bluuebunny/crossref_metadata_2025 huggingface dataset:
Trucks Off the Road: A Volumetric Framework for Evaluating Energy Technologies for Forward Operating Military Base Camps
Authors: Putnam Nathan Hassan , Webber Michael Evan , Seepersad Carolyn Conner
Published: March 2012

The importance of considering energy security and resource efficiency in policies across the Department of Defense (DoD) has recently been emphasized. DoD-sponsored research reports repeatedly encourage consideration of energy efficiency and energy security in all decision-making processes, including those that pertain to Forward Operating Military Base Camp (FOB) equipment. But while energy security and efficiency are valued in the general sense, for FOBs, energy and water are strategically vital and sources of vulnerability. There are incredibly high human and capital costs associated with transporting fuel and water within hostile war zones, where convoys are routinely subjected to mortal danger. A volumetric framework for evaluating field equipment is proposed that simultaneously addresses the broad DoD-wide goals of bolstering energy security and energy efficiency, as well as the immediate and strategically significant goal of “taking [fuel and water delivery] trucks off the road.” The metrics associated with this framework focus on the volume of field equipment itself, as well as the volumes of fuel and water that are either consumed or saved by the equipment over time. For example, solar panels require additional up-front volume to be brought to the FOB, but then spare future volumes of fuel that need not be shipped. Using a volumetric framework described herein, the tradeoffs between up-front and marginal volumetric requirements can be rigorously assessed. Existing metrics, such as those that focus only on equipment lifecycle cost, are unsuitable for evaluating field equipment for FOBs primarily because they are extremely difficult to accurately quantify. By instead focusing on fuel and water volumes that are more easily quantified, decision-makers might gain important insights about the relevant trade-offs and strategic implications of fielding equipment on FOBs. The proposed metrics are compared to existing metrics with respect to their effectiveness for quantifying the true values of energy- and water-saving devices on FOBs in a strategically relevant way. A suite of volume-based metrics is developed by adapting existing economic metrics, including return on investment (ROI), payback period, and net present value (NPV), for a volume-based rather than cost-based analysis. Use of the volumetric framework is illustrated for a few different technologies.
Shaft Motor-Generator Design Assessment for Increased Operational Efficiency in Container Ships
Authors: Gully Benjamin H. , Webber Michael E. , Seepersad Carolyn C.
Published: March 2012

Fuel costs are the sigle most important driver of marginal costs for commercial marine transportation and account for almost 50% of total voyage costs for typical configurations. Hence, there has developed a desire among operators and manufacturers of all classes of ships to embrace innovative ways to reduce the demand for fuels. This research investigates the fuel consumption of a standard container ship architecture based on different scenarios of operation. The approach is to first model fuel consumption from the main propulsion engines and the auxiliary engines based on standard propulsion modes, with a configuration known as a Power Take Off (PTO) system. These preliminary results are then analyzed to identify opportunities for retrofitting this configuration by utilizing the same engine combination, but augmenting the PTO system into a modernized shaft motor-generator system, or Auxiliary Power System (APS). The APS enables electrification, which can potentially decrease system fuel consumption. Lastly, the potential for these fuel savings is evaluated for multiple scales of the APS.
Experimental and Modeling Comparison of Modular Photovoltaic-Thermal Solar Panels
Authors: Annis Nicole C. , Baur Stuart W.
Published: March 2012

The scope of the project included two steps. Step one was to create three prototype photovoltaic-thermal panels and test them. Step two was to model all photovoltaic-thermal panels using TRNSYS 16. The three different photovoltaic-thermal panels were tested simultaneously using the same inlet water source. The first two panels (Panel A & B) consisted of a highly conductive thermal sheeting and different sized copper tubing. The third panel (Panel C) consisted of copper tubing with an aluminum fin. Thermal images were used to verify the heat transfer across the panels and compare the amount of heat radiating off the back of the photovoltaic-thermal panels versus the standard photovoltaic panel. The purpose of this experiment was to create a modular photovoltaic-thermal panel, which would be easily implemented and maintained by the average consumer. A TRNSYS model was created for each photovoltaic-thermal panel to gather approximate year-round efficiency. The thermal efficiencies of photovoltaic-thermal panels A, B and C at 1.9 lpm (0.5 gpm) were 33.6%, 26.4% and 28.7%, respectively. Panels A, B and C at 1.9 lpm (0.5 gpm) had thermal gain plus electrical output equivalents of 394.0, 363.2 and 422.9 watts, respectively. The TRNSYS models of the prototype photovoltaic-thermal (Panels A, B and C) proved to be a poor representation of the actual texted panels.
Hydrogen Production via the Iron/Iron Oxide Looping Cycle
Authors: Singh A. , Al-Raqom F. , Klausner J. , Petrasch J.
Published: March 2012

The iron/iron-oxide looping cycle has the potential to produce high purity hydrogen from coal or natural gas without the need for gas phase separation: Hydrogen is produced from steam oxidation of iron or Wustite yielding primarily Magnetite; Magnetite is then reduced back to iron/Wustite using syngas (CO+H2). A system model has been developed to identify favorable operation conditions and process configurations. Process configurations for three distinct temperature ranges, (i) 500–950 K, (ii) 950–1100 K, and (iii) 1100–1200 K have been developed. The energy content of high temperature syngas from conventional coal gasifiers is sufficient to drive the looping process throughout the temperature range considered. Temperatures around 1000 K are advantageous for both the hydrogen production step and the iron oxide reduction step. Simulations of a large number of subsequent cycles indicate that quasi-steady operation is reached after approximately 5 cycles. Comparison of simulations and experiments indicate that the process is currently limited by chemical kinetics at lower temperatures. Therefore, product recirculation should be used for a scaled-up process to increase reactant residence times while maintaining sufficient fluidization velocity.
Computational Modeling of Dynamic Response of a Latent Thermal Energy Storage System With Embedded Heat Pipes
Authors: Nithyanandam Karthik , Pitchumani Ranga
Published: March 2012

Concentrated solar power plants (CSP) are being explored as the leading source of renewable energy for future power generation. Storing sun’s energy in the form of latent thermal energy of a phase change material (PCM) is desirable for use on demand including times when solar energy is unavailable. Considering a latent thermal energy storage (LTES) system incorporating heat pipes to enhance heat transfer between the heat transfer fluid (HTF) and the PCM, this paper explores the dynamic response of the LTES system subjected to repeated cycles of charging and discharging. A transient computational analysis of a shell-and-tube LTES embedded with two horizontal heat pipes (HHP) is performed for repeated charging and discharging of the PCM to analyze the dynamic performance of the LTES and the augmentation in the cyclic performance of the LTES embedded with heat pipes is investigated. A model low temperature phase change material system is considered in the present study, with the physical results being scalable to high temperature systems used in CSP plants.
Proposed Sustainable Design Alternatives for Low-Income and Middle-Income Housing in a Coastal Area in a Developing Country
Authors: Calderon Marta Lalyvette , Guardado Victor Hugo , Guevara Francisco Eduardo , Martinez Luis Aaron , Molina Gabriel Ricardo , Santos Luis Samai
Published: March 2012

Developing nations face increasing economic and environmental challenges and the search for housing design solutions that approach sustainability by meeting thermal comfort, energy efficiency, environmental and low initial cost criteria is underway. This paper presents the results of a multidisciplinary research project that aimed at designing a low-income house and a middle-income house that perform well from the architectural, thermal comfort, and energy efficiency standpoint while being cost-competitive. Multiple passive cooling strategies were considered and evaluated by energy modeling tools. The thermal and energy performance of the proposed designs were analyzed throughout the design process and the various design iterations. A full budget was prepared for the proposed low-income housing design and first-costs were found to be competitive with conventional housing. The paper discusses the proposed design features, their impact on thermal comfort and energy efficiency and the feasibility of integrating alternative energy systems to the proposed designs.
Three-Dimensional Modeling of Solar Thermochemical Splitting of CO2 in a CR5
Authors: Chen Ken S. , Hogan Roy E.
Published: March 2012

A three-dimensional (3-D) numerical model for simulating the process of solar thermochemical splitting of carbon dioxide (CO2) into carbon monoxide (CO) in a counter-rotating-ring receiver/reactor/recuperator or CR5 are developed in order to account for three-dimensional effects such as edge effect of side walls. The present 3-D model, which is based on our previous two-dimensional first-generation model, takes into account heat transfer, gas-phase flow, multiple-species transport in open channels and through pores of the porous reactant layer, and redox chemical reactions at the gas/solid interfaces. Sample computed results (e.g., temperature distribution, species concentration contours) are presented to illustrate model utility. The model is employed to examine the effects of rates of CO2 and argon neutral gas injection and the redox chemical reactions on thermochemical solar conversion efficiency. Effects of the CR5 width and argon neutral gas injection on O2 crossover are also explored.
Solar Thermochemical Hybrid Trigeneration System With CO2 Capture Using Dimethyl Ether-Fueled Chemical-Looping Combustion
Authors: He Fengjuan , Han Tao , Hong Hui , Jin Hongguang
Published: March 2012

In this paper, we propose a new solar-hybrid trigeneration system with dimethyl ether (DME)-fueled chemical-looping combustion and solar thermal energy at approximately 550°C. The system is investigated using the energy-utilization diagram (EUD). In this system, the concentrated solar thermal energy is utilized to drive the endothermic reduction of CoO with DME in the fuel reactor, producing solid fuel of Co and gaseous CO2 as well as water vapor. Subsequently, the reduced metal oxide Co is transported into the air reactor to be oxidized for regeneration at 1,000 °C. The high-temperature flue gas from the air reactor is introduced into the gas turbine to generate power, and then it enters an absorption chiller with coefficient of performance (COP) of 1.2 to produce cooling. Finally, the high-temperature flue gas is used for the production of domestic hot water at 70 °C through a heat exchanger. The gaseous product from the fuel reactor consists only of CO2 and water vapor, so CO2 can be easily separated through the condensing method with super low extra energy penalty. As a result, the thermal efficiency of the new system is expected to be 96.7%, and the global exergy efficiency can reach 35%. Two important indicators of fuel energy saving ratio (FESR) and solar area saving ratio (SASR) are used to evaluate the performance of the system. FESR can reach 40.6% at a turbine inlet temperature of 1,000 °C, whereas SASR can reach 68.4%. A preliminary experiment is also conducted. The promising results obtained in this study provide a new approach for highly efficient use of solar thermal energy approximately 550°C and offer a possibility of simultaneously utilizing solar energy and alternative fuel for CO2 capture with low energy penalty.
Characterizing Solar PV Output Variability and Effects on the Electric System in Florida, Initial Results
Authors: Meeker Rick , Domijan Alexander , Islam Mujahidul , Omole Adedamola , Islam Arif , Damnjanovic Aleksandar
Published: March 2012

This paper shares initial results from a major collaborative project in Florida underway to study and address effects of high penetration levels of solar photovoltaic (PV) generation on the electric power system. The effort includes characterizing the variability of the solar resource in Florida, where a number of new multi-megawatt solar projects have either recently come online or are in the planning or construction stages (including the largest solar PV generating station in N. America at the time of this writing). Until now, most work on characterizing solar variability has focused on the Southwestern U.S. This paper shares initial results and insights on the variability of Solar PV generation output in Florida on different timescales and provides some preliminary insights into the implications and effects of the variability on the successful integration of increasingly higher penetration levels of solar PV, with respect to the integration technology, control systems, and the electric power system.
Flex House
Authors: Russell Stanley , Weston Mark , Goswami Yogi , Doll Matthew
Published: March 2012

Flex House is a flexible, modular, pre-fabricated zero energy building that can be mass produced and adapted easily to a variety of site conditions and plan configurations. The key factor shaping the design is central Florida’s hot humid climate and intense solar radiation. Flex house combines the wisdom of vernacular Florida houses with state of the art Zero Energy House technologies (ZEH.) A combined system of photovoltaic panels and solar thermal concentrating panels take advantage of the region’s abundant insolation in providing clean renewable energy for the house. Conservation is achieved with state of the art mechanical systems and innovative liquid desiccant dehumidification technology along with highly efficient lighting and appliances. The hybrid nature of the Flex house allows for both an open and closed system to take advantage of the seasonal temperature variation. Central Florida buildings can conserve energy by allowing natural ventilation to take advantage of passive cooling in the mild months of the year and use a closed system to utilize mechanical cooling when temperatures are too high for passive cooling strategies. The building envelope works equally well throughout the year combining an optimum level of insulation, resistance to air infiltration, transparency for daylight, and flexibility that allows for opening and closing of the house. Flex House is designed with a strong connection between interior spaces and the outdoors with carefully placed fenestration and a movable wall system which enables the house to transform in response to the temperature variations throughout the year. The house also addresses the massive heat gain that occurs through the roof, which can generate temperatures in excess of 140 degrees. Flex House incorporates a parasol-like outer structure that shades the roof, walls and courtyard minimizing heat gain through the building envelope. To be implemented on a large scale, ZEH must be affordable for people earning a moderate income. Site built construction is time consuming and wasteful and results in higher costs. Building homes in a controlled environment can reduce material waste, and construction costs while increasing efficiency. Pre-fabricating Flex House minimizes preparation time, waste and safety concerns and maximizes economy, quality control, efficiency and safety during the construction process. This paper is an account of the design and construction of Flex House, a ZEH for central Florida’s hot humid climate.
Design and Analysis of the Aerodynamic Components for a Kilowatt Scale VAWT Optimized for Low Altitude Implementation in Remote Rural Villages
Authors: Fuller Nathan E. , Wiens David M. , Johnston Allison L. , French Jesse J.
Published: March 2012

The ideal operating conditions for traditional horizontal axis wind turbines (HAWTs) are generally described by high velocity, steady winds, and undisturbed, laminar air flow. In the direct vicinity of populated areas, these conditions can only be achieved at altitudes significantly above or beyond the built-up area, typically twice the height of the tallest surrounding obstruction. The cost of tower material and transmission lines makes placing turbines at optimal operating heights cost-prohibitive in low-income, remote villages. Though not ideal for HAWT operation, the wind close to the earth’s surface and in proximity of residences can be utilized with an appropriately designed vertical axis wind turbine (VAWT). These turbines, while having a lower theoretical maximum efficiency, can survive and utilize the turbulent multidirectional winds in this operating region while still providing usable power. This paper highlights the design and analysis work performed by the authors to increase the aerodynamic efficiency of a unique and patented VAWT design in order to optimize it for implementation in remote rural villages. The final product is a kW capacity VAWT of unique geometry based on the previous successful testing of a 100W prototype. Specifically, the authors explored the aerodynamic effects of varying the geometry of the radial arms and center hubs of the turbine using CFD and wind tunnel testing. The design goal was to develop arms with aerodynamic properties that complemented the function of the blades at the appropriate phases of a single revolution. While the previous prototype focused mainly on minimizing drag, this effort sought to design an arm profile that develops high drag in one airflow direction and minimizes drag in the opposite direction. Implementation of these results was realized in a fully functioning drag VAWT. Furthermore, the system was designed to keep the turbine affordable for remote populations with limited resources. This data is compared to theoretical performance calculations, existing wind turbine designs, and against predictions made using scaling factors on preexisting data from the smaller prototype.
Forecasting of Global Horizontal Irradiance Using Sky Cover Indices
Authors: Marquez Ricardo , Gueorguiev Vesselin G. , Coimbra Carlos F. M.
Published: March 2012

This work discusses the relevance of three Sky Cover (SC) indices for solar radiation modeling and forecasting. The three indices are global in the sense that they integrate relevant information from the whole sky and thus encode cloud cover information. However, the three indices also emphasize different specific meteorological processes and sky radiosity components. The three indices are derived from the observed cloud cover via Total Sky Imager (TSI), via measurements of the Infrared Radiation (IR), and via pyranometer measurements of Global Horizontal Irradiance (GHI). We enhance the correlations between these three indices by choosing optimal expressions that are benchmarked against the GHI SC index. The similarity of the three indices allows for a good qualitative approximation of the GHI irradiance when using any of the other two indices. An Artificial Neural Network (ANN) algorithm is employed to improve the quantitative modeling of the GHI sky cover index, thus improving significantly the forecasting details of GHI when all three indices are used.
Determining and Forecasting Regional Carbon Dioxide Emissions of Turkey
Authors: Aslanoglu S. Yeser , Aydinalp Koksal Merih
Published: March 2012

In parallel to the increase in population and industrialization, the electricity demand of Turkey has been increasing rapidly in recent years. This has caused a noticeable increase in CO2 emission from electricity generation, especially due to the use of fossil fuelled power plants. These plants are mostly located in highly industrialized regions to reduce transmission loses and in regions with large amounts of coal and lignite reservoirs. In addition, using vast amounts of low quality lignite with high ash and sulphur contents in these power plants have affected these regions in recent years. Determining the pollutant emissions, and especially CO2 emissions, from these plants has been more significant after the ratification of Kyoto Protocol by Turkey in 2009. Within the context of this study, electricity generation associated CO2 emissions from existing power plants that run between 2001 and 2008 are determined. In addition to this, associated CO2 emissions from the power plants that are planned to be operated between 2009 and 2020 are also estimated. All assessments are made for nine load distribution regions in which electricity is generated and transmitted in Turkey. Therefore, regional electricity generation and associated CO2 emissions, and the shares of renewable sources for electricity generation are determined between 2001 and 2020. To the authors’ knowledge, this is the first study that determines and estimates electricity generation associated CO2 emissions regionally for Turkey.
Graphite Solar Thermal Storage System at 1300K Using Rotating-Reactive-Ceramics Concept
Authors: Tamaura Yutaka , Ishikawa Yosuke , Kaneko Hiroshi
Published: March 2012

The graphite solar thermal storage system composed of Steps 1–4 (Rotating-Reactive-Ceramics-reactor, RRC-reactor, is used in Steps 1,2,3, and Graphite Thermal Storage tank, GTS-tank, is applied for Steps 3,4,5; Step 3 is the interface-process taking place between the surfaces of RRC-reactor and GTS-tank.) has been studied using computer simulation of COMSOL. During a rapid heating of reactive ceramics in RRC-reactor by irradiation of a high flux concentrated solar beam to around 1800K, the beam energy is directly absorbed by formation of an excess amount of the Frenkel defect in nonequilibrium state of the reactive ceramics without releasing the O2 gas (Step 1; beam energy absorption step). When the temperature reaches around 1800K, the O2 releasing reaction takes place and the reactive ceramics is reduced (Step 2; O2 releasing step). By rotating the RRC-reactor, the surface of reduced reactive ceramics comes to closely face to the surface of the top of GTS-tank. By introducing O2 gas into the space between the two surfaces, the reduced ceramics can be oxidized. The calorification energy produced by the oxidation can be transferred to GTS-tank through its surface. (Step 3; calorification and heat transfer step). The heat is successively transferred and stored in GTS-tank by continuous rotation of RRC-reactor (Sep 4; storage step). The high flux of the concentrated solar beam in the Beam-down concentration system can be averaged in the range of 800–1500kW/m2 in Step 3 by the present process. The computer simulation study showed that it is possible to operate the molten salt heat circulation systems for the GTS-tank at the inlet and outlet temperature of 827K and 1173K, respectively.
Heliostat Field Design Using Visualization Method for Optical Heliostat Interaction
Authors: Ouchi Kei , Kaneko Hiroshi , Tamaura Yutaka
Published: March 2012

For the heliostat field design, the optical interaction of heliostat by shadowing and blocking should be considered besides cosine efficiency. In the present study, in order to visualize the optical interaction it is enabled to visualize the power loss image due to a poor heliostat layout. The optical interaction area among the two heliostats is calculated for several hundreds of pairs between the given heliostat and the surrounding heliostats which are virtually seated around the given heliostat. The resultant plot gives a power loss distribution around the given heliostat. An approximation method to calculate the heliostat distribution was applied for the visualization method for a remarkable time reduction for calculation. The magnitude of the interference can be seen easily from the area where the both borders of the optical interaction areas are overlapped. And the arrangement calculation method using the power loss distribution and the cosine efficiency distribution is proposed, which gives theoretically better heliostat field layouts.
High-Temperature Solar Selective Absorber Material Using Surface Microcavity Structures
Authors: Shimizu Makoto , Takeuchi Kimio , Sai Hitoshi , Iguchi Fumitada , Sata Noriko , Yugami Hiroo
Published: March 2012

The spectral properties of thermal radiation can be controlled by surface microstructures with feature size in the optical wavelength range. We applied this technology to solar selective absorbers for concentrated solar power (CSP) generation systems. We investigated the spectral properties and thermal stability of two-dimensional periodic microstructures on a tungsten (W) surface to develop solar selective absorbers for high-temperature applications. The developed absorbers exhibited good spectral selectivity and sufficient thermal stability under vacuum. Although we could verified that the microstructured solar selective absorbers improved CSP efficiency, this method cannot be put into practical use because of cost and time, and also because there is currently no technology for fabricating surface gratings on high melting point materials over a large area. Therefore, we used W–Cu alloys to investigate an approach to mass production of surface microcavity structures over a large area. We then confirmed that the absorptivity in the visible light range could be increased by using this simple method.
Optimization of a Local District Heating Plant Under Fuel Flexibility and Performance
Authors: Rudra Souman , Rossendahl Lasse , From Niels
Published: March 2012

Brovst is a small district in Denmark. Based on the case of Brovst, this paper analyses the role of district heating in future Renewable Energy Systems. The present use of fossil fuels in the Brovst DHP (district heating plant) represents an increasing environmental and climate-related load. So, an investigation has been made to reduce the use of fossil fuels for district heating system and make use of the local renewable resources (Biogas, Solar and Geothermal) for district heating purpose. In this article, the techno-economic assessment is achieved through the development of a suite of models that are combined to give cost and performance data for this district heating system. Different local fuels have been analyzed for different perspectives to find the way to optimize the whole integrated system in accordance with fuel availability and cost. This paper represents the energy system analysis mode energyPRO which has been used to analyses the integration of large scale energy system into the domestic district heating system. A model of the current work on the basis of information from the plant (using fossil fuel) is established and named as a reference model. Then different solutions are calculated for various local fuels in energyPRO. A comparison has been made between the reference model and the basis for individual solutions. The greatest reduction in heat price is obtained by replacing one engine with a new biogas where heat production is divided by 66% of biogas, 13% natural gas engines and 21% natural gas boilers.
Optimizing Energy Conversion Using Organic Rankine Cycles and Supercritical Rankine Cycles
Authors: Chen Huijuan , Goswami D. Yogi , Rahman Muhammad M. , Stefanakos Elias K.
Published: March 2012

The optimization of energy conversion systems is of great significance in the utilization of low-grade heat. This paper presents an analysis of 6 working fluids in 12 thermodynamic cycles to optimize the energy conversion systems. The optimal exergy efficiency of the system is dependent on the type of the thermodynamic cycle, the choice of appropriate working fluid, and the working conditions. A zeotropic mixture of R134a and R245fa shows advantages in energy conversion process, as well as its heat exchange with the heat source and heat sink. The exergy efficiency of a 0.5R134a/0.5R245fa-based supercritical Rankine cycle system is 0.643–0.689 for a turbine inlet temperature of 415–445K, which is about 30% improvement over the exergy efficiency of 0.491–0.521 for a pure R32-based organic Rankine cycle under the same temperature limits. Furthermore, the 0.5R134a/0.5R245fa mixture saves more than 60% of the cooling water during the condensation process than the pure R32, R134a and R245fa.
Thermal Analysis of Low-Cost Dwellings in Mexico Using Greenroofs
Authors: Alpuche Mari´a G. , Marincic Irene , Ochoa Jose´ M. , Moreno Hugo C. , Giottonini Paloma
Published: March 2012

According to the National Energy Balance (1), the electricity consumption in the residential and commercial sector represents thirty-three percent of the total consumed in the country. Most of the energy is consumed during the summer, when it is necessary to use air conditioning to maintain comfort conditions inside buildings. This aspect takes relevance in warm-dry climates, where a deficient design of building envelope and a wrong location of windows can increase the thermal loads producing an extra load to air conditioning systems and high costs by electricity energy consumption. For this reason, adequate design strategies and thermodynamic concepts have to be applied in order to make dwellings comfortable. Two dwellings are simulated and analyzed, the first one is made of regional materials like traditional concrete block walls, reinforced concrete roofs and economic finishes, the second one is proposed with a green roof and insulation in walls. The heat gains through the different constructive elements have been obtained, to analyze their impact on global thermal comfort and the electricity energy consumption of air cooling systems. Also, an exergy analysis has been applied to analyze exergy efficiency of air cooling systems and the influence that the building envelope can have in them with the proposed changes. The minimum exergy expenditure of air conditioning systems required to achieve comfort conditions inside dwellings could be a useful benchmark for the comparison of various dwelling designs.
An Intelligent Sensor Framework for the Power Grid
Authors: Akyol Bora , Haack Jereme , Tews Cody , Carpenter Brandon , Kulkarni Anand , Craig Philip
Published: March 2012

The number of sensors connected to the electric power system is expected to grow by several orders of magnitude by 2020. However, the information networks which will transmit and analyze the resulting data are ill-equipped to handle the resulting volume with reliable real-time delivery. Without the ability to manage and use this data, deploying sensors such as phasor measurement units in the transmission system and smart meters in the distribution system will not result in the desired improvements in the power grid. The ability to exploit the massive data being generated by new sensors would allow for more efficient flow of power and increased survivability of the grid. Additionally, the power systems of today are not capable of managing two-way power flow to accommodate distributed generation capabilities due to concerns about system stability and lack of system flexibility. The research that we are performing creates a framework to add “intelligence” to the sensors and actuators being used today in the electric power system. Sensors that use our framework will be capable of sharing information through the various layers of the electric power system to enable two-way information flow to help facilitate integration of distributed resources. Several techniques are considered including use of peer-to-peer communication as well as distributed agents. Specifically, we will have software agents operating on systems with differing levels of computing power. The agents will cooperate to bring computation closer to the data. The types of computation considered are control decisions, data analysis, and demand/response. When paired with distributed autonomous controllers, the sensors form the basis of an information system that supports deployment of both micro-grids and islanding. Our efforts in the area of developing the next generation information infrastructure for sensors in the power grid form the basis of a broader strategy that enables better integration of distributed generation, distribution automation systems and decentralized control (micro-grids).
Effects of Altitude on Photovoltaic Production of Hydrogen
Authors: Dumas Antonio , Anzillotti Stefano , Madonia Mauro , Trancossi Michele
Published: March 2012

This paper compares hydrogen production by photovoltaic powered electrolysis of water at sea level and at low stratospheric altitudes up to 21 km. All the hydrogen production process has been considered from catchable solar radiation to storage technologies. The evaluation has been performed for 1 m2 of flat horizontal plane. It has been considered the electric energy amount produced considering variations in equilibrium temperature and in solar. Hydrogen production through electrolysis has been evaluated too. Two different methods of hydrogen storage have been evaluated: high pressure compression up to 20 MPa and liquefaction process. The energetic cost of both production processes has been evaluated. The comparison is presented in terms of effective energy deliverable to final users considered in terms of HHV. This evaluation considers also, in the case of liquefaction process the energy which can be recovered by the rigasification process.
Testing Performance, Weathering and Aging of Photovoltaic Modules
Authors: Trancossi Michele
Published: March 2012

This paper presents the ASTM WK22010 proposed standard on testing of photovoltaic modules. It aims to become a general framework that defines objective parameters regarding output production and lifecycle of modules and includes: - quantifying the PV module performance decay from the global effects of extended outdoor weather exposure and induced fatigue stress; - determine the mechanical resistance of modules to weathering from exposure to real outdoor or artificially created conditions, including extreme weather events; - determine the mechanical resistance and decay of optical characteristics of glasses from exposure to real outdoor or artificially created conditions, including extreme weather events; - determine the effective output production of modules and the resulting decay, during the expected module lifetime in real operating conditions and/or predefined artificial weather conditions; in order to predict performance in different real weather conditions from test result parameters.
HLRP Method as a Tool for Optimizing Energy Solutions Options
Authors: Kowalski Gregory J. , Zenouzi Mansour
Published: March 2012

The HLRP method is combined with optimization techniques to determine the best combination of a tri-generation system composed of a hybrid fuel cell system and alternative energy sources such as wind and solar energy. Solar thermal and photovoltaic systems with short term storage are used in this study. A small commercial site in Southern Europe is investigated. The HLRP method is based on using the ratio of the thermal load to the required power as the scaling parameter to analyze a hybrid fuel cell based tri-generation system in terms of performance parameters. The performance parameters, energy utilization factor, carbon dioxide and exergy destruction per total energy load, are reported in a series of graphs. The HLRP analysis is based on ideal performance of the power producing devices and practical performance parameters of all heat transfer devices. The alternative energy systems included in this analysis include state-of-the art performance measures. The previous publications on the HLRP method have focused on its development with short examples that illustrate how it operates as an effective, initial screening tool and limited cost factors. In this paper the application of the HLRP method as an early screening tool to determine the general outline of an efficient, total energy solution is detailed. The tool will be used to compare different solutions based on the fuel consumption (energy utilization factor), carbon dioxide production, exergy destruction and costs. The tradeoffs of reducing costs or increasing carbon dioxide production are illustrated. The solutions are based on a process using regression curves of the generalized graphs. The correlation coefficient for these regression relationships is greater than 0.996. In addition, refinement of the HLRP technique that reports carbon dioxide production and exergy destruction in terms of total energy rather than thermal loads has been adopted. Combining the generalized performance of the fuel consuming components with renewable energy sources leads to a solution based on balancing cost, minimizing fuel consumption or carbon dioxide production.
Analysis of the Energy Saving Potentials for Near-Zero Energy Buildings in Shanghai
Authors: Huang Joe , Seo Donghyun , Krarti Moncef
Published: March 2012

The Changning District in Shanghai has expressed interest to becoming a green neighborhood and has asked for recommendations on how to reduce the energy usage in public buildings in their district. The objective of this short study is to identify the likely range of further reductions in the energy use and carbon emissions of new buildings through energy-efficiency improvements and the use of renewable energy, i.e., solar hot water (SHW), photovoltaics (PV), and ground-source heat pumps (GSHP), as compared to buildings that meet the current public building energy code in Shanghai. This analysis is done using DOE-2.1E computer simulations of three prototypical building models — an office, a hotel, and a mixed-use retail/office building — that have been calibrated against measured energy data from such buildings in the Changning District. After the building models have been calibrated, they are then used to establish the baseline energy use for code-compliant buildings, and to calculate the energy savings for 16 potential EEMs (Energy Efficiency Measures) that exceed the building energy code. A LCC (Life-Cycle Cost) analysis is done to compare the energy cost reductions to the capital costs for the EEMs, with the result that some EEMs are rejected as being not cost-effective over a 25 year period. The usage of the EEMs accepted as cost-effective is found to reduce the energy usage of the three building types by 30–40% in the office, 43–46% in the hotel, and 35% in the retail, depending on the assumed discount rate. If all the EEMs are considered regardless of cost, the energy savings increase to 44% in the office, 47% in the hotel, and 36% in the retail.
Effects of Electrical Contact Resistance on External Energy Losses in Lithium-Ion Battery Packs for Hybrid and Electric Vehicles
Authors: Taheri Peyman , Hsieh Scott , Bahrami Majid
Published: March 2012

Lithium-ion (Li-ion) batteries are favored in hybrid-electric vehicles and electric vehicles for their outstanding power characteristics. In this paper the energy loss due to electrical contact resistance (ECR) at the interface of electrodes and current-collector bars in Li-ion battery assemblies is investigated for the first time. ECR is a direct result of contact surface imperfections and acts as an ohmic resistance at the electrode-collector joints. ECR is measured at electrode connections of a sample Li-ion battery, and a straightforward analysis is presented to evaluate the relevant energy loss. Through the experiments, it is observed that ECR is an important issue in energy management of Li-ion batteries. Effects of surface imperfection, contact pressure, joint type, collector bar material, and interfacial materials on ECR are highlighted. The obtained data show that in the considered battery, the energy loss due to ECR can be as high as 20% of the total energy flow in and out of the battery under normal operating conditions. However, ECR loss can be reduced to 6% when proper joint pressure and/or surface treatment are used. A poor connection at the electrode-collector interface can lead to a significant battery energy loss as heat generated at the interface. At sever conditions, heat generation due to ECR might cause serious safety issues, thermal runaway, sparks, and even melting of the electrodes.
Analysis and Energy Optimization for Biomethanol Production Using Palm Oil Biomass Residues
Authors: Go´mez Rafael , Corredor Lesme , A´vila Adrian , Mendoza Jorge , Bula Antonio
Published: March 2012

Palm oil extraction generates a great amount of biomass residues; i.e. kernel pieces, fiber and fruit bunches. The last is the major quantity, but it has limited usage as an energetic source due to physical-chemical characteristics and high humidity. Biodiesel production requires methanol, which is mainly produced form natural gas in very large industrial plants, oscillating between 700×103 to 1400 x103 tons per year. This paper presents an economical and technical analysis for production of biometanol from oil palm biomass residues, considering the requirements for the year 2019 in Colombia, which are expected to be 92.5 x103 tons. Different technological approximations are considered and the different parts for the selected process are dimensioned, due to the small size of the plant required. The process simulation is carried out using ASPENPLUS™, giving a global efficiency around 48%, and a yield of 43% for the biomass used. The production simulation allows comparing with the international price for methanol, and the cutting point is U$ 152/Ton. This value is compared with the international price of crude oil and it was found that it is only superior when the oil price is under U$ 20. Due to the tendency for oil prices to increase, it is feasible, at least form the economical point of view, to develop a small scale biometanol plant.
MEMS Sensors for Down-Hole Monitoring of Geothermal Energy Systems
Authors: Wodin-Schwartz Sarah , Chan Matthew W. , Mansukhani Kirti Ramesh , Pisano Albert P. , Senesky Debbie G.
Published: March 2012

This paper reviews the limitations in current down-hole monitoring technologies for geothermal energy systems and introduces microelectromechanical systems (MEMS) sensors as a means of optimizing well performance. The use of continuous, real-time, down-hole monitoring can improve geothermal well efficiencies and increase well life. More specifically, monitoring can aid in obtaining accurate temperature and pressure profiles to allow for optimized well reinjection and energy extraction. A variety of materials used in the fabrication of MEMS sensors have been tested in an experimental geothermal environment (critical-point water) and exposed for up to 100 hours. The results obtained from the exposure testing support the use of harsh environment materials to create a suite of sensors that can be permanently located down-hole. MEMS-based temperature and pressure sensors using a harsh environment materials platform are currently in the design phase for down-hole monitoring. In addition to designing harsh environment sensors that can reliably monitor down-hole conditions, suitable packaging must be considered. One vision is to mount the sensors to the well casings through the use of new bonding technologies.
Exergy Recuperation of Mid and Low Quality Heat by Chemical Reactions
Authors: Nakagaki Takao , Ozeki Takayuki , Watanabe Yuuta
Published: March 2012

Conventional thermal power generation, as typified by gas turbines, has steadily increased power generation efficiency by elevating temperature of heat, but there is a limit to the maximum availability of electric energy. Exergy rate is a unified index indicating the quality of energy in deferent forms. We have no way in thermal conversion to extract all of the availability, while almost hydrocarbon fuels have exergy rate around 95%. 25% of exergy is inevitably lost through the combustion process from chemical to heat at maximum temperature of 2000°C. Hydrogen’s low exergy rate provides “exergy recuperation” in which degrading 12% from 95% to 83% can take low quality heat up to availability of 83% as a kind of chemical heat pump. Chemically Recuperated Gas Turbine (CRGT) is a specific example, and dimethyl ether (DME) is one of the most suitable fuels because steam reforming occurs around 300°C. Electrochemical partial oxidation (EPOx) is another way to convert mid-quality heat into electric energy as much as difference between change in Gibbs free energy and change in enthalpy. This paper reports concept and industrially-feasible applications of this unconventional and non-cascadic use of heat.
Impacts of Climate Changes in the Northern Pacific Coast on Related Regional Scale Energy Demands
Authors: Sequera Pedro , Rhone Osei , Gonza´lez Jorge E. , Ghebreegziabher Amanuel T. , Bornstein Robert , Lebassi Bereket
Published: March 2012

For the past few decades sea surface temperatures across the globe have been increasing, causing changes in the global and regional climates. The focus of this study is to determine the impacts of these climate changes in coastal California region and possible linkages to energy infrastructure. The specific goal of this study is to determine the changes in cooling degree days (CDD) for the Northern Pacific Coast of the U.S., with emphasis on the California region for the years 1970 to 2007. Daily, monthly and annual temperature trends in months May, June, July, August and September are used to complement this analysis. Temperature data from more than 300 surface weather stations were obtained from the National Climatic Data Center (NCDC). The work follows recent findings by the authors where the decreasing of maximum summer temperatures in two coastal air basins of California was attributed to the increase in sea breeze flow. This was caused by regional climate changes which led to induced sealand asymmetric warming and referred to as a reverse-reaction of global warming. This study aims to analyze temperature trends along the entire North Pacific Coast and over time, showing how it relates in the same temporal and spatial scales to changes in CDD. Finally, the study explores the possible correlations of decadal trends of CDD with actual summer peak electric utility data demonstrating how regional climate changes are affecting regional energy demands.
Thermodynamic Analysis of CO2 Reduction in the SnO2/SnO Solar Thermochemical Cycle
Authors: Shafirovich Evgeny , Garcia Allen
Published: March 2012

CO2 utilization for the production of valuable chemical products may help mitigate two global problems: increasing CO2 concentration in the atmosphere and depleting petroleum resources. Solar thermochemical cycles for CO2 splitting provide relatively high efficiencies of solar energy conversion while operating at realistic temperatures. In the present paper, the cycles proposed previously are reviewed and a novel cycle, based on SnO2/SnO redox reactions, is proposed. The results of thermodynamic calculations for the CO2 reduction step in this cycle are reported.