1,721,003 research outputs found
Flexible Micro Gas Turbine Rig for Tests on Advanced Energy Systems
No full textThe Thermochemical Power Group (TPG) of the University of Genoa, Italy, has developed a new flexible laboratory to study advanced energy systems based on micro gas turbine technology. In the laboratory a general-purpose experimental rig, based on a modified commercial 100 kW recuperated micro gas turbine, was installed and fully instrumented.
The main objectives of the laboratory is to perform experimental activities related to gas turbine based cycles in both steady-state and transient conditions. The rig layout was defined to include the effects of interaction between the turbomachines (especially the compressor) and further components. This approach is extremely significant for innovative cycle analyses, such as recuperated, humid air, and hybrid (with high temperature fuel cells) configurations.
The facility was partially funded by two Integrated Projects of the EU VI Framework Program (Felicitas and Large-SOFC) and the Italian Government (PRIN project). It was designed with a high flexibility approach including: flow control management, co-generative applications, downstream compressor volume variation, grid-connected or stand-alone operations, recuperated or simple cycles, and room temperature control. In the new EU VII Framework (E-HUB Project), the test rig has been improved with the installation of an absorption cooler to operate the system in tri-generative configuration.
The layout of the whole system, including connection pipes, valves, and instrumentation (in particular mass flow meter locations) was carefully designed to measure all the significant properties with high accuracy performance. Particular attention was devoted to component design, using CFD tools (Fluent), to perform emulation tests on high temperature fuel cell hybrid systems. For this reason, the facility was equipped with a modular cathodic vessel, an anodic recirculation loop (including a vessel and an ejector), and a steam injection system for chemical composition emulation.
To compare tests affected by a significant influence of the ambient temperature variation, such as the performance tests on the machine maximum electrical power and electrical efficiency or on the recuperator effectiveness, the rig was integrated with a compressor inlet temperature control system. This equipment is composed of three air/water heat exchangers located at the air intake, controlled valves and a variable speed pump operating in a closed loop. This circuit was designed to couple the machine air inlet with the absorption cooler.
The large number of experimental data available for the high flexibility test rig design is also used to validate both steady-state (design and off-design) and transient (also real-time) theoretical models. A good level of consistency can be achieved thanks to the complete knowledge of the test rig dimensions, volumes, masses, shaft inertia, thermal capacitances, and operating procedure. Such completeness is difficult to obtain in industrial plants, where details about equipment are often missing or confidential.
This facility is also essential to introduce undergraduate students to micro gas turbine technology, and Ph.D.s to advanced experimental activities in the same field. With this experimental rig, in addition to learning about the thermodynamic cycles and plant layouts, students can also become familiar with their materials, piping, gaskets, technology for auxiliaries, and instrumentation
Laboratory Tests in Cyber-Physical Mode for an Energy Management System Including Renewable Sources and Industrial Symbiosis
No full textThe aim of this paper regards the laboratory validation of an energy management system (EMS) for an industrial site on the Eigerøy island (Norway). It will be the demonstration district in the ROBINSON project for a consequent concept replication. This activity in cyber-physical mode is an innovative approach to finalize the EMS tool with real measurement data with prime movers available at laboratory level, considering the necessary EMS robustness and flexibility for replication on other industrial islands. This EMS was designed and developed to minimize variable costs, producing on/off and set-point signals that, through a model predictive control (MPC) software, establish the system status. This smart grid includes renewable sources (e.g., solar panels, a wind turbine, and syngas) and traditional prime movers, such as a steam boiler for the industry needs. Moreover, an energy storage device is installed composed of an electrolyzer with a hydrogen pressure vessel. The main results reported in this work regard 26-h tests performed in cyber-physical mode thanks to the real-time interaction of hardware and software. So, a real microturbine and real photovoltaic (PV) panels were managed by the EMS in conjunction with software models for components not physically present in the laboratory. Although the optimization target was cost minimization, significant improvement was also obtained in terms of efficiency increase and CO2 emission decrease
Emulatore celle a combustibile: controllo dinamico temperature e pressione stack, monitoraggio remoto impianto ibrido con microturbina
No full textQuesto articolo presenta l'utilizzo di NI Compact FieldPoint e LabVlEW per il monitoraggio ed il controllo di un impianto emulatore di sistemi ibridi con microturbina a gas recuperata (Turbec T100) da 100 kW elettrici, accoppiata con un volume modulare di 4 m3 per l'emulazione di sisterni ibridi con cella a combustibile ad alta temperatura. L'impianto sperimentale, installato presso il laboratorio dell'Università di Genova, DIMSET-TPG, a Savona è il primo esempio in Europa ed il secondo al mondo del suo tipo, in quanto si propone di studiare sperimentalmente l'accoppiamento di una microturbina a gas con un volume modulare, al fine di verificare il funzionamento della macchina e del suo controllo in condizioni di forte off-design tipiche di tali sistemi ibridi e durante i transitori
Laboratory Tests in Cyber-Physical Mode for an Energy Management System Including Renewable Sources and Industrial Symbiosis
No full textThe aim of this paper regards the laboratory validation of an energy management system (EMS) for an industrial site on the Eigerøy island (Norway). It will be the demonstration district in the ROBINSON project, for a consequent concept replication. This activity in cyber-physical mode is an innovative approach to finalize the EMS tool with real measurement data with prime movers available at laboratory level, considering the necessary EMS robustness and flexibility for replication on other industrial islands. This EMS was designed and developed to minimize variable costs, producing on/off and set-point signals that, through a Model Predictive Control (MPC) software, establish the system status. This smart grid includes renewable sources (e.g., solar panels, a wind turbine, and syngas) and traditional prime movers, such as a steam boiler for the industry needs. Moreover, an energy storage device is installed composed of an electrolyzer with a hydrogen pressure vessel.
The main results reported in this work regard 26-hour tests performed in cyber-physical mode thanks to the real-time interaction of hardware and software. So, a real microturbine and real photovoltaic panels were managed by the EMS in conjunction with software models for components not physically present in the laboratory. Although the optimization target was cost minimization, significant improvement was also obtained in terms of efficiency increase and CO2 emission decrease
Ejector Model for High Temperature Fuel Cell Hybrid Systems: Experimental Validation at Steady-State and Dynamic Conditions
No full textThe aim of this work is the experimental validation of a steady-state and transient ejector model for high temperature fuel cell hybrid system applications. This is a mandatory step in performing the steady state and the transient analysis of the whole plant to avoid critical situations and to develop the control system. The anodic recirculation test rig, developed at TPG-University of Genoa, and already used in previous works to validate the ejector design models (0D and computational fluid dynamics), was modified and used to perform tests at transient conditions with the aim of ejector transient model validation. This ejector model, based on a “lumped volume” technique, has been successfully validated against experimental data at steady-state and transient conditions using air or CO2 at room temperature and at 150°C in the secondary duct inlet. Then, the ejector model was integrated with the models of the connecting pipes, and with the volume simulation tool, equipped with an outlet valve, in order to generate an anodic recirculation model. Also in this case, the theoretical results were successfully compared with the experimental data obtained with the test rig. The final part of the paper is devoted to the results obtained with square wave functions generated in the ejector primary pressure. To study the effects of possible fast pressure variations in the fuel line (ejector primary line), the test rig was equipped with a servo-controlled valve upstream of the ejector primary duct to generate different frequency pressure oscillations. The results calculated with the recirculation model at these conditions were successfully compared with the experimental data too
Experimental Validation of an Unsteady Ejector Model for Hybrid Systems
No full textThe aim of this work is the experimental validation of a transient ejector model for hybrid system applications. This is a mandatory step in performing the transient analysis of the whole plant to avoid critical situations and to develop the control system. So, the anodic recirculation test rig already used in previous works to study the ejector design validating the steady-state 0-D and CFD models, was used in this work to perform tests at transient conditions and to validate the ejector transient model.
An initial validation was carried out at steady-state conditions, then the ejector transient model was successfully compared with the experimental data, also under unsteady conditions. A second step was carried out to better investigate the whole anodic recirculation system. So, the validated ejector transient model was connected to the components necessary to simulate the pipes, the valves and the anodic volume. Also in this case, the calculated results were successfully compared with the experimental data obtained with the laboratory test rig. The final part of the paper is devoted to the results obtained at impulse conditions. In fact, this work investigates the effects on the anodic ejector and on the whole anodic circuit coming from fuel line impulses caused by possible unsteadiness conditions. The results obtained with impulses at different frequency values were successfully compared with the experimental data
SOFC Hybrid Plants: Experimental Analysis on a Re-Compression System
No full textSince compressor outlet pressure is an important property in an SOFC based hybrid plant, special attention is devoted to an innovative system able to increase this parameter with a commercial device. This in an essential approach to increase system performance (especially in case of an ejector based
cathodic recirculation) using commercial (and low cost) technology. In details, to avoid the re-design of a completely new microturbine, the coupling of a commercial turbine with a turbocharger has been analyzed from experimental point of view. This innovative plant layout has been studied with an emulator test rig for SOFC hybrid systems. It is an experimental facility based on the coupling of a commercial 100 kW gas turbine with a modular vessel to emulate the dimension of stack cathodic size. For these tests, a turbocharger has been included in the rig for a detailed analysis related to the coupling with the T100 machine. Special attention is focused on the rig modifications necessary to operate these tests and on the experimental results obtained with this facility. The performance obtained with this machine coupling has been demonstrated by the experimental data
Plant Management Tools Tested with a Small-Scale Distributed Generation Laboratory
No full textOptimization of power generation with smart grids is an important issue for extensive sustainable development of distributed generation. Since an experimental approach is essential for implementing validated optimization software, the TPG research team of the University of Genoa has installed a laboratory facility for carrying out studies on polygeneration grids. The facility consists of two co-generation prime movers based on conventional technology: a 100 kWe gas turbine (mGT) and a 20 kWe internal combustion engine (ICE). The rig high flexibility allows the possibility of integration with renewable-source based devices, such as biomass-fed boilers and solar panels.
Special attention was devoted to thermal distribution grid design. To ensure the possibility of application in medium-large districts, composed of several buildings including energy users, generators or both, an innovative layout based on two ring pipes was examined. Thermal storage devices were also included in order to have a complete hardware platform suitable for assessing the performance of different management tools.
The test presented in this paper was carried out with both the mGT and the ICE connected to this innovative thermal grid, while users were emulated by means of fan coolers controlled by inverters. During this test the plant is controlled by a real-time model capable of calculating a machine performance ranking, which is necessary in order to split power demands between the prime movers (marginal cost decrease objective). A complete optimization tool devised by TPG (ECoMP program) was also used in order to obtain theoretical results considering the same machines and load values. The data obtained with ECoMP were compared with the experimental results to obtain a broad validation of the optimization tool
Hybrid System Test Rig: Start-up and Shutdown Physical Emulation
No full textThe University of Genoa (TPG) has designed and developed an innovative test rig for high temperature fuel cell hybrid system physical emulation. It is based on the coupling of a modified commercial 100 kW recuperated micro gas turbine to a special modular volume designed for the experimental analysis of the interaction between different dimension fuel cell stacks and turbomachines. This new experimental approach that generates reliable results as a complete test rig also allows investigation of high risk situations with more flexibility without serious and expensive consequences to the equipment and at a very low cost compared with real hybrid configurations. The rig, developed with the support of the European Integrated Project “FELICITAS,” is under exploitation and improvement in the framework of the new European Integrated Project “LARGE-SOFC” started in January 2007. The layout of the system (connecting pipes, valves, and instrumentation) was carefully designed to minimize the pressure loss between compressor outlet and turbine inlet to have the highest plant flexibility. Furthermore, the servocontrolled valves are useful for performing tests at different operative conditions (i.e., pressures, temperatures, and pressure losses), focusing the attention on surge and thermal stress prevention. This work shows the preliminary data obtained with the machine connected to the volume for the test rig safe management to avoid surge or excessive stress, especially during the critical operative phases (i.e., start-up and shutdown). Finally, the attention is focused on the valve control system developed to emulate the start-up and shutdown phases for high temperature fuel cell hybrid systems. It is necessary to manage the flows in the connecting pipes, including an apt recuperator bypass, to perform a gradual heating up and cooling down as requested during these phases. It is an essential requirement to avoid thermal stress for the fuel cell stack. For this reason, during the start-up, the volume is gradually heated by the compressor outlet flow followed by a well managed recuperator outlet flow and vice versa for the shutdown. Furthermore, operating with a constant rotational speed control system, the machine load is used to reach higher temperature values typical of these kinds of systems
Experimental Investigation on a Recuperator for Hybrid System Applications
No full textThe aim of this work is the experimental analysis of steady-state and transient behavior of a primary surface recuperator installed in a 100 kW commercial micro gas turbine. The machine is integrated in an innovative test rig for high temperature fuel cell hybrid system emulation, designed and installed by Thermochemical Power Group at the University of Genoa in the framework of the Felicitas and LARGE-SOFC European Integrated Projects. The high flexibility of the rig was exploited to perform tests on the recuperator operating in the standard cycle focusing the attention on its performance in transient condition. Start-up tests were carried out in both electrical grid-connected and stand-alone conditions operating with different control strategies. The attention is focused on system response due to control strategy and on boundary temperatures variation for its influence on component life consumption.
Further tests were carried out using the valves installed on the test rig to bypass the air side of the unit. Different operative conditions were analyzed to show the effect of different flow rates on recuperator behavior. The attention is mainly focused on recuperator performance when it operates in unbalanced flow rate conditions (i.e. different mass flow rate values in recuperator sides)
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