ADVANCED ABSORPTION MATERIALS AND THEIR APPLICATION IN REFRIGERATION

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dc.contributor.advisorYang, Bao BYen_US
dc.contributor.authorZheng, Chaolunen_US
dc.contributor.departmentMechanical Engineeringen_US
dc.contributor.publisherDigital Repository at the University of Marylanden_US
dc.contributor.publisherUniversity of Maryland (College Park, Md.)en_US
dc.date.accessioned2021-07-07T05:36:52Z
dc.date.available2021-07-07T05:36:52Z
dc.date.issued2021en_US
dc.description.abstractAbsorption chillers, which utilize heat as the primary energy input, have been considered a more environment-friendly alternative to vapor-compression cooling systems. The thermodynamic properties of absorbent generally limit the performances of absorption chillers. In the first part of the dissertation, a new method to determine the molecular interaction energies is developed. The molecular interaction energies can be related to many macroscopic thermodynamic properties, such as desorption heat and hygroscopicity. From the studies on ionic liquid absorbents, it is found that a shorter alkyl group in anion would produce higher interaction energy with water, thus increasing the hygroscopicity. In contrast, the fluorination of anion would reduce its interaction energy with water, thus reducing the hygroscopicity. A new formula is also developed using interaction energies to predict the desorption heat of absorbents, which is an essential parameter for evaluating absorbent performances. The second part of the dissertation focuses on the development of a microemulsion-based absorption chiller consisting of an electrostatic desorber, a nozzle-based absorber, and an evaporator. Due to the tiny droplet size, it is thermodynamically challenging to regenerate the absorbed water in a liquid form from a microemulsion state. The electrostatic desorber would first utilize heat to transform the microemulsion absorbent into a macroemulsion state. The voltage is then applied to the absorbent to expedite the regeneration. Therefore, the electrostatic desorber can regenerate the absorbed water in a liquid form, which eliminates the latent heat requirement, offering the potential to improve energy efficiency. Inspired by the honeycomb shape, electrodes in the desorber are arranged in a multi-hexagon pattern, enabling a large desorber volume without increasing the voltage amplitude. The potential cooling power is improved by over 50 times compared to the original single-electrode desorber. The nozzle-based absorber&evaporator system utilizes nozzles to generate microemulsion absorbent and water in small droplet size to enhance the absorption and evaporation process. Combining the electrostatic desorber and the absorber&evaporator system, the complete absorption chiller could run continuously and achieve a cooling power of about 100 W.en_US
dc.identifierhttps://doi.org/10.13016/h0a6-molv
dc.identifier.urihttp://hdl.handle.net/1903/27244
dc.language.isoenen_US
dc.subject.pqcontrolledMechanical engineeringen_US
dc.subject.pquncontrolledabsorbenten_US
dc.subject.pquncontrolledabsorption chilleren_US
dc.subject.pquncontrolledelectrostatic desorberen_US
dc.subject.pquncontrolledionic liquiden_US
dc.subject.pquncontrolledmicroemulsionen_US
dc.subject.pquncontrollednon-random two-liquid modelen_US
dc.titleADVANCED ABSORPTION MATERIALS AND THEIR APPLICATION IN REFRIGERATIONen_US
dc.typeDissertationen_US

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