Eventos Anais de eventos
ENCIT 2016
16th Brazilian Congress of Thermal Sciences and Engineering
Thermodynamic Analisys and Simulation of an Organic Rankine Cycle
Submission Author:
Cirilo Seppi Bresolin , RS
Co-Authors:
Paulo Smith Schneider, Cirilo Seppi Bresolin
Presenter: Cirilo Seppi Bresolin
doi://10.26678/ABCM.ENCIT2016.CIT2016-0264
Abstract
This paper proposes a model for simulation of a power cycle that operates on an Organic Rankine Cycle (OCR). Initially, it is analysed the evaporator temperature that maximizes the cycle efficiency for different working fluids. The results of the simulated model are validated comparing to a reference study. Following, an optimization and analyses the model sensibility related to the chosen pinch point between working fluid R245fa and the hot source. The decreasing of the pinch point leads to the reduction of the efficiency of the cycle and to the increase of the heat transfer surface area with the hot source. The change of the pinch point from 10K to 1K results on a linear decreasing of the cycle efficiency in approximately 3% per degree of temperature. At the same time, the same range of the pinch point leads to an increase of the surface of heat exchange, through two different manners. Primarily, between 10K and 5K, linearly, around 10% per temperature unit change. From 5K, this increasing enhances gradually, reaching an elevation of around 20% for pinch points near 1K. Hence, every unit reduction of the pinch point temperature leads to a cycle linearly less efficient and heat exchangers increasingly larger and more expansive. It is presented an analysis of this thermodynamic counterintuitive behaviour.
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