The Experts below are selected from a list of 4116 Experts worldwide ranked by ideXlab platform
Ralf Peters - One of the best experts on this subject based on the ideXlab platform.
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a diesel fuel processor for fuel cell based Auxiliary Power Unit applications
Journal of Power Sources, 2017Co-Authors: Remzi Can Samsun, Joachim Pasel, Daniel Krekel, Matthias Prawitz, Ralf PetersAbstract:Abstract Producing a hydrogen-rich gas from diesel fuel enables the efficient generation of electricity in a fuel-cell-based Auxiliary Power Unit. In recent years, significant progress has been achieved in diesel reforming. One issue encountered is the stable operation of water-gas shift reactors with real reformates. A new fuel processor is developed using a commercial shift catalyst. The system is operated using optimized start-up and shut-down strategies. Experiments with diesel and kerosene fuels show slight performance drops in the shift reactor during continuous operation for 100 h. CO concentrations much lower than the target value are achieved during system operation in Auxiliary Power Unit mode at partial loads of up to 60%. The regeneration leads to full recovery of the shift activity. Finally, a new operation strategy is developed whereby the gas hourly space velocity of the shift stages is re-designed. This strategy is validated using different diesel and kerosene fuels, showing a maximum CO concentration of 1.5% at the fuel processor outlet under extreme conditions, which can be tolerated by a high-temperature PEFC. The proposed operation strategy solves the issue of strong performance drop in the shift reactor and makes this technology available for reducing emissions in the transportation sector.
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a battery fuel cell hybrid Auxiliary Power Unit for trucks analysis of direct and indirect hybrid configurations
Energy Conversion and Management, 2016Co-Authors: Remzi Can Samsun, Carsten Krupp, Ralf Peters, D. Stolten, Sidney Baltzer, Bruno GnorichAbstract:Abstract The idling operation of engines in heavy duty vehicles to cover electricity demand during layovers entails significant fuel consumption and corresponding emissions. Indeed, this mode of operation is highly inefficient and a noteworthy contributor to the transportation sector’s aggregate carbon dioxide emissions. Here, a potential solution to this wasteful practice is outlined in the form of a hybrid battery-fuel cell system for application as an Auxiliary Power Unit for trucks. Drawing on experimentally-validated fuel cell and battery models, several possible hybrid concepts are evaluated and direct and indirect hybrid configurations analyzed using a representative load profile. The results indicate that a direct hybrid configuration is only applicable if the load demand profile does not deviate strongly from the assumed profile. Operation of an indirect hybrid with a constant fuel cell load yields the greatest hybrid system efficiency, at 29.3%, while battery size could be reduced by 87% if the fuel cell is operated at the highest dynamics. Maximum efficiency in truck applications can be achieved by pre-heating the system prior to operation using exhaust heat from the motor, which increased system efficiency from 25.3% to 28.1%, including start-up. These findings confirm that hybrid systems could offer enormous fuel savings and constitute a sizeable step on the path toward energy-efficient and environmentally-friendly heavy duty vehicles that does not necessitate a fuel switch.
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Electrical start-up for diesel fuel processing in a fuel-cell-based Auxiliary Power Unit
Journal of Power Sources, 2016Co-Authors: Remzi Can Samsun, A. Tschauder, Carsten Krupp, Ralf PetersAbstract:As Auxiliary Power Units in trucks and aircraft, fuel cell systems with a diesel and kerosene reforming capacity offer the dual benefit of reduced emissions and fuel consumption. In order to be commercially viable, these systems require a quick start-up time with low energy input. In pursuit of this end, this paper reports an electrical start-up strategy for diesel fuel processing. A transient computational fluid dynamics model is developed to optimize the start-up procedure of the fuel processor in the 28 kWthPower class. The temperature trend observed in the experiments is reproducible to a high degree of accuracy using a dual-cell approach in ANSYS Fluent. Starting from a basic strategy, different options are considered for accelerating system start-up. The start-up time is reduced from 22 min in the basic case to 9.5 min, at an energy consumption of 0.4 kW h. Furthermore, an electrical wire is installed in the reformer to test the steam generation during start-up. The experimental results reveal that the generation of steam at 450 °C is possible within seconds after water addition to the reformer. As a result, the fuel processor can be started in autothermal reformer mode using the electrical concept developed in this work.
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design and test of a 5kwe high temperature polymer electrolyte fuel cell system operated with diesel and kerosene
Applied Energy, 2014Co-Authors: Remzi Ca Samsu, Ralf Peters, Joachim Pasel, Detlef Stolte, Holge Janse, Werne LehneAbstract:A high-temperature PEFC system, developed with the aim of delivering 5kW electrical Power from the chemical energy stored in diesel and kerosene fuels for application as an Auxiliary Power Unit, was simulated and tested. The key components of the system were an autothermal reformer, a water–gas shift reactor, a catalytic burner, and the HT-PEFC stack. The targeted Power level of 5kW was achieved using different fuels, namely GTL kerosene, BTL diesel and premium diesel. Using an integrated system approach, operation without external heat input was demonstrated. The overall analysis showed slight but non-continuous performance loss for 250h operation time.
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Fuel Processing of Diesel and Kerosene for Auxiliary Power Unit Applications
Energy & Fuels, 2013Co-Authors: Joachim Pasel, Remzi Can Samsun, Ralf Peters, D. StoltenAbstract:Apart from necessary balance-of-plant components, such as pumps, blowers, sensors, and heat exchangers, the fuel processing Unit of a high-temperature polymer electrolyte fuel cell (HT-PEFC) system...
Rory F D Monaghan - One of the best experts on this subject based on the ideXlab platform.
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hybrid stirling engine adsorption chiller for truck Auxiliary Power Unit applications
International Journal of Refrigeration-revue Internationale Du Froid, 2017Co-Authors: Barry Flannery, Hans Berresheim, Oliver Finckh, Rory F D MonaghanAbstract:Abstract This paper presents preliminary experimental test results for a novel truck Auxiliary Power Unit (APU) design consisting of a 1 kWe free-piston Stirling engine and 2 kWt zeolite-water adsorption chiller that is Powered via waste heat from the engine's cooling jacket. A prototype system was built and tested to study the interaction dynamics between the Stirling engine and adsorption chiller and to determine the performance of the chiller in extreme ambient temperature conditions. The results show that pulsed thermal loading from the chiller on the engine results in engine Power spikes to 110–115% of rated Power. An average COP of 0.42 ± 0.06 was achieved for the adsorption chiller. An investigation into mitigating the negative effects of low buffering was also conducted and estimates that a buffer volume of 50 litres is sufficient to minimise the effects. This volume can potentially be achieved through integration with the main truck engine eliminating the need for a supplementary tank. The proposed system has many benefits over existing technologies such as low noise, high reliability and clean emissions without any need for additional exhaust treatment.
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development and experimental testing of a hybrid stirling engine adsorption chiller Auxiliary Power Unit for heavy trucks
Applied Thermal Engineering, 2017Co-Authors: Barry Flannery, Hans Berresheim, Oliver Finckh, Robert Lattin, Rory F D MonaghanAbstract:Abstract This paper identifies the key technical requirements for a heavy truck Auxiliary Power Unit (APU) and explores a potential alternative technology for use in a next-generation APU which could eliminate key problems related to emissions, noise and maintenance experienced today by conventional diesel engine-vapour compression APUs. The potential performance of a novel hybrid Stirling engine-adsorption chiller concept is investigated and benchmarked against the incumbent technology using a reduced-order model based on experimental data. Experimental results from a Stirling-adsorption system (SAS) prototype test rig are also presented which highlight system integration dynamics and overall performance. The adsorption chiller achieved an average COP of 0.42 ± 0.06 and 2.3 ± 0.1 kW t of cooling capacity at the baseline test condition. The prototype SAS test rig demonstrates that there appear to be no major technology barriers remaining that would prevent adoption of the SAS concept in a next-generation APU. Such a system could offer a reduction of exhaust emissions, greenhouse gases (GHG), ozone-depleting substances, noise, low maintenance and the potential for fuel flexibility and higher reliability. Preliminary modelling results indicate that the proposed system could offer superior overall electrical and cooling efficiencies compared to incumbent APUs and demonstrate a payback period of 4.6 years.
Remzi Can Samsun - One of the best experts on this subject based on the ideXlab platform.
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a diesel fuel processor for fuel cell based Auxiliary Power Unit applications
Journal of Power Sources, 2017Co-Authors: Remzi Can Samsun, Joachim Pasel, Daniel Krekel, Matthias Prawitz, Ralf PetersAbstract:Abstract Producing a hydrogen-rich gas from diesel fuel enables the efficient generation of electricity in a fuel-cell-based Auxiliary Power Unit. In recent years, significant progress has been achieved in diesel reforming. One issue encountered is the stable operation of water-gas shift reactors with real reformates. A new fuel processor is developed using a commercial shift catalyst. The system is operated using optimized start-up and shut-down strategies. Experiments with diesel and kerosene fuels show slight performance drops in the shift reactor during continuous operation for 100 h. CO concentrations much lower than the target value are achieved during system operation in Auxiliary Power Unit mode at partial loads of up to 60%. The regeneration leads to full recovery of the shift activity. Finally, a new operation strategy is developed whereby the gas hourly space velocity of the shift stages is re-designed. This strategy is validated using different diesel and kerosene fuels, showing a maximum CO concentration of 1.5% at the fuel processor outlet under extreme conditions, which can be tolerated by a high-temperature PEFC. The proposed operation strategy solves the issue of strong performance drop in the shift reactor and makes this technology available for reducing emissions in the transportation sector.
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a battery fuel cell hybrid Auxiliary Power Unit for trucks analysis of direct and indirect hybrid configurations
Energy Conversion and Management, 2016Co-Authors: Remzi Can Samsun, Carsten Krupp, Ralf Peters, D. Stolten, Sidney Baltzer, Bruno GnorichAbstract:Abstract The idling operation of engines in heavy duty vehicles to cover electricity demand during layovers entails significant fuel consumption and corresponding emissions. Indeed, this mode of operation is highly inefficient and a noteworthy contributor to the transportation sector’s aggregate carbon dioxide emissions. Here, a potential solution to this wasteful practice is outlined in the form of a hybrid battery-fuel cell system for application as an Auxiliary Power Unit for trucks. Drawing on experimentally-validated fuel cell and battery models, several possible hybrid concepts are evaluated and direct and indirect hybrid configurations analyzed using a representative load profile. The results indicate that a direct hybrid configuration is only applicable if the load demand profile does not deviate strongly from the assumed profile. Operation of an indirect hybrid with a constant fuel cell load yields the greatest hybrid system efficiency, at 29.3%, while battery size could be reduced by 87% if the fuel cell is operated at the highest dynamics. Maximum efficiency in truck applications can be achieved by pre-heating the system prior to operation using exhaust heat from the motor, which increased system efficiency from 25.3% to 28.1%, including start-up. These findings confirm that hybrid systems could offer enormous fuel savings and constitute a sizeable step on the path toward energy-efficient and environmentally-friendly heavy duty vehicles that does not necessitate a fuel switch.
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Electrical start-up for diesel fuel processing in a fuel-cell-based Auxiliary Power Unit
Journal of Power Sources, 2016Co-Authors: Remzi Can Samsun, A. Tschauder, Carsten Krupp, Ralf PetersAbstract:As Auxiliary Power Units in trucks and aircraft, fuel cell systems with a diesel and kerosene reforming capacity offer the dual benefit of reduced emissions and fuel consumption. In order to be commercially viable, these systems require a quick start-up time with low energy input. In pursuit of this end, this paper reports an electrical start-up strategy for diesel fuel processing. A transient computational fluid dynamics model is developed to optimize the start-up procedure of the fuel processor in the 28 kWthPower class. The temperature trend observed in the experiments is reproducible to a high degree of accuracy using a dual-cell approach in ANSYS Fluent. Starting from a basic strategy, different options are considered for accelerating system start-up. The start-up time is reduced from 22 min in the basic case to 9.5 min, at an energy consumption of 0.4 kW h. Furthermore, an electrical wire is installed in the reformer to test the steam generation during start-up. The experimental results reveal that the generation of steam at 450 °C is possible within seconds after water addition to the reformer. As a result, the fuel processor can be started in autothermal reformer mode using the electrical concept developed in this work.
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Catalytic burner with internal steam generation for a fuel-cell-based Auxiliary Power Unit for middle distillates
International Journal of Hydrogen Energy, 2014Co-Authors: J. Meißner, Remzi Can Samsun, Joachim Pasel, F. Scharf, C. Wiethege, Roland PetersAbstract:Abstract A catalytic burner (CAB) was developed, which utilizes the anode off-gas of a high temperature polymer electrolyte fuel cell (HT-PEFC). This CAB has two functions within the HT-PEFC-system: It has to convert completely all combustible components including methane and carbon monoxide, even in the low ppm range and it has to provide steam to the autothermal reformer (ATR). Thereby it increases the system's overall efficiency. Using computational fluid dynamics and experiments with a simple glass model, two catalytic burners (CAB 2 and CAB 3) were designed and constructed for a high temperature PEFC system with thermal Powers of 18 kW and 28 kW, respectively. The burners were characterized experimentally in detail. Close attention was given to the steam generation capacity and the thermal behavior. The constructed burners allowed complete conversion of low calorific fuel gases and a reformate in part load of the ATR was burned reliably as well. Superheated steam was generated free of oscillation. Experimental findings with CAB 2 resulted in an improved reactor generation with a reduced specific weight and geometric changes.
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Fuel Processing of Diesel and Kerosene for Auxiliary Power Unit Applications
Energy & Fuels, 2013Co-Authors: Joachim Pasel, Remzi Can Samsun, Ralf Peters, D. StoltenAbstract:Apart from necessary balance-of-plant components, such as pumps, blowers, sensors, and heat exchangers, the fuel processing Unit of a high-temperature polymer electrolyte fuel cell (HT-PEFC) system...
Mauro Sgroi - One of the best experts on this subject based on the ideXlab platform.
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ssh2s hydrogen storage in complex hydrides for an Auxiliary Power Unit based on high temperature proton exchange membrane fuel cells
Journal of Power Sources, 2017Co-Authors: M Baricco, Mads Bang, Maximilian Fichtner, B C Hauback, Marc Linder, Carlo Luetto, Pietro Moretto, Mauro SgroiAbstract:Abstract The main objective of the SSH2S (Fuel Cell Coupled Solid State Hydrogen Storage Tank) project was to develop a solid state hydrogen storage tank based on complex hydrides and to fully integrate it with a High Temperature Proton Exchange Membrane (HT-PEM) fuel cell stack. A mixed lithium amide/magnesium hydride system was used as the main storage material for the tank, due to its high gravimetric storage capacity and relatively low hydrogen desorption temperature. The mixed lithium amide/magnesium hydride system was coupled with a standard intermetallic compound to take advantage of its capability to release hydrogen at ambient temperature and to ensure a fast start-up of the system. The hydrogen storage tank was designed to feed a 1 kW HT-PEM stack for 2 h to be used for an Auxiliary Power Unit (APU). A full thermal integration was possible thanks to the high operation temperature of the fuel cell and to the relative low temperature (170 °C) for hydrogen release from the mixed lithium amide/magnesium hydride system.
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biofeat biodiesel fuel processor for a vehicle fuel cell Auxiliary Power Unit study of the feed system
Journal of Power Sources, 2005Co-Authors: Mauro Sgroi, Gianluca Bollito, Guido Saracco, Stefania SpecchiaAbstract:Abstract An integrated Auxiliary Power Unit (APU) based on a 10 kW e integrated biodiesel fuel processor has been designed and is being developed. Auto-thermal reforming (ATR) and thermal cracking (TC) were considered for converting the fuel into a hydrogen-rich gas suitable for PEM fuel cells. The fuel processor includes also a gas clean-up system that will reduce the carbon monoxide in the primary processor exit gas to below 10 ppm via a new heat-integrated CO clean-up Unit, based on the assembly of catalytic heat exchange plates, so as to meet the operational requirements of a PEMFC stack. This article is devoted to the study and selection of the proper feed strategy for the primary fuel processor. Different pre-treatment and feed alternatives (e.g. based on nozzles or simple coils) were devised and tested for the ATR processors, which turned out to be the preferred primary processing route. A nozzle-based strategy was finally selected along with special recommendations about the constituent materials and the operating procedures to be adopted to avoid coking and nozzle corrosion as well as to allow a wide turn down ratio.
D. Stolten - One of the best experts on this subject based on the ideXlab platform.
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a battery fuel cell hybrid Auxiliary Power Unit for trucks analysis of direct and indirect hybrid configurations
Energy Conversion and Management, 2016Co-Authors: Remzi Can Samsun, Carsten Krupp, Ralf Peters, D. Stolten, Sidney Baltzer, Bruno GnorichAbstract:Abstract The idling operation of engines in heavy duty vehicles to cover electricity demand during layovers entails significant fuel consumption and corresponding emissions. Indeed, this mode of operation is highly inefficient and a noteworthy contributor to the transportation sector’s aggregate carbon dioxide emissions. Here, a potential solution to this wasteful practice is outlined in the form of a hybrid battery-fuel cell system for application as an Auxiliary Power Unit for trucks. Drawing on experimentally-validated fuel cell and battery models, several possible hybrid concepts are evaluated and direct and indirect hybrid configurations analyzed using a representative load profile. The results indicate that a direct hybrid configuration is only applicable if the load demand profile does not deviate strongly from the assumed profile. Operation of an indirect hybrid with a constant fuel cell load yields the greatest hybrid system efficiency, at 29.3%, while battery size could be reduced by 87% if the fuel cell is operated at the highest dynamics. Maximum efficiency in truck applications can be achieved by pre-heating the system prior to operation using exhaust heat from the motor, which increased system efficiency from 25.3% to 28.1%, including start-up. These findings confirm that hybrid systems could offer enormous fuel savings and constitute a sizeable step on the path toward energy-efficient and environmentally-friendly heavy duty vehicles that does not necessitate a fuel switch.
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Fuel Processing of Diesel and Kerosene for Auxiliary Power Unit Applications
Energy & Fuels, 2013Co-Authors: Joachim Pasel, Remzi Can Samsun, Ralf Peters, D. StoltenAbstract:Apart from necessary balance-of-plant components, such as pumps, blowers, sensors, and heat exchangers, the fuel processing Unit of a high-temperature polymer electrolyte fuel cell (HT-PEFC) system...