bluuebunny/crossref_metadata_2025 huggingface dataset:
Energy and Environmental Assessment of Plug-In Hybrid Vehicles in the New York Metropolitan Area Using MATPOWER Power System Simulation Package
Authors: Acquaviva Jonathan , Foster Earl , Ferdon Charles , Zhang K. Max
Published: October 2010

The effects of plug-in hybrid vehicles in New York City could be substantial to the city’s efforts to achieve future climate change goals and environmental initiatives. This study focuses on these effects as they correlate to the energy supply system, transportation network, and air quality control. To accomplish this analysis a variety of techniques were used to model the transportation and electric networks around New York City. The transportation system is modeled through close manipulation of U.S Census Data collected in 2000 and 2003 in which citizens were asked questions pertaining to their daily journeys to work. The power grid for the Northeast Power Coordinating Council (NPCC) is modeled using a MATLAB program entitled MATPOWER developed by professors and students at Cornell University. By incorporating real-time load datum, this program has the capability of rendering accurate depictions of changes in power plant loads, emissions, and costs. In addition, the program will distinguish the type of energy used on the margin and locate the geographic region of that energy source. With this capability, the focus of this study surrounded three main objectives: to estimate market growth of PHEVs in the New York metropolitan area, investigate how fuel used to generate power changes with increase in demand, and to analyze the effects on emissions from cars and power plants. Initial analysis indicates that the introduction of plug-in hybrid electric vehicles into the New York City commuter fleet will have a net positive effect on reducing both total emissions and localized emissions around the city’s transportation infrastructure. At an ambitious rate of 20% PHEV penetration, New York could save nearly 625,000 gallons of gasoline per day. This is equivalent to 33,000 barrels of oil. At the current gasoline prices in New York State of $2.087 per gallon, this is a daily savings of $1.3 million dollars per day. In addition, at this penetration the PHEV’s would displace over 29,000 metric tonnes of net carbon dioxide per day.
Thermal Conversion of Mixed Wastes From Biodiesel Manufacturing for Production of Fuel Gas
Authors: Atong Duangduen , Sricharoenchaikul Viboon
Published: October 2010

Thermochemical conversion process has become a viable technology for managing excess waste from various industries while producing value added fuel products. In the work reported here, distribution of products (solid, liquid, and gas) by thermal conversion of wastes from biodiesel production process which are extracted physic nut and palm shell mixed with glycerol waste was carried out using a medium scale tubular reactor with feeding rate of 5 g/min. Several important operating parameters were studied including the proportion of each waste (100:0 – 70:30), reaction temperature (700 – 900°C) and air to fuel ratio (AF) 0.0 – 0.6. It was found that when the temperature increased, the quantity of solid and liquid product decreased while gas product increased. For conversion to CO2, CO, CxHy and H2, when the temperature increased, CO2 decreased while yields of CO, CH4 and H2 increased. Greater conversion to CO2, CO, H2 with AF increased from 0.0 to 0.3. Higher AF from 0.3 to 0.6 resulted in lesser CO and H2 while conversion to CO2 increased. On the other hand, CxHy decreased when AF changed from 0.0 to 0.6. The maximum heating values of gas product in this study are 3.48 MJ/m3 and 2.27 MJ/m3 for glycerol waste mixed with physic nut waste and palm shell waste, respectively (both at 30% glycerol wastes and reaction temperature of 900°C). The maximum of mole ratio of H2 to CO obtained is 0.59 for physic nut and 0.37 for palm shell mixed wastes. Relatively high CxHy, low product gas heating value and H2 to CO ratio indicated the need for further product upgrading before using as raw material for other advanced fuel production processes such as Fisher-Tropsch, DME, or methanol syntheses beside direct heat and power utilization.
What’s Left Over: Process Loading in High Performance Buildings
Authors: Naqvi Afaan , Roberts Cole , Woods James , Dimmel Michael , Tregaskes Richard
Published: October 2010

As an increasing number of buildings aspire to significant energy reduction and higher Leadership in Energy and Environmental Design (LEED®) certifications, it is clear that non-regulated process loads are the single greatest remaining opportunity in high performance design. Historically outside the purview of state and national energy design standards, the performance of transformers, elevators, escalators, process systems, and consumer information technology underscore a significant challenge and rising opportunity. This paper examines the impact of non-regulated loads on high performance buildings, ranging from first cost to energy performance and occupant behavior.
Parametric Vehicle Dynamics and Emissions Analysis of a Crossover SUV
Authors: White Darris , Barott William , McKisson J. E. , Freeman Kyle , Sabatini Vincent , Trussel Mark
Published: October 2010

A team of students and faculty from Embry Riddle are participating in the DOE and GM sponsored EcoCAR Challenge. As part of this three year program, the Embry Riddle EcoEagles team, will design and build a power-split extended-range electric vehicle. This paper chronicles the first year of development, which includes a parametric study of each vehicle component and configuration, hardware-in-the-loop simulations and well-to-wheel emissions analysis and compliments works by other team members [1,2]. Key vehicle parameters that were evaluated included; fuel stock, driveline configuration, engine size, motor size, energy storage system size and control strategy. The team used a range of design tools to evaluate available components within space, time and financial constraints. Per the sponsor’s guidelines, the base vehicle was a Saturn Vue and the crush zones of the vehicle could not be modified. Using Siemens NX, a packaging analysis was conducted to determine which driveline configurations were viable options for this vehicle. Once the viable design space was established, each configuration was modeled using Argonne National Laboratory’s Powertrain System Analysis Toolkit and Matlab to determine predicted fuel economies. The Greenhouse Gases, Regulated Emissions, and Energy Use in Transportation (GREET) model was used to predict emissions for each configuration. Based on this analysis, an electric four-wheel-drive configuration was selected. On the front wheels, the vehicle is propelled in a compound hybrid configuration using a 1.3 liter diesel engine operating on B20 biodiesel and a 50kW electric motor. The rear wheels are propelled by a 55kW electric motor that is connected through the road to the engine. The combined electric power of 105kW and 320Volt, 11kW Battery Pack allows an all-electric operating range of approximately 20 miles. This configuration substantially reduces petroleum energy usage and improves fuel economy when compared to the stock vehicle. The predicted improvements are a 50% reduction in petroleum usage and a similar improvement in fuel economy.
Energy Storage for a Sustainable Development
Authors: Fradette Michael , Zhang Ke Max
Published: October 2010

The CU Green, Palamanui Project Team worked to create an integrated document for the developers of Palamanui, a 725 acre community on the Big Island of Hawaii consisting of residential sections, a business park, town center, university, and hotel, regarding how the development can be more sustainable and environmental aware. The document addresses engineering issues, alongside architectural and environmental issues, including but not limited to solar generation, energy storage, plug in hybrid vehicles (PHEV), microgrids, smart architectural and landscape design, load management, waste water treatment, and the business aspects of each technology. The team worked together to combine engineering, environmental, social, architectural, and business aspects into a single overarching document recommending how the development can move towards sustainability. The following paper addresses the energy storage aspects for the Palamanui development, analyzing different technologies, operating scenarios, and financial results. Incorporating an energy-storage system in the Palamanui development is beneficial for all involved parties. Residents benefit from a more reliable grid, with increased distributed generation. The community and environment will benefit from increased solar generation and a reduction in required peak generation from HELCO, corresponding to a decrease in greenhouse gas emissions and pollutants. Lastly, the developers benefit because the property can be marketed as a sustainable development with a more reliable grid, thus increasing market value. The storage system can exist as a centralized plant, being a large battery bank or compressed-air-energy storage system (CAES), or the system can be distributed throughout the development as plug-in hybrid vehicles (PHEV) or individual home batteries. Of the many energy storage methods available, three are seriously considered for the Palamanui development: sodium sulfur battery banks, lead-acid battery banks, and small-scale CAES in fabricated vessels. Battery banks and CAES operate under the same concept, drawing energy from the grid during times of low demand (10 p.m. to 6 a.m.) or from excess solar generation. During times of peak demand, stored energy is discharged to the grid to meet daily loads. Of all the systems analyzed, the final recommendation is block storage distributed throughout the development using sodium-sulfur (NaS) batteries. Sodium-sulfur batteries are the most appealing because of the small footprint, long lifetime, and lower lifetime cost. CAES systems with natural-gas prove to be too expensive with Hawaii’s high natural-gas prices. CAES without natural-gas has potential, but with little to no commercial testing having been done on this systems, further investigation is required and strongly recommended.
A Dual-Source Organic Rankine Cycle (DORC) for Improved Efficiency in Conversion of Dual Low- and Mid-Grade Heat Sources
Authors: Doty F. David , Shevgoor Siddarth
Published: October 2010

Detailed thermodynamic and systems analyses show that a novel hybrid cycle, in which a low-grade (and low-cost) heat source (340 K to 460 K) provides the boiling enthalpy and some of the preheating while a mid-grade source (500 K to 800 K) provides the enthalpy for the final superheating, can achieve dramatic efficiency and cost advantages. Four of the more significant differences from prior bi-level cycles are that (1) only a single expander turbine (the most expensive component) is required, (2) condenser pressures are much higher, (3) the turbine inlet temperature (even with a low-grade geothermal source providing much of the energy) may be over 750 K, and (4) turbine size is reduced. The latent heat of vaporization of the working fluid and the differences in specific heats between the liquid and vapor phases make full optimization (approaching second-law limits) impossible with a single heat source. When two heat sources are utilized, this problem may be effectively solved — by essentially eliminating the pinch point. The final superheater temperature must also be increased, and novel methods have been investigated for increasing the allowable temperature limit of the working fluid by 200 to 350 K. The usable temperature limit of light alkanes may be dramatically increased by (1) accommodating hydrogen evolution from significant dehydrogenation; (2) periodically or continually removing undesired reaction products from the fluid; (3) minimizing the fraction of time the fluid spends at high temperatures. Detailed simulation results are presented for the case where (1) the low-grade heat source (such as geothermal) is 400 K and (2) the mid-grade Concentrated Solar Power (CSP) heat source is assumed to be 720 K. For an assumed condensing temperature of 305 K and working fluid flow rate of 100 kg/s, preliminary simulations give the following: (1) low-grade heat input is 25 MWT; (2) mid-grade heat input is 24 MWT; (3) the electrical output power is 13.5 MWE; and (4) the condenser rejection is only 35 MWT. For comparison, with a typical bi-level ORC generating similar power from this geothermal source alone, the low-grade heat requirement would be ∼100 MWT.
Dynamic Modeling of a Wind Hydrogen System
Authors: Hwang J. J. , Chang W. R.
Published: October 2010

Dynamic behaviors of an integrated wind hydrogen system have been modeled mathematically. It is based on a combination of fundamental theories of mechanics, thermodynamics, mass transfer, fluid dynamics, and empirical electrochemical relationships. The model considers wind hydrogen system to be composed of three subsystems, i.e., a wind generator, an electrolyzer, and a hydrogen tank. An additional pressure switch model is presented to visualize the hydrogen storage dynamics under a constant outflow condition. Validation of the wind hydrogen model system is evaluated according to the measured data from the manufacturer’s data. Then, using wind power as the primary energy input and hydrogen as energy storage simulated the power system. Finally, flow and electrical characteristics and efficiencies of each subsystem as well as the entire system are presented and discussed. The present model will integrate with fuel cell systems to realize the stand-alone renewable power generator in the future work.
Parabolic Sun Tracking Solar Distillation System
Authors: Badran Omar O. , Arafat Ismail M. A. , Abdallah Salah A.
Published: October 2010

The main aim of the present study is to draw attention to the possibilities and to the measures of appropriate utilization of renewable energy to achieve what is called “water self-sufficient” for arid regions in Jordan. Also to put efforts of increasing the use of renewable energy sources to lower cost of potable water pumping and gives more economical benefits. Another aim of the current research is to utilize the new control algorithm and the developed computer capabilities in the field of sun tracking in order to improve the efficiency of solar distillers. The new tracking method is utilized for water distillation taking advantage of high possible concentration of parabolic trough collector to reach high levels of daily yield per square meter. The present research utilizes the techniques of image processing to catch the core of the sun as the target, also used artificial intelligence techniques to predict the sun position in abnormal conditions (i.e. cloudy, dusty, rainy). The results of sun tracking using image processing found to be accurate and reliable according to the self monitoring of the focus point validated by the solar radiation results. Water distillation yield shows high percentage output of distillate of about 65% of water supplied to distiller. Mechanical design was tested for high ability to withstand the extra loading. It was found that the output yield reached to noticeable levels, because of the use of the parabolic collector that promoted the solar still efficiency.
Assessing the Potential for Algal Biofuels Production in Texas
Authors: Wogan David M. , da Silva Alexandre K. , Webber Michael
Published: October 2010

This paper describes a unique analytical model created to assess the maximum potential for algae production in Texas. The model, which merges engineering, biology and geosciences into a singular analysis, aims to identify suitable growth locations and estimate the quantity of algae-based oils that can be potentially produced in Texas. The model incorporates geographically- and temporally-resolved data on sunlight, anthropogenic CO2 emissions, and saline or brackish water availability. These data are then overlaid with first-order biological approximations for algae growth calculations in order to create maps of algae growth potential. Solar insolation data were obtained from measurement locations throughout the state for varying time scales spanning many years from the Texas Solar Radiation Database (TSRDB). CO2 emissions were compiled from area and point sources (such as natural gas and coal-fired power plants) from the Energy Information Administration and Environmental Protection Agency. Water data for wastewater treatment plants and saline aquifers were obtained from the Texas Commission on Environmental Quality and the Texas Water Development Board. A home-built MATLAB code uses these data, along with engineering approximations and the ability to manipulate different assumptions to calculate algae growth by location and time period. For each location, the model calculates potential oil yield, biomass produced, growth rates, water and CO2 consumed and land used. Standard pond and tubular photobioreactor dimensions have been used to model real world production facilities. Realistic limits for growth rates, photosynthetic efficiencies, photosynthetic flux tolerances and oil content are also incorporated. These parameters can be varied to approximate different algae strains and growth conditions. The model assumes reactors to have ideal mixing, optimal pH and temperature controls in place. This preliminary resource assessment estimates that Texas receives an average of 375 W/m2 annually, produces 409 million tons per year of CO2 from the industrial and electrical power sectors and has approximately 1.4 trillion gallons per year of available water on a sustainable basis. The computational model estimates that between 44 and 167 million tons of algal biomass and 3.1 to 12 billion gallons of lipids can be produced annually in Texas based on the combination and availability of these resources.
Water Heating and Dehumidification With Heat Pump Utilizing Solar, Ambient and Waste Heat
Authors: Hawlader M. N. A. , Amin Zakaria Mohd. , Ye Shaochun , Win Kyaw Thura
Published: October 2010

The low temperature operation of a heat pump makes it an excellent match for the use of solar energy. At the National University of Singapore, a solar assisted heat pump system has been designed, fabricated and installed to provide water heating and drying. The system also utilizes the air con waste heat, which would normally be released to atmosphere adding to global warming. Experimental results show that the two-phase unglazed solar evaporator-collector, instead of losing energy to the ambient, gained a significant amount due to low operating temperature of the collector. As a result, the collector efficiency attains a value greater than 1, when conventional collector equations are used. With this evaporator-collector, the system can be operated even in the absence of solar irradiation. The waste heat was collected from an air-con system, which maintained a room at 20–22 °C. In the condenser side, water at 60 °C was produced at a rate of 3 liter/minute and the drying capacity was 2.2kg/hour. Maximum COP of the system was found to be about 5.5.
Enhanced Performance With an Impinging Jet Flow Configuration for PEMFC
Authors: Poh Hee Joo , Birgersson Erik , Mujumdar Arun. S.
Published: October 2010

A flow structure which delivers the reactant transversely to the MEA using an impinging jet configuration at cathode side is proposed and modeled to examine its effectiveness for enhanced PEMFC performance, especially at high current densities. A two dimensional, non-isothermal, multi-phase model was developed to predict the performance of an impinging jet. The computational model was validated with published experimental data for a conventional PEMFC. For enhanced performance, a macro-porous gas diffusion layer with permeability in the order of 1e−09 m2 is required for the impinging jet design to be effective. Compared to standard channel flow, a single impinging jet design can improve fuel cell performance up to 80% at high current densities. A multiple impinging jet design is further suggested as an effective way to achieve flow and species uniformity with results in more uniform catalyst utilization. Compared to a single impinging jet, a multiple jet gives up to 14% predicted enhancement at a high current density at about 2A/cm2. Experimental validation is needed for the proposed impinging jet configurations.
A Criteria for Size Separation Using Maximum Entropy Production
Authors: Liu Chuan-ping , Wang Li , Jia Min , Tong Lige
Published: October 2010

In order to study analytically the nature of the size separation in granular mixture, we present the maximum entropy production principle based on kinetic temperature of granular mixture. For simplicity we apply this principle to size separation of a sphere binary mixture in vibrated bed, and we find a new thermodynamic mechanism of size separation phenomenon. With the irreversible processes such as elastic collisions and frictions, the kinetic energy is dissipated rapidly in system, which induces the entropy production. By the fact that the entropy production rate always has the absolute maximum at the stable state of granular mixture, we find the crossover from “Brazil Nut Effect” to its reverse by changing particles size and density, and our result is about satisfied with Schnautz’s experiment.
Energy End-Use Models of the U.S. Organic and Inorganic Chemicals Industries
Authors: Ozalp Nesrin , Hyman Barry
Published: October 2010

In this paper, energy end-use models of U.S. Organic Chemicals and the U.S. Inorganic Chemicals industries are given. The energy end-use model is developed based on the waste heat recovery characterization of the U.S. Chemical Industry and the onsite power and steam generation model. The primary database used in this study is the Energy Information Administration’s (EIA) data: EIA 906, EIA-920, EIA-860B and MECS (Manufacturing Energy Consumption Survey). Based on the results found from the models; the majority of the fuel is used for the end-uses in these manufacturing sectors either directly or through onsite power and steam generation. The approach to create these models is applicable to all other industries for which data is available and the model is consistent with the most available U.S. Department of Energy data, which is currently given for 2002 while the data for 2006 is under progress. When used in conjunction with similar models for other years, it can be used to identify the changes and trends in energy utilization even at the prime mover level of detail.
Study on Energy Saving Retrofitting Strategies for Existing Public Buildings in Shanghai
Authors: Li Yuming , Pan Yiqun , Chen Chen
Published: October 2010

Public buildings include office building, schools, hotels, hospitals, retails and others. This paper selects two types of existing public buildings — office and hotel to conduct research. It firstly introduces and analyzes the feasible energy saving retrofitting strategies and technologies for existing public buildings in Shanghai, mainly about building envelope, HVAC system and lighting system. Then it builds up prototypical models, with whole building energy analysis software—EnergyPlus, for office and hotel respectively to simulate and calculate the annual energy saving and payback period of the various strategies. Therefore the different features of the two types of buildings and the energy saving effects of various strategies used on them are studied. The results show that the energy saved by each one strategy may be different for different types of existing buildings. For office buildings, such ECMs (energy conservation measures) as external shading, energy efficient lighting system, daylighting in perimeter area and variable pumps have short payback period. While for hotels, external shading, variable pumps and temperature reset have short payback period.
Cooling Loads Prediction of 2010 Shanghai World Expo
Authors: Pan Yiqun , Qu Yan , Li Yuming
Published: October 2010

The paper predicts and studies on the cooling loads of the pavilions in 2010 Shanghai World Expo based on the general planning of the expo. The simulation models are established using DOE-2, for the various pavilions: 5 permanent pavilions, national pavilions, international organization pavilions, corporate pavilions, and temporary exhibition pavilions. The modularization method is used to simplify the simulation models of the temporary exhibition pavilions. The cooling loads of the various pavilions from May 1st to Oct 31st 2010 are simulated and analyzed, including hourly cooling loads, monthly cooling loads and hourly cooling loads on summer design day. Lastly, three factors — weather, visitor flow rate and outdoor air supplying mode, are selected to conduct the uncertainty analysis on their impact on the cooling loads.
Sensor Networks for Lighting Control
Authors: Tiller Dale K. , Henze Gregor P. , Guo Xin , Waters Clarence E.
Published: October 2010

This paper summarizes results from a research program investigating the development and application of sensor networks to lighting control and building energy management. Commercial, industrial and residential buildings often incorporate systems used to determine occupancy, however, current sensor technology and control algorithms limit the effectiveness of these devices in both energy management and security systems. These systems rely on single measurement points to detect occupancy, and as a result there can be significant uncertainty associated with the measurement of occupancy. Long time delay and high detector sensitivity settings compensate for this uncertainty, and as a result, more energy is wasted than if occupancy were more accurately measured. A network of inexpensive occupancy sensors provides a more accurate, reliable and robust occupancy measurement, and is potentially more economical in terms of initial investment and operating costs, than single-point detection systems. We show that it may be possible with a sensor network to reduce the operating time of occupancy-based building systems by an extra 20% (compared to current systems) and that the simple payback periods associated with wireless sensor networks applied in generic small and large commercial buildings may be less than two years.
Enhanced Gasification of Waste Glycerol Over Ni/SiC Catalyst for Fuel Gas Production
Authors: Atong Duangduen , Sricharoenchaikul Viboon
Published: October 2010

The amount of waste glycerol from biodiesel production increases sharply due to greater use of this alternative fuel from high cost and adverse environmental effect of conventional fossil fuel. The crude glycerol can convert to fuel gas (mainly CO, H2, and CH4) through thermochemical conversion processes such as gasification and pyrolysis. In this study, pyrolysis and gasification of glycerol waste were studied in a laboratory scale quartz tube reactor using silicon carbide (SiC) as a bed medium. In order to improve the conversion efficiency while minimizing tar formation, nickel catalyst supported by SiC was synthesized using wet impregnation method and used in some trials. It was found during pyrolysis runs that carbon and hydrogen conversion of glycerol increased with temperature of 600–800°C in the range of 18.72–95.33% and 16.26–96.30%, respectively. When varying the air fuel ratio from 0–0.25 at 800°C, complete conversion of crude glycerol may be achieved both for pyrolysis and gasification conditions. This may be due to the dominant of steam gasification reactions from 13.56% moisture content in crude glycerol which controls the overall reactions at that high temperature. However at lower temperature of 600°C, carbon and hydrogen conversion of crude glycerol decreased to 18.72–42.23% and 16.26–35.27%, respectively. Increase in residence time from 1.3–4.0 second did not significantly affect the conversion efficiency for pyrolysis at 600°C which indicated that the kinetic of these decomposition reactions proceed at rapid rates even at the minimum hold time used in this work. Catalytic conversion of crude glycerol with 10% nickel on silicon carbide (Ni/SiC) was performed using pyrolysis condition at 600°C to obtain higher conversion efficiency. The results revealed that non-reduced and reduced catalyst, could increase the production of synthesis gas as much as 1.02 and 0.56 times when compared with non-catalytic process, respectively. It may be suggested from high energy content as well as product gas quality that using Ni/SiC catalyst is suitable for thermal conversion of waste glycerol to fuel gas that may be further utilized with minimum treatment. The obtained synthesis gas may be utilized for direct heat and power or further transformed to other alternatives fuels which help increase value and at the same time minimize the waste management requirement of this industrial waste.
Exergy Analysis of Second Generation Micro Heat Sinks Under Flow Boiling Conditions
Authors: Kos¸ar Ali
Published: October 2010

An exergy analysis was performed for flow boiling of R-123 in a hydrofoil-based micro pin fin heat sink. It was found that exergy efficiencies decreased with mass velocity at fixed heat input, pressure drop and pumping power under flow boiling conditions, and exergy efficiency could be better represented using the exit mass quality. The outcome of this study also proved noteworthy in view that exergy efficiency could be utilized to assess thermodynamic performance.
A Design Methodology Enabling the Efficient High-Fidelity Design of Combined Cycle Power Plants
Authors: Prior Matthew A. , Stults Ian C. , Daskilewicz Matthew J. , Duncan Scott J. , German Brian J. , Mavris Dimitri N.
Published: October 2010

The demand for greater efficiency, lower emissions, and higher reliability in combined cycle power plants has driven industry to use higher-fidelity plant component models in conceptual design. Normally used later in preliminary component design, physics-based models can also be used in conceptual design as the building blocks of a plant-level modeling and simulation (M&S) environment. Although better designs can be discovered using such environments, the linking of multiple high-fidelity models can create intractably large design variable sets, long overall execution times, and model convergence limitations. As a result, an M&S environment comprising multiple linked high-fidelity models can be prohibitively large and/or slow to evaluate, discouraging design optimization and design space exploration. This paper describes a design space exploration methodology that addresses the aforementioned challenges. Specifically, the proposed methodology includes techniques for the reduction of total model run-time, reduction of design space dimensionality, effect visualization, and identification of Pareto-optimal power plant designs. An overview of the methodology’s main steps is given, leading to a description of the benefit and implementation of each step. Major steps in the process include design variable screening, efficient design space sampling, and surrogate modeling, all of which can be used as precursors to traditional optimization techniques. As an alternative to optimization, a Monte Carlo based method for design space exploration is explained conceptually. Selected steps from the methodology are applied to a fictional but representative example problem of combined cycle power plant design. The objective is to minimize cost of electricity (COE), subject to constraints on base load power and acquisition cost. This example problem is used to show relative run-time savings from using the methodology’s techniques compared to the alternative of performing optimization without them. The example additionally provides a context for explaining design space visualization techniques that are part of the methodology.
Integration Solar Cycles for Natural Gas and Coal Power Plants
Authors: Libby Cara , Golden Gary , Bell Robin
Published: October 2010

As fossil fuel prices rise and emission allowances are implemented, solar augmented steam cycles might be an attractive option for energy companies. The system utilizes steam generated by a solar field in a conventional natural gas or coal-powered steam cycle, offsetting some of the fuel required to generate power. Many energy companies are interested in adding solar power to their generating mix, but today most solar applications are not cost-competitive with other power generating options. Solar augmentation potentially is the lowest cost option for adding solar power to the generation fleet. The highest intensity solar energy typically is within a few hours of peak summer loads, making it a particularly attractive renewable option.
Modeling, Testing, and Evaluation of a Building-Integrated Photovoltaic-Thermal Collector
Authors: Corbin Charles D. , Brandemuehl Michael J.
Published: October 2010

The performance of Building-Integrated Photovoltaic-Thermal (BIPV/T) collector is examined in this study. A full scale-test collector is monitored over several weeks in the summer of 2008 and measured data is used to calibrate a heat transfer model implemented in a common scientific computing software package. Following calibration, error between experimental measurements and the calibrated model outputs is within the limits of measurement uncertainty. Collector simulations are constructed to examine thermal efficiency, the effectiveness of the collector as a night-sky radiator, the effect of heat collection on electrical efficiency, the effect of two common exterior convection coefficients on collector performance, and the effect of eliminating the air gap between the PV and absorber surfaces. Overall collector thermal efficiency is relatively low compared to existing collectors. However, the potential low cost of the system could allow larger collector areas to compensate for low efficiency, especially in warm climates. Combined thermal and electrical efficiency can be as high as 34%. Additional analysis also indicates that the predicted thermal performance is highly dependent on the thermal resistance between the PV cells and the absorber plate and is sensitive to assumptions regarding wind-driven convection heat transfer coefficients.
Energy Systems Analyses for Ultralow Energy Communities
Authors: Hartranft Thomas , Feickert Carl A. , Zhivov Alexander , Holcomb Frank H.
Published: October 2010

In an increasingly energy constrained world, the Army and its logistic support envisions a future where its energy needs are designed and fulfilled by an elegant suite of ultra low energy solution options that can be tailored for adaptation at any Army installation or forward deployed base (FOB). Presently there is no overarching power delivery-energy storage-demand architecture and methodology to accomplish this. The Army’s present and future energy requirements are a mix of ultra-low and high energy intensity command and control facilities. Garrison Commanders must also have the capability to continuously adjust their ultra low energy suite in real time, by the tailoring and optimization of energy usage to accomplish strategic mission, security, and environmental goals. To address these issues requires the development of a properly designed and executed suite of ultra low energy systems that would enable adaptable, modular, scalable building-block power and thermal energy architecture so as to accommodate a full spectrum of local mission needs, from a few clustered facilities, an installation subsection, a full installation or deployed base. Accommodating this variability in an ultra-low energy environment will require a seamless blend of building automation, utility management and control systems, and power delivery systems with the capability to offer integration of onsite power, energy storage, and energy conservation. The controlling features embodied in the integrated suite of tools, systems analyses and methodologies, must not only optimize design but also day-to-day and hour-by-hour operation. What is envisioned is developing a prototype master plan for an ultra low energy community system that has been field tested at several specific Army campuses. A workshop of leading energy scientists and engineers has been convened to define the technology required to implement this vision. This paper presents the clarified summaries of their collective deliberations, and defines a way forward for a research program capable of achieving ultra low energy applications, for installations to deployed bases.
Potential for Energy Savings Through Residential Hot Water Distribution System Improvements
Authors: Hendron Robert , Burch Jay , Hoeschele Marc , Rainer Leo
Published: October 2010

Hot water distribution systems have received a great deal of attention recently, as residential energy efficiency programs target measures that can drive whole-house energy savings beyond the 50% level. Unfortunately, evaluating distribution losses and the resulting thermal interactions with space conditioning loads is very complicated, and must be performed using advanced simulation tools and realistic hot water event schedules, including appropriate event volumes, draw sequencing, and time between draw events. The authors developed a simplified methodology for the analysis of distribution losses based on detailed modeling of alternative system designs using HWSIM, a model specifically designed for this application. Curve fits were then applied to the results so they could be extrapolated to many different house designs and climate regions. The authors also performed preliminary analysis of whole house energy effects of alternate hot water distribution systems in two climates.
The Effect of Fossil Fuel Prices on Flexible CO2 Capture Operation
Authors: Cohen Stuart M. , Fyffe John , Rochelle Gary T. , Webber Michael E.
Published: October 2010

Coal consumption for electricity generation produces over 30% of U.S. carbon dioxide (CO2) emissions, but coal is also an available, secure, and low cost fuel that is currently utilized to meet roughly half of America’s electricity demand. While the world transitions from the existing fossil fuel-based energy infrastructure to a sustainable energy system, carbon dioxide capture and sequestration (CCS) will be a critical technology that will allow continued use of coal in an environmentally acceptable manner. Techno-economic analyses are useful in understanding the costs and benefits of CCS. However, typical techno-economic analyses of post-combustion CO2 capture systems assume continuous operation at a high CO2 removal, which could use 30% of pre-capture electricity output and require new capacity installation to replace the output lost to CO2 capture energy requirements. This study, however, considers the inherent flexibility in post-combustion CO2 capture systems by modeling power plants that vary CO2 capture energy requirements in order to increase electricity output when economical under electricity market conditions. A first-order model of electricity dispatch and a competitive electricity market is used to investigate flexible CO2 capture in response to hourly electricity demand variations. The Electric Reliability Council of Texas (ERCOT) electric grid is used as a case study to compare plant and grid performance, economics, and CO2 emissions in scenarios without CO2 capture to those with flexible or inflexible CO2 capture systems. Flexible CO2 capture systems can choose how much CO2 to capture based on the competition between CO2 and electricity prices and a desire to either minimize operating costs or maximize operating profits. Coal and natural gas prices have varying degrees of predictability and volatility, and the relative prices of these fuels have a major impact on power plant operating costs and the resulting plant dispatch sequence. Because the chosen operating point in a flexible CO2 capture system affects net power plant efficiency, fuel prices also influence which CO2 capture operating point may be the most economical and the resulting dispatch of power plants with CO2 capture. Several coal and natural gas price combinations are investigated to determine their impact on flexible CO2 capture operation and the resulting economic and environmental impacts at the power plant and electric grid levels. This study investigates the costs and benefits of flexible CO2 capture in a framework of a carbon-constrained future where the effects of major energy infrastructure changes on fuel prices are not entirely clear.
Renewable Energy and Water System (REWS) at Musco Family Co. Olive Plant
Authors: Schubert Frank , Parkinson Ian
Published: October 2010

This paper presents the results of a demonstration of a unique water distillation system at the Musco Family Olive Plant in Tracy, California. The Musco REWS (Renewable Energy/Water System) was developed by Combined Solar Technologies (CST) of Carmel Valley, California using its SteamBoy™ brine boiler technology. The system is powered using solar thermal and biomass energy. The notoriously hard to clean waste water from the olive canning process was a challenge for CST, a start-up company who had previously done successful technology demonstration projects for the California Department of Water Resources (agricultural drainage water) and Clint Eastwood’s Tehama Golf course Water Treatment Plant (Reverse Osmosis Brine). The olive waste water at the Musco plant contained a high concentration of salts as well as organic materials. CST successfully treated water directly from the plants waste water stream (12,000 TDS) as well as the water from the plants Title 27 ponds (67,000 TDS). The CST processed water averaged 250 TDS. The CST REWS at the Musco olive facility uses one of the plants waste (olive pits) streams to provide the heat energy for the process. The olive pits are combusted in fluid bed burners that are specially designed for olive pit combustion. The Musco plants 200 tons per week of olive pits contain 8800 btu/lb (dry). The olive pits are fed into the CST burners where the heat energy is used to heat a heat transfer fluid (HTF) to 450F. The HTF is then directed to the SteamBoy™ brine boilers. The heat from the HTF evaporates the plants waste water under pressure. The resulting pressurized saturated steam is then used to power SteamBoy™ steam engine/generator sets. The engines are set up to leave large quantities of heat in the exhaust. That heat is used to take the remaining solids and sludge to a dry state in custom built drying pans that separate the minerals from the water, leaving a very high concentration of organics in the remaining water. That water is used in the burners for temperature control and as a way to eliminate the organics with combustion. The exhaust from the combustion of the olive pits goes first though an electrostatic particle separator and then to a selective catalytic reduction system. From there the exhaust is directed to bubbling algae tanks that reduce the CO2 by over 50%. The system has completed a successful demonstration phase and is now being upgraded to a full scale plant (50,000 GPD).
Life Cycle Analysis of Automotive Ethanol Produced From Municipal Solid Waste
Authors: Curtiss Peter S. , Kreider Jan F.
Published: October 2010

The trend of increasing petroleum prices has prompted the consideration of other fuels for transportation. Ethanol has received a great deal of attention based on the hope that it is possible to develop a sustainable and relatively environmentally responsible alternative to gasoline. Currently, the biofuels industry depends heavily on the use of cereal crops as the feedstock for the ethanol refineries. This practice, however, has led to concern over the diversion of food supplies to fuel supplies; price increases of corn and corn-dependent products (milk, beef, etc.) have already been blamed on the market forces pushing crops towards fuel production. Additionally, sufficient land water exist in the US for cereal crop-based biofuels. Another method for producing ethanol uses waste products as the main feedstock. The waste can consist of anything fermentable — agricultural field remnants, yard clippings, and paper and food waste all are potentially inputs to the ethanol production process. An added benefit of such a system is the decrease in the amount of material that must be disposed in landfills or dumps. This paper briefly discusses the conversion of municipal solid waste (MSW) to ethanol for use as an automotive replacement fuel.
Improved Efficiency of Dye Sensitized Solar Cells Using Aligned Carbon Nanotubes
Authors: Sayer Robert A. , Hodson Stephen L. , Fisher Timothy S.
Published: October 2010

Dye sensitized solar cells (DSSCs) offer many advantages in comparison to their Si-based counterparts, including lower cost of raw materials, faster manufacturing time, and the ability to be integrated with flexible substrates. Although many advances have been made in DSSC fabrication over recent years, their efficiency remains lower than commercially available Si photovoltaic cells. Here we report improved efficiency of TiO2/anthocyanin dye solar cell using aligned arrays of carbon nanotubes (CNTs) as a counter electrode. Dense vertically oriented CNT arrays are grown directly on the counter electrode using microwave plasma chemical vapor deposition and a tri-layer (Ti/Al/Fe) catalyst. The resulting arrays are 30 micrometers in height and have a number density of approximately five hundred million per square millimeter. By directly growing the CNTs on the counter electrode substrate, electrical interface conductance is enhanced. The performance of both as-grown and N-doped (using a nitrogen plasma) CNT arrays is reported. The fabricated DSSCs are tested under AM1.5 light. Increased short circuit current is observed in comparison to graphite and Pt counter electrodes. We attribute this improvement to the large surface area created by the 3D structure of the arrays in comparison to the planar geometry of the graphite and Pt electrodes as well as the excellent electrical properties of the CNTs.
Integrated Energy Resource Plan for Alaska’s Northwest Arctic Borough
Authors: Yanity Brian B. , Hermanson Jay S.
Published: October 2010

Straddling the Arctic Circle on the Chukchi Sea, the Northwest Alaska Native Association (NANA) region constitutes the boundaries of the Northwest Arctic Borough (NWAB), and has a population of about 7,600 people. The high cost of energy in the NANA region is one of the leading threats to the long term sustainability and well-being of the region. As a result of complex and lengthy logistics, the region has some of the highest energy prices in the nation. In addition to the cost of fossil fuels, NANA region residents are increasingly aware of the effects of greenhouse gases on climate change and the resulting coastal erosion along the Chukchi Sea. NANA Regional Corporation, along with other regional stakeholders, has developed a regional integrated energy plan. This approach includes community specific energy options analyses, benefit-cost analyses of competing alternatives, analysis of available literature and past experiences, surveying of professional opinion, and a regional energy summit that involved multiple stakeholders. Since the mid-1990s, the NANA region has been an Alaska leader in promoting and developing renewable energy resources with wind turbine installations in Kotzebue and Selawik. Promising wind energy potential is under investigation in several more communities, and other known energy resources being studied include geothermal, small-scale hydropower, and a substantial biomass potential in the upper Kobuk River area. Also under investigation are stranded natural gas sources and even solar PV installations for some communities. Energy security in the region will be achieved by a combination of infrastructure improvement and development of appropriate energy technologies, both traditional and renewable. It is the vision of NANA region stakeholders to be 75% reliant on regionally available energy resources for heating and electric generation purposes by the year 2030, and to decrease the need for transportation fuel imported into the region by 50% by the year 2030. As part of this vision, imported fossil fuels would remain as emergency/back-up fuel only. With proper planning, a synergy can be developed between different energy sources and uses, with the composition of the optimal ‘energy-mix’ custom-tailored for each community in the NANA region. The energy planning process will be conducted with the understanding that the optimum mix may change over time.