Entransy-dissipation-based thermal resistance analysis of heat exchanger networks

Qian, Ximei; Li, Zhen; Li, Zhi Xin

doi:10.1007/s11434-011-4733-3

Cited by 27 publications

(7 citation statements)

References 22 publications

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“…Then, Guo et al [11] proposed the extremum entransy dissipation principle for optimizing heat transfer processes where the extremum entransy dissipation corresponds to the optimal heat transfer performance when a thermodynamic cycle is not involved. This new principle has been applied to optimizing heat conduction [11][12][13][14][15][16][17][18][19], convective heat transfer [20][21][22][23], thermal radiation [24] processes and the heat transfer in heat exchanger [25][26][27][28][29][30][31][32][33], with all the studies confirming that the optimal results can be obtained based on the extremum entransy dissipation principle.…”

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confidence: 74%

Analysis of condenser shell side pressure drop based on the mechanical energy loss

Zeng

Jiang

2012

Chin. Sci. Bull.

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The condenser performance is strongly affected by the tube arrangement. The steam pressure drop in the tube bundle influences the condenser back pressure, which is an important indicator of the condenser performance used to compare different condenser tube arrangements. The condenser shell side pressure drop is studied here using the mechanical energy loss of the steam flow in the condensers. The mechanical energy loss is due to the flow resistance of the tube bundle and the steam condensation. Three typical tube arrangements are analyzed numerically. The results show that a higher condenser shell side pressure drop for different tube arrangements always corresponds to a larger mechanical energy loss. The mechanical energy loss is mainly in the periphery of the tube bundle, indicating that the flow pattern and the mechanical energy losses are markedly determined by the tube bundle profile. The condenser shell side pressure drop can be reduced by reducing the total mechanical energy loss when the steam enters the tube bundle more uniformly. Thus, a well designed tube arrangement will reduce the mechanical energy loss, and also the shell side pressure drop.power plant condenser, tube arrangement, shell side pressure drop, mechanical energy loss Citation:Zeng H, Meng J A, Li Z X. Analysis of condenser shell side pressure drop based on the mechanical energy loss.

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confidence: 74%

Analysis of condenser shell side pressure drop based on the mechanical energy loss

Zeng

Jiang

2012

Chin. Sci. Bull.

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“…Chen et al [57,58] derived the expressions of equivalent thermal resistance of heat exchanger networks with high and low temperatures based on entansy dissipation. Qian et al [59] investigated three typical heat exchange networks, and found that the thermal resistance is a monotonic function of heat transfer quantity. Cheng et al [60] defined the effectiveness of heat exchanger couple, compared the relationships among entropy generation, entransy dissipation, heat resistance and the effectiveness of heat exchanger couple, and found that only the heat resistance is a monotonic function of the effectiveness of heat exchanger networks.…”

Section: Heat Exchangermentioning

confidence: 99%

Progress in entransy theory and its applications

Chen

2012

Chin. Sci. Bull.

115

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The entransy and entransy dissipation extremum principle proposed have opened up a new direction for the heat transfer optimization. The emergence and development of entransy theory are reviewed. Entransy theory and its applications are summarized from several aspects, such as heat conduction, heat convective, heat radiation, heat exchanger design and mass transfer, etc. The emphases are focused on four aspects, i.e., the comparison between entropy generation rate and entransy dissipation rate, the combination of entransy dissipation extreme principle with finite time thermodynamics, the combination of entransy dissipation extreme principle with the heat conduction constructal theory, and the combination of entransy dissipation extreme principle with the heat convective constructal theory. The scientific features of entransy theory are emphasized. Influenced by oil crisis in the 1970's directly, the heat transfer enhancement was world-widely paid attention by the scientific community, and was quickly developed into one of very important branches in thermal science and technology fields. With the progress of social development ideas, such as sustainable development, low-carbon technology and low-carbon economy, the concept of heat transfer enhancement has developed into a broader scope concept of heat transfer optimization [1]. In the past 30 years, the basic theory of heat transfer optimization has been made considerable progresses, and finite-time thermodynamics, field synergy principle, constructal theory as well as entransy theory are the representative achievements. The emergences of these theories promoted the developments of thermodynamics and heat transfer. Finite-time thermodynamics, which combined thermodynamics, heat transfer and fluid mechanics, provided a theoretical fundament for performance optimizations of practical processes and devices with the constraints of a finite size and finite time. Field synergy principle unified the essential physical understandings of convective heat transfer and heat transfer enhancement phenomena, and provided a theoretical fundament for the development of heat transfer enhancement technology to achieve better energy saving effects. Constructal theory, which was called the thermodynamics of non-equilibrium system with configuration in the field of thermal science, provided a theoretical fundament for the unified descriptions of the generation of flow structures in natural organization and the designs of various flow structures. Fourier's law of heat conduction, Newton's law of cooling and Stephen-Boltzmann law of blackbody radiation only gave the concept of heat transfer rate, while the concepts of entransy and entransy dissipation lay the foundation of defining the concept of heat transfer efficiency which did not appear in the heat transfer theory before. Entransy theory provided a new theoretical fundament for heat transfer optimization, which is different from that of the entropy generation minimization.

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“…Examples include the cooling system of electronic devices [1], the thermochemical heat storage system [2], the ground source heat pump system [3], and the thermal control systems of spacecraft [4]. As heat transfer optimization of HE networks can improve heat transport performance and energy utilization, the optimization and analyses of the heat transfer processes in HE networks have received more and more attention [4,5].…”

Section: Introductionmentioning

confidence: 99%

“…For two-stream HE networks, Qian et al [5] applied the entransy theory to analyze three typical two-stream HE networks, and found that the minimum EDBTR of the HE networks always corresponds to the maximum heat transfer rates, while the minimum EG does not. For one-stream HE networks, Chen et al [6] optimized the heat transfer in a thermal network with two HEs, and showed that the maximum ED corresponds to the maximum heat transfer rate with prescribed wall temperatures of the HEs, while the minimum EG does not.…”

Section: Introductionmentioning

confidence: 99%

Application of Entransy Optimization to One-Stream Series-Wound and Parallel Heat Exchanger Networks

Cheng

Liang

2014

Heat Transfer Engineering

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Entransy theory has developed in recent years to describe heat transfer behavior from another point of view. Entransy dissipation is proposed to evaluate the irreversibility of heat transfer and is used to optimize heat transfer processes. We apply this theory to the one-stream series-wound and parallel heat exchanger (HE) networks. The heat transfer optimization for the HE networks includes the distribution of the heat transfer area or heat load. The distribution of the cold fluid flow rate in parallel HE networks can also be optimized. For these problems, physical and mathematical models are set up, analyzed, and discussed with the entransy theory. It is found that the optimization objectives of these problems and the optimization directions of the extremum entransy dissipation principle are consistent. The optimized results for the distribution optimization problem with given heat load are in agreement with the uniformity principle of temperature difference field. Examples of simple one-stream HE networks are given; the distributions of the heat transfer area or heat load are optimized by the extremum entransy dissipation method.

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Entransy-dissipation-based thermal resistance analysis of heat exchanger networks

Cited by 27 publications

References 22 publications

Analysis of condenser shell side pressure drop based on the mechanical energy loss

Analysis of condenser shell side pressure drop based on the mechanical energy loss

Progress in entransy theory and its applications

Application of Entransy Optimization to One-Stream Series-Wound and Parallel Heat Exchanger Networks

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