Design for upgradeability - a simulation-based approach

摘要

Major engineering products like process plant, power stations and ships have lives of over 20 years. Technical and market changes may require mid-life upgrading, such as increasing output capacity or installing new process equipment. The question for the designer is how far to design for upgradeability, e.g. by provision of more space or services than is required initially. A methodology has been developed for evaluating whether designs incorporating some upgrade capability may be more economic than those which do not. A range of upgrade frameworks from 'bare minimum' to large 'overdesign' are evaluated to show which are likely to show the greatest economic benefit over the life cycle of the product. Since this depends on a probabilistic view of say input costs, output quantities or selling prices, a simulation model is needed to compare the alternatives. A spreadsheet-based evaluation has been developed which allows the user to incorporate a range of values, e.g. expectation of future regulatory changes (e.g. on emissions). This simulation based approach presents the designer with a range of expected outcomes, from which he may select the optimal extent of designing for upgradeability. Some results for a steel mill are presented.