Innovative Adsorbent Heat Exchangers: Design and Evaluation

Schnabel, Lena; Füldner, Gerrit; Velte, Andreas; Laurenz, Eric; Bendix, Philip; Kummer, Harry; Wittstadt, Ursula

doi:10.1007/978-3-319-71641-1_12

Cited by 8 publications

(14 citation statements)

References 41 publications

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“…They are, however, still not widespread in the market because of deficiencies regarding costs and efficiency in comparison to conventional vapor compression heat pumps. In order to overcome those limitations intensive research and development activities have been undertaken regarding the development of new adsorbents with high adsorbing ability [5][6][7] and thermodynamic features matching the working conditions, highly efficient evaporation and condensation elements [8,9], and more efficient heat exchanger designs [10,11].…”

Section: Introductionmentioning

confidence: 99%

“…Among those, the highest technological readiness level was reached for zeolites and zeo-type materials like SAPO-34 [1,4,12]. All those adsorbents are characterized by a low intrinsic thermal conductivity [10,11]. In order to obtain high power densities of the adsorption systems, the adsorbent is combined with heat exchanger structures, typically made from metals like aluminum, copper, or steel.…”

Section: Introductionmentioning

confidence: 99%

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Zeolite NaY-Copper Composites Produced by Sintering Processes for Adsorption Heat Transformation—Technology, Structure and Performance

et al. 2021

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In adsorption heat pumps, the adsorbent is typically combined with heat conducting structures in order to ensure high power output. A new approach for the direct integration of zeolite granules into a copper structure made of short copper fibers is presented here. Zeolite NaY granules with two different grain sizes are coated with copper fibers and powder and sintered to larger structures. The sorption dynamics of these structures were measured and evaluated in terms of heat and mass transfer resistances and compared to the loose grain configuration of the same material. We found that the thermal conductivity of such a composite structure is approximately 10 times higher than the thermal conductivity of an adsorbent bed with NaY granules. Sorption equilibrium measurements with a volumetric method indicate that the maximum uptake is not altered by the manufacturing process. Furthermore, the impact of the adsorbent–metal structure on the total thermal mass of an adsorption heat exchanger is evaluated. The price of the superior thermal conductivity is a 40% higher thermal mass of the adsorption heat exchanger compared to the loose grain configuration.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Zeolite NaY-Copper Composites Produced by Sintering Processes for Adsorption Heat Transformation—Technology, Structure and Performance

et al. 2021

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“…Under the temperature conditions depicted in Figure 1, aluminium fumarate undergoes the full uptake step of about 0.3 kg/kg [10], compared to little more than 0.1 kg/kg for silica gel. This advantage may be used to reduce the amount of adsorbent or to increase the power density by, e.g., shorter cycles [12]. The material is potentially a low-cost material due to widely available educts (Al-salts and fumaric acid) and a water-based synthesis route [13].…”

Section: Introductionmentioning

confidence: 99%

“…The increase in volume specific cooling power (VSCP)-thus the reduction in specific costs-while keeping a reasonably high COP, is one of the major development challenges for adsorption chillers [12]. Typical values for COPs of market-available adsorption chillers are in the order of 0.5 to 0.65 [14].…”

Section: Introductionmentioning

confidence: 99%

A Novel Approach for the Determination of Sorption Equilibria and Sorption Enthalpy Used for MOF Aluminium Fumarate with Water

et al. 2020

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Adsorption chillers offer an environmentally friendly solution for the valorisation of waste or solar heat for cooling demands. A recent application is high efficiency data centre cooling, where heat from CPUs is used to drive the process, providing cooling for auxiliary loads. The metal organic framework aluminium fumarate with water is potentially a suitable material pair for this low temperature driven application. A targeted heat exchanger design is a prerequisite for competitiveness, requiring, amongst other things, a sound understanding of adsorption equilibria and adsorption enthalpy. A novel method is employed for their determination based on small isothermal and isochoric state changes, applied with an apparatus developed initially for volume swing frequency response measurement, to samples with a binder-based adsorbent coating. The adsorption enthalpy is calculated through the Clausius–Clapeyron equation from the obtained slopes of the isotherm and isobar, while the absolute uptake is determined volumetrically. The isotherm confirms the step-like form known for aluminium fumarate, with a temperature dependent inflection point at p rel ≈ 0.25, 0.28 and 0.33 for 30 °C, 40 °C and 60 °C. The calculated differential enthalpy of adsorption is 2.90 ± 0.05 MJ/kg (52.2 ± 1.0 kJ/mol) on average, which is about 10–15% higher than expected by a simple Dubinin approximation.

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“…The increase of volume specific cooling power (VSCP) -thus reduction of specific costs -while keeping a reasonably high COP is one of the major development challenges for adsorption chillers [13]. Typical values for COPs of market available adsorption chillers are in the order of 0.5 to 0.65 [14].…”

Section: Introductionmentioning

confidence: 99%

A novel approach for the determination of sorption equilibria and sorption enthalpy used for MOF aluminium fumarate with water

Laurenz¹,

Füldner²,

Schnabel³

et al. 2020

Preprint

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Adsorption chillers offer an environmentally friendly solution for the valorisation of waste or solar heat for cooling demands. A recent application is high efficiency data centre cooling, where heat from CPUs is used to drive the process, providing cooling for auxiliary loads. The metal organic framework aluminium fumarate with water is potentially a suitable material pair for this low temperature driven application. A targeted heat exchanger design is a prerequisite for competitiveness, requiring, amongst other things, a sound understanding of adsorption equilibria and adsorption enthalpy. A novel method is employed for their determination based on small isothermal and isochoric state changes, applied with an apparatus developed initially for volume swing frequency response measurement, to samples with a binder-based adsorbent coating. The adsorption enthalpy is calculated through the Clausius–Clapeyron equation from the obtained slopes of the isotherm and isobar, while the absolute uptake is determined volumetrically. The isotherm confirms the step-like form known for aluminium fumarate, with a temperature dependent inflection point at prel ≈ 0.25, 0.28 and 0.33 for 30 °C, 40 °C and 60 °C. The calculated differential enthalpy of adsorption is 2.90 ± 0.05 MJ/kg (52.2 ± 1.0 kJ/mol) on average, which is about 10–15% higher than expected by a simple Dubinin approximation.

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Innovative Adsorbent Heat Exchangers: Design and Evaluation

Cited by 8 publications

References 41 publications

Zeolite NaY-Copper Composites Produced by Sintering Processes for Adsorption Heat Transformation—Technology, Structure and Performance

Zeolite NaY-Copper Composites Produced by Sintering Processes for Adsorption Heat Transformation—Technology, Structure and Performance

A Novel Approach for the Determination of Sorption Equilibria and Sorption Enthalpy Used for MOF Aluminium Fumarate with Water

A novel approach for the determination of sorption equilibria and sorption enthalpy used for MOF aluminium fumarate with water

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