Albuquerque, New Mexico
June 24, 2001
June 24, 2001
June 27, 2001
6.768.1 - 6.768.13
Optimal Life Cycle Cost Analysis and Design of Thermal Systems
Nand K. Jha and Bahman Litkouhi Professor Department of Mechanical Engineering Manhattan College, Riverdale, New York, 10471
1. Introduction and background
Life cycle cost is the sum of all of the costs associated with a product from inception to disposal. LCC seeks to maximize thermal systems contribution to the society while minimizing combined cost of design, manufacturing, customer, and environment. Most researchers agree that decisions made during design of materials, manufacturing process, sizes, etc affect more than 75% of the LCC. Materials and manufacturing process used will affect the cost associated with reuse, recycle, disposal as well as environment. In industry, a life cycle cost design indicates that the first cost alone is not enough to evaluate fully an article for system, but that all costs occurred over the life of the system must be considered. A thermal system needs heavy financial investment and must include capital cost, operating cost, service and repair cost including total retirement cost. It has been found that due to governmental regulation, environmental concern and safety considerations, it is necessary to consider how to retire the system and costs related to retirement must be included in the optimal design. In order to achieve this goal, we should be able to formulate the design model and prepare the model for optimization based on the life cycle cost (LCC)3. In this paper, we discuss these steps in the context of a gas transmission system design. We develop a reasonably realistic model of a representative gas pipeline transmission system and use it as benchmark problem to evaluate the applicability of optimization technique. Although numerous optimization techniques are available and every one claims to obtain optimal solution for every kind of design problems but in reality it is not so. We have used Geometric Programming in this paper based on our experience of this technique in design and manufacturing problems. Other attribute of this technique is its ability to predict the proportions of various cost terms even before the design is attempted. However, we want to test the applicability of other similar nonlinear programming techniques to the optimal design problems based on life cycle costs and compare accuracy and other pertinent evaluation parameters later.
LCC is divided in to two main categories, 1) acquisition cost and 2) support cost. The acquisition costs are the costs associated with the design and build of the product. All of the cost required for research and development, design, tooling, other non-recurring cost and the product unit cost are included in the acquisition cost. The support cost is all of the cost incurred after the product is delivered to the customer. The support cost is typically very high in case of thermal system products.
Proceedings of the 2001 American Society for Engineering Education Annual Conference & Exposition Copyright© 2001, American Society for Engineering Education
Jha, N., & Litkouhi, B. (2001, June), Optimal Life Cycle Analysis And Design Of Thermal Systems Paper presented at 2001 Annual Conference, Albuquerque, New Mexico. https://peer.asee.org/9632
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