Entropy generation analysis of a microchannel-condenser for use in a vapor compression refrigeration cycle

Türkakar, Göker; Okutucu-Özyurt, Tuba; Kandlikar, Satish G.

doi:10.1016/j.ijrefrig.2016.06.028

Cited by 7 publications

(15 citation statements)

References 16 publications

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“…With simplifying assumptions such as steady-state and no heat generation rate in the system, the total entropy generation rate is the difference between entropy flow out of and into the system. Assuming that the process under investigation is a microchannel condenser [47] which uses air and R134a as the refrigerant, Eq. ( 1) reduces to Eq.…”

Section: Fundamental Formulationsmentioning

confidence: 99%

“…Recently, several investigations have been done in this area [7,26,27,32,[63][64][65][66]. The analysis of entropy generation rate of single-phase flows in microchannels [7,26,27,32,[63][64][65] is fairly straightforward compare to that of multiphase flows [47,65,66]. In both of these categories, the entropy generation rate is either evaluated by solving ordinary or partial differential equations, i.e., sub-system modeling [26,27,32] or by simple algebraic equations, i.e., system modeling [7,47,65].…”

Section: Entropy Generation Rate In Single-phase and Multiphase Flows In Microchannelsmentioning

confidence: 99%

“…The analysis of entropy generation rate of single-phase flows in microchannels [7,26,27,32,[63][64][65] is fairly straightforward compare to that of multiphase flows [47,65,66]. In both of these categories, the entropy generation rate is either evaluated by solving ordinary or partial differential equations, i.e., sub-system modeling [26,27,32] or by simple algebraic equations, i.e., system modeling [7,47,65]. Depending on the complexity of the problem and the simplifying assumptions, the differential equations for single-phase flow, analyses of entropy generation rate can be solved analytically [26,27] or numerically [32,64].…”

Section: Entropy Generation Rate In Single-phase and Multiphase Flows In Microchannelsmentioning

confidence: 99%

“…Hence, the second simulation approach, i.e., system model, is mostly used for the analysis of entropy generation rate in microchannels with multiphase flow [47,65] or concentric heat exchangers [7]. In this approach, only the input and output characteristics of the fluid are considered.…”

Section: Entropy Generation Rate In Single-phase and Multiphase Flows In Microchannelsmentioning

confidence: 99%

“…By writing the entropy generation rate equations for the air at the inlet and outlet using temperature and pressure, the total rate of entropy generation of the air within the system is determined. Assuming air as an ideal gas and constant specific heats the refrigerant entropy change is expressed as [47]:…”

Section: Entropy Generation Rate In Single-phase and Multiphase Flows In Microchannelsmentioning

confidence: 99%

See 4 more Smart Citations

Generation of entropy in micro thermofluidic and thermochemical energy systems-A critical review

Torabi

Karimi

Torabi

et al. 2020

International Journal of Heat and Mass Transfer

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Micro energy systems have progressed significantly over the last two decades, as has the utilization of micro thermofluidic and thermochemical systems. Several studies were conducted to analyze the thermophysical and chemical characteristics of these systems. In general, the large rates of heat and mass transfer typically encountered in these microsystems make them susceptible to significant irreversibilities and as a result, poor second-law performances. Although the understanding and modelling of entropy generation rate in microsystems is an inevitable part of their performance analyses, no reviews were found on the second law analysis, and more specifically on the entropy generation rate of micro thermal and thermochemical systems.To address this shortcoming, the current review explores the mechanisms of entropy generation rate in these micro energy systems and identifies the possible future avenues of research in this field. The existing literature on entropy generation rate in micro single and multiphase thermofluidic systems, with the inclusion of various effects such as magnetic and electric fields, nanoparticles and thermochemical reactions are reviewed in detail. The unexplored and less investigated areas such as second law analysis of micro porous systems using pore-scale modeling and entropy generation rate of airflow through microchannels with inserts are identified, and recommendations are made for future research.

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Section: Fundamental Formulationsmentioning

confidence: 99%

Section: Entropy Generation Rate In Single-phase and Multiphase Flows In Microchannelsmentioning

confidence: 99%

Section: Entropy Generation Rate In Single-phase and Multiphase Flows In Microchannelsmentioning

confidence: 99%

Section: Entropy Generation Rate In Single-phase and Multiphase Flows In Microchannelsmentioning

confidence: 99%

Section: Entropy Generation Rate In Single-phase and Multiphase Flows In Microchannelsmentioning

confidence: 99%

See 3 more Smart Citations

Generation of entropy in micro thermofluidic and thermochemical energy systems-A critical review

Torabi

Karimi

Torabi

et al. 2020

International Journal of Heat and Mass Transfer

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Energetic and entropic analyses of double-diffusive, forced convection heat and mass transfer in microreactors assisted with nanofluid

Guthrie

Torabi

Karimi

2018

J Therm Anal Calorim

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This paper investigates the energetic and entropic characteristics of a microchannel with thick walls. A first order, catalytic chemical reaction is imposed on the inner surfaces of the microchannel walls and local thermal non-equilibrium approach is employed to analyse heat transfer within the porous section of the microchannel. Further, endo/exothermic physicochemical processes are incorporated into the fluid phase and solid structure of the microchannel. Two models describing the fluid-porous interface conditions known as Models A and B are incorporated. It is shown that for both interface models, and with the considered parametric values, the optimum thickness of the porous insert to achieve the maximum Nu is around 0.6. However, when PEC is considered this optimum thickness may vary between 0 and 0.5. It is further shown that depending on the specification of the microreactor, either of Models A or B may result in the prediction of the minimum total entropy generation rate. It is also demonstrated that by altering the endothermicity of the microreactor it is possible to find an optimal value, which minimises the total rate of entropy generation.

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Compact and microchannel heat exchangers: A comprehensive review of air-side friction factor and heat transfer correlations

Qasem

Zubair

2018

Energy Conversion and Management

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Entropy generation analysis of a microchannel-condenser for use in a vapor compression refrigeration cycle

Cited by 7 publications

References 16 publications

Generation of entropy in micro thermofluidic and thermochemical energy systems-A critical review

Generation of entropy in micro thermofluidic and thermochemical energy systems-A critical review

Energetic and entropic analyses of double-diffusive, forced convection heat and mass transfer in microreactors assisted with nanofluid

Compact and microchannel heat exchangers: A comprehensive review of air-side friction factor and heat transfer correlations

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