Cell Hybrid System Research Articles

Material optimum choices and parametric design strategies of a photon-enhanced solar cell hybrid system

A novel design concept of the solar hybrid system consisting of a solar concentrator, a photon enhanced thermionic emission device (PETED), and a thermoelectric generator (TEG) is proposed. The main irreversible losses in the system are taken into account. The energy balance equations of the cathode and anode of the PETED are directly used to expound that the cathode and anode temperatures of the PETED may be changed through the different choices of the energy bandgap and electron affinity of the cathode material, the reduced electric current of the TEG, and the structure parameter of the hybrid device. Analytic expressions for the power output and efficiency of the hybrid system are derived. The maximum efficiency of the hybrid system is calculated and it is proved that the hybrid system can effectively enhance the conversion efficiency of solar energy. The optimal values of some important parameters, such as the energy bandgap and electron affinity of the PETED, the reduced electric current of the TEG, the structure parameter of the hybrid device, and the solar concentration of the hybrid system, are determined. The results obtained here will be helpful for the reasonable choice of cathode materials and the optimum design of practical hybrid devices.

The characteristics of regenerative energy for PEMFC hybrid system with additional generator

This study focuses on the use of the Polymer Electrolyte Membrane Fuel Cell (PEMFC) hybrid system, which consists of a generator, a supercapacitor, and a battery, to obtain regenerative energy. The fuel cell is a Nexa™ Power Module of Ballard Power Systems Inc., and the battery is a Ni-MH battery of Global Battery Co., Ltd. The supercapacitor, which features an excellent power density and capacity of 30 V and 100F, can minimize its power consumption via a cell balancing circuit. This study aimed to evaluate the characteristics of regenerative energy and suggest solutions to increase regenerative energy using a vehicle simulation.In this study, the rated RPM of the motor was set to 3000 RPM which was reliable motor speed. Because the flywheel was connected directly to the motor, the flywheel speed was set to 3000 RPM to save the maximum kinetic energy. The motor stops and the generator activate regenerative braking using the energy of the flywheel when the flywheel reaches the set speed. Upon activation, the characteristics of regenerative braking, including the voltage, current, power, and energy change, can be obtained. The storage efficiency of the supercapacitor or the battery can be calculated from the stored energy. The experimental results exhibited five characteristic intervals when the regenerative braking energy, which is generated from the generator, is stored in the supercapacitor. Twenty-one percent of the regenerative energy was stored in the supercapacitor, and 15% was stored in the battery. The supercapacitor outperforms the battery in storing regenerative energy because its response speed is faster.

Comparative study of artificial intelligence techniques for sizing of a hydrogen-based stand-alone photovoltaic/wind hybrid system

As non-polluting reliable energy sources, stand-alone photovoltaic/wind/fuel cell (PV/wind/FC) hybrid systems are being studied from various aspects in recent years. In such systems, optimum sizing is the main issue for having a cost-effective system. This paper evaluates the performance of different artificial intelligence (AI) techniques for optimum sizing of a PV/wind/FC hybrid system to continuously satisfy the load demand with the minimal total annual cost. For this aim, the sizing problem is formulated and four well-known heuristic algorithms, namely, particle swarm optimization (PSO), tabu search (TS), simulated annealing (SA), and harmony search (HS), are applied to the system and the results are compared in terms of the total annual cost. It can be seen that not only average results produced by PSO are more promising than those of the other algorithms but also PSO has the most robustness. As another investigation, the sizing is also performed for a PV/wind/battery hybrid system and the results are compared with those of the PV/wind/FC system.

Recent Advances in Biofuel Cells: From Enzyme Immobilization to Implanted Devices

The ever-increasing depletion of fossil fuels and the need for clean methods of producing electricity have stimulated the emergence of abiotic and enzyme-based fuel cells that convert chemical energy into electrical energy at room temperature [1]. Taking into account that the interface activity was related to the immobilized amount of catalysts and the specific surface of the conductive substrate, 3D structures were designed via the use of carbon nanotubes as building block [2]. Carbon nanotubes exhibit nanowire morphology, biocompatibility and excellent conductivity. Furthermore, nanotube modified electrodes offer a large electroactive surface together with a highly porous three-dimensional structure. The recent advances in term of enzyme immobilization via functionalized films electropolymerized onto nanotube coatings will be described. For instance, the combination of carbon nanotube coating and electropolymerized photoreactive films constitutes an original strategy for the covalent immobilization of proteins by irradiation. We describe, here, the successful electrogeneration of a photoactivatable polypyrrole-diazirine film onto multi-walled carbon nanotube coatings and its use for the covalent binding of proteins [3].Moreover, the oriented immobilization of laccase on carbon nanotube was carried out to enhance the direct electron transfer. The possibility to functionalize carbon nanotubes by attaching specific docking sites for enzymes via electrogenerated polymer or pyrene derivatives exhibiting p-stacking interactions will be reported [4,5].We report also the first example of a glucose/H2O2 biofuel cell operating at 5 mM glucose under air (Figure 1). At a bienzymatic cathode, the direct wiring of horseradish peroxidase achieves the electrocatalytic reduction of H2O2 produced during the oxidation of glucose [6]. This represents a novel alternative to the use of laccases or bilirubin oxidases in conventional glucose/O2biofuel cells for implantable applications.Taking into account that conductive nanostructured materials such as carbon nanotubes became highly appropriate candidates for the elaboration of biofuel cells and electrochemical supercapacitors, we report here for the first time, the original combination of these two devices. The possibility to recharge supercapacitors with an internal energy source could thus represent a significant improvement for the performance of biofuel cells. In this context, we propose an original hybrid battery-capacitor system using a compression of enzymes-carbon nanotubes as supercapacitors and electrodes for a biofuel cell setup (Figure 1). This hybrid supercapacitor/biofuel cell enables high power discharge cycles, the carbon nanotube disks being continuously recharged through the biocatalytic energy conversion under physiological conditions [7].Figure 1: Schematic presentation of the functioning principle of a glucose-H2O2biofuel cell and scheme of the electrochemical double layer supercapacitor – biofuel cell hybrid system.

Exergy Analysis of Photovoltaic Panels-Coupled Solid Oxide Fuel Cell and Gas Turbine-Electrolyzer Hybrid System

Exergy losses represent true losses of potential to generate a desired product, exergy efficiencies always provide a measure of approach to ideality, and the links between exergy and both economics and environmental impact can help develop improvements. In this study, PV-coupled Solid Oxide Fuel Cell (SOFC) and Gas Turbine (GT)-electrolyzer hybrid power generation system is considered to determine the contribution of different hybrid system components in the total exergy loss. The number of panels, the power of SOFC–GT, and the power of electrolyzer can have different values. Therefore, to obtain the optimum combination from ecological, economical, and reliability points of view, a multi-objective optimization algorithm (PESA) is considered. This optimization method chooses a set of optimum solutions that is known as Pareto frontier. The exergy loss of some of these optimum solutions is compared with each other. The effect of panel angle and SOFC–GT fuel type on the hybrid system exergy loss is considered in this study. Also, the hybrid system exergy loss is determined in different months of the year to obtain the worst month from exergy loss view.

Techno-economic analysis of wind turbine–PEM (polymer electrolyte membrane) fuel cell hybrid system in standalone area

Providing reliable, environmentally friendly, and affordable energy has been a goal for many countries throughout the world. Hydrogen is presented as new energy sources during the last years which can be utilized instead of fossil fuel. One of the most promising clean methods of obtaining hydrogen is using renewable sources like wind and solar energy via electrolysis. In present work, a techno-economic evaluation of wind-hydrogen hybrid system (wind turbine, electrolysis, and PEM (polymer electrolyte membrane) fuel cell) in household size will be considered. In order to save the extra energy of wind turbine, electrolysis is used to convert this energy into hydrogen chemical energy. Generated hydrogen is stored in hydrogen storage tank. PEM fuel cell is applied to convert chemical energy of hydrogen into electrical power with high efficiency when extra power is required. Results show that wind energy in Manjil and Binaloud (two cities which have wind power plant in Iran) has greater wind speed in comparison with other cities. Also result shows that in standalone application, the size of wind turbine is bigger than the on-grid one to supply the full load consumption and it makes the standalone application too expensive.

Research of Power System for Hydrogen-Electric Hybrid Fuel Cell Vehicles

Fuel Cell Vehicle (FCV) is the ideal solution for Sustainable Mobility in the future. A new type of hydrogen fuel battery –Lithium-ion battery hybrid power system was introduced; The current hydrogen fuel cell vehicles power system and automotive hydrogen storage system at home and abroad are summarized. Energy efficiency factors as well as means to improve energy efficiency of fuel cell hybrid system were discussed.

Results of a 20 000 h lifetime test of a 7 kW direct methanol fuel cell (DMFC) hybrid system – degradation of the DMFC stack and the energy storage

First-ever lifetime test of a DMFC system lasting 25 600 h with a dynamic load profile of a material handling vehicle.

Supercapacitor/biofuel cell hybrids based on wired enzymes on carbon nanotube matrices: autonomous reloading after high power pulses in neutral buffered glucose solutions

An original supercapacitor/biofuel cell hybrid system based on compression of enzyme–carbon nanotubes enables high power discharge cycles with autonomous reloading.

Optimization of molten carbonate fuel cell (MCFC) and homogeneous charge compression ignition (HCCI) engine hybrid system for distributed power generation

In a previous study, a new hybrid system of molten carbonate fuel cell (MCFC) and homogeneous charge compression ignition (HCCI) engine was developed, where the HCCI engine replaces the catalytic burner and produces additional power by using the left-over heating values from the fuel cell stack. In the present study, to reduce the additional cost and footprint of the engine system in a hybrid configuration, the possibility of engine downsizing is investigated by using two strategies, i.e. the use of a turbocharger and the use of high geometric compression ratio for the engine design, both of which are to increase the density of the intake charge and thus the volumetric efficiency of the engine. Combining these two strategies, we suggest a new engine design with ∼60% of displacement volume of the original engine. In addition, operating strategies are developed to run the new hybrid system under part load conditions. It is successfully demonstrated that the system can operate down to 65% of the power level of the design point, while the system efficiency remains almost unchanged near 63%.

Influence of Contamination with Inorganic Impurities on the Durability of a 1 kW DMFC System

AbstractIEK‐3 at Forschungszentrum Jülich successfully replaced the battery tray of a horizontal order picker (ECE 220, Jungheinrich) with a direct methanol fuel cell (DMFC) hybrid system in the kilowatt class. The DMFC combined with a lithium‐ion battery forms the hybrid drive for electrically driven horizontal order pickers. Such vehicles are used to transport and collect goods for orders in warehouses. The order picker is fueled by pure methanol to achieve a maximum range with the smallest possible space for the battery tray. An advantage of such energy systems is that there is no need for the relatively complicated and time‐consuming recharging of the conventional lead‐acid batteries, nor are spare batteries required for multishift operation. This study focuses on the influence of contamination with inorganic impurities on the durability of the 1 kW DMFC system V3.3‐1. The data from a long‐term test will be presented, in which the DMFC system was subjected to a realistic dynamic load profile for 3,000 h. The impurities identified in the post‐mortem analysis of the membrane electrode assembly will be outlined as well the influence of selected impurities, the sources of these impurities and how the DMFC V3.3‐2 system was modified on the basis of these findings.

Regenerative braking for fuel cell hybrid system with additional generator

The fuel cell hybrid system for automobiles consists of a fuel cell/battery or fuel cell/super-capacitor. The motor in the regenerative braking system revives electrical energy instead of dissipating heat during braking. In this study, an additional generator in a fuel cell/battery hybrid system is equipped and tested as an alternative to using a motor for regenerative braking. The fuel cell hybrid system uses the Nexa™ Power Module from Ballard Power Systems Inc. and a Ni-MH battery from Global Battery Co., Ltd. In the hybrid system, the battery's voltage undershoots, while the fuel cell's voltage does not undershoot. In this study, the fuel cell hybrid system is affected by the load share rates due to the SoC of the battery. Therefore, the SoC of the battery needs to be managed. Also, the dynamic performance of the fuel cell is more stable when comprising the hybrid system. In addition, the efficiency of regenerative braking by using the generator is 63.8%. This shows that the efficiency is significantly improved compared with the 24.2% efficiency of regenerative braking using the motor.

Control of a fuel cell based on the SIRMs fuzzy inference model

A typical working mode for the fuel cell hybrid system is that the fuel cell produces constant power output while the auxiliary storage energy device such as ultracapacitor or battery provides the deviation between the desired power demand and the value of the actual operation. This paper concentrates on the control of the fuel cell flow system. The system which is like an under-actuated mechanical system needs to control two objects (the cathode pressure and the air flow) with one manipulated variable (the set voltage of the air mass flow controller). A SIRMs-based fuzzy inference model is successfully implemented in the system. Online random search optimization algorithm based on Simulink C-S functions is developed to adjust the parameters in the model. By alternative control of the two objects, experimental results demonstrate the realization of the control strategy with one adjustment means.

Performance Analysis of Proton Exchange Membrane Fuel Cell-four Temperature Level Absorption Refrigeration Hybrid System

The general model of a proton exchange membrane(PEM) fuel cell and four-temperature-level absorption refrigeration cycle hybrid system, affected by kinds of losses including the electrochemical and thermodynamic irreversibility losses, is established. Expressions for the equivalent efficiency and power output of the hybrid system, the coefficient of performance and cooling load of the absorption refrigeration cycle are derived. The general performance characteristics of the hybrid system are analyzed through numerical simulation and calculation, and the influences of the some operating parameters are analyzed and discussed in detail, finally the optimal operation regions of some parameters such as current density, power output and efficiency are determined. The waste heat produced in the PEM fuel cell is fully utilized to drive the absorption refrigerator, which greatly raises the power output and efficiency of the fuel cell hybrid system.

Energy and exergy-based working fluid selection for organic Rankine cycle recovering waste heat from high temperature solid oxide fuel cell and gas turbine hybrid systems

SUMMARY This paper performed a comparative analysis of organic Rankine cycle (ORC) using different working fluids, in order to recover waste heat from a solid oxide fuel cell-gas turbine hybrid power cycle. Depending on operating parameters, criteria for the choice of the working fluid were identified. Results reveal that due to a significant temperature glide of the exhaust gas, the actual ORC cycle thermal efficiency strongly depends on the turbine inlet temperature, exhaust gas temperature, and fluid's critical point temperature. When exhaust gas temperature varies in the range of 500 K to 600 K, R123 is preferred among the nine dry typical organic fluids because of the highest and most stabilized mean thermal efficiency under wide operating conditions and its reasonable condensing pressure and turbine outlet specific volume, which in turn results in a feasible ORC cycle for practical concerns. Copyright © 2012 John Wiley & Sons, Ltd.

Feasibility and Optimal Reliable Design of Renewable Hybrid Energy System for Rural Electrification in Iran

A hybrid hydro/wind/photovoltaic base on hydrogen storage system is designed to supply power demand. The aim of the optimization problem is minimization of net present cost of the hybrid system to reliable supply of the demand. The system is investigated in the north west of Iran (Meshkinshahr) and the local data is applied. About 12 villages (corresponding to 680 people) are found in the upper Blue Qarahsou river gorge and far remote areas, which makes the task of their electrification via grid system very difficult. The hydro potentials are analyzed with the help of GIS data of Iran. Meteorological data from renewable energy organization (SUNA) of Iran and other sources, such as NASA, is used for the estimation of solar and wind energy potentials. In this paper, hydro/PV/wind/ fuel cell hybrid system is compared with above system without hydro unit. An advanced variation of genetic algorithm (GA) is proposed to solve the optimization problem. The developed algorithm is compared with HOMER software and the results show that GA accuracy is better than HOMER software. Result reveals the effects of components outages on the reliability and cost of the proposed hybrid system. Thus, they are directly dependent on component’s reliabilities, i.e. Outages result need for a larger generating system for supplying the load with the acceptable reliability. Different system types and their component sizes are identified having a cost of energy less than 0.3 $/KWh.

Comparative assessment of residential energy options in Ontario, Canada

In this paper, the electricity, heating and cooling demands of a Southern Ontario residence are assessed and compared. Five specific systems are analyzed: ground and air source heat pumps, stand-alone PV, PV/fuel cell hybrid and a wind turbine/fuel cell hybrid system. Actual monitored data from a residence using a ground source heat pump is taken as a reference and compared with the others. Average weather conditions, electricity prices and average electricity loads in Toronto, Ontario, are used as reference data. Thermodynamic, economic and environmental comparisons are performed. It is found that heat pump systems offer significant advantages over the other systems.

Triple-layer based control strategy for molten carbonate fuel cell – hybrid system

Abstract Based on mathematical modelling and numerical simulations, a control strategy for a Molten Carbonate Fuel Cell Hybrid System (MCFC-HS) is presented. Adequate maps of performances with three independent parameters are shown. The independent parameters are as follows: stack current, fuel mass flow and compressor outlet pressure. Those parameters can be controlled by external load, fuel valve and turbine-compressor shaft speed, respectively. The control system is purposed to meet many constraints: e.g. stack temperature, steam-to-carbon ratio, compressor surge limitation, etc. The aim is to achieve maximum efficiency of power generated within these constraints. Governing equations of MCFC-HS modelling are given. An operational line of the MCFC-GT system is presented which fulfils several constraints (temperature difference, cell temperature, etc.) The system is able to achieve efficiency of more than 62% even in part-load operation.

The Research of Fuzzy Control Algorithm for Fuel Cell Hybrid System

The key technology of the fuel cell battery hybrid system is the energy management strategy. As an improved energy control method, the fuzzy-control algorithm is proposed to optimize the energy utilization efficiency. According to the characteristics of the hybrid system, the parameters of our new method are set as follows: Firstly, the State of Charge (SOC) of the Lithium-ion batteries and the power requirement of the hybrid system are set as two input parameters. Secondly, the provided power of the fuel cell, the provided power of the Lithium-ion batteries and the recovery power of braking energy are set as the output parameters. Our main efforts are analyzing the composition and the energy flow characteristics of different fuel cell hybrid systems, studying the expert rule table and establishing the mathematical model. The theoretical and experimental results of indicate that this new algorithm can make the vehicle power utilization efficiency up to 60% or more. Besides, we designed a vehicle controller prototype using our new mehtod. The measurement data of the actual prototype show that it can also make the fuel cell and the Lithium-ion batteries work in their best condition and provide good fuel economy and overall system efficiency

고분자 전해질 연료전지를 이용한 무인비행체 동력시스템 설계

3 Agency for defense development, chochiwongil 462, Yuseong-Ku, Daejeon 305-152, Korea Abstract >> In this paper, the development and performance analysis of a fuel cell-powered unmanned aerial vehicle is described. A fuel cell system featuring 1 kW proton exchange membrane fuel cell combined with a highly pressurized fuel supply system is proposed. For the higher fuel consumption efficiency and simplification of overall system, dead-end type operation is chosen and each individual system such as purge system, fuel supply system, cooling system is developed. Considering that fluctuation of exterior load makes it hard to stabilize fuel cell performance, the power management system is designed using a fuel cell and lithium-ion battery hybrid system. After integration of individual system, the performance of unmanned aerial vehicle is analyzed using data from flight and laboratory test. In the result, overall system was properly operated but for more duration of flight, research on weight lighting and improvement of fuel efficiency is needed to be progressed.