Numerical modeling of falling-film plate generator and rectifier designed for NH3—H2O absorption machines

Wirtz, Mathilde; Stutz, Benoı̂t; Phan, Hai Trieu; Boudéhenn, François

doi:10.1007/s00231-021-03111-z

Cited by 7 publications

(5 citation statements)

References 16 publications

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“…In contrast, the average film thickness decreases along the plate in the heated section due to vapor desorption which leads to a decrease in the solution flow rate and interfacial shear stress (the vapor flow rate increasing in the vapor flow direction). The almost negligible interfacial shear stress observed in the adiabatic section supports Wirtz et al's hypothesis [4]. The increase in average film thickness in that part during the transition from 4 to 0.8 mm is directly attributed to the reduction in plate's width.…”

Section: Counter-current and Co-current Flow Configurationssupporting

confidence: 79%

“…Flooding should occur when the predicted superficial velocity is above the one predicted by the correlations. Drosos [13], Sudo [12] and Oskabe & Kawasaki [11] correlations predicts flooding in all the configurations whereas no flooding was observed in nominal conditions (s = 4mm) [4]. Biton correlation [10] predicts the onset of flooding for a channel thickness of 1.24 mm whereas the one predicted by the correlation developed in this study is close to 1mm.…”

Section: Flooding Prediction In the Combined Generatormentioning

confidence: 45%

“…In this context, Wirtz et al [3] introduced a generator-rectifier component, merging both functions into a single, compact element. To understand the heat and mass transfer within the combined generator, a one-dimensional numerical model was developed and validated through experimental measurements [3,4]. The model assumed sufficient plates spacing, neglecting hydrodynamic interactions between the liquid and vapor flows.…”

Section: Introductionmentioning

confidence: 99%

“…The current work contributes to the development of compact absorption chillers with plate heat exchangers and falling films, building upon Wirtz et al's research [4]. The existing numerical model is refined for applicability in confined spaces.…”

Section: Introductionmentioning

confidence: 99%

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Numerical modeling of a confined falling liquid film sheared by a gas flow in a plate heat exchanger of an NH₃/H₂0 absorption chiller

Sleiman,

Collignon,

Phan

et al. 2024

J. Phys.: Conf. Ser.

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In recent years, the demand for cooling has seen a substantial increase, primarily due to rising summertime temperatures. Conventional mechanical compression air conditioners have played a predominant role in fulfilling this demand, albeit at the cost of significant electricity consumption. In response, absorption chillers have emerged as an eco-friendly alternative, powered by sustainable heat sources like solar energy or industrial waste heat. The present work is conducted within the framework of developing compact absorption chillers incorporating plate heat exchangers. It builds upon prior research by improving an existing numerical model for falling film plate heat exchangers within an NH3/H2O absorption chiller. This former numerical model evaluates the coupled heat and mass transfer between the liquid film and the vapor flow while excluding hydrodynamic interactions at the liquid-vapor interface. The current investigation aims to address compactness and cost-efficiency limitations in absorption chillers. The consequences of operation within confined spaces were numerically evaluated. An innovative analytical model was developed to quantify the influence of the interactions at the liquid-vapor interface. Shear stress and interfacial perturbations were considered compared to the classical Nusselt model, enabling the evaluation of the changes in the average film thickness and the flooding phenomenon. This analytical model was then added to the previously developed heat and mass transfer model. The numerical model was applied to both the desorber and absorber units. The results show that increased confinement has minimal effects on the transfer coefficients. Additionally, an approach is suggested for estimating flooding in confined spaces and the results are compared with various correlations available in the literature.

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Section: Counter-current and Co-current Flow Configurationssupporting

confidence: 79%

Section: Flooding Prediction In the Combined Generatormentioning

confidence: 45%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Numerical modeling of a confined falling liquid film sheared by a gas flow in a plate heat exchanger of an NH₃/H₂0 absorption chiller

Sleiman,

Collignon,

Phan

et al. 2024

J. Phys.: Conf. Ser.

View full text Add to dashboard Cite

show abstract

“…The operating parameters of the generator set are classified as controllable or uncontrollable. Based on the correlation analysis of carbon sensitivity, a carbon sensitivity computational method will be built based on the variation of ζ cp [37][38][39]. The carbon sensitivity calculation model includes boiler-side parameters, turbine-side parameters, plant power, and multiple parameters simultaneously.…”

Section: Calculation Of Sensitivity Analysis Of Carbon Emission Param...mentioning

confidence: 99%

Analysis of Carbon Emissions and Emission Reduction from Coal-Fired Power Plants Based on Dual Carbon Targets

2023

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The emission of greenhouse gases poses enormous pressure on current carbon emissions and carbon reduction. Accurate quantification of carbon emissions from coal-fired power plants is of great significance for achieving the dual carbon goal. To enable enterprises to better understand their carbon emissions, this study constructs a carbon emission model and carbon emission data accounting model for coal-fired power plants. Case data calculations and a carbon emission reduction analysis were conducted. The experiment showcases that the carbon sensitivity of the inner side of the boiler under control conditions is higher than that of the operating parameters controlled on the inner side of the steam turbine, with a maximum total value of 16.67 g/MJ; the annual average low calorific value of coal remains between 16,000 kJ/kg; the activity level of coal remains between 30,000 TJ; and the oxidation probability of coal char during combustion fluctuates, with a maximum of 99.8%. In the calculation of coal-fired carbon emissions, the fitting difference between the emissions of generator unit 1 and generator unit 2 is maintained within 2%. Overall, the CO2 emissions of power plants involved in the study are generally high. The model built through this study has well analyzed the carbon emissions of power plants. It is of great significance for the actual carbon emission reduction of coal-fired power plants.

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Simulation of an ammonia-water absorption cycle using exchanger effectiveness

Braccio

Phan

Wirtz

et al. 2022

Applied Thermal Engineering

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Numerical modeling of falling-film plate generator and rectifier designed for NH3—H2O absorption machines

Cited by 7 publications

References 16 publications

Numerical modeling of a confined falling liquid film sheared by a gas flow in a plate heat exchanger of an NH₃/H₂0 absorption chiller

Numerical modeling of a confined falling liquid film sheared by a gas flow in a plate heat exchanger of an NH₃/H₂0 absorption chiller

Analysis of Carbon Emissions and Emission Reduction from Coal-Fired Power Plants Based on Dual Carbon Targets

Simulation of an ammonia-water absorption cycle using exchanger effectiveness

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Numerical modeling of falling-film plate generator and rectifier designed for NH3—H2O absorption machines

Cited by 7 publications

References 16 publications

Numerical modeling of a confined falling liquid film sheared by a gas flow in a plate heat exchanger of an NH3/H20 absorption chiller

Numerical modeling of a confined falling liquid film sheared by a gas flow in a plate heat exchanger of an NH3/H20 absorption chiller

Analysis of Carbon Emissions and Emission Reduction from Coal-Fired Power Plants Based on Dual Carbon Targets

Simulation of an ammonia-water absorption cycle using exchanger effectiveness

Contact Info

Product

Resources

About

Numerical modeling of a confined falling liquid film sheared by a gas flow in a plate heat exchanger of an NH₃/H₂0 absorption chiller

Numerical modeling of a confined falling liquid film sheared by a gas flow in a plate heat exchanger of an NH₃/H₂0 absorption chiller