Matching Items (19)
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- All Subjects: energy
- Creators: Chemical Engineering Program
- Creators: Phelan, Patrick E
- Resource Type: Text
Description
A relatively simple subset of nanotechnology - nanofluids - can be obtained by adding nanoparticles to conventional base fluids. The promise of these fluids stems from the fact that relatively low particle loadings (typically <1% volume fractions) can significantly change the properties of the base fluid. This research explores how low volume fraction nanofluids, composed of common base-fluids, interact with light energy. Comparative experimentation and modeling reveals that absorbing light volumetrically (i.e. in the depth of the fluid) is fundamentally different from surface-based absorption. Depending on the particle material, size, shape, and volume fraction, a fluid can be changed from being mostly transparent to sunlight (in the case of water, alcohols, oils, and glycols) to being a very efficient volumetric absorber of sunlight. This research also visualizes, under high levels of irradiation, how nanofluids undergo interesting, localized phase change phenomena. For this, images were taken of bubble formation and boiling in aqueous nanofluids heated by a hot wire and by a laser. Infrared thermography was also used to quantify this phenomenon. Overall, though, this research reveals the possibility for novel solar collectors in which the working fluid directly absorbs light energy and undergoes phase change in a single step. Modeling results indicate that these improvements can increase a solar thermal receiver's efficiency by up to 10%.
ContributorsTaylor, Robert (Author) / Phelan, Patrick E (Thesis advisor) / Adrian, Ronald (Committee member) / Trimble, Steve (Committee member) / Posner, Jonathan (Committee member) / Maracas, George (Committee member) / Arizona State University (Publisher)
Created2011
Description
Plasmon resonance in nanoscale metallic structures has shown its ability to concentrate electromagnetic energy into sub-wavelength volumes. Metal nanostructures exhibit a high extinction coefficient in the visible and near infrared spectrum due to their large absorption and scattering cross sections corresponding to their surface plasmon resonance. Hence, they can serve as an attractive candidate for solar energy conversion. Recent papers have showed that dielectric core/metallic shell nanoparticles yielded a plasmon resonance wavelength tunable from visible to infrared by changing the ratio of core radius to the total radius. Therefore it is interesting to develop a dispersion of core-shell multifunctional nanoparticles capable of dynamically changing their volume ratio and thus their spectral radiative properties. Nanoparticle suspensions (nanofluids) are known to offer a variety of benefits for thermal transport and energy conversion. Nanofluids have been proven to increase the efficiency of the photo-thermal energy conversion process in direct solar absorption collectors (DAC). Combining these two cutting-edge technologies enables the use of core-shell nanoparticles to control the spectral and radiative properties of plasmonic nanofluids in order to efficiently harvest and convert solar energy. Plasmonic nanofluids that have strong energy concentrating capacity and spectral selectivity can be used in many high-temperature energy systems where radiative heat transport is essential. In this thesis，the surface plasmon resonance effect and the wavelength tuning ranges for different metallic shell nanoparticles are investigated, the solar-weighted efficiencies of corresponding core-shell nanoparticle suspensions are explored, and a quantitative study of core-shell nanoparticle suspensions in a DAC system is provided. Using core-shell nanoparticle dispersions, it is possible to create efficient spectral solar absorption fluids and design materials for applications which require variable spectral absorption or scattering.
ContributorsLv, Wei (Author) / Phelan, Patrick E (Thesis advisor) / Dai, Lenore (Committee member) / Prasher, Ravi (Committee member) / Arizona State University (Publisher)
Created2012
Description
Waste heat energy conversion remains an inviting subject for research, given the renewed emphasis on energy efficiency and carbon emissions reduction. Solid-state thermoelectric devices have been widely investigated, but their practical application remains challenging because of cost and the inability to fabricate them in geometries that are easily compatible with heat sources. An intriguing alternative to solid-state thermoelectric devices is thermogalvanic cells, which include a generally liquid electrolyte that permits the transport of ions. Thermogalvanic cells have long been known in the electrochemistry community, but have not received much attention from the thermal transport community. This is surprising given that their performance is highly dependent on controlling both thermal and mass (ionic) transport. This research will focus on a research project, which is an interdisciplinary collaboration between mechanical engineering (i.e. thermal transport) and chemistry, and is a largely experimental effort aimed at improving fundamental understanding of thermogalvanic systems. The first part will discuss how a simple utilization of natural convection within the cell doubles the maximum power output of the cell. In the second part of the research, some of the results from the previous part will be applied in a feasibility study of incorporating thermogalvanic waste heat recovery systems into automobiles. Finally, a new approach to enhance Seebeck coefficient by tuning the configurational entropy of a mixed-ligand complex formation of copper sulfate aqueous electrolytes will be presented. Ultimately, a summary of these results as well as possible future work that can be formed from these efforts is discussed.
ContributorsGunawan, Andrey (Author) / Phelan, Patrick E (Thesis advisor) / Buttry, Daniel A (Committee member) / Mujica, Vladimiro (Committee member) / Chan, Candace K. (Committee member) / Wang, Robert Y (Committee member) / Arizona State University (Publisher)
Created2015
Description
The residential building sector accounts for more than 26% of the global energy consumption and 17% of global CO2 emissions. Due to the low cost of electricity in Kuwait and increase of population, Kuwaiti electricity consumption tripled during the past 30 years and is expected to increase by 20% by 2027. In this dissertation, a framework is developed to assess energy savings techniques to help policy-makers make educated decisions. The Kuwait residential energy outlook is studied by modeling the baseline energy consumption and the diffusion of energy conservation measures (ECMs) to identify the impacts on household energy consumption and CO2 emissions.
The energy resources and power generation in Kuwait were studied. The characteristics of the residential buildings along with energy codes of practice were investigated and four building archetypes were developed. Moreover, a baseline of end-use electricity consumption and demand was developed. Furthermore, the baseline energy consumption and demand were projected till 2040. It was found that by 2040, energy consumption would double with most of the usage being from AC. While with lighting, there is a negligible increase in consumption due to a projected shift towards more efficient lighting. Peak demand loads are expected to increase by an average growth rate of 2.9% per year. Moreover, the diffusion of different ECMs in the residential sector was modeled through four diffusion scenarios to estimate ECM adoption rates. ECMs’ impact on CO2 emissions and energy consumption of residential buildings in Kuwait was evaluated and the cost of conserved energy (CCE) and annual energy savings for each measure was calculated. AC ECMs exhibited the highest cumulative savings, whereas lighting ECMs showed an immediate energy impact. None of the ECMs in the study were cost effective due to the high subsidy rate (95%), therefore, the impact of ECMs at different subsidy and rebate rates was studied. At 75% subsidized utility price and 40% rebate only on appliances, most of ECMs will be cost effective with high energy savings. Moreover, by imposing charges of $35/ton of CO2, most ECMs will be cost effective.
The energy resources and power generation in Kuwait were studied. The characteristics of the residential buildings along with energy codes of practice were investigated and four building archetypes were developed. Moreover, a baseline of end-use electricity consumption and demand was developed. Furthermore, the baseline energy consumption and demand were projected till 2040. It was found that by 2040, energy consumption would double with most of the usage being from AC. While with lighting, there is a negligible increase in consumption due to a projected shift towards more efficient lighting. Peak demand loads are expected to increase by an average growth rate of 2.9% per year. Moreover, the diffusion of different ECMs in the residential sector was modeled through four diffusion scenarios to estimate ECM adoption rates. ECMs’ impact on CO2 emissions and energy consumption of residential buildings in Kuwait was evaluated and the cost of conserved energy (CCE) and annual energy savings for each measure was calculated. AC ECMs exhibited the highest cumulative savings, whereas lighting ECMs showed an immediate energy impact. None of the ECMs in the study were cost effective due to the high subsidy rate (95%), therefore, the impact of ECMs at different subsidy and rebate rates was studied. At 75% subsidized utility price and 40% rebate only on appliances, most of ECMs will be cost effective with high energy savings. Moreover, by imposing charges of $35/ton of CO2, most ECMs will be cost effective.
ContributorsAlajmi, Turki (Author) / Phelan, Patrick E (Thesis advisor) / Kaloush, Kamil (Committee member) / Huang, Huei-Ping (Committee member) / Wang, Liping (Committee member) / Hajiah, Ali (Committee member) / Arizona State University (Publisher)
Created2019
Description
Just for a moment! Imagine you live in Arizona without air-conditioning systems!
Air-conditioning and refrigeration systems are one of the most crucial systems in anyone’s house and car these days. Energy resources are becoming more scarce and expensive. Most of the currently used refrigerants have brought an international concern about global warming. The search for more efficient cooling/refrigeration systems with environmental friendly refrigerants has become more and more important so as to reduce greenhouse gas emissions and ensure sustainable and affordable energy systems. The most widely used air-conditioning and refrigeration system, based on the vapor compression cycle, is driven by converting electricity into mechanical work which is a high quality type of energy. However, these systems can instead be possibly driven by heat, be made solid-state (i.e., thermoelectric cooling), consist entirely of a gaseous working fluid (i.e., reverse Brayton cycle), etc. This research explores several thermally driven cooling systems in order to understand and further overcome some of the major drawbacks associated with their performance as well as their high capital costs. In the second chapter, we investigate the opportunities for integrating single- and double-stage ammonia-water (NH3–H2O) absorption refrigeration systems with multi-effect distillation (MED) via cascade of rejected heat for large-scale plants. Similarly, in the third chapter, we explore a new polygeneration cooling-power cycle’s performance based on Rankine, reverse Brayton, ejector, and liquid desiccant cycles to produce power, cooling, and possibly fresh water for various configurations. Different configurations are considered from an energy perspective and are compared to stand-alone systems. In the last chapter, a new simple, inexpensive, scalable, environmentally friendly cooling system based on an adsorption heat pump system and evacuated tube solar collector is experimentally and theoretically studied. The system is destined as a small-scale system to harness solar radiation to provide a cooling effect directly in one system.
Air-conditioning and refrigeration systems are one of the most crucial systems in anyone’s house and car these days. Energy resources are becoming more scarce and expensive. Most of the currently used refrigerants have brought an international concern about global warming. The search for more efficient cooling/refrigeration systems with environmental friendly refrigerants has become more and more important so as to reduce greenhouse gas emissions and ensure sustainable and affordable energy systems. The most widely used air-conditioning and refrigeration system, based on the vapor compression cycle, is driven by converting electricity into mechanical work which is a high quality type of energy. However, these systems can instead be possibly driven by heat, be made solid-state (i.e., thermoelectric cooling), consist entirely of a gaseous working fluid (i.e., reverse Brayton cycle), etc. This research explores several thermally driven cooling systems in order to understand and further overcome some of the major drawbacks associated with their performance as well as their high capital costs. In the second chapter, we investigate the opportunities for integrating single- and double-stage ammonia-water (NH3–H2O) absorption refrigeration systems with multi-effect distillation (MED) via cascade of rejected heat for large-scale plants. Similarly, in the third chapter, we explore a new polygeneration cooling-power cycle’s performance based on Rankine, reverse Brayton, ejector, and liquid desiccant cycles to produce power, cooling, and possibly fresh water for various configurations. Different configurations are considered from an energy perspective and are compared to stand-alone systems. In the last chapter, a new simple, inexpensive, scalable, environmentally friendly cooling system based on an adsorption heat pump system and evacuated tube solar collector is experimentally and theoretically studied. The system is destined as a small-scale system to harness solar radiation to provide a cooling effect directly in one system.
ContributorsAlelyani, Sami M (Author) / Phelan, Patrick E (Thesis advisor) / Wang, Liping (Committee member) / Stechel, Ellen B (Committee member) / Calhoun, Ronald J (Committee member) / Alalili, Ali R (Committee member) / Arizona State University (Publisher)
Created2018
Description
Solid oxide fuel cells have become a promising candidate in the development of high-density clean energy sources for the rapidly increasing demands in energy and global sustainability. In order to understand more about solid oxide fuel cells, the important step is to understand how to model heterogeneous materials. Heterogeneous materials are abundant in nature and also created in various processes. The diverse properties exhibited by these materials result from their complex microstructures, which also make it hard to model the material. Microstructure modeling and reconstruction on a meso-scale level is needed in order to produce heterogeneous models without having to shave and image every slice of the physical material, which is a destructive and irreversible process. Yeong and Torquato [1] introduced a stochastic optimization technique that enables the generation of a model of the material with the use of correlation functions. Spatial correlation functions of each of the various phases within the heterogeneous structure are collected from a two-dimensional micrograph representing a slice of a solid oxide fuel cell through computational means. The assumption is that two-dimensional images contain key structural information representative of the associated full three-dimensional microstructure. The collected spatial correlation functions, a combination of one-point and two-point correlation functions are then outputted and are representative of the material. In the reconstruction process, the characteristic two-point correlation functions is then inputted through a series of computational modeling codes and software to generate a three-dimensional visual model that is statistically similar to that of the original two-dimensional micrograph. Furthermore, parameters of temperature cooling stages and number of pixel exchanges per temperature stage are utilized and altered accordingly to observe which parameters has a higher impact on the reconstruction results. Stochastic optimization techniques to produce three-dimensional visual models from two-dimensional micrographs are therefore a statistically reliable method to understanding heterogeneous materials.
ContributorsPhan, Richard Dylan (Author) / Jiao, Yang (Thesis director) / Ren, Yi (Committee member) / Chemical Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
Description
Within recent years, metal-organic frameworks, or MOF’s, have gained a lot of attention in the materials research community. These micro-porous materials are constructed of a metal oxide core and organic linkers, and have a wide-variety of applications due to their extensive material characteristic possibilities. The focus of this study is the MOF-5 material, specifically its chemical stability in air. The MOF-5 material has a large pore size of 8 Å, and aperture sizes of 15 and 12 Å. The pore size, pore functionality, and physically stable structure makes MOF-5 a desirable material. MOF-5 holds applications in gas/liquid separation, catalysis, and gas storage. The main problem with the MOF-5 material, however, is its instability in atmospheric air. This inherent instability is due to the water in air binding to the zinc-oxide core, effectively changing the material and its structure. Because of this material weakness, the MOF-5 material is difficult to be utilized in industrial applications. Through the research efforts proposed by this study, the stability of the MOF-5 powder and membrane were studied. MOF-5 powder and a MOF-5 membrane were synthesized and characterized using XRD analysis. In an attempt to improve the stability of MOF-5 in air, methyl groups were added to the organic linker in order to hinder the interaction of water with the Zn4O core. This was done by replacing the terepthalic acid organic linker with 2,5-dimethyl terephthalic acid in the powder and membrane synthesis steps. The methyl-modified MOF-5 powder was found to be stable after several days of exposure to air while the MOF-5 powder exhibited significant crystalline change. The methyl-modified membrane was found to be unstable when synthesized using the same procedure as the MOF-5 membrane.
ContributorsAnderson, Anthony David (Author) / Lin, Jerry Y.S. (Thesis director) / Ibrahim, Amr (Committee member) / Chemical Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
Description
The recovery of biofuels permits renewable alternatives to present day fossil fuels that cause devastating effects on the planet. Pervaporation is a separation process that shows promise for the separation of ethanol from biologically fermentation broths. The performance of thin film composite membranes of polydimethylsiloxane (PDMS) and zeolite imidazolate frameworks (ZIF-71) dip coated onto a porous substrate are analyzed. Pervaporation performance factors of flux, separation factor and selectivity are measured for varying ZIF-71 loadings of pure PDMS, 5 wt%, 12.5 wt% and 25 wt% at 60 oC with a 2 wt% ethanol/water feed. The increase in ZIF-71 loadings increased the performance of PDMS to produce higher flux, higher separation factor and high selectivity than pure polymeric films.
ContributorsLau, Ching Yan (Author) / Lind, Mary Laura (Thesis director) / Durgun, Pinar Cay (Committee member) / Lively, Ryan (Committee member) / Barrett, The Honors College (Contributor) / School of International Letters and Cultures (Contributor) / Chemical Engineering Program (Contributor)
Created2014-05
Description
Currently, approximately 40% of the world’s electricity is generated from coal and coal power plants are one of the major sources of greenhouse gases accounting for a third of all CO2 emissions. The Integrated Gasification Combined Cycle (IGCC) has been shown to provide an increase in plant efficiency compared to traditional coal-based power generation processes resulting in a reduction of greenhouse gas emissions. The goal of this project was to analyze the performance of a new SNDC ceramic-carbonate dual-phase membrane for CO2 separation. The chemical formula for the SNDC-carbonate membrane was Sm0.075Nd0.075Ce0.85O1.925. This project also focused on the use of this membrane for pre-combustion CO2 capture coupled with a water gas shift (WGS) reaction for a 1000 MW power plant. The addition of this membrane to the traditional IGCC process provides a purer H2 stream for combustion in the gas turbine and results in lower operating costs and increased efficiencies for the plant. At 900 °C the CO2 flux and permeance of the SNDC-carbonate membrane were 0.65 mL/cm2•min and 1.0×10-7 mol/m2•s•Pa, respectively. Detailed in this report are the following: background regarding CO2 separation membranes and IGCC power plants, SNDC tubular membrane preparation and characterization, IGCC with membrane reactor plant design, process heat and mass balance, and plant cost estimations.
ContributorsDunteman, Nicholas Powell (Author) / Lin, Jerry (Thesis director) / Dong, Xueliang (Committee member) / Barrett, The Honors College (Contributor) / Chemical Engineering Program (Contributor) / School of Sustainability (Contributor)
Created2014-05
Description
The two central goals of this project were 1) to develop a testing method utilizing coatings on ultra-thin stainless steel to measure the thermal conductivity (k) of battery electrode materials and composites, and 2) to measure and compare the thermal conductivities of lithium iron phosphate (LiFePO4, "LFP") in industry-standard graphite/LFP mixtures as well as graphene/LFP mixtures and a synthesized graphene/LFP nanocomposite. Graphene synthesis was attempted before purchasing graphene materials, and further exploration of graphene synthesis is recommended due to limitations in purchased product quality. While it was determined after extensive experimentation that the graphene/LFP nanocomposite could not be successfully synthesized according to current literature information, a mixed composite of graphene/LFP was successfully tested and found to have k = 0.23 W/m*K. This result provides a starting point for further thermal testing method development and k optimization in Li-ion battery electrode nanocomposites.
ContributorsStehlik, Daniel Wesley (Author) / Chan, Candace K. (Thesis director) / Dai, Lenore (Committee member) / Barrett, The Honors College (Contributor) / Chemical Engineering Program (Contributor)
Created2014-05