Rationalisation of second law analysis of heat exchangers

Hesselgreaves, John E.

doi:10.1016/s0017-9310(99)00364-6

Cited by 262 publications

(114 citation statements)

References 9 publications

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“…Hesselgreaves [107] considered heat exchangers with zero and finite pressure drop. When looking at zero pressure drop, Hesselgreaves [107] included balanced counterflow, flow imbalance, unbalanced counterflow, parallel flow, condensing on one side and evaporation on one side.…”

Section: Recuperator or Heat Exchangermentioning

confidence: 99%

“…Hesselgreaves [107] found that, for zero pressure drop, flow imbalance increases entropy generation and that it is advantageous to let the highest capacity rate stream be the hot stream. Thermodynamic analyses for the balanced cross-flow recuperative plate-type heat exchanger with unmixed fluids were done by Oğulata et al [102].…”

Section: Recuperator or Heat Exchangermentioning

confidence: 99%

“…(24) for an ideal gas in the flow channels of the heat exchanger. This equation or a similar version is also used in the literature by various authors [1,8,11,102,103,107,108] and is recommended by the authors of this paper. According to Ordóñez and Bejan [108], entropy is also generated due to the discharge at the (24)), the inlet and outlet temperatures and pressures, and the heat loss from the recuperator are required.…”

Section: Recuperator or Heat Exchangermentioning

confidence: 99%

“…The heat loss to the environment from the surface of the recuperator can be a significant factor and it is recommended that it is included in solar thermal Brayton cycle analysis. Hesselgreaves [107], Oğulata et al [102] and Ordόñez and Bejan [108] suggested that the NTU -e (effectiveness -number of transfer units) method, based on the second law of thermodynamics, can be used to get the outlet temperatures and the total heat transfer rate from the hot fluid to the cold fluid. This is shown in the literature by Haugwitz [109] and Le Roux et al [33 -35].…”

Section: Recuperator or Heat Exchangermentioning

confidence: 99%

See 3 more Smart Citations

A review on the thermodynamic optimisation and modelling of the solar thermal Brayton cycle

Roux

Bello‐Ochende

Meyer

2013

Renewable and Sustainable Energy Reviews

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Many studies have been published on the performance and optimisation of the Brayton cycle and solar thermal Brayton cycle showing the potential, merits and challenges of this technology. Solar thermal Brayton systems have potential to be used as power plants in many sun-drenched countries. It can be very competitive in terms of efficiency, cost and environmental impact. When designing a system such as a recuperative Brayton cycle there is always a compromise between allowing effective heat transfer and keeping pressure losses in components small. The high temperatures required in especially the receiver of the system presents a challenge in terms of irreversibilities due to heat loss. In this paper, the authors recommend the use of the total entropy generation minimisation method. This method can be applied for the modelling of a system and can serve as validation when compared with first-law modelling. The authors review various modelling perspectives required to develop an objective function for solar thermal power optimisation, including modelling of the sun as an exergy source, the Gouy-Stodola theorem and turbine modelling.With recommendations, the authors of this paper wish to clarify and simplify the optimisation and modelling of the solar thermal Brayton cycle for future work. The work is applicable to solar thermal studies in general but focuses on the small-scale recuperated solar thermal Brayton cycle.2

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Section: Recuperator or Heat Exchangermentioning

confidence: 99%

Section: Recuperator or Heat Exchangermentioning

confidence: 99%

Section: Recuperator or Heat Exchangermentioning

confidence: 99%

Section: Recuperator or Heat Exchangermentioning

confidence: 99%

See 2 more Smart Citations

A review on the thermodynamic optimisation and modelling of the solar thermal Brayton cycle

Roux

Bello‐Ochende

Meyer

2013

Renewable and Sustainable Energy Reviews

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show abstract

“…A new approach, the equipartition of temperature difference, EoTD, was proposed as a short-cut for minimizing entropy production by Balkan [7]. However, the entropy production minimization method also causes some inconsistencies and paradoxes [9][10][11]. Guo et al [12] pointed out that the focus of entropy production minimization was on the heat-work conversion process, while the rate and efficiency of heat transfer related more to heat exchanger designs.…”

mentioning

confidence: 99%

The entransy dissipation minimization principle under given heat duty and heat transfer area conditions

Guo

Cheng

2010

Chin. Sci. Bull.

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Under given heat duty and heat transfer area conditions, the equipartition of the entransy dissipation (EoED) principle, the equipartition of the temperature difference (EoTD) principle, and the equipartition of the heat flux (EoHF) principle are applied to the optimization design of a heat exchanger with a variable heat transfer coefficient. The results show that the difference between the results obtained using the EoED and EoTD principles is very small, far smaller than that between the results obtained using the EoED and EoHF principles. The correct entransy dissipation minimization principle is chosen to optimize the parameters in the hot and cold fluids in a two-fluid heat exchanger, under given heat duty and heat transfer area conditions. The results indicate that the proper choice of the two alternative fluids has an important role in the successful application of the entransy dissipation minimization principle. The fluid that could improve the total heat transfer coefficient should be chosen, or the fluid that makes the temperature profiles of the hot and cold fluids parallel and decreases the temperature difference between the hot and cold fluids after optimization simultaneously, could be the proper one. entransy dissipation, heat exchanger, equipartition of entransy dissipation, equipartition of temperature difference, equipartition of heat flux Citation:Guo J F, Xu M T, Cheng L. The entransy dissipation minimization principle under given heat duty and heat transfer area conditions. Chinese Sci Bull, 2011Bull, , 56: 2071Bull, −2076Bull, , doi: 10.1007 With the rapidly increasing price of petroleum and coal, the efficient use of energy resources has become one of the most effective ways of reducing demand on those resources. The heat exchanger as an energy utilization device is widely used in power engineering, petroleum refineries, and chemical and food industries. Hence, reducing unnecessary energy dissipation in a heat exchanger to improve its performance is an important goal. The heat transfer occurring in the heat exchange process usually involves heat conduction under a finite temperature difference, and with fluid friction and mixing. These are the typical irreversible non-equilibrium thermodynamic processes. In recent decades, the application of the second law of thermodynamics in heat exchangers has attracted a lot of attention [1].

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Second‐Law Based Thermodynamic Analysis of a Novel Heat Exchanger

Lei¹,

Wu²,

Zhang³

et al. 2008

Chem Eng & Technol

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In the present investigation, second-law based thermodynamics analysis was applied to a new heat exchanger with helical baffles. The helical baffles are designed as quadrant ellipses and each baffle occupies one quadrant of the crosssection of the shell side. Experimental tests were carried out with cold water in the tube side with a constant flow rate, and hot oil on the shell side with flow rate range from 4-24 m 3 /h. The temperatures and pressures for the inlet and outlet of both sides were measured. The heat transfer, pressure drop, entropy generation, and exergy loss of the new heat exchanger were investigated and compared with the results for a conventional shell-and-tube heat exchanger with segmental baffles. The computed results indicated that both the entropy generation number and exergy losses of the new heat exchanger design are lower than those of the heat exchanger with segmental baffles, which means that the novel heat exchanger has a higher efficiency than the heat exchanger with segmental baffles, from the second-law based thermodynamics viewpoint.

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Rationalisation of second law analysis of heat exchangers

Cited by 262 publications

References 9 publications

A review on the thermodynamic optimisation and modelling of the solar thermal Brayton cycle

A review on the thermodynamic optimisation and modelling of the solar thermal Brayton cycle

The entransy dissipation minimization principle under given heat duty and heat transfer area conditions

Second‐Law Based Thermodynamic Analysis of a Novel Heat Exchanger

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