Heat Transfer Accompanied by Adsorption/Desorption of Water Vapour in Adsorption Heat Pump of Packed Bed Type.

Watanabe, Fujio; Watabe, Yoshito; Katsuyama, Hitoshi; Kozuka, Jun; Hasatani, Masanobu; Marumo, Chisato

doi:10.1252/kakoronbunshu.19.83

Cited by 15 publications

(3 citation statements)

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“…For example, the zeolite-water pair showed low adsorbability of approximately 30 wt.% of the adsorbent. On the other hand, the ACethanol pair showed much higher adsorption properties of more than 150 wt.% of the adsorbent [11].…”

Section: Introductionmentioning

confidence: 94%

Influence of surface functionalities on ethanol adsorption characteristics in activated carbons for adsorption heat pumps

Kil

Kim

Hata

et al. 2014

Applied Thermal Engineering

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To develop high-performance activated carbons (ACs) for adsorption heat pumps (AHPs), it is important to characterize the adsorption behaviors of the refrigerant molecules in the pores of ACs. Not only pore structures, such as pore size and shape, but also surface functionalities strongly influences the adsorption behaviors, especially for polar molecules, such as water and ethanol, which are typical refrigerants for AHP. In this study, we examined the influence of surface functional groups on the adsorption behaviors of ethanol molecules in carbon micropores using model ACs with different amounts of oxygen-containing surface functional groups but comparable porosities. For the AC with an increased amount of surface functional groups, ethanol adsorption/desorption isotherms showed significant decreases in the adsorption amounts and shortened adsorption equilibrium times compared to those with less surface functional groups throughout the entire relative pressure region. This suggests diffusional hindrance of ethanol molecules in micropores with abundant surface functional groups. To verify our hypothesis, we examined the influence of surface functional groups on the adsorption behavior of ethanol molecules using a solid-state NMR technique. The NMR results revealed that the hydroxyl group of ethanol molecules strongly interacts with the surface functional groups, giving rise to an oriented adsorption of ethanol molecules in the micropores with oxygen-containing surface functional groups. Furthermore, electrochemical analyses confirmed that diffusion resistance of electrolyte ions in the micropores increases after the introduction of oxygen-containing surface functional groups, which supports our hypothesis.

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Section: Introductionmentioning

confidence: 94%

Influence of surface functionalities on ethanol adsorption characteristics in activated carbons for adsorption heat pumps

Kil

Kim

Hata

et al. 2014

Applied Thermal Engineering

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“…Authors reported study on sorption characteristics of honeycomb type sorption element composed of organic sorbent (3) and water vapor sorption characteristics of powder type organic sorbent in a moist air fluidized bed (4) . Concerning inorganic adsorbent, the study on mass transfer characteristics of water vapor of honeycomb type element and packed bed were reported (5), (6) .…”

Section: Introductionmentioning

confidence: 99%

Sorption Characteristics of Organic Sorbent Coated on Heat Transfer Surface of a Heat Exchanger Under the Low Temperature

Inaba

Komatsu

Horibe

et al. 2008

JTST

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This paper describes the transient sorption characteristics of organic sorbent under the low temperature. Our previous research result has shown that the organic sorbent had a large amount of water vapor uptake ability, and was also excellent in processability and deterioration resistance. The measured results of sorption isotherm equilibrium revealed that the organic polymer sorbent was a kind of material which sorption ability depends on temperature. The experiments in which the moist air was passed into the heat exchanger coated with sorption material were conducted under various conditions of the air flow velocity, the brine temperature and the air absolute humidity. It is found that the sorption rate of vapor is affected most greatly by the air absolute humidity. Finally the average mass transfer coefficient of the organic sorbent is non-dimensionalized as a function of Reynolds number, non-dimensional temperature and non-dimensional vapor pressure of saturation.

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“…Yamazeki et al (1991) and Murata et al (1993) used a heat exchanger with catalyzed walls as a hydrogenation reactor for a benzene/cyclohexane chemical heat pump. For a silica gel-water adsorption chemical heat pump, Watanabe et al (1993) employed silica gel supported on copper tubing inside which heat-removing fluid was delivered. For a chemical heat pump using the hydration of calcium oxide, Ogura et al (1991Ogura et al ( , 1992Ogura et al ( , 1993 proposed metal fins inserted into the reactor to enhance heat transfer.…”

Section: Introductionmentioning

confidence: 99%

Improvement of Heat Transfer in a Packed-Bed Reactor for a Chemical Heat Pump Using Sodium Carbonate Decahydrate Dehydration

Matsumura

Yoshida

1997

Ind. Eng. Chem. Res.

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To improve the heat transfer characteristics of a gas−solid packed-bed reactor, an inert solvent was added to the reactor. For sodium carbonate decahydrate dehydration, used in a chemical heat pump, n-pentanol was chosen as a solvent, and the dehydration rate in the solvent was measured. The dehydration rate was found to be proportional to the total surface area of the decahydrate particles, and the rate equation was determined. Particle size distribution (less than 400 μm) remained unchanged for a three-time cyclic operation. The packed-bed of decahydrate with n-pentanol solvent showed considerable improvement in heat transfer characteristics compared with the case having no solvent, and cold heat generation was more than doubled. A simulation study showed that the addition of n-pentanol may make it possible to construct a high-performance heat pump with cold storage capability, attaining 280 K in less than 5 s and total heat release within 1600 s.

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Heat Transfer Accompanied by Adsorption/Desorption of Water Vapour in Adsorption Heat Pump of Packed Bed Type.

Cited by 15 publications

References 0 publications

Influence of surface functionalities on ethanol adsorption characteristics in activated carbons for adsorption heat pumps

Influence of surface functionalities on ethanol adsorption characteristics in activated carbons for adsorption heat pumps

Sorption Characteristics of Organic Sorbent Coated on Heat Transfer Surface of a Heat Exchanger Under the Low Temperature

Improvement of Heat Transfer in a Packed-Bed Reactor for a Chemical Heat Pump Using Sodium Carbonate Decahydrate Dehydration

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