Poster Abstracts

The Renewable Methane Energy System

Jim Beyer
Mechanical Engineering
Master's Program

This poster describes a future energy system based on a greater use of alternate energy resources. Instead of relying on exotic fuels like hydrogen, the system uses a hybrid of electricity and methane (derived from renewable
sources) to power our future. A key component to making this system work is the Sabatier reactor, a 19th century device that combines hydrogen and carbon dioxide to produce methane. Since electricity and methane (in the form of natural gas) are already used today, no major infrastructure changes are needed to deliver this energy. Important changes needed to affect this energy system include the addition of more alternate energy resources, plug-in hybrid electric vehicles, smart grid technology, and combined heat and power (CHP) technology.

Ion-cut Synthesis for High-Efficiency Energy Conversion Devices

R.R. Collino1, B.B. Dick2, M.D. Thouless1,3, and R.S. Goldman3-5*
1Mechanical Engineering, 2Engineering Physics, 3Materials Science and Engineering, 4Physics, 5Electrical Engineering and Computer Science
University of Michigan, Ann Arbor, MI 48109
*Corresponding Author: rsgold@umich.edu

A major technological hurdle to global energy sustainability is the replacement of environmentally harmful and rapidly depleting energy sources with ecologically responsible and renewable sources. Solar power is one promising avenue to clean energy; however, the relative efficiency, availability, or cost of solar power as compared to polluting power sources such as fossil fuels can preclude its widespread application. In terms of efficiency of solar cells and solar concentrators, the majority of energy (up to 95%) is converted to waste heat [1]. The pairing of thermoelectric devices with solar cells and/or solar concentrators is a promising route to recovery of otherwise wasted energy. To this end, we are studying nanostructured materials for efficient conversion of both light and heat from the sun to electricity, as well as the development of a thin-film layer transfer technique to reduce materials cost.

The realization of high efficiency photovoltaic and thermoelectric devices at low materials cost may be accomplished by using thin layers containing device structures on an inexpensive ‘carrier’ wafer. We are developing a novel process for device manufacture involving simultaneous GaAsN nanostructure synthesis and layer transfer: “ion-cut synthesis.” This is a technique that would permit thin films of photovoltaic and thermoelectric material to be supported on a cheaper wafer. This approach will enable the efficient conversion of both light and heat to electricity, providing a possible solution to the challenge of cost-efficient energy sustainability.

[1] J.I. Rosell, X. Vallverdu, M.A. Lechon, M. Ibanez, Energy Conversion and Management 46, 3034 (2005).

X- and γ-ray emissions observed in the decay of 237Np and 233Pa

Daniel DeVries
Doctoral Student
Department of Chemistry

Nuclear energy is one of the most widely used, carbon free, technologies for generating electricity. Many problems still exist with the safe disposal of the radioactive waste from these reactors. 237Np is one waste nuclei produced in relatively large amounts in the once-through fuel cycle. Its 2.1 million year half-life results in a low specific activity that persists long after fission products have decayed. Gamma-ray spectroscopy is the tool most often employed to answer questions of “how much” or “how pure.” Solvent extraction was used to prepare pure solutions of 237Np and 233Pa. Portions were used for liquid scintillation counting (disintegration rates) and γ-ray spectroscopy with HPGe detectors. X- and γ-ray intensities observed in the 237Np decay were verified, with a new result of 15.08±0.04% for the 29 keV γ ray (~5σ higher than previous reports). K X- and γ-ray intensities observed in the 233Pa decay were verified with new results for the L X-ray intensities (~55% total L intensity), approximately twice previously reported total intensity.

Layer-by-layer Assembly of Carbon Nanocolloids for Fuel Cells

Peter Ho
PhD student
Chemical Engineering

We proposed using layer-by-layer assembly for the construction of fuel cells electrodes. Layer-by-layer assembly utilizes electrostatic, hydrogen bonding, and van der Waals forces to build up multilayered nanocomposites that show extraordinary homogeneity and strength. The way LBL technique fabricates composites gives possibilities to fine tune the membranes to our desired properties. LBL membranes consist of carbon nanocolloids showed great capability in PEM fuel cell application as they can be utilized in membrane electrode assemblies (MEAs) as catalyst layers, gas diffusion layers, or proton exchange membranes. By studying and carefully designing the fabrication processes and the materials incorporated, controlled nanostructures with well placed catalyst nanoparticles are expected to tremendously improve the performance as well as catalyst utilization in PEM fuel cells.

Far-Infrared Spectroscopy of the Earth’s Tropospher

Darshan Karwat
PhD Aerospace Engineering
Email: dippind@umich.edu
Advisors: Dr. Martin Mlynczak, & Dr. David Johnson
Science Directorate, Atmospheric Sciences Branch
NASA Langley Research Centre, Hampton, VA

The purpose of this research is to study the radiation emitted by the troposphere of the Earth’s atmosphere in the far-infrared region of the emission spectrum. Particularly, this research is looking for signatures of the influence of greenhouse gases, such as water vapour and carbon dioxide.

The radiative balance of the troposphere, and consequently, the climate, is strongly influenced by radiative cooling associated with emission of infrared radiation by water vapour, particularly at far-infrared (far-IR) wavelengths greater than 15 mm to 50 mm. The distribution of water vapour and associated far-IR radiative forcings and feedbacks are well-recognized as major uncertainties in understanding and predicting future climate. Approximately half of the outgoing longwave radiation (OLR) from the Earth occurs beyond 15mm. Cirrus clouds, too, modulate the OLR in the far-IR. Despite this fundamental importance, far-IR emission has rarely been directly measured from space, airborne, or ground-based platforms. Far-IR measurements will help achieve a more comprehensive understanding of the Earth’s energy cycle through direct observations of the radiative cooling effects of tropospheric water vapour. They will also help obtain a more accurate understanding of the radiative impact of cirrus clouds on climate by directly observing their radiative and microphysical properties at far-IR wavelengths (Mlynczak, Harries, Rizzi, Stackhouse, Kratz, Johnson, Mertens, Garcia, Soden, 2002).
The Far-Infrared Spectroscopy of the Troposphere (FIRST) instrument is designed to do just this. FIRST is a Fourier Transform spectrometer designed to measure the far-IR emission spectrum of the Earth and its atmosphere. FIRST is designed to provide a high spectral resolution (0.625 cm-1), a high spatial resolution (0.2 km for balloon altitude, 10 km from orbit), a high calibration accuracy (<0.1% uncertainty), and global coverage from orbit (Mlynczak, Johnson, Latvakoski, Jucks, Watson, Kratz, Bingham, Traub, Wellard, Hyde, Liu, 2006).

FIRST was tested on two high-altitude balloon missions in June 2005 and September 2006. Analyses are now being done on the data collected to validate robustness. Data were analyzed and visualized using codes developed in Matlab. The data obtained from FIRST show remarkable agreement with data collected from NASA’s Atmospheric Infrared Sounder satellite, thus demonstrating the calibration accuracy of FIRST. As expected, the radiation measured at far-IR wavelengths does not vary significantly with respect to time. This research is crucial in understanding the processes that drive climate change, and is thus essential in protecting our planet.

Engineering Characterization of CEUS Earthquake Ground Motions for Designing Nuclear Power Plants

Jongwon Lee, Ph.D. Candidate, Civil and Environmental Engineering

Earthquake engineering evolved from a fledgling discipline that was based on limited theories and empirical observations in the 1950s to one that is soundly based on scientific principles and mechanics in the 1980s. This evolution was a direct result of the design and construction of commercial nuclear power plants and their need to withstand potential earthquake shaking. Within the past couple of years, seventeen electrical utility companies have announced their intent to submit applications to the US Nuclear Regulatory Commission for at least thirty new nuclear plant licenses, with all of proposed plants to be located in the central/eastern US (CEUS) (NEI, 2007). This statistic highlights the need to have up-to-date and accurate seismic hazard information for the CEUS. In addition to safety reasons, the estimated seismic hazard significantly influences the cost of a nuclear power plant, even controlling its economic feasibility. Inherent to performing a seismic hazard analysis are earthquake ground motion correlations relating earthquake magnitude, site-to-source distance, and site condition to various engineering parameters used to characterize earthquake ground motions (e.g., strong ground motion duration and characteristic period). In this context, this poster presents the new correlations for ground motion characteristic parameters for the CEUS and compares them to correlations for the western US (WUS) motions. The correlations were developed using the non-linear random-effects regression techniques and an up-to-date earthquake ground motion database: 620 horizontal motions consisting of 28 recorded motions and 592 scaled motions (e.g., McGuire et al., 2001; Boore, 1983; Silva and Lee, 1987) for the CEUS; 648 horizontal motions from 49 earthquakes for the WUS. The newly developed correlations will play a significant role in the seismic design of new nuclear power plants.

Reference:
Boore, D. M. (1983). Stochastic simulation of high-frequency ground motions based on seismological models of the radiated spectra, Bulletin of the Seismological Society of America, 73(6), 1856-1894.

McGuire, R. K., Silva, W. J. and Costantino, C. J. (2001). Technical basis for revision of regulatory guidance on design ground motions: Hazard-and risk-consistent ground motion spectra guidelines. NUREG/CR-6728, US Nuclear Regulatory Commission, Washington, DC.

Nuclear Energy Institute (NEI) (2007). http://www.nei.org/resourcesandstats/documentlibrary/
newplants/graphicsandcharts/newnuclearplantstatus/

Silver, W. J. and Lee, K. (1987). WES RASCAL Code for Synthesizing Earthquake Ground Motions; Report 24, State-of-the-art for assessing earthquake hazards in the United States, US Army Engineering Waterways Experiment Station, Vicksburg, MS, Miscellaneous paper S-73-1

Modeling of light trapping in thin film solar cells using periodic and random optical gratings on ZnO/Ag back reflectors

Albert Lin
Electrical Engineering and Computer Science
Email: shihchun@umich.edu

Thin film solar cells have a trade-off associated with light absorption and collection of photo-generated carriers due to the optical absorption properties and carrier diffusion length in the materials used. The optical path length for thin film solar cells may be dramatically increased through light diffraction and internal reflection, increasing solar cell efficiency. Several techniques have been used for “light trapping” in solar cells based on pattering of the back reflector in the device structure, including random texturing and lithographically defined periodic gratings. Optimization of light trapping in solar cells is complex due to the broad spectrum of solar radiation and the diffractive nature of light. In this work, light-trapping in ZnO/a-Si/ZnO/Ag solar cell structures is investigated by numerical simulation. Varying optical grating techniques are investigated, including periodic gratings of varying geometry (rectangular, blazed, and triangular), random rectangular gratings, and the design of optimal gratings using a genetic algorithm approach.

For periodic rectangular gratings, quantum efficiency versus groove height for 400nm (blue light) and 800nm (red light) illumination is calculated. Comparison is made with respect to flat cells and relative improvement is about 15%. Quantum efficiency as a function of groove period at fixed groove height is also calculated. Maximum occurs around P (period) =1um and efficiency decreases with further increased groove period. For randomized patterns, groove heights of adjacent rectangular gratings are varied randomly. The quantum efficiency of randomized gratings is comparable to the best periodic gratings for lambda equals to 800nm. At the end, genetic algorithm is proposed as a way to further increase solar cell efficiency.

Real-time, Self-learning Optimization of Engine Calibration

Andreas A. Malikopoulos
PhD Mechanical Engineering
Advisors: Professor Dennis N. Assanis and Professor Panos Y. Papalambros

Fossil fuels are an unsustainable resource and our planet has only a finite number of deposits. Two-thirds of the oil used around the world currently goes to power transportation vehicles, of which half goes to passenger cars and light trucks. Being conscious of our fuel use will help to conserve resources for future generations. Advanced engine technologies such as fuel injections systems, variable geometry turbocharging (VGT), and exhaust gas recirculation (EGR), have increased the number of controllable variables and our ability to optimize engine operation. The determination of the optimal values of these variables, referred to as engine calibration, is especially critical for optimizing fuel economy. State-of-the-art methods of engine calibration seldom guarantee continuously optimal engine operation, especially during transient cases. We present the theoretical framework and algorithmic implementation which makes the engine learn the optimal values of the controllable variables in real time while running a vehicle. The engine progressively perceives the driver’s driving style and eventually learns to operate in a manner that optimizes fuel economy. The effectiveness of the approach is demonstrated through simulation of a diesel engine, which learns to optimize fuel economy with respect to two controllable variables, i.e., injection timing and VGT blade position.

Fiber Based Organic Lighting Emitting Devices for Applications in Lighting

Brendan O’Connor, Doctoral student, Mechanical Engineering
Jun Rong Ong, Undergraduate, Materials Science and Engineering

Area lighting represents one fifth of the U.S national electrical energy consumption and contributes significantly to emission of CO2. Cost-effective and energy efficient lighting technologies are thus of growing interest. Organic-based light emitting devices (OLEDs) are a viable alternative to fluorescent lamps or the more traditional inorganic semiconductor-based LEDs, in part due to the potential low cost of processing and ability to efficiently generate warm light. In pursuit of novel OLED architectures amenable to low-cost, high throughput processing on inexpensive substrates, we demonstrate OLEDs deposited on fibers. We analyze the performance of individual fiber-based OLEDs, including their efficiency and emission spectrum. The efficiency and electrical characteristics of fiber-based OLEDs compare well with those of analogous planar devices; furthermore, unlike planar OLEDs, emission spectra of fiber OLEDs are constant over the full range of observation angles – an important property for area lighting and other novel applications, e.g. in woven light-emitting fabrics and fabric-reinforced composites.

Biodiesel Production Using Ethyl Esterification of Oleic Acid

Tanawan Pinnarat
PhD Chemical Engineering
Email: tanawanp@umich.edu
Advisor: Professor Phillip E.Savage

Alternative energy has attracted attention in the last decade because of more concern for environmental issues and the need for energy choices other than fossil fuel. Biodiesel is one alternative which has the potential to compete with diesel fuel from petroleum. The advantage of biodiesel over diesel oil is its environmentally friendly properties, and it can be used directly in an unmodified diesel engine with similar performance to diesel fuel. Biodiesel is usually produced by transesterification with either acid or base catalyst. However, the production cost is high and there are problems associated with the purity of raw material and separation of catalyst. Transesterification without catalyst at supercritical condition was developed to overcome the problem of water and free fatty acid in the feedstock and the difficulty of separation at the end of the process. The only drawback of this method is the severe conditions, which require more energy that increases the cost of production. The two step biodiesel production, which is hydrolysis of triglycerides followed by the alkyl esterification of hydrolyzed product, has the potential to produce biodiesel with low production cost compared to the conventional method. No pretreatment is required and separation of the final product is quite simple. However, the supercritical condition used in alkyl esterification requires more energy with its high pressure and temperature. It might be possible to perform the esterification at milder condition. Unfortunately, there is no information in the literature about biodiesel production without catalyst at non-supercritical conditions. Therefore, conditions at lower temperature and pressure will be studied to determine the possibility of lowering the production cost. This study will show the preliminary results of biodiesel production by using ethyl esterification of oleic acid. The supercritical and non-supercritical condition was used. The results show that non-supercritical conditions (250oC, 270oC, 320oC, at 20 bar) give higher conversion compared to supercritical conditions (250oC at 200 bar). It shows a possibility to produce biodiesel under non-supercritical and non-catalyzed conditions. In addition, the alcohol to oil ratio effect was also studied. Kinetics and mechanism of this reaction will be investigated to gain more understanding and find the optimum condition for the biodiesel production.

Biomass Gasification in Supercritical Water

Authors: Phillip Savage, Fernando Resende and Gregory DiLeo, University of Michigan, Ann Arbor, MI

Biomass, in the form of intentionally cultivated energy crops or agricultural residues, is a renewable source of liquid and gas fuels. Its use does not increase the net amount of CO2 in the atmosphere, because the carbon released from the biomass originally came from the atmosphere during the photosynthesis process. Furthermore, converting biomass to fuels could reduce reliance on international fossil fuels resources and lead to improved energy security.

The main obstacle that technologies to convert biomass have not yet overcome is the formation of significant amounts of char and tar as pyrolysis byproducts. In addition, many types of biomass have a high moisture content, and need to be dried prior to thermal processing. This step requires energy and reduces the overall thermal efficiency.
One technology proposed as an alternative for wet biomass is Supercritical Water Gasification (SCWG), where the reaction medium is water above its thermodynamic critical point (374 °C, 218 atm). The major components of biomass, such as cellulose and lignin, can be dissolved in supercritical water, leading to hydrolysis reactions rather than pyrolysis. This different reaction pathway reduces formation of char and tar.
In terms of thermal efficiency, SCWG offers the advantage of eliminating the need to dry biomass, since water is the solvent. This is especially important for biomass of high moisture content, which could be expensive to gasify by conventional methods.
We gasified cellulose and lignin in supercritical water at 400-700 °C. The reactions were conducted in quartz tubes, at times with Ni added wires. These reactors allowed the homogeneous and heterogeneous SCWG rates to be quantified separately for the first time. Homogeneous SCWG of cellulose (no catalyst or metal present) produces CO2 as the major compound, except at the lowest cellulose loadings (5 wt.%) where CH4 became the major product. Manipulating the cellulose loading (wt %) and water density provides a means to control the product selectivity. In general, higher H2 yields were obtained from cellulose at the longer reaction times, higher water densities, higher cellulose loadings, and higher temperatures. Results from SCWG of cellulose in quartz reactors differ from those obtained from nominally “uncatalyzed” SCWG in stainless steel reactors. In quartz, the total gas yields are lower and the H2 mole fraction in the gas is also lower. Nickel significantly changes the gas product compositions.

Introduction to Nuclear Energy

Nick Touran, PhD Student
Department of Nuclear Engineering and Radiological Science

Every day, we're becoming more concerned about energy. Global warming, dependence on
foreign oil, shortage of resources, and increasing population constantly top the headlines. Nuclear energy offers compelling solutions to many of these problems, but its public image is distorted at best. We offer facts on both the good and bad aspects of nuclear energy, hoping to open up minds to this vast energy resource that is often disregarded. We provide non-esoteric overviews of nuclear reactors, closing the fuel cycle, implementing the thorium fuel cycle, issues with nuclear waste, and the accident at Chernobyl. The public is screaming for a feasible alternative to fossil fuels; this presentation will
attempt to help it realize that one already exists.

Mobile Processing Units for Distributed Biofuels Production

Alexander Voice
Chemical Engineering
Undergraduate - Senior

The global energy economy is in a state of flux. Concerns about the environmental effects of traditional fossil fuels, in addition to economic factors, national security interests, political motivations, and venture capital are all fueling a rapidly growing alternative energy industry. Given that there is no comprehensive plan to replace the existing energy sources in the United States with sustainable ones, and given that each of myriad alternative energy sources require vastly different production and distribution infrastructures, it is worrisome that this industry is evolving at breakneck speed. Therefore, we argue that a fundamental reevaluation of the energy production and distribution infrastructure is in order, primarily in the category of liquid transportation fuels.

On this project, we will advocate a flexible system of manufacturing biofuels, based on a network of mobile units. This type of system will provide benefits in terms of adaptability and scalability, in addition to facilitating localized fuel production, which in the long run may prove more sustainable. The main objective of this research will be to design several mobile processing units (MPU), which will be the key enabling element to the development of a mobile biofuels network.
These MPUs will be evaluated in terms of their marginal cost of production and commercial viability. We will also evaluate the life cycle net energy balance, in addition to comparing materials usage and emissions with the existing methods of biofuels production.

Nanostructured materials for hydrogen production from solar energy

Leon Webster (Applied Physics) with Peter Aurora (Mechanical Engineering), Rachel Goldman (Materials Science and Engineering) and Levi Thompson (Chemical Engineering)

Photoelectrochemical (PEC) cells are used to produce hydrogen from water and solar energy. A PEC cell typically consists of photoanode where water is oxidized, a cathode where hydrogen is evolved and an electrolyte. A major obstacle to their use is the poor efficiency of the photoanode, typically a metal oxide such as TiO2. These materials have a high bandgap and cannot harvest light from a significant portion of the solar spectrum. Furthermore, by some accounts, the rate of water oxidation will need to be increased by more than an order of magnitude to keep pace with the production of electrons and holes [1]. We explore three strategies for improving the photoanode performance: producing the photocatalyst in the form of nanotubes to improve collection efficiencies, incorporating nanocrystalline gold into the nanotubes to improve activity, and incorporating high efficiency solar cells to collect more of the solar spectrum.

References
1. Basic Research Needs for Solar Energy Utilization, http://www.sc.doe.gov/bes/reports/files/SEU_rpt.pdf (2005)

Why Do States Adopt Renewable Portfolio Standards?: An Empirical Investigation

Name: Tom Lyon and Haitao Yin
Department: Erb Institute
Status: Haitao Yin: Post-doc at Erb Institute; Tom Lyon, Professor at Ross Business School and SNRE

We present the first empirical analysis of the factors that drive state governments to adopt a Renewable Portfolio Standard (RPS), and the factors that lead to the inclusion of in-state requirements given the adoption of an RPS. We find that states with poor air quality, strong democratic presence in the state legislature and organized renewable developers are more likely to adopt an RPS. Economic benefits do not seem to be an important driver for RPS adoption although they have been widely touted in the legislative process. In-state requirements are more likely in states with poor air quality, rich renewable energy resources, and low amounts of existing renewable electricity generation. In-state requirements are also positively correlated with the percentage of congressional seats occupied by Democrats and negatively correlated with the presence of a Republican governor.

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