Document Type : Research Paper
Authors
1
Center of Excellence in Design and Optimization of Energy Systems, School of Mechanical Engineering, College of Engineering, University of Tehran, P.O. Box 11155-4563, Tehran, Iran
2
Sharif University of Tech, Tehran, Iran
3
University of Pittsburgh, Pittsburgh, United States
Abstract
Heat recuperation is often used to improve the overall cycle efficiency of gas turbines. However, generally in small- scale gas turbines, it has a negative effect on turbine inlet temperature, pressure ratio and pressure drops, and thus decreases the overall cycle efficiency. In this paper, a thermodynamic model is performed to evaluate recovered heat as a function of heat exchanger effectiveness, pressure drops, and defines the overall cycle energy and exergy efficiency. A high heat exchanger effectiveness, and low pressure drops are favorable to achieve maximal cycle energy efficiency. The main challenge in recuperator designis to find compromise between these conflicting requirements. Hence, a thermodynamic model is developed to determine recuperator design with an aim to maximize overall cycle energy and exergy efficiency. Further, to analyze Iran's manufacturing and its technological capabilities,a pre-requisite is considered for the proposed model. Hence, Iran's capability level could be determined. Finally, a case study of selecting recuperator of a 200kW gas turbine is conducted. Industrial gas turbines show performance characteristics that distinctly depend on ambient and operating conditions. They are influenced by site elevation, ambient temperature, and relative humidity. Proper application of gas turbines requires consideration of these factors. Thus, in this study, the effect of ambient conditions on overall cycle energy and exergy efficiency is performed by the proposed thermodynamic model.
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