Ammonia–water absorption in vertical tubular absorbers

Fernández-Seara, José; Sieres, Jaime; Rodríguez, Cristóbal; Vázquez, M.

doi:10.1016/j.ijthermalsci.2004.09.001

Cited by 49 publications

(24 citation statements)

References 37 publications

(56 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Mass transfer between the vapour and the liquid phases results from the combined contribution of molecular diffusion and a bulk transport of material through the interface [10][11][12][13][14][15]. The molar flux of ammonia from the bulk vapour to the interface and from the interface to the bulk liquid is obtained from Eqs.…”

Section: Mass Transfer Equationsmentioning

confidence: 99%

“…The characteristics of each flow pattern are reviewed in Ref. [10]. Therefore, herein only the criteria and correlations implemented in the model to calculate the characteristic flow parameters are summarised.…”

Section: Flow Patterns and Flow Parametersmentioning

confidence: 99%

“…Ref. [10] reports a detailed analysis of the heat and mass transfer processes during the absorption of ammonia into water in a co-current vertical tubular absorber of the shell and tubes type using water as cooling medium. In the analysis of the absorption process inside the tubes the churn, slug and bubbly flow patterns are considered separately as well as the simultaneous heat and mass transfer processes in the liquid and vapour phases and the heat transfer to the cooling medium.…”

Section: Introductionmentioning

confidence: 99%

“…[10]. However, further modifications have been introduced to take into account the new absorber con- figuration and geometry and the use of air as cooling medium.…”

Section: Introductionmentioning

confidence: 99%

“…The results shown herein are focused on the particularities introduced by the air cooling of the absorber and those results that do not bring a new contribution to the results shown in Ref. [10] are avoided for the sake of brevity.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Analysis of an air cooled ammonia–water vertical tubular absorber

Fernández-Seara¹,

Uhía²,

Sieres³

2007

International Journal of Thermal Sciences

Self Cite

View full text Add to dashboard Cite

Section: Mass Transfer Equationsmentioning

confidence: 99%

Section: Flow Patterns and Flow Parametersmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…[10]. However, further modifications have been introduced to take into account the new absorber con- figuration and geometry and the use of air as cooling medium.…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Analysis of an air cooled ammonia–water vertical tubular absorber

Fernández-Seara¹,

Uhía²,

Sieres³

2007

International Journal of Thermal Sciences

Self Cite

View full text Add to dashboard Cite

Performance characteristics of an ammonia-water absorption heat pump system

Gadalla

Ibrahim

Hassan

2013

Int. J. Energy Res.

View full text Add to dashboard Cite

SUMMARY The influences of the performance parameters and the heat transfer characteristics of the absorption heat pump using ammonia–water mixture are theoretically carried out. There is a pronounced effect of the ammonia concentration ξ after rectifier on the temperature glides that has been investigated. At ξ = 0.9000 and saturation pressures of 75 and 0.5 bar, the temperature glides are 64.4°C and 81.21°C, respectively, whereas these glides are 0°C and 16.1°C at ξ = 0.9999 and at the same pressures. This mixture property considerably affects the absorption system performance and the design of the rectifier as well as other absorption components. A correlation of the Nusselt number, Nu, is developed and compared with some published work in the literature for plate type heat exchanger. The effects of ammonia concentration ξ, mass fraction spread Δξ, specific solution circulation ratio f, and pressure ratio Rp on the refrigerant mass flow rate, the pressure drop, and the heat transfer coefficients during the condensation, the evaporation, and the absorption processes are investigated. It was found that increasing ammonia mass fraction spread Δξ results in both specific circulation ratio f and Rp that have insignificant effects on the refrigerant mass flow rate. Mounting Δξ at constant f reduces the pressure drop gradually and subsequently starts to increase as Δξ escalates. The ammonia concentration ξ has insignificant effect on the evaporation heat transfer coefficient but has a little effect on the condensation and the absorber heat transfer coefficients. The ammonia mass fraction spread Δξ and f have considerable effects on the heat transfer coefficient for different absorption heat pump components. Rp has a pronounced effect on the evaporation heat transfer coefficient, although it has a slight effect on the condensation and the absorber heat transfer coefficients. The effect of Rp on the heat transfer coefficient may be eliminated in the absorber for Δξ > 0.18. Copyright © 2013 John Wiley & Sons, Ltd.

show abstract

The influence of hybrid nanofluid and coolant flow direction on bubble mode absorption improvement

Jaballah

Hamida

Almeshaal

et al. 2020

Math Methods in App Sciences

View full text Add to dashboard Cite

This paper aims to study the influence of hybrid nanofluid and coolant flow direction on mass and heat transfer improvement for a bubble absorber in order to reduce the absorber length required for complete absorption. Hybrid nanofluid is used as the cooling medium. A finite difference method was used to solve the system of nonlinear differential equations. The absorber length is divided into differential elements of an incremental length dL along the absorber length. A parametric study comparing two different flow configuration (co/countercurrent coolant flow direction) of the bubble absorber was conducted to gage the influence of solid volume fraction (0% ≤ Phi ≤ 2%), direction of coolant flow, type of working fluid on heat, and mass transfer enhancement. The results show that the absorption process depends on the direction of coolant flow and the type of working medium. The absorption rate with coolant in countercurrent flow direction is higher than that cocurrent flow direction. In addition, results reveal that the heat and mass transfer, the mass absorption flux, the absorber thermal load, Stanton, and Reynolds number in binary hybrid nanofluids are enhanced more than that the binary nanofluid and NH3/H2O solution, which increase the absorption rate and consequently decrease the absorber length. The type of working medium and the solid volume fraction are the key parameters. Also results reveal that an optimal absorber length is found when using binary hybrid nanofluid as a working medium.

show abstract

Ammonia–water absorption in vertical tubular absorbers

Cited by 49 publications

References 37 publications

Analysis of an air cooled ammonia–water vertical tubular absorber

Analysis of an air cooled ammonia–water vertical tubular absorber

Performance characteristics of an ammonia-water absorption heat pump system

The influence of hybrid nanofluid and coolant flow direction on bubble mode absorption improvement

Contact Info

Product

Resources

About