Author: Cody L. JacobucciPublisher:
ISBN:
Category :
Languages : en
Pages : 96
Book Description
Adsorption systems have a wide range of applications that sit at the forefront of challenges presented by climate change, spanning direct air carbon capture, to atmospheric water harvesting, to thermal energy storage. Decades of research and development have led to the optimization of adsorption materials to customize them for a specific application by tailoring their affinity for particular molecules, among other properties. The rapid discovery and development of new metal organic frameworks (MOF), a class of materials that prove to be more customizable than more traditional adsorbents such as zeolites and silica gel, offer promise for sorption systems to be further enhanced. However, the practical design of these systems for climate control and atmospheric water harvesting has yet to be perfected. Adsorption systems need to balance many factors to be successful for a given objective, weighing the kinetics of a given process against the device mass and volume for a variety of operational conditions. This thesis aims to elucidate design principles and optimization guidelines to facilitate the design and analysis of future sorption systems that are general enough to grow with the field as material and manufacturing capabilities expand. In this work, we describe the theoretical model used to design and optimize a waste heat driven air conditioning system for an internal combustion engine vehicle. The proposed device has a tube and fin architecture, where each fin has copper foam brazed to it to serve as a porous, conductive scaffold for the deposition of AQSOA Z02. The device will use the waste heat from the engine coolant at 90°C for desorption, and produce 1.5 kW cooling power over a 400 second cycle. The proposed design met all of the specifications proposed by Ford for automotive air conditioning systems, marking a significant milestone for the deployment of adsorption-based cooling for portable cooling applications. The design optimization process is repeated to produce a 1:10 scale prototype delivering an average cooling power of 150 W, which is currently under fabrication. In order to validate our model, we conducted a series of adsorbent coating characterizations in a custom adsorption bed simulator. We found good agreement with the model for traditional immersion drying fabrication techniques. We also propose a new boiling assisted channel templating (BACT) method to facilitate better vapor transport through the coatings to increase the potential cooling power via enhanced adsorption kinetics, reduce material waste, and decrease required fabrication time. This resulted in a performance of a specific cooling power of 1875 W/kg Z02 for a 120 second cycle- a record high number for Z02 under these operating conditions. Preliminary analysis suggests it would enable a system level specific cooling power of 375 W/kg of the entire adsorbent bed, compared to our previously proposed design with a specific cooling power of 200 W/kg. In the final chapter, we will review the lessons learned from this work and describe the next steps that we think are essential in translating adsorption technology out of the lab and into real devices for adsorption driven cooling. We also provide recommendations as to how this framework can easily be applied to other adsorption systems, such as atmospheric water harvesting, and next steps for enhancing the performance of BACT samples.
