Fuel Cells

Design and Implementation of On-Line Self-Tuning Control for PEM Fuel Cells

by Kary Thanapalan

Co-authored with; Williams. J.G., Liu.G.P., Rees.D.,
The World Electric Vehicle Journal, Vol 2, Issue 4, pp.7-17, 2008

This paper presents the modelling and real time implementation of PEM (polymer electrolyte membrane) fuel cell flow... more This paper presents the modelling and real time implementation of PEM (polymer electrolyte membrane) fuel cell flow control. Flow control presents a critical performance requirement to achieving dynamic power responses for electric vehicle motor demands. However a fuel cell’s complex structure and reactant requirements traditionally result in an unsatisfactory response to such dynamic loading instances. This in turn causes brief power losses associated with driving patterns such as acceleration and hill climbing. To improve the fuel cell’s dynamic response to such drive cycles, this paper presents new methodology for system identification and controller design. The fuel cell is modelled initially with established linear model and parameter estimation methods. The approach is then expanded to an on-line system identification LabVIEW programme to account for the non-linear and time varying characteristics. Based upon this identification process, a novel LabVIEW self-tuning PID controller is implemented in real time to control the response. The self-tuning controller continuously re-calculates the critical gain and period, and then adjusts the controller actions accordingly. Conclusions are then summarised from the results and future ongoing work is discussed briefly.

Water-free proton-conducting polysiloxanes: A study on the effect of heterocycle structure

by Sergio Granados

Macromolecules 2007

Proton-conducting, thermally and electrochemically stable, heterocycle-grafted polysiloxanes have been synthesized via... more Proton-conducting, thermally and electrochemically stable, heterocycle-grafted polysiloxanes have been synthesized via hydrosilylation of vinyl or allyl functionalized weakly basic heterocyclic motifs with a polymethylhydrosiloxane precursor. The basicity of the amphoteric heterocycles was tuned by introducing electronwithdrawing groups, whose presence also produced a decrease in the polymers’ glass transition temperature. The proton conductivity depended strongly on the Tg of the polymer matrix and the volume fraction of proton carriers, while the effect of reducing the pKa of the heterocycle was less pronounced. The resulting polymers showed the
highest reported proton conductivities of up to 0.1 mS/cm at temperatures below 80 °C and up to 5 mS/cm at 180
°C when doped with trifluoroacetic acid.

A fuel cell-based hybrid power supply for portable electronics devices

by Valeria Boscaino

Experimental test on a fuel cell-supercapacitor hybrid power supply for a digital still camera

by Valeria Boscaino

A steady state and dynamic fuel cell model including temperature effects.

by Valeria Boscaino

Research on the Model Emulator and Experiment Checkout of the Fuel Cell

by Valeria Boscaino

FPGA implementation of a fuel cell emulator

by Valeria Boscaino

A fuel cell-battery hybrid power supply for portable applications

by Valeria Boscaino

A fuel cell-supercapacitor power supply for portable applications

by Valeria Boscaino

A fuell cell-supercapacitor hybrid power supply for portable applications

by Valeria Boscaino

Fuel cell modelling for power supply systems design

by Valeria Boscaino

A steady-state and dynamic fuel cell model for power electronics design

by Valeria Boscaino

A FUELL CELL-BASED HYBRID POWER SUPPLY FOR PORTABLE ELECTRONICS DEVICES

by Valeria Boscaino

A fuel cell model emulator, including temperature effects

by Valeria Boscaino

High Accuracy Modelling of Hybrid Power Supplies

by Valeria Boscaino

Fuel cells for micro-combined heat and power generation

by Iain Staffell

published in Energy and Environmental Science
co-authored with A. Hawkes, D. Brett and N. Brandon

Micro-combined heat and power (CHP) holds great potential for lowering energy cost and CO2 emissions in the... more Micro-combined heat and power (CHP) holds great potential for lowering energy cost and CO2 emissions in the residential housing sector. Of the various micro-CHP technologies, fuel cells, and in particular solid oxide fuel cells, show great promise due to their high electrical efficiency and resulting low heat-to-power ratio that is better suited to residential applications. However, fuel cells are still under development and the capital cost of units available today remains high. This paper looks at the technological aspects and operating modes of fuel cells relevant to micro-CHP as well as examining the state of commercial development, life cycle issues and the techno-economics of fuel cells for micro-CHP at the residential scale.

UK microgeneration. Part II: technology overviews

by Iain Staffell

one of the top three papers across all Thomas Telford journals in 2010
published in the Proceedings of the ICE - Energy

This paper reviews the current status of microgeneration technologies at the domestic scale. Overviews are given for... more This paper reviews the current status of microgeneration technologies at the domestic scale. Overviews are given for nine such technologies, grouped into three sections: (a) low carbon heating: condensing boilers, biomass boilers and room heaters, air source and ground source heat pumps; (b) renewables: solar photovoltaic panels, flat plate and evacuated tube solar thermal panels and micro-wind; and (c) combined heat and power: Stirling engines, internal combustion engines and fuel cells.

Reviews of the construction, operation and performance are given for the leading commercial products of each technology. Wherever possible, data are presented from the field, giving the actual prices paid by customers, efficiencies and energy yields experienced in real-world use, reliability and durability, and the problems faced by users. This information has a UK focus but is generally relevant in the international context.

Two issues are found to be prevalent throughout the microgeneration industry. Total installed costs are a premium and vary substantially between technologies, between specific products (e.g. different models of solar panel), and between individual installations. Performance in the field is found in many cases to differ widely from manufacturers’ quotes and laboratory studies, often owing to installation and operational problems. Despite this, microgeneration has demonstrated substantial improvements over conventional generation in terms of fossil fuel consumption, carbon dioxide emissions and energy cost, provided that the appropriate technologies are employed, being installed and operated correctly according to the load requirements of the house and their physical location.

Lower carbon cars by reducing dissipation in hydrogen hybrids

by Iain Staffell

published in the International Journal of Low-Carbon Technologies
co-authored with K. Kendall

Fossil fuel is the major source of energy for all forms of motor vehicle, with gasoline and diesel fuels dominating... more Fossil fuel is the major source of energy for all forms of motor vehicle, with gasoline and diesel fuels dominating our personal transport. Although biofuels have been used to inject some renewable energy into the transport system, imports of oil and gas to Europe, the USA and Japan continue to rise. A move to reduce energy consumption and carbon emissions by driving more efficient vehicles is therefore necessary. This paper considers a shift to reduced friction hydrogen electric vehicles that give three major benefits: (i) sourcing hydrogen from low carbon sources like wind, biomass, nuclear and solar; (ii) using an electric drivetrain to minimize energy conversion to heat; and (iii) reducing resistances to motion to give lower energy requirements for traction. This energy dissipation due to friction proves to be a complex mixture of tyre losses, brake adhesion, wind resistance, fuel conversion inefficiency, motor resistance, drivetrain losses, auxiliary power consumption and so on. By considering the addition of many loss terms, it is shown that the energy dissipation in fuel cell-powered vehicles resolves into a linear function of vehicle weight.

Life cycle assessment of an alkaline fuel cell CHP system

by Iain Staffell

published in the International Journal of Hydrogen Energy
co-authored with A. Ingram

A life cycle assessment (LCA) of an alkaline fuel cell based domestic combined heat and power (CHP) system is... more A life cycle assessment (LCA) of an alkaline fuel cell based domestic combined heat and power (CHP) system is presented. Literature on non-noble, monopolar cell design and stack construction was reviewed, and used to produce a life cycle inventory for the construction of a 1 kW stack. Inventories for the ancillary components of other commercial fuel cell products were consulted, and combined with information on the fuel processing requirements of alkaline cells to suggest a hypothetical balance of plant that would be required to produce AC electricity and domestic grade heat from natural gas and air.

The emissions from manufacturing and disposing of this fuel cell CHP system were estimated to be equivalent to 510–1000 kg of CO2 and 1.0–2.0 kg of particulate matter. As with platinum based polymer electrolyte fuel cells (PEMFC), emissions of sulphur dioxide were the most significant impact, resulting in degraded human health in the regions where catalyst metals are mined. Improving the operating lifetime and reducing catalyst loadings were identified as the most effective routes to reducing this environmental impact, as they are with other fuel cell technologies.

These impacts were compared to the results of existing LCAs for other fuel cell technologies. It was found that an alkaline fuel cell stack produces less environmental impact than an equivalent solid oxide or phosphoric acid (SOFC or PAFC) stack, while no conclusive comparison with PEMFC could be made. The inclusion of energy consumption during stack manufacture and data on the more exotic material inputs were highlighted as a problem in these studies.

Estimating future prices for stationary fuel cells with empirically derived experience curves

by Iain Staffell

published in the International Journal of Hydrogen Energy
co-authored with R.J. Green

Fuel cells presently require an order of magnitude cost reduction to become a commercial success in domestic energy... more Fuel cells presently require an order of magnitude cost reduction to become a commercial success in domestic energy markets. Previous analyses using learning curves have shown that competitive costs are feasible, but these have been unanimously based on theoretical estimates.

Empirical price data is presented for polymer electrolyte fuel cell CHP systems installed in Japanese homes between 2004 and 2008. Experience curves are fitted to this data, taking account of the number of systems produced before and during this period. The average unsubsidised price of a 0.7–1.0 kW system is ¥3.33 M (€23,000) as of early 2009, and has fallen by 19.1–21.4% for every doubling in production.

These empirical experience curves predict that prices will fall below €10,000/kW once 60–90 thousand units are sold; but that tens of millions of units are required before they reach cost targets of around €1000/kW. Even with rapid deployment, attaining unsubsidised economic viability before 2025 will be challenging.