Hybrid Mode Operation Research Articles

Experimental and techno-economic analysis of solar-assisted heat pump drying of biomass

Drying enhances the attributes of biomass, such as storability and heating value. In regions with low solar radiation, solar drying has demonstrated limited economic viability. Hybrid systems, combining solar drying with a stable heat source such as a heat pump, present an opportunity to improve drying performance and achieve cost savings, especially with time-variable electricity pricing. To quantify this potential, we constructed an experimental drying system in Finland, incorporating an air-source heat pump and solar thermal collectors for drying woody biomass. Experimental work, consisting of 316 h of operation in varied conditions, evaluated the performance of the hybrid drying system. Subsequently, we developed data-driven models to estimate drying rates and power consumption in both hybrid and solar operation modes. Finally, these models were integrated into a techno-economic optimization model to assess the economic feasibility of the concept through hourly simulations. Hybrid drying experiments resulted in a significantly improved average drying rate (33.0 kg/h ± 5.4 kg/h) compared to solar drying (9.0 kg/h ± 3.2 kg/h) with a 45% increase in specific electricity consumption. The experimental work also revealed limited operating flexibility in colder temperatures due to an exponentially increasing preheating time (up to 4.2 h at 0 °C). With techno-economic modelling, the simulations yielded a simple payback time of 7.5 years for a commercial-scale drying system without investment subsidies. Applying an optimized operating strategy, system operation shifted on average from hybrid mode (96–33%) to solar mode (3–36%) and inactive state (1–31%) with an increased electricity price level, highlighting the need for advanced operation planning. Commercial deployment should prioritize use cases with high value increase through drying or obtaining compensation from avoided biogenic CO2 emissions through drying, as these two parameters were shown to have the greatest impact on the investment payback time.

Efficient lithium recovery from simulated brine using a hybrid system: Direct contact membrane distillation (DCMD) and electrically switched ion exchange (ESIX)

Seawater reverse osmosis (SWRO) brine is a readily available resource hub in many countries, fulfilling the country's freshwater need by SWRO, yet lower in a concentration of high-demand elements like Li. This study outlines developing a novel hybrid system that combines direct contact membrane distillation (DCMD) and electrically switched ion exchange (ESIX) to facilitate simultaneous SWRO brine enrichment followed by selective Li recovery. The DCMD process concentrates the SWRO brine utilizing electrospun nanofiber membranes (ENMs) composed of polyvinylidene fluoride (PVDF). Incorporating reduced graphene oxide (rGO) nanoparticles augments the morphological, thermal, and mechanical stability of the PVDF ENMs. The water contact angle (WCA) of the 1-rGO/PVDF ENM stands at 142.08°, a testament to an enhanced hydrophobic property which resulted in a 12 % freshwater recovery from simulated SWRO brine and a 2.4-fold increase in Li+ concentration. The durability of the 1-rGO/PVDF ENM is evident in its minimal 11 % reduction in WCA after 15 h of brine concentration. In the context of hybrid operation, a Li-selective LiAlO2 electrode, coupled with an activated carbon counter electrode, demonstrated remarkable Li recovery for Li capture solutions enriched by the rGO-PVDF membrane in the DCMD phase. Compared to the Li concentration in the DCMD feed, sequential Li capture and release cycles recovered 91.8 % of Li, thereby underlining the critical role of the hybrid mode operation in concentrating Li from simulated brine solutions.

Research on the complete vehicle control strategy of the composite accumulator hydraulic hybrid power system

The compound accumulator is an energy storage device consisting of a large accumulator and a small accumulator. Compared with the traditional single accumulator hydraulic hybrid vehicle, it has the characteristics and advantages of fast braking response for the small accumulator and more energy recovery for the large accumulator, combining braking characteristics and energy recovery rate. This paper proposes the control strategy for parallel hydraulic hybrid vehicle based on compound accumulator, which can determine the working timing for large and small accumulators according to the specific driving conditions, thereby improving the braking performance and fuel economy for the vehicle. Under NEDC conditions, this paper uses dynamic programming algorithm to find the optimal control sequence for torque distribution and energy management of the hydraulic hybrid vehicle with composite accumulator, obtains the control rules and logic thresholds of the logic threshold control strategy, and obtains the switching rule of the working timing of the composite accumulator. The simulation of specific cycle conditions is carried out to verify the rationality of vehicle control strategy and to explore the energy-saving mechanism of parallel hydraulic hybrid power system based on composite accumulator. The NEDC urban cycle test was carried out, and the comparison between the test and simulation results showed that the hydraulic hybrid operation mode, large and small accumulator pressure, and engine fuel consumption during the test were basically consistent with the simulation results and verified the control effect of the vehicle control strategy and the energy-saving mechanism of the parallel hydraulic hybrid system based on the composite accumulator.

Exergoeconomic assessment of a cogeneration pulp and paper plant under bi-operating modes

In the current study, the exergoeconomic analysis of a cogeneration pulp and paper plant under bi-operating modes at different environment temperatures of 290, 295, 305, 310, and 320 K was investigated. Two operating modes of the cogeneration system, i.e., a hybrid operating mode using a power boiler and a recovery boiler and a singular operating mode using a power boiler only, were considered. Natural gas was utilized as the main fuel in the power boiler, while black liquor with heavy fuel oil was employed in the recovery boiler. The total capital investment, total operating, exergy, unit exergy, and exergy destruction costs for each operating mode were evaluated. The results indicated that the total capital investment cost was 3420.27 $/h, and the total capital investment and the operation and maintenance costs in the hybrid and singular modes were 5853.27 and 6226.67 $/h, respectively. As well, the unit exergy cost and the exergy cost of steam introduced by the power boiler were 39.31 $/MWh and 2503.69 $/h, respectively. Where these values for the recovery boiler were 34.69 $/MWh and 554.30 $/h, respectively. Furthermore, the exergy destruction costs at an environment temperature of 320 K for the power and recovery boilers were 1436.6 and 213.63 $/h, respectively. In the hybrid mode, the soda at a 10% concentration was recovered, with a rate of 32 t per hour desired for the cooking process in the pulp mill. In addition, the use of black liquor as a bio-fuel in the recovery boiler saved 14% of the consumption of natural gas.

Hybridization of a RoR HPP with a BESS—The XFLEX HYDRO Vogelgrun Demonstrator

In the XFLEX HYDRO Vogelgrun demonstrator, a run-of-river hydropower plant, the hybridization of one turbine-generator unit with a battery energy storage system is being investigated. This paper describes the integration methodology of the hybrid control algorithm without replacing the existing speed governor of the unit. Furthermore, the comparison of the performances of a non-hybrid and hybrid unit is discussed, and first experiences gained during the operation and monitoring of the hybrid operating mode are presented.

Techno-economic analysis of dynamic, end-to-end optimal pharmaceutical campaign manufacturing using PharmaPy.

Increased interest in the pharmaceutical industry to transition from batch to continuouos manufacturing motivates the use of digital frameworks that allow systematic comparison of candidate process configurations. This paper evaluates the technical and economic feasibility of different end-to-end optimal process configurations, viz. batch, hybrid and continuous, for small-scale manufacturing of an active pharmaceutical ingredient. Production campaigns were analyzed for those configurations containing continuous equipment, where significant start-up effects are expected given the relatively short campaign times considered. Hybrid operating mode was found to be the most attractive process configuration at intermediate and large annual production targets, which stems from combining continuous reactors and semi-batch vaporization equipment. Continuous operation was found to be more costly, due to long stabilization times of continuous crystallization, and thermodynamic limitations of flash vaporization. Our work reveals the benefits of systematic digital evaluation of process configurations that operate under feasible conditions and compliant product quality attributes.

Dopant network processing units as tuneable extreme learning machines

Inspired by the highly efficient information processing of the brain, which is based on the chemistry and physics of biological tissue, any material system and its physical properties could in principle be exploited for computation. However, it is not always obvious how to use a material system’s computational potential to the fullest. Here, we operate a dopant network processing unit (DNPU) as a tuneable extreme learning machine (ELM) and combine the principles of artificial evolution and ELM to optimise its computational performance on a non-linear classification benchmark task. We find that, for this task, there is an optimal, hybrid operation mode (“tuneable ELM mode”) in between the traditional ELM computing regime with a fixed DNPU and linearly weighted outputs (“fixed-ELM mode”) and the regime where the outputs of the non-linear system are directly tuned to generate the desired output (“direct-output mode”). We show that the tuneable ELM mode reduces the number of parameters needed to perform a formant-based vowel recognition benchmark task. Our results emphasise the power of analog in-matter computing and underline the importance of designing specialised material systems to optimally utilise their physical properties for computation.

Hybrid normal-superconducting Aharonov-Bohm quantum thermal device

We propose and theoretically investigate the behavior of a ballistic Aharonov-Bohm (AB) ring when embedded in a N-S two-terminal setup, consisting of a normal metal (N) and superconducting (S) leads. This device is based on available current technologies and we show in this work that it constitutes a promising hybrid quantum thermal device, as a quantum heat engine and quantum thermal rectifier. Remarkably, we evidence the interplay of single-particle quantum interferences in the AB ring and of the superconducting properties of the structure to achieve the hybrid operating mode for this quantum device. Its efficiency as a quantum heat engine reaches of the Carnot efficiency, and we predict a thermal rectification factor attaining 350%. These results make this device highly promising for future phase-coherent caloritronic nanodevices.

Thermodynamic analysis of a cogeneration system in pulp and paper industry under singular and hybrid operating modes

In the present study, a thermodynamic analysis of a cogeneration system in a pulp and paper industry under different operating modes i.e., singular and hybrid with a variable ambient temperature is conducted according to actual operating data. For singular operating mode, the power boiler is only employed using natural gas while for hybrid operating mode, the power boiler with the recovery boiler is employed using natural gas and black liquor as main fuels, respectively. The results show that for hybrid operating mode in comparison with the singular one, the thermal efficiency of turbine and condenser is enhanced by 1.36 and 7.7%, respectively while it is reduced by 2.8% for the power boiler. In addition, the overall thermal efficiency under singular and hybrid operating modes is 87.4 and 53.7%, respectively. For hybrid operating mode, the exergy destruction of power boiler decreases by almost 10% compared with that for the singular operating mode. Also, at hybrid operating mode, the soda is recovered with a mass flow rate of 33 tons/hour that is required for the cooking process in the chemical pulp section and additionally the consumption of natural gas in the power boiler is reduced by 11.8%.

A 60-GHz Hybrid FMCW-Doppler Radar for Vibration Detection With a Robust I/Q Calibration Method

In the field of noncontact sensing, both the continuous-wave (CW) Doppler radar and the frequency-modulated CW (FMCW) radar have their own superiorities. A combination of these two radar modes would be a suitable choice to accommodate various application scenarios. This article presents a 60-GHz hybrid FMCW-Doppler radar transceiver fabricated in a 65-nm CMOS process. An on-chip frequency quadrupler driven by a 15-GHz external signal source is utilized for the 60-GHz hybrid waveform generation. Based on the hybrid operating modes, a robust I/Q imbalance calibration method is also proposed. Specifically, in the Doppler radar mode, the imbalance factors are extracted by evaluating the quadrature beat signals during the FMCW period, and then the interferometry signals are calibrated to improve the detection performance. Unlike the trajectory-based ellipse-fitting method, the accuracy of the estimated imbalance factor is independent of the target displacement. Compared with the test-signal-based imbalance factors extraction ahead of the target detection, the real-time extraction during the target detection is more efficient and can also mitigate the estimation errors caused by environmental variations. With the proposed hybrid radar system and the I/Q calibration method, an 80-mm linear displacement is recovered with a 0.016-mm root mean square error (RMSE), and a periodic vibration with a 1- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{m}$ </tex-math></inline-formula> amplitude is detected with a 16.4-dB signal-to-noise ratio (SNR). Multiple-target detection is also performed in the FMCW radar mode, and the vibration trajectories are recovered accurately.

Time-resolved resonant soft X-ray scattering combined with MHz synchrotron X-ray and laser pulses at the Photon Factory.

A picosecond pump-probe resonant soft X-ray scattering measurement system has been developed at the Photon Factory storage ring for highly efficient data collection. A high-repetition-rate high-power compact laser system has been installed to improve efficiency via flexible data acquisition to a sub-MHz frequency in time-resolved experiments. Data are acquired by gating the signal of a channel electron multiplier with a pulse-counting mode capable of discriminating single-bunch soft X-ray pulses in the dark gap of the hybrid operation mode in the storage ring. The photoinduced dynamics of magnetic order for multiferroic manganite SmMn2O5 are clearly demonstrated by the detection of transient changes in the resonant soft X-ray scattering intensity around the Mn LIII- and O K-edges.

An adaptive energy management strategy for supercapacitor supported solar-powered electric vehicle charging station

Abstract Large-scale electric vehicle integration into the grid is expected in the imminent future. Congestion caused by these integrations can be addressed through a hybrid AC/DC microgrid. The DC sub-grid is exclusively dedicated to incorporating electric vehicles. Solar-powered charging station supported with a supercapacitor energy storage system in the DC sub-grid reduces the stress on the AC sub-grid. This paper presents a hybrid AC/DC microgrid voltage/frequency stability improvement strategy based on adaptive DC-link voltage regulation assisted by energy storage. The proposed volatility-based approach is an efficient strategy to enhance the microgrid stability during generation intermittency and load fluctuations. The combined control scheme of the interlinking converter and supercapacitor energy storage in the independent and hybrid operation modes achieve energy balance with the variations in solar irradiation and the addition/disconnection of electric vehicles. The proposed energy management strategy is tested in real-time under various volatile conditions to validate the performance. The hybrid microgrid with proposed energy management strategy provided a frequency improvement of 0.55% and voltage improvement of 5.4%.

Research on Modeling, Stability and Dynamic Characteristics of Voltage-controlled Grid-connected Energy Storage Inverters Under High Penetration

With the increasing penetration of renewable energy, the power grid is characterised by weak inertia and weak voltage support. Some current-controlled inverters have been modified to voltage-controlled inverters and are gradually being used in distributed systems, thus constituting a multi-inverter hybrid operation mode system, which brings more severe challenges to the system's stable operation. In this paper, a framework consisting of three main parts of this particular voltage-controlled energy storage inverter is built. Each part's small-signal transfer function matrices are established by their control and structure. Based on this, the sensitivity of the SCR (short-circuit ratio) variation and droop coefficients of grid-connected inverter systems to stability is analysed in both dq domain and pos-neg sequence domain. The coupling of the inverter output active and reactive power and the effect of grid voltage disturbances are analysed under SCR variations in dq domain. Finally, the accuracy of the proposed model, the stability and dynamic response are verified by simulation and experimental platform of a 20 kW energy storage inverter system.

A Dual-Mode Hybrid Step-Up Converter with Stable Output for Vibration Energy Harvesting

A dual-mode hybrid step-up circuit for electromagnetic energy harvesting (EVEH) is proposed in this paper, with the merits of continuous output power delivery with and without external vibrations, simple architecture, and no need for extra circuits to start up. The proposed hybrid converter combines a multi-stage voltage multiplier (VM) with a boost regulator, which utilizes the winding inductance of the electromagnetic energy harvester as a boost inductor. With external vibration, the proposed circuit powers the load and stores energy in the super-capacitor through VM mode. When external vibration disappears, it automatically switches to boost mode and powers the load using the energy stored in the supercapacitor. For hybrid mode operation, the number of VM stages is optimized considering the following three aspects: sufficient voltage gains when vibration is on, time durations to provide constant power when vibration is off for as long as possible, and low losses at VM stage. A GaN-based dual-mode hybrid converter is built to verify the output regulation capability with an in-house-designed electromagnetic energy harvester. The outputs of the hybrid circuit achieve 4.05 V and 1.64 mW at a 100-Hz external vibration frequency and an acceleration of 0.7 g. The peak efficiency of the proposed hybrid converter reaches 60.7%. When external vibration disappears, the circuit is able to maintain a stable output for 13 s with a super-capacitor of 0.1 F.

Research on Hybrid Real-Time Picking Routing Optimization Based on Multiple Picking Stations

In the order picking process of the warehouse center, considering the rapid increase in the volume of orders arriving at the picking center at the time of the promotional festival, a hybrid operation mode with multiple picking tables is used to meet the picking requirements of the huge number of real-time orders. Therefore, in this paper, a hybrid picking mode is proposed, taking into account both the idle degree of picking stations and their order item centers of gravity, and a new reinforcement learning algorithm embedding mechanism (PRL) with placeholder control is designed to solve the problem of a huge number of real-time item orders arriving at the picking center system on promotional holidays and in inconsistent quantities, and numerical simulations are performed for this algorithm. The experimental results show that the PRL algorithm in hybrid picking mode can handle a huge number of orders simultaneously and improve picking efficiency effectively.

Dynamic Traffic Light System to Reduce The Waiting Time of Emergency Vehicles at Intersections within IoT Environment

Traditional traffic light system, which works based on fixed cycle can be a main reason for traffic jam, due to lack of adaptation to road conditions. Traffic jam has a bad impact on drivers and road users due to the time delay it causes for road users to reach their destinations. This delay can cause a life threat in case of emergency vehicles, such as ambulance vehicles and police cars. One key solution to solve traffic jam on intersections is the dynamic traffic lights, where traffic light operation adapts based on the intersection traffic conditions. Since few of researches projects in the literature interested in solving traffic jam problem for emergency vehicles, the contribution of this paper is to introduces a novel approach to operate traffic light system. The new approach consists of two algorithms which are pure operation mode and hybrid operation mode. These operation modes aim to reduce the waiting time of emergency vehicles on traffic intersections. They assume that there is a smart infrastructure system uses Internet of Things (IoT) that can detect emergency vehicles arrival to an intersection. The smart infrastructure system switches traffic light operation from fixed cycle mode to dynamic mode. The dynamic mode manages traffic lights at intersections to reduce the waiting time of emergency vehicles. The paper presents a simulation of the proposed algorithms, highlights their advantages. In order to evaluate the efficiency of the new technique, we compared our approach with Wen algorithm in the literature and the Traditional traffic light system. Our evaluation study indicated that the proposed algorithms outperformed Wen technique and the Traditional system under different traffic scenarios

Simulation of plasma scenarios for CFETR phase II based on engineering design parameters

The China fusion engineering testing reactor (CFETR) is a proposed tokamak nuclear fusion reactor in China, the purpose of which is to achieve large-scale power generation at the DEMO level and tritium self-sufficiency. Given that energy generation via this reactor can possibly solve energy crises in the future, the hybrid and steady-state operation modes for phase II of the CFETR under 1 GW discharge power targets are investigated comprehensively herein as per its engineering design parameters and using the integrated code METIS. The optimized condition for hybrid operation of the CFETR is obtained by adopting the dual neutral beam injection scheme under optimized energy and injection. With the electron cyclotron current drive and lower hybrid current drive deposited at the same off-axis position, the CFETR steady-state operation scenario is obtained by controlling the peak values of these driven current profiles. Moreover, it is found that the internal transport barrier (ITB) towards the plasma core can be controlled via selection of an appropriate peak driven current. Overall, these aspects are essential for evaluating the performance metrics and predictive physics of the CFETR. They also serve as a guide for prospective experiments that can be conducted in the future.

Coordinated Control of Diesel Generators and Batteries in DC Hybrid Electric Shipboard Power System

Hybrid electric ships powered by diesel generators and batteries are the main configuration for shipboard microgrids (SMGs) in the current maritime industry. Extensive studies have been conducted for the hybrid operation mode, whereas the all-electric operation mode and the switching between the aforementioned two modes in a system with multiple generators and batteries have not been tested. In this paper, a coordinated approach for a hybrid electric ship is proposed, where two operation modes have been simultaneously considered. More specifically, for achieving an efficient operation with reduced generator wear losses, the governor-less diesel-engine-driven generators have been adopted in the study. According to the practical operation conditions, two operation modes, the all-electric and hybrid modes, are preset. Based on these, the coordination of the generators acting as the main power sources and batteries regulating the power flow and improving the generator efficiency is studied. The governor-less diesel generators are regulated to inject the rated power in order to maximize the generator efficiency, while the DC bus voltage is regulated by DC/DC converters. For the benefit of the overall lifespan of battery banks, power sharing during charging and discharging states have been realized by the state of charge (SoC)-based adaptive droop regulator. For the test of two operation modes, as well as the mode switching, a simulation assessment in a 1 kV DC SMG has been conducted. The simulation results show that the DC bus voltage can be controlled well, and that the power sharing among batteries follows the design. Additionally, smooth transients can be observed during mode switching when the proposed control scheme is applied.

Research on Energy Efficiency Design Index Calculation Method for the Hybrid Ship

The Marine Energy Efficiency Design Index (EEDI) is recognized as an effective tool to measure the level of carbon emissions from ships at home and abroad. It will play an important role in the assessment of carbon emissions from the shipping industry, especially under the current and future development goal of carbon neutrality. Various green technologies to reduce the carbon emissions of ships have been demonstrated and applied. Hybrid power system is one of them. Compared with traditional direct propulsion, it can significantly reduce the energy consumption and carbon emissions of ships in inland waters such as the Yangtze River. Based on the characteristics of the hybrid power system, this paper firstly analyzes the power types of the hybrid power system during ship navigation. Then, according to the principle and elements of EEDI calculation method, it puts forward the key problems that should be solved in ship EEDI calculation of hybrid power system. Then, according to different hybrid operation modes, it also puts forward the calculation method of EEDI of each power mode and the calculation method of acquired EEDI of hybrid ship. Finally, the calculation and analysis of a 7500DWT hybrid bulk carrier show that the EEDI calculation method for hybrid ships proposed in this paper is scientific and reasonable.

Annual Thermal Performance of an Industrial Hybrid Direct–Indirect Solar Air Heating System for Drying Applications in Morelos-México

A theoretical–experimental annual analysis of a hybrid industrial direct–indirect solar air heating system performance for drying was conducted considering temperatures, useful energy Qu, efficiency η, and solar fraction SF. The direct solar air heating system located in Morelos, México, has flat-plate solar air collectors, and the indirect system has flat-plate solar water collectors, a thermal storage tank, a cross-flow fin, and a tube heat exchanger. A validated TRNSYS program modeled the process; the validation was carried out by comparing each component outlet temperature and useful energy with the respective experimental field data. The analysis considered annual usage over seven days a week, nine hours a day (from 09:00 to 18:00 h), and three operation modes. For the direct, indirect, and hybrid operation modes, the Qu values were 31.60, 55.19, and 75.18 MWh/yr; the annual η values were 0.44, 0.41, and 0.42; and the annual SF values were 0.45, and 0.73 for the indirect and hybrid mode, respectively. The hybridization of the direct–indirect solar air heating system increased annual performance by up to 58% in Qu and 42% in SF. The parametric analysis showed that a characteristic working nomogram of the hybrid system could be achieved, correlating the useful energy, efficiency, solar fraction, and operation temperature at a specified mass flow rate, and working temperature.