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- All Subjects: engineering
- Creators: Phelan, Patrick
Although there have been many attempts to adapt EIP methodology to existing industrial sharing networks, most of them have failed for various factors: geographic restrictions by governmental organizations on use of technology, cost of technology, the inability of industries to effectively communicate their upstream and downstream resource usage, and to diminishing natural resources such as water, land and non-renewable energy (NRE) sources for energy production.
This paper presents a feasibility study conducted to evaluate the comparative environmental, economic, and geographic impacts arising from the use of renewable energy (RE) and NRE to power EIPs. Life Cycle Assessment (LCA) methodology, which is used in a variety of sectors to evaluate the environmental merits and demerits of different kinds of products and processes, was employed for comparison between these two energy production methods based on factors such as greenhouse gas emission, acidification potential, eutrophication potential, human toxicity potential, fresh water usage and land usage. To complement the environmental LCA analysis, levelized cost of electricity was used to evaluate the economic impact. This model was analyzed for two different geographic locations; United States and Europe, for 12 different energy production technologies.
The outcome of this study points out the environmental, economic and geographic superiority of one energy source over the other, including the total carbon dioxide equivalent emissions, which can then be related to the total number of carbon credits that can be earned or used to mitigate the overall carbon emission and move closer towards a net zero carbon footprint goal thus making the EIPs truly sustainable.
Based on findings of previous studies, there was speculation that two well-known experimental design software packages, JMP and Design Expert, produced varying power outputs given the same design and user inputs. For context and scope, another popular experimental design software package, Minitab® Statistical Software version 17, was added to the comparison. The study compared multiple test cases run on the three software packages with a focus on 2k and 3K factorial design and adjusting the standard deviation effect size, number of categorical factors, levels, number of factors, and replicates. All six cases were run on all three programs and were attempted to be run at one, two, and three replicates each. There was an issue at the one replicate stage, however—Minitab does not allow for only one replicate full factorial designs and Design Expert will not provide power outputs for only one replicate unless there are three or more factors. From the analysis of these results, it was concluded that the differences between JMP 13 and Design Expert 10 were well within the margin of error and likely caused by rounding. The differences between JMP 13, Design Expert 10, and Minitab 17 on the other hand indicated a fundamental difference in the way Minitab addressed power calculation compared to the latest versions of JMP and Design Expert. This was found to be likely a cause of Minitab’s dummy variable coding as its default instead of the orthogonal coding default of the other two. Although dummy variable and orthogonal coding for factorial designs do not show a difference in results, the methods affect the overall power calculations. All three programs can be adjusted to use either method of coding, but the exact instructions for how are difficult to find and thus a follow-up guide on changing the coding for factorial variables would improve this issue.
In the far field, a VO2-based metamaterial thermal emitter with switchable emittance in the mid-infrared has been theoretically studied. When VO2 is in the insulating phase, high emittance is observed at the resonance frequency of magnetic polaritons (MPs), while the structure becomes highly reflective when VO2 turns metallic. A VO2-based thermal emitter with tunable emittance is also demonstrated due to the excitation of MP at different resonance frequencies when VO2 changes phase. Moreover, an infrared thermal emitter made of graphene-covered SiC grating could achieve frequency-tunable emittance peak via the change of the graphene chemical potential.
In the near field, a radiation-based thermal rectifier is constructed by investigating radiative transfer between VO2 and SiO2 separated by nanometer vacuum gap distances. Compared to the case where VO2 is set as the emitter at 400 K as a metal, when VO2 is considered as the receiver at 300 K as an insulator, the energy transfer is greatly enhanced due to the strong surface phonon polariton (SPhP) coupling between insulating VO2 and SiO2. A radiation-based thermal switch is also explored by setting VO2 as both the emitter and the receiver. When both VO2 emitter and receiver are at the insulating phase, the switch is at the “on” mode with a much enhanced heat flux due to strong SPhP coupling, while the near-field radiative transfer is greatly suppressed when the emitting VO2 becomes metallic at temperatures higher than 341K during the “off” mode. In addition, an electrically-gated thermal modulator made of graphene covered SiC plates is theoretically studied with modulated radiative transport by varying graphene chemical potential. Moreover, the MP effect on near-field radiative transport has been investigated by spectrally enhancing radiative heat transfer between two metal gratings.
For most electrochemical processes the oxygen reduction is very vita reaction. Pt loading in the electrocatalyst contributes towards the total cost of electrochemical devices. Reducing the Pt loading in electrocatalysts with high efficiency is important for the development of fuel cell technologies. To this end, this thesis work reports the approach to lower down the Pt loading in electrocatalyst based on N-doped carbon nanotubes derived from Zeolitic Imidazolate Frameworks (ZIF-67) for oxygen reduction. This electrocatalyst perform with higher electrocatalytic activity and stability for oxygen reduction in fuel cell testing. The electrochemical properties are mainly due to the synergistic effect from N-doped carbon nanotubes derived from ZIF and Pt loading. The strategy with low Pt loading forecasts in emerging highly active and less expensive electrocatalysts in electrochemical energy devices.
This thesis focuses on: (i) methods to obtain greater power density by optimizing content of wet-proofing agent (PTFE) and fine-grained, hydrophobic, microporous layer (MPL); (ii) modeling full factorial analysis of PEMFC for evaluation with experimental results and predicting further improvements in performance; (iii) methods to obtain high levels of performance with low Pt loading electrodes based on N-doped carbon nanotubes derived from ZIF-67 and Pt.