<p> The island of Puerto Rico, a commonwealth of the United States of America, has a population of 3,725,789 according to the 2010 census, and generates 11,100 tons daily of waste. In the Island, landfilling is the dominant form of waste disposal. Most municipal solid waste landfills (MSWLF) in Puerto Rico are a principal source of land, water, and air pollution. In addition, the scarcity of appropriate land to open new landfill facilities make this type of waste disposal an unsustainable form of waste management for the Island. </p><p> This study evaluated the current situation of the MSWLFs in Puerto Rico and the geographic limitations of continuing with this type of waste disposal on the Island. As alternatives to this problem, the principal waste-to-energy (WTE) technologies, combustion and gasification, are evaluated as environmentally responsible forms for disposal of non-recycled waste. </p><p> The evaluation methodology used is based on a multi-criteria decision-making model that uses a subjective rank-order weighting method. Evaluation of WTE technologies is performed by comparing dissimilar indicators in five interest areas: technical, economic, environmental, socio-political, and risk. The methodology is composed of two-components: an expert survey and data analysis. </p><p> An evaluation of the environmental interest area was performed to assess which of the WTE technologies studied herein, combustion or gasification, is more environmentally responsible. In addition, using the relevant scores in different interest areas, they were evaluated to determine the economic benefits of these WTE technologies as viable waste management alternatives for Puerto Rico.</p><p>

abstract: The main objective of this research is to develop an approach to PV module lifetime prediction. In doing so, the aim is to move from empirical generalizations to a formal predictive science based on data-driven case studies of the crystalline silicon PV systems. The evaluation of PV systems aged 5 to 30 years old that results in systematic predictive capability that is absent today. The warranty period provided by the manufacturers typically range from 20 to 25 years for crystalline silicon modules. The end of lifetime (for example, the time-to-degrade by 20% from rated power) of PV modules is usually calculated using a simple linear extrapolation based on the annual field degradation rate (say, 0.8% drop in power output per year). It has been 26 years since systematic studies on solar PV module lifetime prediction were undertaken as part of the 11-year flat-plate solar array (FSA) project of the Jet Propulsion Laboratory (JPL) funded by DOE. Since then, PV modules have gone through significant changes in construction materials and design; making most of the field data obsolete, though the effect field stressors on the old designs/materials is valuable to be understood. Efforts have been made to adapt some of the techniques developed to the current technologies, but they are too often limited in scope and too reliant on empirical generalizations of previous results. Some systematic approaches have been proposed based on accelerated testing, but no or little experimental studies have followed. Consequently, the industry does not exactly know today how to test modules for a 20 - 30 years lifetime. This research study focuses on the behavior of crystalline silicon PV module technology in the dry and hot climatic condition of Tempe/Phoenix, Arizona. A three-phase approach was developed: (1) A quantitative failure modes, effects, and criticality analysis (FMECA) was developed for prioritizing failure modes or mechanisms in a given environment; (2) A time-series approach was used to model environmental stress variables involved and prioritize their effect on the power output drop; and (3) A procedure for developing a prediction model was proposed for the climatic specific condition based on accelerated degradation testing / Dissertation/Thesis / Doctoral Dissertation Industrial Engineering 2014

<p> The direct capture of solar heat is now commercial for electrical generation at 550 &deg;C (1000 &deg;F), which has provoked interest in solar driven approaches to commodity and fuels production at higher temperatures. However, conventional commodity and fuels facilities often operate continuously regardless of weather and nighttime conditions. Conversely, direct sunlight is immediately lost upon shading by clouds and sunset. Beyond inconvenience, this intermittency has the potential to destroy high temperature equipment through thermal fatigue and thermal shock. To overcome interruptions in solar availability we propose the inclusion of direct sunlight in commodities and fuels production as a supplement to conventional electrical heating. Within this regime conventional utilities are ideally sourced from sustainable stored or orthogonal energy sources. Control is needed to substitute solar, which can be lost within seconds during transient weather, with electrical heat. To explore control strategies for the alternation of solar and electrical heat a new facility was constructed at the University of Colorado, Boulder. Specifically, a 45 kW 18 lamp high-flux solar simulator was erected that approximates the sunlight found in actual concentrated solar plants. Calorimetry was analyzed for the measurement of extreme radiance in this testbed. Results from calorimeter design were applied to radiation measurement from the lamps, which were capable of delivering 9.076&plusmn;0.190 kW of power to a ?10 cm target with a peak flux of 12.50 MW/m² (12,500 &ldquo;suns&rdquo;). During this characterization a previously unknown observer effect was seen that differentiates radiative heat from lamps and the energy delivered by sunlight in actual concentrated solar facilities. This characterization allowed confident experimentation within the lamp testbed for control studies on a 15 kW solar-electric tube furnace for commodities and fuels production. Furnace electric heat was manipulated by four different linear control strategies for the rejection weather transients reproduced by the high-flux solar simulator lamps. These included feedback, feedforward feedback, model predictive control, and model predictive control with a weather forecast. It was found that model predictive control with a forecast best maintained furnace conditions. Prior researchers have suggested that forecasts would be useful in solar control, which was shown across simulation and experiment.</p><p>

<p> The lignocellulosic biorefinery concept provides an attractive alternative to energy, fuels and chemical production from petroleum-derived and other non-renewable resources. However, the realization of this technology is limited by the economic climate and the technical challenges of maximizing the biorefinery production yield.</p><p> This dissertation is an investigation of utilizing targeted Engineered Biomass Deconstruction (EBD), or mechanical refining, to overcome the inherent recalcitrance of the lignocellulosic biomass. This recalcitrant nature is often considered the limiting factor for the commercialization of cellulosic biorefineries &ndash; including second generation cellulosic ethanol production facilities &ndash; which increases the direct costs for the process inputs of the deconstruction steps. This includes requirements of high temperature and chemical charges during pretreatment and high enzyme dosages during enzymatic hydrolysis unit operations.</p><p> First, the effects of mechanical refining on the digestibility lignocellulosic biomass is explored at the laboratory scale. Comparisons of two common laboratory scale refiners, PFI mill and valley beater, confirm improvements in enzymatic hydrolysis with increased mechanical refining severity for all biomass pretreatments; including, kraft (NaOH, Na₂S), green liquor (Na2CO3, Na₂S), and sodium carbonate (Na₂CO₃) pretreatments. A maximum in refining improvement is observed, highlighting the ability of EBD to generate the most value for the lignocellulosic biorefinery at moderate pretreatment severities and hydrolysis conditions.</p><p> Second, Engineered Biomass Deconstruction is compared at lab, pilot and industrial scales. Using the same industrially sourced sodium carbonate pretreated biomass, similar enzymatic hydrolysis kinetics and their respective improvements with mechanical refining were observed for all mechanical refining scales, with the most similar kinetics being between commercial scale and pilot scale refining. Successful simulation of industrial scale refining allows the use of pilot scale refining for optimization of Engineered Biomass Deconstruction at the pilot scale.</p><p> Third, utilizing the same commercial sodium carbonate biomass, the pilot scale mechanical refining conditions were optimized. Close to theoretical maximums in enzymatic hydrolysis conversion were achieved using pilot scale EBD compared to the total carbohydrate conversion of 39% for unrefined hardwood sodium carbonate biomass. Mechanical refining conditions of temperature, plate gap width, and consistency were controlled to optimize the Engineered Biomass Deconstruction process. Optimum conditions for the pilot refiner were found to be to 0.13 mm plate gap width, and 20% biomass consistency, at ambient temperature, which produced a total carbohydrate conversion of 90%.</p><p> Following the optimization of EBD conditions, efforts were made to fundamentally understand the reason for the improvement in biomass digestibility with mechanical refining. The motivation of this understanding would facilitate the development and application of engineered biomass deconstruction technologies within the lignocellulosic biorefinery concept. Non-hydrolytic fluorescent recombinant protein probes with carbohydrate binding modules of similar size to commercially available cellulases were used a model for the enzyme adsorption process for the initial stages of enzymatic hydrolysis. Model substrates were used to confirm the selective binding of the fluorescent protein probes to cellulose. Confocal laser scanning microscopy allowed for visualization and quantitative imaging of the fluorescent markers within the lignocellulosic biomass matrix. Relationships between the maximum fluorescent intensities and the different lignocellulosic biomass were observed. The distribution of adsorbed enzymes in the cell wall were altered by the mechanical refining actions of external fibrillation, internal delamination, and cutting. This indicates that improved biomass accessibility to enzymes throughout the lignocellulosic biomass matrix is related to enhanced enzymatic hydrolysis.</p><p> This work highlights the effectiveness of Engineered Biomass Deconstruction and its benefits when applied within the lignocellulosic biorefinery concept. Future research should be targeted for further optimization of mechanical refiner operating conditions including specific development of new refiner plate designs for application in a lignocellulosic biorefinery.</p><p>

<p> Increased share of Renewable Energy Sources (RES) in the generation mix requires higher flexibility in power system resources. The intermittent nature of the RES calls for higher reserves in power systems to smooth out the unpredictable power fluctuations. Grid-tied energy storage systems are practical solutions to facilitate the massive integration of RES. The deployment of Battery Energy Storage Systems (BESS) on the power grids is experiencing a significant growth in recent years. Thanks to intensive research and development in battery chemistry and power conversion systems, BESS costs are reducing. However, much more advancements in battery manufacturing as well as additional incentives from the market side are still needed to make BESS a more cost-effective solution. Planning and operation of the BESS significantly influence its profitability. It is quite important to find optimal sizes of batteries and inverters. Sizing of the BESS for two different applications is addressed in this work. In the first application, the BESS is co-located with Pumped Storage Hydro (PSH) to meet the Day-Ahead (DA) schedule of wind generation. In the second application, a method for BESS sizing in the presence of PV-induced ramp rate limits is proposed. In this thesis, two methods based on Receding Horizon Control (RHC) for the optimal operation of the BESS are introduced. A co-located BESS and wind farm is considered in both methods. In one method, electricity market participation is not considered, and the goal is solely meeting the DA schedule utilizing the BESS. A novel predictive control method is proposed in this part and the efficiency of the method is evaluated through long-run simulations using actual historical wind power. </p><p> In the second scenario, market participation of the BESS is taken into account. The deviation from the DA schedule can be compensated through the BESS, or by purchasing power from the real-time electricity market. The optimization problem based on physical and operational constraints is developed. The problem is solved through an RHC scheme while using updated wind power and electricity price forecasts. In this thesis, a Ridge-regression forecast model for electricity price and an ARIMA forecast model for wind power are developed. Simulation results using actual historical data for wind power and electricity price demonstrate that the proposed algorithm increases the average daily profit. In order to evaluate the impact of the BESS lifetime and price on average daily profit, different scenarios are defined and simulated. Although they increase the complexity of the problem, much more realistic result might be obtained when all details and constraints are considered. </p><p>

<p> Due to the increased demand for reliable and resilient controls in advanced power generation systems, new control methods are required to tackle traditional problems within these systems. This work discusses a control method and an estimation method for advanced control systems. The control method is sliding mode controls of a higher order, which is used to control the nonlinear wind energy conversion system while lessening the chattering phenomena that causes mechanical wear when using first order sliding mode controls. The super-twisting algorithm is used to create a second order sliding mode control. The estimation method is the derivation of a Resilient Extended Kalman filter, which can estimate and control the system through sensor undergoing failures with a binomial distribution rate and known mean value. Simulations on these dynamical systems are presented to show the effectiveness of the proposed control methods; the former is applied to a wind energy conversion system and the latter is applied to an single machine infinite bus. Both methods are also compared with more traditional methods in their respective applications, those being first order sliding mode controls and the Extended Kalman filter. </p><p>

To achieve the goal of sustainable development, the building energy system was evaluated from both the first and second law of thermodynamics point of view. The relationship between exergy destruction and sustainable development were discussed at first, followed by the description of the resource abundance model, the life cycle analysis model and the economic investment effectiveness model. By combining the forgoing models, a new sustainable index was proposed. Several green building case studies in U.S. and China were presented. The influences of building function, geographic location, climate pattern, the regional energy structure, and the technology improvement potential of renewable energy in the future were discussed. The building’s envelope, HVAC system, on-site renewable energy system life cycle analysis from energy, exergy, environmental and economic perspective were compared. It was found that climate pattern had a dramatic influence on the life cycle investment effectiveness of the building envelope. The building HVAC system energy performance was much better than its exergy performance. To further increase the exergy efficiency, renewable energy rather than fossil fuel should be used as the primary energy. A building life cycle cost and exergy consumption regression model was set up. The optimal building insulation level could be affected by either cost minimization or exergy consumption minimization approach. The exergy approach would cause better insulation than cost approach. The influence of energy price on the system selection strategy was discussed. Two photovoltaics (PV) systems – stand alone and grid tied system were compared by the life cycle assessment method. The superiority of the latter one was quite obvious. The analysis also showed that during its life span PV technology was less attractive economically because the electricity price in U.S. and China did not fully reflect the environmental burden associated with it. However if future energy price surges and PV system cost reductions were considered, the technology could be very promising for sustainable buildings in the future.

Sustainable energy is a core concern worldwide for the foreseeable future. Technologically, its key trends are distributed and renewable energy resources and smart grid capabilities. At the same time, a global need for sustainable energy is meeting increasingly diverse energy policy and economics. To plan with such complex contexts and systems, a novel distributed energy software tool and its initial implementation is presented: the Energy Systems Evaluator Online (ESEO). Its contributions include: (1) A flexible model framework that can simulate current and expected distributed energy systems; (2) An architecture specifying the modular design needed for distributed energy planning software in general; (3) A working implementation as the first general energy planning tool deployed via the Internet with collaborative capabilities.

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