Catalyst of Change
A fuel cell based domestic combined heat and power unit has
benefited from Dassault Systèmes technology. Nick Lerner reports
The World Business Council for Sustainable Development states that buildings consume 40 per cent of the world’s primary energy, making it the most energy-hungry sector. The use of a Ceres Power combined heat and power (CHP) unit installed in a home is a compelling alternative to centralised generation with its associated transmission and heat losses.
Mass market deployment of Ceres Power CHP products generating electricity and heat at the point of use would reduce the need for investment in centralised power stations and grid infrastructure. The high efficiency energy conversion of the fuel cell also improves energy security by reducing the overall use of scarce resources and by having the capability to operate on a range of conventional and alternative fuels.
Generation
Ceres Power’s unique metal supported fuel cell located at the heart of a complex generation and exchange system is an electrochemical engine that makes heat and electricity. Fuel such as mains natural gas passes over the anode side and air passes over the cathode. Sandwiched between the anode and cathode is the very thin, gas tight, electrolyte layer. An external circuit connects the anode to the cathode and provides the mechanism to power electrical devices. Finally, modern power conversion technology allows the DC electricity from a fuel cell to be exported to the UK national electricity grid and provide the consumer further reward for their investment when they are generating excess electricity.
The combination of the materials used to make the fuel cell components; the type of fuel used and the operating temperature allow electricity to be generated directly via a chemical reaction rather than burning the fuel and then using a more traditional and inefficient mechanical generation. Ceres Power use Dassault Systèmes DYMOLA and ABAQUS to simulate and evaluate the potential and behaviour of design options without having to build physical prototypes. Mark Selby, senior engineer at Ceres Power explains: “We evaluate alternative designs with DYMOLA because it allows us to simulate performance, and cost benefit analysis in a virtual environment. This helps us to make better-informed decisions about how to optimise products. This not only reduces the need to make physical prototypes, but it also lets us measure the implication of decisions at various production levels. This is because alternative technologies become available at different production volumes.”
DYMOLA provides insight into the effects of changing a component specification or arrangement, in this context. The software also reveals its implications for the control system which is developed against the same models using co-simulation technology. This re-use of effort is vital to being a competitive company.
“DYMOLA takes out guess work so that physical prototypes have predictable performance. This means that we build far fewer prototypes than would otherwise be required, saving thousands of hours in the development cycle,” adds Selby. “Risk is reduced with this methodology and high level decision support is introduced because DYMOLA is able to simulate in real-time, the precise operational characteristics of design options. It also allows us to introduce ‘faults’ to check system response and take appropriate design or control programming decisions.”
Criteria
DYMOLA demonstrates great benefits to Ceres Power’s communication with its supply chain by allowing very accurate target specifications to be issued and balances to be introduced on target cost/performance criteria.”There is always a trade off between price and performance in the supply chain, DYMOLA helps us to get maximum value at the best possible price while fully understanding both commercial and technical cost benefit choices, and their implications,” he continues.
DYMOLA is of benefit in three distinct areas at Ceres Power. In the advanced engineering environment it helps develop and support component design through the simulated application of physics. In relation to control systems development, it allows functions to be observed and programmed and their effects monitored and developed. In a systems integration role DYMOLA reveals inter-relationships and ensures that electric and mechanical systems and the software that links them all work in harmony.
Another aspect of Product Lifecycle Management (PLM) at Ceres is explained by Matt Harrington, Ceres Power lead engineer who talks about the use of Dassault Systèmes SIMULIA simulation software, ABAQUS. “ABAQUS simulation software is used alongside DYMOLA to simulate mechanical forces and resultant stresses arising through manufacturing and assembly. Furthermore, by integration with third party CFD software, component and assembly responses to thermal and pressure differentials can clearly be visualised and functional designs enhanced,” he says. A common use is assembly simulation of gasket sealing stresses integrated with endplate designs. A new application is current field visualisation around electrical contacts within the fuel cell, further illustrating the range and versatility of the Abaqus tool.”
According to Harrington, ABAQUS allows mechanical engineering simulation, in great detail, to continually improve understanding and functional performance of the Fuel Cell Stack. This is at a supporting sub level to DYMOLA which invaluably provides overall system operability simulations. Together DYMOLA and ABAQUS are enabling Ceres Power to develop and perfect a highly efficient, price competitive, advanced fuel cell based CHP system that will be making a strong contribution towards lowering our carbon footprint into the future.
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