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  • 1.
    Hedström, Lars
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Saxe, Maria
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Folkesson, Anders
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Wallmark, Cecilia
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Haraldsson, Kristina
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Bryngelsson, Mårten
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Alvfors, Per
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Key factors in planning a sustainable energy future including hydrogen and fuel cells2006In: Bulletin of Science, Technology & Society, ISSN 0270-4676, E-ISSN 1552-4183, Vol. 26, no 4, p. 264-277Article in journal (Refereed)
    Abstract [en]

    In this article, a number of future energy visions, especiallythose basing the energy systems on hydrogen, are discussed.Some often missing comparisons between alternatives, from asustainability perspective, are identified and then performedfor energy storage, energy transportation, and energy use invehicles. It is shown that it is important to be aware of thelosses implied by production, packaging, distribution, storage,and end-use of hydrogen when suggesting a "hydrogen economy."It is also shown that for stationary electric energy storage,fuel cell electrolyzers could be feasible. Zero-tailpipeemissionvehicles are compared. The battery electric vehicle has thehighest electrical efficiency, but other requirements implythat plug-in hybrids or fuel cell hybrids might be a betteroption in some types of vehicles. Finally, a simplified exampleis applied to the overall results and used to discuss the needsand nature of an energy system based on intermittent energysources. 

  • 2.
    Hedström, Lars
    et al.
    KTH, Superseded Departments, Chemical Engineering and Technology.
    Wallmark, Cecilia
    KTH, Superseded Departments, Chemical Engineering and Technology.
    Alvfors, Per
    KTH, Superseded Departments, Chemical Engineering and Technology.
    Rissanen, Markku
    Stridh, Bengt
    Ekman, Josefin
    Description and modelling of the solar–hydrogen–biogas-fuel cell system in GlashusEtt2004In: Journal of Power Sources, ISSN 0378-7753, E-ISSN 1873-2755, no 131, p. 340-350Article in journal (Refereed)
    Abstract [en]

    The need to reduce pollutant emissions and utilise the world's available energy resources more efficiently has led to increased attention towards e.g. fuel cells, but also to other alternative energy solutions. In order to further understand and evaluate the prerequisites for sustainable and energy-saving systems, ABB and Fortum have equipped an environmental information centre, located in Hammarby Sjostad, Stockholm, Sweden, with an alternative energy system. The system is being used to demonstrate and evaluate how a system based on fuel cells and solar cells can function as a complement to existing electricity and heat production. The stationary energy system is situated on the top level of a three-floor glass building and is open to the public. The alternative energy system consists of a fuel cell system, a photovoltaic (PV) cell array, an electrolyser, hydrogen storage tanks, a biogas burner, dc/ac inverters, heat exchangers and an accumulator tank. The fuel cell system includes a reformer and a polymer electrolyte fuel cell (PEFC) with a maximum rated electrical output of 4 kW(el) and a maximum thermal output of 6.5 kW(th). The fuel cell stack can be operated with reformed biogas, or directly using hydrogen produced by the electrolyser. The cell stack in the electrolyser consists of proton exchange membrane (PEM) cells. To evaluate different automatic control strategies for the system, a simplified dynamic model has been developed in MATLAB Simulink. The model based on measurement data taken from the actual system. The evaluation is based on demand curves, investment costs, electricity prices and irradiation. Evaluation criteria included in the model are electrical and total efficiencies as well as economic parameters.

  • 3.
    Larsson, Mårten
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Mosheni, Farzad
    Sweco, Sweden.
    Wallmark, Cecilia
    Sweco, Sweden.
    Grönkvist, Stefan
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Alvfors, Per
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Energy system analysis of the implications of hydrogen fuel cell vehicles in the Swedish road transport system2015In: International journal of hydrogen energy, ISSN 0360-3199, E-ISSN 1879-3487, Vol. 40, no 35, p. 11722-11729Article in journal (Refereed)
    Abstract [en]

    The focus on pathways to reduce the use of fossil fuels in the transport sector is intense in many countries worldwide. Considering that biofuels have a limited technical production potential and that battery electric vehicles suffer from technical limitations that put constraints on their general use in the transport sector, hydrogen-fuelled fuel cell vehicles may become a feasible alternative. Introduction of hydrogen in the transport sector will also transform the energy sector and create new interactions. The aim of this paper is to analyse the consequences and feasibility of such an integration in Sweden. Different pathways for hydrogen, electricity and methane to the transport sector are compared with regard to system energy efficiency. The well-to-wheel energy efficiencies for hydrogen and electricity are used for estimating the energy resources needed for hydrogen production and electric vehicles for a future Swedish transport sector based on renewable fuels. The analysis reveal that the well-to-wheel system efficiencies for hydrogen fuel cell vehicles are comparable to those of methane gas vehicles, even when biomethane is the energy source. The results further indicate that an increased hydrogen demand may have a less than expected impact on the primary energy supply in Sweden.

  • 4.
    Wallmark, Cecilia
    KTH, Superseded Departments, Chemical Engineering and Technology.
    Design and evaluation of stationary polymer electrolyte fuel cell systems2004Doctoral thesis, comprehensive summary (Other scientific)
    Abstract [en]

    The objectives of this doctoral thesis are to give a basisincluding methods for the development of stationary polymerelectrolyte fuel cell (PEFC) systems for combined heat andpower production. Moreover, the objectives include identifyingprerequisites, requirements and possibilities for PEFC systemsproducing heat and power for buildings in Sweden. The PEFCsystem is still in a pre-commercial state, but low emissionlevels, fast dynamics and high efficiencies are promisingcharacteristics.

    A thermodynamic model to simulate stationary PEFC systemshas been constructed and pinch technology and exergy analysesare utilised to design and evaluate the system. The finalsystem configuration implies a high total efficiency ofapproximately 98 % (LHV).

    A flexible test facility was built in connection with theresearch project to experimentally evaluate small-scalestationary PEFC systems at KTH. The research PEFC system hasextensive measurement equipment, a rigorous control system andallows fuel cell systems from approximately 0.2 to 4 kWel insize to be tested. The simulation models of the fuel processorand the fuel cell stack are verified with experimental datataken from the test facility. The initial evaluation andsimulation of the first residential installation of a PEFCsystem in Sweden is also reported. This PEFC system, fuelled bybiogas and hydrogen, is installed in an energy system alsoincluding a photovoltaic array, an electrolyser and hydrogenstorage.

    Technical aspects of designing a fuel cell system-basedenergy system, including storages and grid connections, whichprovides heat and power to a building are presented in thisthesis. As a basis for the technical and economic evaluations,exemplifying energy systems are constructed and simulated. Fuelcell system installations are predicted to be economicallyunviable for probable near-term conditions in Sweden. The mainfactor in the economic evaluations is the fuel price. However,fuel cell system installations are shown to have a higher fuelutilisation than the conventional method of energy supply.

    The methods presented in this thesis serve as a collectedbasis for continued research and development in the area.

    Keywords:Small-scale, stationary, fuel cell system,polymer electrolyte fuel cell, PEFC system, reformer,thermodynamic modelling, pinch technology, exergy analyses,system configuration, test facility, experiments, application,simulation, installation, energy system, energy storage, heatand power demand.

  • 5.
    Wallmark, Cecilia
    et al.
    KTH, Superseded Departments, Chemical Engineering and Technology.
    Alvfors, Per
    KTH, Superseded Departments, Chemical Engineering and Technology.
    A pinch and exergy analysis of the configuration of a stationary polymer electrolyte fuel cell system2004In: Energy-Efficient, Cost-Effective and Environmentally-Sustainable Systems and Processes, Vols 1-3 / [ed] Rivero, R; Monroy, L; Pulido, R; Tsatsaronis, G, MEXICO: INST MEXICANO DEL PETROLEO , 2004, p. 703-715Conference paper (Refereed)
    Abstract [en]

    In this paper, a pinch-based evaluation and a detailed exergy analysis are applied in order to evaluate the configuration of a stationary polymer electrolyte fuel cell system. The low-pressure fuel cell system includes natural gas steam reforming and is designed to supply a building with heat and power. The exergy balance is calculated from the exergy content of the flows in the system, with the condensed water taken into consideration. By introducing the heat supplied from the combustor to the pinch composite curves, the design and evaluation of the heat exchanger network is aided. The convenient presentation obtained of the energy balance and the exergy destruction points out the importance of the different losses within the 23 components in the fuel cell system and will be used as a basis for future research. The analysis makes it clear that the total efficiency of the system configuration is nearly optimised at 98 % LHV (89 % HHV), but that the electrical efficiency is low. To increase the electrical efficiency, the design of the fuel cell stack has to be improved. The only way to increase the thermal efficiency without changing any system parameters is to decrease the return temperature from the heat sink. The modelling work is described in comparison to measured data. The thermodynamic equations, including a methodology for handling condensed water, are attached to the paper.

  • 6.
    Wallmark, Cecilia
    et al.
    KTH, Superseded Departments, Chemical Engineering and Technology.
    Alvfors, Per
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Design of stationary PEFC system configurations to meet heat and power demands2002In: Journal of Power Sources, ISSN 0378-7753, E-ISSN 1873-2755, Vol. 106, no 02-jan, p. 83-92Article in journal (Refereed)
    Abstract [en]

    This paper presents heat and power efficiencies of a modeled PEFC system and the methods used to create the system configuration. The paper also includes an example of a simulated fuel cell system supplying a building in Sweden with heat and power. The main method used to create an applicable fuel cell system configuration is pinch technology. This technology is used to evaluate and design a heat exchanger a PEFC system working under stationary conditions, in order to find a solution with high heat utilization. The heat exchanger network for network in the system connecting the reformer, the burner, gas cleaning, hot-water storage and the PEFC stack will affect the heat transferred to the hot-water storage and thereby the heating of the building. The fuel, natural gas, is reformed to a hydrogen-rich gas within a slightly pressurized system. The fuel processor investigated is steam reforming, followed by high- and low-temperature shift reactors and preferential oxidation. The system is connected to the electrical grid for backup and peak demands and to a hot-water storage to meet the varying heat demand for the building. The procedure for designing the fuel cell system installation as co-generation system is described, and the system is simulated for a specific building in Sweden during I year. The results show that the fuel cell system in combination with a burner and hotwater storage could supply the building with the required heat without exceeding any of the given limitations. The designed co-generation system will provide the building with most of its power requirements and would further generate income by sale of electricity to the power grid.

  • 7.
    Wallmark, Cecilia
    et al.
    KTH, Superseded Departments, Chemical Engineering and Technology.
    Alvfors, Per
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Technical design and economic evaluation of a stand-alone PEFC system for buildings in Sweden2003In: Journal of Power Sources, ISSN 0378-7753, E-ISSN 1873-2755, Vol. 118, no 02-jan, p. 358-366Article in journal (Refereed)
    Abstract [en]

    This paper deals with the prerequisites for a stand-alone fuel cell system installed to avoid replacing or upgrading an ageing, distant power grid connection which only supplies a few buildings with their power demands. The importance of sizing the included components in the energy system is presented in economic terms. The size of the fuel cell system and the energy storage system (battery, hot-water storage and hydrogen storage) are discussed in relation to the yearly distribution of the buildings' power demand. The main design idea is to decrease the size of the fuel cell system without making the battery too expensive and that the power requirements are fulfilled over test periods with decided length and power output. The fuel cell system installation is not economically viable for the presented conditions, but in the paper future feasible scenarios are presented. The calculated incomes are shown as a function of the size of the fuel cell system and energy storage, the electricity costs, the fuel costs including transportation, the prices of electricity and heat, and the fuel cell system costs and efficiencies. The main factor in the system's economic performance is the fuel price, which contributes more than half the costs for the fuel cell system-based energy system. The cost of the power grid is also determining for the result, where the distance to the main power grid is the important factor. The evaluation is performed from the utility company's point of view.

  • 8.
    Wallmark, Cecilia
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Enback, Sofia
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Rissanen, Markku
    Alvfors, Per
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Lindbergh, Göran
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Integration of the components in a small-scale stationary research PEFC system2006In: Journal of Power Sources, ISSN 0378-7753, E-ISSN 1873-2755, Vol. 159, no 1, p. 613-625Article in journal (Refereed)
    Abstract [en]

    With the primary aim of studying the integration of the components in a polymer electrolyte fuel cell (PEFC) system, a test facility for research on small-scale stationary PEFC systems has been built at the Royal Institute of Technology in Stockholm. In this paper the PEFC system with control system and measurement equipment is described in detail together with the first experimental data. The research PEFC system has a flexible configuration and allows fuel cell systems from approximately 0.2 to 4 kW(el) to be tested. The main feed is natural gas, but the fuel cell stack can also be run on humidified hydrogen. The main limitation in the system integration is the power mismatch of the fuel cell stack and fuel processor. The paper begins with a literature review of research/test PEFC systems.

1 - 8 of 8
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