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Quadrennial Technology Review: An Assessment of Energy Technologies and Research Opportunities, 2015

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... Currently, transportation sector alone consumes about 30% of the total energy in the USA [1]. Almost 95% of this energy comes from petroleum-based fuels [1,2]. ...
... Currently, transportation sector alone consumes about 30% of the total energy in the USA [1]. Almost 95% of this energy comes from petroleum-based fuels [1,2]. This situation raises two concerns: energy sources depletion and environmental impact: as projected, the worldwide oil reserves can only sustain 40-50 years at current consumption rate. ...
Article
Previously, the authors have developed an advanced combustion control, namely the trajectory-based combustion control, to further leverage the flexibility of free piston engine (FPE). With the assistance of this control method, the FPE enables optimization of both engine efficiency and emissions by implementing optimal piston trajectories. Extensive simulations have been conducted to prove the effectiveness of this combustion control on fossil fuels. In this paper, the investigation is extended to renewable fuels. Seven renewable fuels are considered herein including hydrogen, biogas, syngas, ethanol, dimethyl ether (DME), biodiesel, and Fischer-Tropsch fuel. The influences of both compression ratio (CR) and piston motion pattern between the two dead centers on the combustion process are considered in the study, which demonstrates the ultimate fuel flexibility and large tolerance of fuel impurity possessed by the FPE. In addition, the simulation results show that at a fixed CR, the thermal efficiency of the FPE can still be enhanced (5% in DME case) by varying the piston motion patterns alone. Furthermore, specific asymmetric piston trajectories are synthesized to further improve the engine thermal efficiency (8% in hydrogen case) and reduce the NOx emission simultaneously (around 70% reduction in hydrogen case). In other words, due to its ultimate fuel flexibility, large tolerance of fuel impurity, and controllable piston trajectory, the FPE, with the trajectory-based combustion control, enables a co-optimization of renewable fuels and engine operation.
... However, longer time performance is still needed for the s-CO2 application. [38]) ...
... There are four primary research focuses on the s-CO2 cycle material application: Carburization and sensitization, high-temperature corrosion, erosion, and creep and fatigue. [38] Carburization and sensitization focus on the long-term carburization behavior and maximum use temperature of the ferritic-martensitic and austenitic steels, which help identify the degradation mechanisms and for prediction of the useful life. High-temperature corrosion focuses on the long-time period testing of the candidate alloy to establish oxidization reaction kinetics and the rate of internal carburization and also on how impurities affect the corrosion rate at a higher-pressure level. ...
Conference Paper
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Around the 1960s, the proposal of the supercritical dioxide (s-CCO2) power-cycle was first introduced; however, because of various obstacles, the development was slow at that time. With current worldwide emission and power problems, the s-CO2 power cycle has regained more attention because of its unique properties as a working fluid for power-cycle, and zero-emission potential. Each s-CO2 power cycle requires various components for compression, expansion, and heat exchange operation. Among various working fluid, s-CO2 has four significant advantages favorable for developers: 1. Relatively low and achievable critical conditions (∼7.3Mpa, ∼31°C). 2. The high density (∼400kg/m3) results in a very compact turbomachinery design. 3. The low dynamic-viscosity of s-CO2 can reduce the overall flow friction loss. 4. Low compressibility value which can reduce the overall system compression works. All these advantages make the s-CO2 the perfect working fluid for next-generation high-efficiency power-cycle design. This paper in two parts reviews the s-CO2 cycle technologies for power generation and critically assesses the recent challenges and development status. This paper, Part I, focuses on the general cycle concepts, thermodynamic properties, materials selection, and other components considerations.
... Este trabajo tiene el objetivo de realizar una priorización de la investigación científica, desarrollo tecnológico y generación de innovación (I+D+i) en el área de la eficiencia energética y las energías renovables. Las diferentes líneas de investigación, así como los proyectos analizados fueron clasificados por motivos prácticos y de comparabilidad en siete categorías (DOE, 2015): El proceso de desarrollo fue llevado a cabo siguiendo el esquema de technology roadmapping, complementado con la metodología AHP para el proceso de priorización. Para estas dos metodologías se realizó una recolección de información de base sobre el contexto energético nacional y sobre las actividades científicas y tecnológicas que se llevan a cabo a escala global, regional (América Latina) y nacional. ...
... Por motivos de comparabilidad y para facilitar los análisis, los proyectos se han agrupado por líneas de investigación siguiendo un patrón propuesto en un estudio llevado a cabo en Estados Unidos sobre priorización de investigación en eficiencia energética y energía renovable (DOE, 2015). Estas líneas son: distribución de electricidad, tecnologías de generación eléctrica, eficiencia energética (EE) en edificios del sector residencial y comercial, eficiencia energética en la industria, combustibles alternativos y eficiencia energética en el transporte. ...
Book
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La matriz energética nacional está marcada por el elevado consumo en el sector transporte, seguido de lejos por el consumo en la industria. De forma paralela, la estructura de generación eléctrica evidencia la alta participación de la generación térmica e hidroeléctrica y la reducida participación de otras tecnologías de energía renovable. Se han realizado grandes avances para incrementar la participación de la energía renovable en la matriz energética nacional y mejorar la eficiencia energética. Muestra de ello son las políticas, regulaciones y proyectos implementados con este fin, que están plasmadas la Constitución de la República, el Plan Nacional del Buen Vivir (PNBV) y diferentes regulaciones del sector eléctrico. En el contexto económico mundial, es innegable la importancia del desarrollo científico-tecnológico y la generación de innovación, lo que exige la implementación de un proceso de planificación y priorización a mediano y largo plazo que permita que los resultados de la actividad científica se alineen con los objetivos estratégicos y metas de alcance nacional. Este documento muestra el proceso de elaboración de una propuesta de priorización de la actividad científica, el desarrollo tecnológico y la generación de innovaciones en eficiencia energética y energías renovables. Para esto se tomó como base la metodología de roadmapping tecnológico y se usó la herramienta de evaluación multicriterio AHP (Analytic Hierarchy Process, Proceso Analítico Jerárquico) para la priorización de las temáticas de investigación, tomando como principal insumo los aportes recogidos desde el sector académico del país. El primer capítulo de este documento presenta y analiza el contexto energético nacional, tomando como principal insumo el Balance Energético Nacional 2015. En el Capítulo II se analizan comparativamente los recursos y el desarrollo tecnológico en eficiencia energética y energías renovables a nivel nacional, regional y global. El Capítulo III muestra los resultados de un sondeo de las actividades de investigación, desarrollo e innovación (I+D+i) en energía realizadas en el Ecuador, ejecutado mediante encuestas al sector académico del país. Finalmente, el Capítulo IV recoge toda la información de los tres capítulos anteriores como insumos para la estructuración del modelo AHP para la priorización estratégica de las temáticas de investigación. Este documento muestra –como resultado del proceso de priorización– la investigación, el desarrollo y la innovación en tecnologías de generación eléctrica con inclusión de energías renovables, la eficiencia energética en transporte, la producción de combustibles alternativos y la distribución de electricidad como temáticas prioritarias, tomando en cuenta factores de apuntalamiento de la soberanía energética, reducción de gases de efecto invernadero (GEI) y producción de tecnología local. Este trabajo constituye el primer paso para la construcción de una propuesta de I+D+i en eficiencia energética y energías renovables a mediano plazo, en el que se ha puesto mayor énfasis en el análisis del sector académico nacional. En futuras actualizaciones del documento se integrará el análisis del sector productivo y el sector público necesarios para generar una propuesta integral de la investigación científica nacional en este ámbito con un horizonte a mediano plazo.
... The ACMV system typically combines an air conditioning system that removes the excess heat from the room air and the ventilation system replaces the contaminated room air with fresh air to provide better indoor air quality (IAQ) (Yao and Lin 2014b). The two systems account for more than 60% of the overall energy utilization in buildings (Department of Energy 2015). Many countries have adopted several techniques to cope up with the energy needs of these systems (Zheng et al. 2018). ...
Article
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In this paper, the performance of an integrated variable refrigerant flow (VRF) system with the stratum ventilation (SV) system was numerically examined and compared with the experimental measurements in terms of temperature distribution and airflow patterns. In total six different configurations were designed and analyzed. The results suggest that configuration 5 was greatly satisfied the airflow movement needs. The positive thermal gradient with a modest airflow velocity (< 0.8 m/s) was setup in the entire breathing zone. The indoor temperature in the range of 20°C-22°C was seen throughout the occupied space, except for some places near the walls. Furthermore, a very strong airflow throw from the SV supply terminals was observed with the recommended value of face velocity. Hence, the VRF-SV hybrid system could achieve a better thermal comfort (TC) and indoor air quality (IAQ) in large ACMV applications. ARTICLE HISTORY
... Residential and commercial buildings consume about 60% of the electricity globally 2 . Improving building energy efficiency becomes essential to meet energy savings and carbon emission reduction goals 3 . As the electrification progresses, there is an ongoing trend to replace traditional fossil fuel with renewable power generations. ...
Article
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This paper presents a synthetic building operation dataset which includes HVAC, lighting, miscellaneous electric loads (MELs) system operating conditions, occupant counts, environmental parameters, end-use and whole-building energy consumptions at 10-minute intervals. The data is created with 1395 annual simulations using the U.S. DOE detailed medium-sized reference office building, and 30 years’ historical weather data in three typical climates including Miami, San Francisco, and Chicago. Three energy efficiency levels of the building and systems are considered. Assumptions regarding occupant movements, occupants’ diverse temperature preferences, lighting, and MELs are adopted to reflect realistic building operations. A semantic building metadata schema - BRICK, is used to store the building metadata. The dataset is saved in a 1.2 TB of compressed HDF5 file. This dataset can be used in various applications, including building energy and load shape benchmarking, energy model calibration, evaluation of occupant and weather variability and their influences on building performance, algorithm development and testing for thermal and energy load prediction, model predictive control, policy development for reinforcement learning based building controls.
... In recent years, further progress has been made in the identification and implementation of energy demand reduction strategies in buildings. This trend was created by an increased adoption of more efficient equipment, better insulation, more efficient windows, and population shifts to warmer climates [2]. This shift in how energy is consumed in homes has seen that even if per-household energy consumption has steadily declined, more homes are using air-conditioning than in the past. ...
Article
The potential for application of downdraught cooling in the United States of America (U.S.) depends on its climatic characteristics. However, due to the large geographic span of the country, it varies due to differences in latitude, and a range of geographic features influencing climate, including altitude, topography and terrain. This study describes the development of climatic applicability maps of downdraught cooling in the U.S., which can aid designers in the initial identification of the correct cooling strategy for the geographic area of interest. The proposed approach is based on a set of maps, which are derived from two related climatic indexes: dry bulb temperature to wet bulb temperature depression (DBT−WBT), representing the climatic opportunity, and 26 °C minus wet bulb temperature (26 °C−WBT), representing the climatic opportunity against the theoretical cooling requirement for each location. The downdraught cooling strategy and degree of applicability is classified in the map, based on the aforementioned climatic and cooling parameters. Finally, four representative buildings in four different regions with different climatic conditions were selected for climatic analysis. This resulted in the identification of some climate zones for downdraught cooling application in the U.S. and the suggestion of appropriate design strategies for each of them.
... Concerns over increase in global primary energy consumption [1], greenhouse gas emissions, climate change [2], enormous amount of wasted energy [3], and dependency on the conventional fossil fuel energy resources [4] have made researchers eager for seeking low-grade heat driven sustainable heating and cooling methods. Adsorption technologies, including adsorption thermal energy storage (ATES) [5], adsorption cooling systems [6], adsorption heat pumps [7], and desiccant air conditioning systems [8], can steer the energy sources toward low-carbon sustainable alternatives, e.g., thermal solar, industrial low-grade waste-heat and geothermal energy. ...
Article
Low thermal conductivity in packed bed adsorbers is a crucial challenge facing widespread adoption of low-grade heat adsorption thermal energy storage systems. In this work, thermal conductivities of 2-mm diameter AQSOA FAM-Z02 packed bed adsorbers with different numbers of adsorbent layers are measured, using a NETZSCH HFM 436/3/1E Lambda, in the temperature range of 10-80 °C and under atmospheric pressure. Effects of thermal contact resistance (TCR) between the adsorbent particles and the bed metal surfaces are deconvoluted from the total thermal resistance. Effective thermal conductivities of the adsorber packed bed are 0.188 and 0.204 W m⁻¹ K⁻¹ at temperatures of 10 and 80 °C, respectively. It is observed that the relative importance of TCR compared to the total thermal resistance of a monolayer FAM-Z02 packed bed, is 67% at 25 °C and under contact pressure of 0.7 kPa, which is significant and should be considered in the design of adsorption systems.
Article
This paper solves the inverse dynamics of a tethered kite analytically. Specifically, the paper presents a procedure for determining the angle of attack, induced roll angle, and tether tension magnitude needed to achieve a desired combination of translational kite position, velocity, and acceleration. The focus of the paper is on energy harvesting kites. However, the underlying approach is applicable to other kite systems, such as kites for propulsion (e.g., SkySails). Solving inverse kite dynamics analytically is valuable for trajectory optimization, online state estimation, and the analysis of fundamental limitations on kite maneuvers. Previous work in the literature presents several models of kite dynamics, with varying degrees of fidelity and complexity. However, the nonlinearity of these models often makes them difficult to use for optimization, estimation, and control. The paper shows that, under reasonable assumptions, inverse kite dynamics can be solved in terms of the roots of a fourth-order polynomial function of angle of attack. This function has a geometric interpretation, providing insight into the multiplicity of resulting solutions. Moreover, for special cases including a kite with non-cambered wings, these solutions can be computed analytically. A simulation validates the success of the proposed approach in computing inverse kite dynamics for a cross-current trajectory.
Article
Summer peak electric demand of commercial buildings and districts is typically driven by the cooling load. This paper presents a novel approach to holistically optimize both the air- and water-side of the HVAC system in existing commercial districts. Therefore, this paper is different from the existing literature in its focus on integrated optimization of both air- and water-side of the HVAC system in a district scale as opposed to only airside or waterside. Methodologies proposed in this paper for integrated optimization of air- and water-side are brand-agnostic and their capabilities are demonstrated using a chilled water plant at Colorado School of Mines’ campus. Based on the results for the test district, Mines’ integrated air- and water-side optimizations of the HVAC system reduces its peak electric demand by 15% and 13%, respectively, for August 19 and 20, 2019. The air- and water-side optimization of the HVAC system resulted in greater savings than that achieved with only the waterside demand optimization method discussed in authors' previous paper focused on existing commercial districts.
Article
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Electrochromic (EC) smart windows offer a promising paradigm for intelligent control of heat and light, reducing ≈40% building‐energy expenses, which are widely expected as a key contributor to future global carbon neutrality and sustainability. Enabling arbitrarily shaped EC film devices can unlock promising capabilities in various smart building systems and intelligent color‐changeable wearable devices. Regrettably, their wide deployment has been largely limited by the complicated edge encapsulation processes; otherwise, the leakage/loss of electrolyte and environmental corrosions would rapidly lead to device failure. This article reports a blood coagulation‐analogous strategy to tackle this critical challenge by introducing an oxygen‐sensitive prepolymer (i.e., alkyd resin) as the electrolyte additive, making it free of packaging. When exposed to the air, this prepolymer can rapidly cure and form a dense solid barrier through a free radical reaction with the CH bond on the 1,4‐diene side chains, without sacrificing any EC performances, including excellent mechanical flexibility and robustness. Besides the fast self‐packageable and arbitrarily tailorable capabilities, they can also deliver outstanding environmental‐stability after harsh aging. This mechanism potentially makes large‐scale customized production and thus the application of EC devices become possible and may significantly boost the broad application of such a sustainable and fashionable technology.
Chapter
Energy is one of the critical issues that directly impact the economy, the environment, and the security of human beings. All energy technologies require materials; therefore, the types and amounts of materials consumed vary widely. While materials science and engineering are only one aspect of the response to the energy challenges, it primarily has a crucial part to play in creating the advanced energy systems. In the past, it has contributed significantly to advances in the safe, reliable, and efficient use of energy and available natural resources. Now materials research is being performed from structural materials, functional materials to high photon energies, which can offer promising solutions to achieve accessible, renewable, and sustainable energy pathways for the future. Particularly, the growing importance of environmental issues is such that energy generation, conservation, storage, and security of supply will continue to be major drivers for materials technology. Sustainable energy production and use are needed while at the same time meeting socioeconomic and environmental targets: The high priority of energy makes it important to sustain research, development, and modeling of materials for energy applications; the knowledge-base of high-integrity structural and functional materials should be recovered, captured, and developed for future power generation; transferable material solutions and methods across the complete energy portfolio should be examined to attain maximum efficiency and competitive advantages. With the advent of nanomaterials and innovative multifunctional materials, materials science and engineering is expected to play an increasing role in sustainable technologies for energy generation, storage, and distribution, as well as efficient utilization of future energy. Principal areas of advanced materials development include but not limited to sustainable structural and functional materials for fossil power, solar energy, wind energy, geothermal energy, biofuels, ocean energy and hydropower, nuclear power, as well as advanced energy-harvesting technologies. This chapter will introduce fundamentals and basic design guidelines of advanced energy systems with accompany of materials solutions and environmental compliance of energy materials.
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