scholarly journals Effect of Heat Leak and Finite Thermal Capacity on the Optimal Configuration of a Two-Heat-Reservoir Heat Engine for Another Linear Heat Transfer Law

Entropy ◽  
2003 ◽  
Vol 5 (5) ◽  
pp. 519-530 ◽  
Author(s):  
Tong Zheng ◽  
Lingen Chen ◽  
Fengrui Sun ◽  
Chih Wu
Keyword(s):  
Heat Transfer ◽  
Heat Engine ◽  
Thermal Capacity ◽  
Optimal Configuration ◽  
Heat Leak ◽  
Heat Reservoir ◽  
Linear Heat

scholarly journals Optimal temperatures and maximum power output of a complex system with linear phenomenological heat transfer law

2009 ◽  
Vol 13 (4) ◽  
pp. 33-40 ◽  
Author(s):  
Lingen Chen ◽  
Jun Li ◽  
Fengrui Sun
Keyword(s):  
Complex System ◽  
Heat Transfer ◽  
Power Output ◽  
Finite Time ◽  
Heat Engine ◽  
Thermal Capacity ◽  
Maximum Power ◽  
Finite Time Thermodynamics ◽  
Maximum Power Output ◽  
Different Temperatures

A complex system including several heat reservoirs, finite thermal capacity subsystems with different temperatures and a transformer (heat engine or refrigerator) with linear phenomenological heat transfer law [q ? ?(T -1)] is studied by using finite time thermodynamics. The optimal temperatures of the subsystems and the transformer and the maximum power output (or the minimum power needed) of the system are obtained.

scholarly journals Maximum work output of multistage continuous Carnot heat engine system with finite reservoirs of thermal capacity and radiation between heat source and working fluid

2010 ◽  
Vol 14 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Jun Li ◽  
Lingen Chen ◽  
Fengrui Sun
Keyword(s):  
Heat Transfer ◽  
Heat Source ◽  
Heat Sink ◽  
Heat Engine ◽  
Thermal Capacity ◽  
Working Fluid ◽  
Work Output ◽  
Maximum Work ◽  
Engine System ◽  
Maximum Work Output

Optimal temperature profile for maximum work output of multistage continuous Carnot heat engine system with two reservoirs of finite thermal capacity is determined. The heat transfer between heat source and the working fluid obeys radiation law and the heat transfer between heat sink and the working fluid obeys linear law. The solution is obtained by using optimal control theory and pseudo-Newtonian heat transfer model. It is shown that the temperature of driven fluid monotonically decreases with respect to flow velocity and process duration. The maximum work is obtained. The obtained results are compared with those obtained with infinite low temperature heat sink.

Effect of Heat Transfer Law on the Ecological Optimization of a Generalized Irreversible Carnot Engine

2005 ◽  
Vol 12 (03) ◽  
pp. 249-260 ◽  
Author(s):  
Xiaoqin Zhu ◽  
Lingen Chen ◽  
Fengrui Sun ◽  
Chih Wu
Keyword(s):  
Heat Transfer ◽  
Heat Engine ◽  
Optimization Criterion ◽  
Working Fluid ◽  
Entropy Production Rate ◽  
Heat Leak ◽  
Ecological Performance ◽  
Heat Leakage ◽  
Internal Irreversibility ◽  
Ecological Optimization

The optimal ecological performance of a irreversible Carnot engine with the losses of heat-resistance, heat leak and internal irreversibility, in which the transfer between the working fluid and the heat reservoirs obeys a generalized heat transfer law Q ∝ ∆(Tn), is derived by taking an ecological optimization criterion as the objective, which consists of maximizing a function representing the best compromise between the power and entropy production rate of the heat engine. Some special examples are discusses. A numerical example is given to show the effects of heat transfer law, heat leakage and internal irreversibility on the optimal performance of the generalized irreversible heat engine. The results can provide some theoretical guidance for the designs of practical engine.

Optimal Configuration and Performance of Heat Engines with Heat Leak and Finite Heat Capacity

2002 ◽  
Vol 09 (01) ◽  
pp. 85-96 ◽  
Author(s):  
Lingen Chen ◽  
Shengbing Zhou ◽  
Fengrui Sun ◽  
Chih Wu
Keyword(s):  
Heat Capacity ◽  
High Temperature ◽  
Low Temperature ◽  
Heat Engine ◽  
Optimal Configuration ◽  
Working Fluid ◽  
Heat Leak ◽  
Heat Engines ◽  
And Performance ◽  
Maximum Work Output

The optimal configuration of a class of two-heat-reservoir heat engine cycles in which the maximum work output can be obtained under a given cycle time is determined with the considerations of heat leak, finite heat capacity high-temperature source and infinite heat capacity low-temperature heat sink. The heat engine cycles considered in this paper include: (1) infinite low- and high-temperature reservoirs without heat leak, (2) infinite low- and high-temperature reservoirs with heat leak, (3) finite high-temperature source and infinite low-temperature sink without heat leak, and (4) finite high-temperature source and infinite low-temperature sink with heat leak. It is assumed that the heat transfer between the working fluid and the reservoirs obeys Newton's law. It is shown that the existence of heat leak doesn't affect the configuration of a cycle with an infinite high-temperature source. The finite heat capacity of a high temperature source without heat leak makes the cycle a generalized Carnot heat engine cycle. There exists a great difference of the cycle configurations for the finite high-temperature source with heat leak and the former three cases. Moreover, the relations between the optimal power output and the efficiency of the former three configurations are derived, and they show that the heat leak affects the power versus efficiency characteristics of the heat engine cycles.

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