CFD simulation of heat and mass transfer in an absorber that uses the pair ammonia/water as a working fluid

Lima, Álvaro Augusto Soares; Villa, Alvaro Antonio Ochoa; Costa, José Ângelo Peixoto da; Guerrero, Jorge Recarte Henriquez

doi:10.1016/j.ijrefrig.2018.11.010

Cited by 26 publications

(16 citation statements)

References 42 publications

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“…The Reynolds number was considered from 6300 to 12,640 for different coil diameters at a water inlet velocity of 0.5 m/s so the flow was assumed to be turbulent. The numerical analysis was carried out using ANSYS Fluent 18.2 based on the CFD codes which are used to describe the complex behaviors of the heat and mass transfer [24][25][26] and also are implemented in various problems [27][28][29]. The upwind second-order method was applied for the discretization of continuity, momentum, and energy equations.…”

Section: Grid Generation and Numerical Methodsmentioning

confidence: 99%

A parametric study of the heat exchanger copper coils used in an indirect evaporative cooling system

2019

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Due to the lower energy consumption in the evaporative cooling, it is the subject of numerous studies. Evaporative cooling considers a green cooling system which does not require any chemical reaction and does not depend on the hazardous material. The present study mainly focused on parametric analysis of an indirect evaporative cooling system using the computational fluid dynamics method. The numerical simulation of an indirect evaporative cooling system was carried out using ANSYS Fluent 18.2. The effects of the water inlet velocity, air inlet velocity, coil diameters (d c ) and the number of the heat exchanger copper coils were numerically investigated. The flow was considered as threedimensional, turbulent, and incompressible. The results indicated that the increment of the coil diameter and water inlet velocity had a positive effect on the performance of the indirect evaporative cooling system. The maximum water outlet temperature was obtained at 285.05 K for the water inlet velocity of 0.5 m/s. Moreover, the saturation efficiency is decreased by increasing air inlet velocity. On the other hand, saturation efficiency was increased at all air inlet velocities by increasing the coil diameter.

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Section: Grid Generation and Numerical Methodsmentioning

confidence: 99%

A parametric study of the heat exchanger copper coils used in an indirect evaporative cooling system

2019

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“…The use of the two ejectors and the nonadiabatic air-cooled absorber provide benefits for the simplification of the ARS Lima et al [85] Verify the heat and mass transfer process in absorber that uses…”

Section: Author Goal Significant Findingsmentioning

confidence: 99%

“…The intensification of mass and heat transfer processes in absorption systems represents the main goal of its optimal thermal behavior. That is why many authors have been investigating ways to enhance those processes [85,93,97]. Some possible improvements are the use of different working fluids, water added on the absorbent, configuration of the absorber, and generator, as seen in Figure 8 showing a flow chart on how and why the intensification on the heat and mass transfer has been so important to enhance the performance of the absorption refrigeration systems.…”

Section: Heat and Mass Transfer Processes In Absorption Cooling Syste...mentioning

confidence: 99%

“…Additionally, the system activation temperatures are relatively high for single-effect systems, which often do not allow full use of solar energy as an activation source, limiting its use in the residential sector and places where solar radiation is limited, a fact highlighted in the literature [18,19,60]. Among these limitations, the search for alternative working fluids led to the development of the NH 3 /LiNO 3 and NH 3 /(LiNO 3 + H 2 O) working fluids to minimize the complexity of the absorption refrigeration system that uses NH 3 /H 2 O [85,122], as well as problems related to vacuum pressures, corrosion, and crystallization of the solution, as verified in use and LiBr/H 2 O in several works [90,123,124].…”

Section: Final Considerations On the Absorption Refrigeration Systems...mentioning

confidence: 99%

“…To sum up this state-of-the-art research, the theoretical study could be a tool to allow researchers to analyze different scenarios in absorption refrigeration systems that use binary/ternary mixtures without spending too much time and money on research because it is an easy and straightforward way to obtain the results [85,86]. However, this will depend on the sophistication and precision of the model and, increasingly, on the mixture's properties [63,65,73,74,87].…”

Section: Theoretical and Numerical Assessment On Absorption Chillermentioning

confidence: 99%

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Absorption Refrigeration Systems Based on Ammonia as Refrigerant Using Different Absorbents: Review and Applications

et al. 2020

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The interest in employing absorption refrigeration systems is usually related to electricity’s precariousness since these systems generally use thermal rejects for their activation. The application of these systems is closely linked to the concept of energy polygeneration, in which the energy demand to operate them is reduced, which represents their main advantage over the conventional vapor compression system. Currently, the solution pairs used in commercial absorption chillers are lithium bromide/water and ammonia/water. The latter pair has been used in air conditioning and industrial processes due to the ammonia operation’s low temperature. Few review papers on absorption chillers have been published, discussing the use of solar energy as the input source of the systems, the evolution of the absorption refrigeration cycles over the last decades, and promising alternatives to increase the performance of absorption refrigeration systems. There is a lack of consistent studies about designing requirements for absorption chillers, so an updated review covering recent advances and suggested solutions to improve the use and operation of those absorption refrigeration systems using different working fluids is relevant. Hence, this presents a review of the state-of-the-art of ammonia/absorbent based absorption refrigeration systems, considering the most relevant studies, describing the development of this equipment over the years. The most relevant studies in the open literature were collected to describe this equipment’s development over the years, including thermodynamic properties, commercial manufacturers, experimental and numerical studies, and the prototypes designed and tested in this area. The manuscript focuses on reviewing studies in absorption refrigeration systems that use ammonia and absorbents, such as water, lithium nitrate, and lithium nitrate plus water. As a horizon to the future, the uses of absorption systems should be rising due to the increasing values of the electricity, and the environmental impact of the synthetic refrigerant fluids used in mechanical refrigeration equipment. In this context, the idea for a new configuration absorption chiller is to be more efficient, pollutant free to the environment, activated by a heat substantiable source, such as solar, with low cost and compactness structure to attend the thermal needs (comfort thermal) for residences, private and public buildings, and even the industrial and health building sector (thermal processes). To conclude, future recommendations are presented to deal with the improvement of the refrigeration absorption chiller by using solar energy, alternative fluids, multiple-effects, and advanced and hybrid configurations to reach the best absorption chiller to attend to the thermal needs of the residential and industrial sector around the world.

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Numerical Simulation of the Mass-Transfer Process Between Ammonia and Water in the Absorption Chiller

Volf

Demianenko

Starynskyi

et al. 2020

Advances in Design, Simulation and Manufacturing III

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CFD simulation of heat and mass transfer in an absorber that uses the pair ammonia/water as a working fluid

Cited by 26 publications

References 42 publications

A parametric study of the heat exchanger copper coils used in an indirect evaporative cooling system

A parametric study of the heat exchanger copper coils used in an indirect evaporative cooling system

Absorption Refrigeration Systems Based on Ammonia as Refrigerant Using Different Absorbents: Review and Applications

Numerical Simulation of the Mass-Transfer Process Between Ammonia and Water in the Absorption Chiller

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