Modelling of isobaric stages of adsorption cooling cycle: An optimal shape of adsorption isobar

Okunev, B. N.; Gromov, A. P.; Aristov, Yu. I.

doi:10.1016/j.applthermaleng.2013.01.018

Cited by 17 publications

(4 citation statements)

References 23 publications

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“…Moreover, the predicted step positions (α) of COFs in Figure 3d−f demonstrated that all high-performing COFs generally exhibited lower step positions (α ≤ 0.4) under varying working conditions, consistent with the preferential stepwise adsorption or type V isotherm from both the thermodynamic and energetic perspectives. 14,36,38,39 Specifically, COFs with 0.2 < α ≤ 0.4 are favorable for heating and cooling, whereas COFs with 0 < α ≤ 0.2 are better candidates for ice making, which is resulted from the high working capacity at defined operating conditions (Figure S6). Besides, the top-performing COFs exhibited not only the high working capacity (ΔW) and relatively low step positions but also the moderate averaged enthalpy of adsorption (−⟨ΔH ads ⟩ ∼40 kJ/mol), both of which are favorable for the COP of MOFs (Figures S7 and S8).…”

Section: Methodsmentioning

confidence: 99%

Screening of Covalent–Organic Frameworks for Adsorption Heat Pumps

Xia

Song

2019

ACS Appl. Mater. Interfaces

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Exploring high-performing adsorption-driven heat pumps (AHPs) remains a challenging task owing to the low working capacity, high regeneration temperature, and low energy efficiency of conventional adsorbents. Quick discovery of the novel promising adsorbents could help to improve the coefficient of performance of AHPs for heating (COP H ) and cooling (COP C ). Herein, we reported an approach to identify the high-performing covalent−organic frameworks (COFs) for heating, cooling, and ice making by high-throughput computational screening based on grand canonical Monte Carlo simulations and, for the first time, machine learning. It was demonstrated that compared with metal−organic frameworks (MOFs), COFs were more suitable adsorbents of AHPs for cooling because of their weak interaction toward ethanol that favors stepwise adsorption. Structure−property relationship analysis revealed that the average enthalpy of adsorption commensurate with the enthalpy of evaporation will benefit the performance of AHPs besides the high working capacity and low step positions of adsorption isotherms. In order to reduce the computational cost of screening, a random forest model was developed to successfully predict the COP C of both COFs and MOFs.

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Section: Methodsmentioning

confidence: 99%

Screening of Covalent–Organic Frameworks for Adsorption Heat Pumps

Xia

Song

2019

ACS Appl. Mater. Interfaces

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“…Regardless of the working pair, an adsorption isotherm with one single very steep uptake step is preferred from an energetic perspective, as this will display the highest thermodynamic efficiency . Also from a dynamic perspective, a stepwise isotherm is preferred, , as only a small change in relative sorbate pressure is needed for a large change in loading, that is, a large heat effect (see, e.g., AQSOA-Z01, Figure ). Hysteresis during desorption is undesired, as this will increase the required desorption temperature.…”

Section: Introductionmentioning

confidence: 99%

Adsorption-Driven Heat Pumps: The Potential of Metal–Organic Frameworks

et al. 2015

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“…Regardless of the working fluid, an adsorption isotherm with a single very steep uptake step is preferred from an energy perspective, as this will display the highest thermodynamic efficiency . Also from a dynamic perspective, a stepwise isotherm is preferred, , as only a small change in the relative sorbate pressure is needed for a large change in loading. Hysteresis during desorption is undesired, as this will increase the required desorption temperature.…”

Section: Introductionmentioning

confidence: 99%

Metal–Organic Frameworks in Adsorption-Driven Heat Pumps: The Potential of Alcohols as Working Fluids

et al. 2015

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A large fraction of global energy is consumed for heating and cooling. Adsorption-driven heat pumps and chillers could be employed to reduce this consumption. MOFs are often considered to be ideal adsorbents for heat pumps and chillers. While most published works to date on this topic have focused on the use of water as a working fluid, the instability of many MOFs to water and the fact that water cannot be used at subzero temperatures pose certain drawbacks. The potential of using alcohol-MOF pairs in adsorption-driven heat pumps and chillers is investigated. To this end, 18 different selected MOF structures in combination with either methanol or ethanol as a working fluid are considered, and their potential is assessed on the basis of adsorption measurements and thermodynamic efficiencies. If alcohols are used instead of water, then (1) adsorption occurs at lower relative pressures for methanol and even lower pressure for ethanol, (2) larger pores can be utilized efficiently, as hysteresis is absent for pores smaller than 3.4 nm (2 nm for water), (3) larger pore sizes need to be employed to ensure the desired stepwise adsorption, (4) the effect of (polar/apolar) functional groups in the MOF is far less pronounced, (5) the energy released or taken up per cycle is lower, but heat and mass transfer may be enhanced, (6) stability of MOFs seems to be less of an issue, and (7) cryogenic applications (e.g., ice making) become feasible. From a thermodynamic perspective, UiO-67, CAU-3, and ZIF-8 seem to be the most promising MOFs for both methanol and ethanol as working fluids. Although UiO-67 might not be completely stable, both CAU-3 and ZIF-8 have the potential to be applied, especially in subzero-temperature adsorption chillers (AC).

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Modelling of isobaric stages of adsorption cooling cycle: An optimal shape of adsorption isobar

Cited by 17 publications

References 23 publications

Screening of Covalent–Organic Frameworks for Adsorption Heat Pumps

Screening of Covalent–Organic Frameworks for Adsorption Heat Pumps

Adsorption-Driven Heat Pumps: The Potential of Metal–Organic Frameworks

Metal–Organic Frameworks in Adsorption-Driven Heat Pumps: The Potential of Alcohols as Working Fluids

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