This dissertation focuses on the introduction and development of an integrated model-based design and optimization platform to solve the optimal design and optimal control, or hardware and software co-design, problem for hybrid electric propulsion systems. Specifically, the hybrid and plug-in hybrid electric powertrain systems with diesel and natural gas (NG) fueled compression ignition (CI) engines and large Li-ion battery energy storage system (ESS) for propelling a hybrid electric marine vessel are investigated. The combined design and control optimization of the hybrid propulsion system is formulated as a bi-level, nested optimization problem. The lower-level optimization applies dynamic programming (DP) to ensure optimal energy management for each feasible powertrain system design, and the upper-level global optimization aims at identifying the optimal sizes of key powertrain components for the powertrain system with optimized control. Recently, Li-ion batteries became a promising ESS technology for electrified transportation applications. However, these costly Li-ion battery ESSs contribute to a large portion of the powertrain electrification and hybridization costs and suffer a much shorter lifetime compared to other key powertrain components. Different battery performance modelling methods are reviewed to identify the appropriate degradation prediction approach. Using this approach and a large set of experimental data, the performance degradation and life prediction model of LiFePO4 type battery has been developed and validated. This model serves as the foundation for determining the optimal size of battery ESS and for optimal energy management in powertrain system control to achieve balanced reduction of fuel consumption and the extension of battery lifetime. In modelling and design of different hybrid electric marine propulsion systems, the life cycle cost (LCC) model of the cleaner, hybrid propulsion systems is introduced, considering the investment, replacement and operational costs of their major contributors. The costs of liquefied NG (LNG), diesel and electricity in the LCC model are collected from various sources, with a focus on present industrial price in British Columbia, Canada. The greenhouse gas (GHG) and criteria air pollutant (CAP) emissions from traditional diesel and cleaner NG-fueled engines with conventional and optimized hybrid electric powertrains are also evaluated. To solve the computational expensive nested optimization problem, a surrogate model-based (or metamodel-based) global optimization method is used. This advanced global optimization search algorithm uses the optimized Latin hypercube sampling (OLHS) to form the Kriging model and uses expected improvement (EI) online sampling criterion to refine the model to guide the search of global optimum through a much-reduced number of sample data points from the computationally intensive objective function. Solutions from the combined hybrid propulsion system design and control optimization are presented and discussed. This research has further improved the methodology of model-based design and optimization of hybrid electric marine propulsion systems to solve complicated co-design problems through more efficient approaches, and demonstrated the feasibility and benefits of the new methods through their applications to tugboat propulsion system design and control developments. The resulting hybrid propulsion system with NG engine and Li-ion battery ESS presents a more economical and environmentally friendly propulsion system design of the tugboat. This research has further improved the methodology of model-based design and optimization of hybrid electric marine propulsion systems to solve complicated co-design problems through more efficient approaches, and demonstrated the feasibility and benefits of the new methods through their applications to tugboat propulsion system design and control developments. Other main contributions include incorporating the battery performance degradation model to the powertrain size optimization and optimal energy management; performing a systematic design and optimization considering LCC of diesel and NG engines in the hybrid electric powertrains; and developing an effective method for the computational intensive powertrain co-design problem. / Graduate

<p>The goal of this project was to evaluate three main proposals, by the Property Management Department (PMD) of St. Louis County, which the department hoped would reduce energy consumption at their Duluth Jail facility. This particular facility was opened in 1995 and houses approximately 170 inmates. Despite its relatively new construction, the building produces some of the highest utility bills of all of the County’s buildings.</p><p>The proposals put forth by the PMD were the following: to reduce natural gas consumption by using solar water heating for the domestic hot water; to reduce heating and cooling costs by enclosing a light well which is currently open to the sky with a transparent, insulated roof; and to utilize a white roof to reduce cooling demand during the summertime.</p><p>The solar water heating proposal was evaluated by determining the energy the solar system could provide annually and comparing these energy- and monetary savings to the cost of the system. Two solar options were evaluated; one system with 20 collectors and another with 50. Both systems also included condensing boilers to provide supplementary heating during times of low solar output. The annual savings of the 20- and 50 collector systems were 128 and 173 MWh, respectively. This led to a payback period of approximately 17 years for the 20 collector system and 16 years for the 50 collector system.</p><p>Enclosing the open light well, which is an open area inside the perimeter of the building which is designed to give rooms on the inside of the building natural daylight, was evaluated by performing an energy flow analysis comparing the existing condition with one in which a roof topped the well. This involved calculating the U-values of the walls before the skyroof and then using heating and cooling degree days to determine the heat flows through the walls. The enclosed light well was evaluated by performing an energy balance on the well to determine the temperature of the enclosed well. This temperature could then be used to calculate the heat flow through the enclosed light well’s walls. The difference in these heat flows between the two options was then converted to an economic cost to evaluate a payback period. Two grades of Kalwall-brand insulation were evaluated; the “Nanogel” grade and a mid-range grade. The Nanogel-enclosed light well reduced the heating demand by 16 MWh but increased the cooling load by 9 MWh, while the mid-grade enclosed well decreased the heating load by 11 MWh but increased the cooling load by 4 MWh. These added up to net annual savings of $650 for the Nanogel roof and $470 for the mid-grade skyroof. However, the investment costs were so high that the payback periods were between 450 and 550 years.</p><p>Two white roofing options were considered and corresponded to a newly installed roof and one that had weathered for 3 years, thereby reducing its reflectivity. These options were evaluated by determining the mean monthly roof temperatures throughout a typical year and calculating the heat flows through the roofs based on these temperatures. The temperatures were determined by performing a heat balance on the roofs’ surfaces and considering the solar radiation incident on the roofs. The heat flows with the existing black colored roof and the proposed white roofs were thencompared and converted into heating and cooling costs. The white roofs led to summertime air-conditioning savings but created more wintertime heat losses and therefore caused net annual energy cost increases of $560 and $240 for the new and weathered roofs, respectively.</p><p>The recommendations therefore were to implement the solar thermal system but not the other two proposals. Other areas which might benefit from additional investigations include lighting efficiency improvements, water use reductions, and replacement of the existing boilers with either more efficient natural gas units or wood-pellet/biomass boilers.</p>

Thesis (LL.M. (Import and Export Law))--North-West University, Potchefstroom Campus, 2008.

The theory of the abyssal abiotic petroleum origin considers oil and natural gas to begenerated in the Earth’s upper mantle. Hydrocarbons migrate further through the deep faults into the Earth’s crust, where they can form oil and gas deposits in any kind of rock in any kind of structural position. Until recently one of the main obstacles for further development of this theory has been the lack of the data covering processes of generation and transformations of hydrocarbons. Experimental data, presented in this thesis, confirms the possibility of hydrocarbons formation from mantle inorganic compounds (water, Fe, CaCO3 or graphite) at temperature and pressure of the upper mantle (1500 K and 5 GPa). Experiments were carried out in CONAC high pressure device and multianvil apparatus BARS. Compositions of received gas mixtures were similar to natural gas. Quantity of hydrocarbons depended on the cooling regime of reaction mixture under pressure. Slow cooling favored higher quantity. We found that donor of carbon (CaCO3 or graphite) determines formation of “dry” (methane-rich) gas or “wet” (light hydrocarbons-rich) gas. Experiments in laser-heated diamond anvil cells showed that methane and ethane partially react under upper mantle thermobaric conditions (2-5 GPa, 1000-1500 K) to form mixture of hydrocarbons: methane, ethane, propane and n-butane – main compounds of natural gas. Similarity of final product mixture obtained from methane and ethane means thermodynamic stability of hydrocarbons in the thermobaric conditions of the upper mantle and equilibrium character of the observed processes. / QC 20101203

In this thesis, we develop partial differential equation (PDE) based numerical methods to solve certain optimal stochastic control problems in finance. The value of a stochastic control problem is normally identical to the viscosity solution of a Hamilton-Jacobi-Bellman (HJB) equation or an HJB variational inequality. The HJB equation corresponds to the case when the controls are bounded while the HJB variational inequality corresponds to the unbounded control case. As a result, the solution to the stochastic control problem can be computed by solving the corresponding HJB equation/variational inequality as long as the convergence to the viscosity solution is guaranteed. We develop a unified numerical scheme based on a semi-Lagrangian timestepping for solving both the bounded and unbounded stochastic control problems as well as the discrete cases where the controls are allowed only at discrete times. Our scheme has the following useful properties: it is unconditionally stable; it can be shown rigorously to converge to the viscosity solution; it can easily handle various stochastic models such as jump diffusion and regime-switching models; it avoids Policy type iterations at each mesh node at each timestep which is required by the standard implicit finite difference methods. In this thesis, we demonstrate the properties of our scheme by valuing natural gas storage facilities---a bounded stochastic control problem, and pricing variable annuities with guaranteed minimum withdrawal benefits (GMWBs)---an unbounded stochastic control problem. In particular, we use an impulse control formulation for the unbounded stochastic control problem and show that the impulse control formulation is more general than the singular control formulation previously used to price GMWB contracts.

The goal of this project was to evaluate three main proposals, by the Property Management Department (PMD) of St. Louis County, which the department hoped would reduce energy consumption at their Duluth Jail facility. This particular facility was opened in 1995 and houses approximately 170 inmates. Despite its relatively new construction, the building produces some of the highest utility bills of all of the County’s buildings. The proposals put forth by the PMD were the following: to reduce natural gas consumption by using solar water heating for the domestic hot water; to reduce heating and cooling costs by enclosing a light well which is currently open to the sky with a transparent, insulated roof; and to utilize a white roof to reduce cooling demand during the summertime. The solar water heating proposal was evaluated by determining the energy the solar system could provide annually and comparing these energy- and monetary savings to the cost of the system. Two solar options were evaluated; one system with 20 collectors and another with 50. Both systems also included condensing boilers to provide supplementary heating during times of low solar output. The annual savings of the 20- and 50 collector systems were 128 and 173 MWh, respectively. This led to a payback period of approximately 17 years for the 20 collector system and 16 years for the 50 collector system. Enclosing the open light well, which is an open area inside the perimeter of the building which is designed to give rooms on the inside of the building natural daylight, was evaluated by performing an energy flow analysis comparing the existing condition with one in which a roof topped the well. This involved calculating the U-values of the walls before the skyroof and then using heating and cooling degree days to determine the heat flows through the walls. The enclosed light well was evaluated by performing an energy balance on the well to determine the temperature of the enclosed well. This temperature could then be used to calculate the heat flow through the enclosed light well’s walls. The difference in these heat flows between the two options was then converted to an economic cost to evaluate a payback period. Two grades of Kalwall-brand insulation were evaluated; the “Nanogel” grade and a mid-range grade. The Nanogel-enclosed light well reduced the heating demand by 16 MWh but increased the cooling load by 9 MWh, while the mid-grade enclosed well decreased the heating load by 11 MWh but increased the cooling load by 4 MWh. These added up to net annual savings of $650 for the Nanogel roof and $470 for the mid-grade skyroof. However, the investment costs were so high that the payback periods were between 450 and 550 years. Two white roofing options were considered and corresponded to a newly installed roof and one that had weathered for 3 years, thereby reducing its reflectivity. These options were evaluated by determining the mean monthly roof temperatures throughout a typical year and calculating the heat flows through the roofs based on these temperatures. The temperatures were determined by performing a heat balance on the roofs’ surfaces and considering the solar radiation incident on the roofs. The heat flows with the existing black colored roof and the proposed white roofs were thencompared and converted into heating and cooling costs. The white roofs led to summertime air-conditioning savings but created more wintertime heat losses and therefore caused net annual energy cost increases of $560 and $240 for the new and weathered roofs, respectively. The recommendations therefore were to implement the solar thermal system but not the other two proposals. Other areas which might benefit from additional investigations include lighting efficiency improvements, water use reductions, and replacement of the existing boilers with either more efficient natural gas units or wood-pellet/biomass boilers.

In this thesis, we develop partial differential equation (PDE) based numerical methods to solve certain optimal stochastic control problems in finance. The value of a stochastic control problem is normally identical to the viscosity solution of a Hamilton-Jacobi-Bellman (HJB) equation or an HJB variational inequality. The HJB equation corresponds to the case when the controls are bounded while the HJB variational inequality corresponds to the unbounded control case. As a result, the solution to the stochastic control problem can be computed by solving the corresponding HJB equation/variational inequality as long as the convergence to the viscosity solution is guaranteed. We develop a unified numerical scheme based on a semi-Lagrangian timestepping for solving both the bounded and unbounded stochastic control problems as well as the discrete cases where the controls are allowed only at discrete times. Our scheme has the following useful properties: it is unconditionally stable; it can be shown rigorously to converge to the viscosity solution; it can easily handle various stochastic models such as jump diffusion and regime-switching models; it avoids Policy type iterations at each mesh node at each timestep which is required by the standard implicit finite difference methods. In this thesis, we demonstrate the properties of our scheme by valuing natural gas storage facilities---a bounded stochastic control problem, and pricing variable annuities with guaranteed minimum withdrawal benefits (GMWBs)---an unbounded stochastic control problem. In particular, we use an impulse control formulation for the unbounded stochastic control problem and show that the impulse control formulation is more general than the singular control formulation previously used to price GMWB contracts.

Coal Seam Gas (CSG) is a form of natural gas (mainly methane) sorbed in underground coal deposits. Mining this gas involves drilling a well directly into an underground coal seam, and pumping out the water (CSG water) flowing through it. Presently, CSG is under exploration in New Zealand (NZ); however, there is concern about CSG water disposal in NZ mainly because of the controversy that this activity has generated in some basins in the United States (US). The first part of this thesis studies CSG water from a well in Maramarua (NZ) and compares it to water from US basins. The NZ CSG water from this well had high pH (7.8), alkalinity in the order of 360 mg/l as CaCO₃, high sodium (334 mg/l), bicarbonate (435 mg/l), and chloride (146 mg/l). These ions also occur in US CSG waters, and their concentrations follow the same trend - high sodium, bicarbonate, and chloride with low calcium, magnesium, and sulphate concentrations. Prior to this work, little detailed analyses of CSG water quality variability from a well had been carried out. A Factor Analysis of 33 Maramarua samples was conducted and revealed that about one third of the variations were due to sample degassing, which induced calcium carbonate precipitation - this was supported by experimental work (sample sparging) and geochemical modelling (MINTEQA2). This finding is important for CSG water management because, as calcium concentrations decrease, higher SAR values are generated, and this can cause problems if CSG waters are disposed on land. In the second part, this thesis assesses the potential environmental effects of disposing CSG waters in NZ by formulating management options and a simple wastewater treatment system. This was carried out by studying the ecological response (soils, plant, and aquatic life) resulting from CSG water disposal operations in the US, and by applying relevant salinity and sodicity guidelines to the interaction between soils and CSG waters from Maramarua. This work showed that similar problems are likely to occur in NZ if CSG water disposal takes place without proper controls. Such a study has never been carried out in a region before actual CSG development has taken place, so this work shows how to quantify the effects arising from CSG water disposal prior to full scale production. This can be particularly useful for CSG stakeholders wanting to develop this resource in other regions around the world. A simple treatment system using Ngakuru zeolites has proven effective in reducing the SAR of Maramarua CSG water. Laboratory results indicate that these zeolites work by exchanging sodium cations in the water by other cations contained within the zeolite structure but with slow ion exchange kinetics. The calculated sodium absorption capacity for these natural zeolites ranged from 11.3 meq/100g to 16.7 meq/100g (flow-through conditions without previous regeneration). In addition, these experiments showed that the ion exchange process is accompanied by some dissolution (sulphate, boron, TOC, sodium, calcium, magnesium, potassium and reactive silica), but mainly at the beginning of the treatment process. Nevertheless, using this system, 180 grams of zeolite material were used to treat an initial 1.83 litres of Maramarua CSG water thus reducing potential soil infiltration problems to nil. As more CSG water was treated, the zeolites kept reducing SAR values but at a lesser rate until 4.53 litres of CSG water had been treated. A step-by-step methodology to assess treatment design options for these materials has been developed and will aid future researchers and engineers. This thesis presents the first comprehensive study of CSG water management in NZ. It also presents an ion exchange treatment system using natural zeolites already available in NZ. In conclusion, the research finds that, whether through adequate management or active treatment, CSG waters can be safely disposed without creating major environmental problems, and can even be used in beneficial applications.

Thesis (LL.M. (Import and Export Law))--North-West University, Potchefstroom Campus, 2008.

Thesis (LL.M. (Import and Export Law))--North-West University, Potchefstroom Campus, 2008.