pressure energy is utilized by turbines rather than fuel cells could enhance the electric power, and the system under the optimal energy cascade utilization condition obtain 537.13 kW of electric power and maintain the efficiency of fuel cells at 56.79 %. Further, for the system under optimal energy cascade utilization, there exists an optimal fuel utilization ratio of the fuel cells (0.7) which maximizes the electric power (539.37 kW), and the system electric power increases with decreasing current density of the fuel cells. Finally, the effect of power generation on propulsion is not significant. The maximum decrease in specific thrust and specific impulse is less than 0.4 % and 0.8 % per 100 kW power generation respectively. This research provides a novel scheme to achieve power generation for hypersonic vehicles.

Геометрическая модель главного корпуса Ивановской ТЭЦ-2 в ПВК Ansys

Modeling of the heat-air regime in the main body of the TPP in the scientific and technical literature is given insufficient attention. To simulate the heat-air regime in the main building of a thermal power plant, it is necessary to develop a geometric model of the boiler-turbine shop. A mathematical model of the heat-air regime in the main building of the TPP will allow us to develop energy-saving measures and improve the microclimate in the premises of the plant. The study has been carried out using mathematical modeling methods based on the DesignModeler graphic editor in ANSYS software. A geometric model of the boiler-turbine shop of Ivanovo combined heat and power plant-2 (CHPP-2) has been developed. It allows us to develop a mathematical model of heat and mass transfer in the air space of the main building of the plant. The three-dimensional geometric model of Ivanovo CHPP-2 is the first stage of the development of an integrated mathematical model of the heat-air regime of the main building. Its aim is to evaluate measures that reduce consumption of thermal and electrical energy for the in-house needs.