Introducing Life Cycle Cost Analysis in an Undergraduate Gas Turbine Engine Design Capstone Course

2021 ◽  
Author(s):  
Aaron Byerley ◽  
Steve Brandt
Author(s):  
Aaron R. Byerley ◽  
Steve A. Brandt

Abstract The purpose of this paper is to introduce the basics of life cycle cost analysis for use in an undergraduate, senior-level capstone, gas turbine engine design course. This paper will support the heightened interest within the military acquisition community that now requires life cycle cost analysis to be included in the proposals submitted by defense contractors. The capstone design course includes both the gas turbine engine cycle selection and engine component design that supports a particular aircraft application. While the students have been taught how to estimate the fuel costs, engine development costs, and the time-varying production costs of engines, they have not yet been provided instruction on how to factor all three types of costs into an engineering economics, time-value-of-money, present value analysis. This paper will fill that gap and serve as a resource for the students who must now consider life cycle cost as an element in their design decision matrix along with engine performance, technical risk, and development time. The typical case compares an engine where the upfront development and production costs associated with a more advanced level of technology are high early on in the life cycle but over time has a lower fuel cost compared to an engine with a lower development and production cost but with a higher fuel cost. This paper illustrates how the aerodynamics, thermodynamics, and engineering economics can be brought together to inform and defend a decision about which of the two (or more) alternatives is best. The engineering economic analysis is spreadsheet based and uses inflation adjusted, total annual costs to calculate the present value for use in a decision matrix.


2010 ◽  
Vol 132 (4) ◽  
Author(s):  
Vaibhav Malhotra ◽  
W. E. Lear ◽  
J. R. Khan ◽  
S. A. Sherif

A life cycle cost analysis was performed to compare life cycle costs of a novel gas turbine engine to those of a conventional microturbine with similar power capacity. This engine, called the high-pressure regenerative turbine engine (HPRTE), operates on a pressurized semiclosed cycle and is integrated with a vapor absorption refrigeration system. The HPRTE uses heat from its exhaust gases to power the absorption refrigeration unit, which cools the high-pressure compressor inlet of the HPRTE to below ambient temperatures and also produces some external refrigeration. The life cycle cost analysis procedure is based on principles laid out in the Federal Energy Management Program. The influence of different design and economic parameters on the life cycle costs of both technologies is analyzed. The results of this analysis are expressed in terms of the cost ratios of the two technologies. The pressurized nature of the HPRTE leads to compact components resulting in significant savings in equipment cost versus those of a microturbine. Revenue obtained from external refrigeration offsets some of the fuel costs for the HPRTE, thus proving to be a major contributor in cost savings for the HPRTE. For the base case of a high-pressure turbine (HPT) inlet temperature of 1373 K and an exit temperature of 1073 K, the HPRTE showed life cycle cost savings of 7% over a microturbine with a similar power capacity.


Author(s):  
Vaibhav Malhotra ◽  
W. E. Lear ◽  
J. R. Khan ◽  
S. A. Sherif

A Life cycle cost analysis (LCCA) was performed to compare life cycle costs of a novel gas turbine engine to that of a conventional microturbine with similar power capacity. This engine, called the High Pressure Regenerative Turbine Engine (HPRTE) operates on a pressurized semiclosed cycle and is integrated with a Vapor Absorption Refrigeration System (VARS). The HPRTE uses heat from its exhaust gases to power the absorption refrigeration unit which cools the high-pressure compressor inlet of the HPRTE to below ambient temperatures and also produces some external refrigeration. The life cycle cost analysis procedure is based on principles laid out in the Federal Energy Management Program (FEMP). The influence of different design and economic parameters on the life cycle costs of both technologies is analyzed. The results of this analysis are expressed in terms of the cost ratios of the two technologies. The pressurized nature of the HPRTE leads to compact components resulting in significant savings in equipment cost versus those of a microturbine. Revenue obtained from external refrigeration offsets some of the fuel costs for the HPRTE, thus proving to be a major contributor in cost savings for the HPRTE. For the base case of a high-pressure turbine (HPT) inlet temperature of 1373 K and an exit temperature of 1073 K, the HPRTE showed life cycle cost savings of 7% over a microturbine with a similar power capacity.


Author(s):  
Dale Grace ◽  
Christopher A. Perullo ◽  
Jared Kee

Selecting the appropriate level of filtration for a gas turbine helps to minimize overall unit costs and maximize net revenue. When selecting a filter type and configuration, one must consider the initial costs, operational costs, and ongoing maintenance costs for both the filter and corresponding impacts on unit performance. Calculations are complex, and a fully functional framework is needed to properly account for all aspects of the life cycle and provide an opportunity to optimize filter selection and water wash scenarios for specific plant operating conditions. Decisions can generally be based on several different criteria. For instance, one may wish to minimize maintenance costs, maximize revenue, minimize fuel consumption, etc. For criteria that can be expressed in monetary terms, Life Cycle Cost Analysis (LCCA) is a means to simultaneously consider all criteria and reduce them to a single parameter for optimization using present value arithmetic. To be practically applied, the analysis must include all the significant inputs that would have an impact on the relative comparison between alternatives, while excluding minor inputs that would unduly add to complexity. This paper provides an integrated, quantitative, and transparent approach to life cycle cost analysis for gas turbine inlet filtration. Most prior art tends to focus either on how to perform the life cycle cost analysis (with simplified assumptions on the impact of filtration on performance), or on a specific technical aspect of filtration such as filter efficiency and performance, the impact of dust on compressor blading and fouling, or the impact of fouling on overall gas turbine performance. Many of these studies provide useful insight into specific aspects of gas turbine degradation due to fouling, but make simplifying assumptions that can lead to inaccuracies in application. By heavily leveraging prior work, this paper provides the reader with an overview of all aspects of the functionality required to perform such a life cycle analysis for gas turbine filtration. This work also serves as a technical summary of the underlying physics models that lead to the development of EPRI’s Air Filter Life-Cycle Optimizer (AFLCO) software. The software tool provides a method to account for the influence of gas turbine type, operating conditions, load profile, filtration choices, and wash type and frequency on overall life-cycle costs. The AFLCO tool is focused on guiding the user to make optimum filter selections and water wash scheduling, accounting for all the significant parameters that affect the economic outcome. Revenue and cost quantities are considered simultaneously to determine the net present value of gross revenue minus filtration and water wash costs over a multiple year analysis period. The user defines the scenarios and the software displays the net present value (NPV) and present value difference between the scenarios. The preferred configuration from an LCCA perspective is that which yields the highest present value for net revenue. The user can iterate on multiple scenarios to seek further increases in NPV. The paper provides relevant example case studies to illustrate how LCCA evaluations of inlet air filters and water wash frequency can be applied to optimize gas turbine economic performance. The intent of the paper is to provide the user with a summary of prior work that can be integrated to provide a more holistic, complete life cycle cost analysis and describes the framework used within the AFLCO software. The underlying technical analysis in this paper can be applied to any life cycle cost analysis.


Author(s):  
Melissa Wilcox ◽  
Klaus Brun

Gas turbine inlet filtration systems play an important role in the operation and life of gas turbines. There are many factors that must be considered when selecting and installing a new filtration system or upgrading an existing system. The filter engineer must consider the efficiency of the filtration system, particles sizes to be filtered, the maintenance necessary over the life of the filtration system, acceptable pressure losses across the filtration system, required availability and reliability of the gas turbine, and how the filtration system affects this, washing schemes for the turbine, and the initial cost of any new filtration systems or upgrades. A life cycle cost analysis provides a fairly straightforward method to analyze the lifetime costs of inlet filtration systems, and it provides a method to directly compare different filter system options. This paper reviews the components of a gas turbine inlet filtration system life cycle cost analysis and discusses how each factor can be quantified as a lifetime cost. In addition, an example analysis, which is used to select a filtration system for a new gas turbine installation, is presented.


2011 ◽  
Vol 4 (5) ◽  
pp. 158-161 ◽  
Author(s):  
A. Morfonios A. Morfonios ◽  
◽  
D. Kaitelidou D. Kaitelidou ◽  
G. Filntisis G. Filntisis ◽  
G. Baltopoulos G. Baltopoulos ◽  
...  

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