Finite Time Thermodynamic Optimization or Entropy Generation Minimization of Energy Systems

Abstract:In recent decades, the approach known as Finite-Time Thermodynamics has provided a fruitful theoretical framework for the optimization of heat engines operating between a heat source (at temperature hs T ) and a heat sink (at temperature cs T ). The aim of this paper is to propose a more complete approach based on the association of Finite-Time Thermodynamics and the Bond-Graph approach for modeling endoreversible heat engines. This approach makes it possible for example to find in a simple way the characteristics of the optimal operating point at which the maximum mechanical power of the endoreversible heat engine is obtained with entropy flow rate as control variable. Furthermore it provides the analytical expressions of the optimal operating point of an irreversible heat engine where the energy conversion is accompanied by irreversibilities related to internal heat transfer and heat dissipation phenomena. This original approach, applied to an analysis of the performance of a thermoelectric generator, will be the object of a future publication.

Section: Endoreversible Heat Enginementioning

confidence: 99%

Association of Finite-Time Thermodynamics and a Bond-Graph Approach for Modeling an Endoreversible Heat Engine

Dong

El-Bakkali

Descombes³

et al. 2012

“…In recent decades, the approach known as Finite-Dimension Thermodynamics has provided a fruitful theoretical framework for the optimization of heat engines operating between a heat source (at temperature T hs ) and a heat sink (at temperature T cs ) [2][3][4][5][6][7][8][9][10][11][12][13][14][15]. The main idea of this approach is the coupling of a converter with two heat exchangers of finite dimension which connect the converter to thermostats.…”

Section: Introductionmentioning

confidence: 99%

Association of Finite-Dimension Thermodynamics and a Bond-Graph Approach for Modeling an Irreversible Heat Engine

Dong

El-Bakkali

Feidt

et al. 2012

Abstract:In recent decades, the approach known as Finite-Dimension Thermodynamics has provided a fruitful theoretical framework for the optimization of heat engines operating between a heat source (at temperature T hs ) and a heat sink (at temperature T cs ). We will show in this paper that the approach detailed in a previous paper [1] can be used to analytically model irreversible heat engines (with an additional assumption on the linearity of the heat transfer laws). By defining two dimensionless parameters, the intensity of internal dissipation and heat leakage within a heat engine were quantified. We then established the analogy between an endoreversible heat engine and an irreversible heat engine by using the apparent temperatures (T cs → T λ,φ cs , T hs → T

“…In the realm of finite time thermodynamics, two issues are of essential importance-one is to determine the extremum of objective function and study the interrelation of different objective functions, the other is to determine the optimal thermodynamic process for given optimization objectives [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16]. Curzon and Ahlborn [17] demonstrated that the efficiency at maximum power point is ].…”

Section: Introductionmentioning

confidence: 99%

Maximum Profit Configurations of Commercial Engines

Chen

2011

An investigation of commercial engines with finite capacity low-and high-price economic subsystems and a generalized commodity transfer law [commodity flow processes, in which effects of the price elasticities of supply and demand are introduced, is presented in this paper. Optimal cycle configurations of commercial engines for maximum profit are obtained by applying optimal control theory. In some special cases, the eventual state-market equilibrium-is solely determined by the initial conditions and the inherent characteristics of two subsystems; while the different ways of transfer affect the model in respects of the specific forms of the paths of prices and the instantaneous commodity flow, i.e., the optimal configuration.