Theoretical analysis of the enhancement effect of ultrasonic oscillation on NH3-H2O falling film absorption process

Absorption refrigeration can utilize low grade heat, but the application is limited by the huge system size and low energy efficiency. The mass transfer area of absorber occupies more than 50% of the whole system. The improvement absorption effect of the absorber is significant to reduce the system...

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Bibliographic Details
Published in:Applied thermal engineering 2022-07, Vol.211, p.1
Main Authors: Zhou, Runfa, Wang, Minqi, Li, Shuhong
Format: Article
Language:English
Subjects:
Absorbers
Absorption
Ammonia
Energy efficiency
Mass transfer
Mathematical models
Oscillators
Refrigeration
Sound intensity
Surface chemistry
Ultrasonic technology
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Summary:Absorption refrigeration can utilize low grade heat, but the application is limited by the huge system size and low energy efficiency. The mass transfer area of absorber occupies more than 50% of the whole system. The improvement absorption effect of the absorber is significant to reduce the system size and improve the energy efficiency ratio. A method to enhance the mass transfer in an ammonia-water falling absorber by implementing ultrasonic oscillators is proposed in this paper. A mathematical model of the absorber with the installing of oscillator is established. The solution of the model shows that the total mass transfer coefficient and the ammonia absorbed rate are increased by 22.53% and 20.25%, respectively, when the sound intensity at the surface of oscillator is 20 W/m2. The enhancement effect increases with oscillation output power, the ammonia absorbed rate increases by 31.2% when the sound intensity at the surface of oscillator is 50 W/m2.
ISSN:1359-4311
1873-5606
DOI:10.1016/j.applthermaleng.2022.118421