The GCTool

Argonne's GCtool puts a powerful new tool in the hands of those responsible for developing the next generation of transportation technologies and power-plant systems.

When it comes to designing new, improved vehicles, the pressure is on. With prices rising at the pump and ever more stringent federal and state regulations on emissions, the automotive industry is being squeezed as never before to design and bring to market highly efficient, environmentally friendly, affordable cars and trucks. An essential role in this effort is played by computer software that lets designers "try out" different system configurations, without the expense and delays of actually building numerous prototypes. But new modeling tools, programs offering significantly greater speed, flexibility, and user-friendliness, are needed if the industry is to cope with the increasing demands placed on it.

Enter Argonne National Laboratory's General Computational Toolkit (GCtool), a software package developed specifically for designing, analyzing, and comparing fuel cell systems and other power-plant configurations, including automotive, space-based, and stationary systems. GCtool provides a convenient, flexible framework for integrating various component models, in C or any C-linkable language, into simple or complex system configurations. A library of models for subcomponents and property tables common to many different systems and powertrains are available, and users can easily add their own models as needed.

Features

The program's great strength is its flexibility – it can be used to define arbitrary system configurations, handling models of any level of sophistication and permitting arbitrary flows, system/subsystem decomposition, and system constraints. It performs both steady-state and dynamic analyses, allows unlimited parameter sweeps, and performs constrained optimizations (in contrast to conventional programs, where specifying constraints has often been a problem). Users need not run GCtool over and over again to examine each individual change in system parameters; looping statements and other logical functions automate the process.

GCtool's C-language interpreter and model design (each model is really just a data structure in C and a collection of functions) support rapid system prototyping. The software achieves rapid turnaround times in interfacing with component models, both those precompiled by Argonne and custom models created by the user. Models can be in any C-linkable language, at any level of complexity (from lumped to three-dimensional).

The GCtool environment is highly user-friendly; usually, users are capable of actively programming in less than a week. System configurations are set up with point-and-click features, using on-screen graphics; model parameters are easily changed; and pop-up windows are used to edit system configurations and for line and surface plots. Other important features include the following.

• The model library offers four different types of fuel cells — proton exchange membrane (PEM), molten carbonate, phosphoric acid, and solid oxide cells. Other ready-to-use component models include various kinds of heat exchangers (heat pipes, condenser, thermal radiator, etc.), fluid devices (splitter, nozzles, diffuser, gas turbine, pump, etc.), reactors and reformers, and vehicle systems (including an electric motor and generator).
• The property codes include a fast gas-phase chemical equilibrium code capable of handling an arbitrary number of species, a multiphase chemical equilibrium code, one for condensable pure substances, and a steam/water code. Special-purpose procedures are also available for dealing with sodium and potassium.
• GCtool uses a system of "stacks" – the gas stack, shaft stack, power stack, etc. – to pass information between models; each model takes from a given stack the inputs it requires and adds to the stack the outputs it generates.
• The program's powerful mathematical utilities include a nonlinear equation solver, a constrained nonlinear optimizer (which handles both linear and nonlinear constraints), an integrator, and a solver for ordinary differential equations.

Applications

With its tremendous adaptability, Argonne's GCtool can be applied to a broad range of power-plant types.

• Fuel cell systems, including polymer electrolyte, molten carbonate, phosphoric acid, and solid oxide designs
• Pressurized fluidized-bed combustion (PFBC) and integrated gasification/combined-cycle (IGCC) plants
• Coal combustion systems
• Open-cycle and liquid-metal magnetohydrodynamic (MHD) systems, as well as MHD ship propulsion systems
• Space power (fuel cell, MHD, and thermionic) systems

This software tool has been used successfully in analyzing a variety of polymer electrolyte fuel cell (PEFC) systems using different fuels, fuel storage methods, and fuel processing techniques. Examples include compressed hydrogen systems; metal hydride, glass microsphere, and sponge-iron hydrogen storage systems; and fuel cell systems with reformers for methanol, natural gas, and gasoline, using either partial-oxidation or steam reforming.

Using GCtool, researchers have evaluated atmospheric and pressurized PEFC automotive systems. These analyses included the identification of key constraints and important design parameters to meet those constraints, off-design operation, system dynamic and transient performance, and the effects of operation at extreme temperatures. Users have also analyzed system start-up from cold and warm conditions and determined system performance and efficiency during ramp-up and ramp-down transients.

Other applications of GCtool include such disparate uses as flow-sheet simulation for the actinide recycling program and analysis of shipbuilding activities at Newport News, Virginia.

Technology Transfer

The development of GCtool at Argonne is supported by funding from the Department of Energy's Office of Energy Efficiency and Renewable Energy, Office of Transportation Technologies, Office of Advanced Automotive Technologies.

At present, more than 50 organizations outside of Argonne are using GCtool for systems analysis and evaluation. Some of these users are private-sector fuel cell companies and universities engaged in assisting the U.S. Department of Energy with program planning and the development of new fuel processing technologies for automotive applications.

Technical Details

Major technical features and advantages of GCtool include the following:

• Interpreted front end for rapid systems prototyping
• Graphical user interface for editing system diagrams
• Can be used on a personal computer with Windows 95, 98, or NT
• Detailed 100 page manual with examples in the FAQ section
• Software will be delivered electronically

Licensing Information

To license GCtool from Argonne, print a copy of the agreement (Commercial or Educational/Non-Profit), arrange for signature by your organization, and send the signed license agreement to:

Aaron Sauers
Software Licensing Coordinator
Technology Development and Commercialization
Building 201
Argonne National Laboratory
9700 S. Cass Ave.
Argonne, IL 60439

Please contact Aaron Sauers by phone at 630-252-7878 or e-mail to alert him that you are sending the agreement, signed by your organization.