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Energy efficiency

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Articles 1 - 22 of 22

Full-Text Articles in Mechanical Engineering

Note On The Rate And Energy Efficiency Limits For Additive Manufacturing, Timothy Gutowski, Sheng Jiang, Daniel Cooper, Gero Corman, Michael Hausmann, Jan-Anders Manson, Timo Schudeleit, Konrad Wegener, Matias Sabelle, Jorge Ramos-Grez, Dusan P. Sekulic Oct 2017

Note On The Rate And Energy Efficiency Limits For Additive Manufacturing, Timothy Gutowski, Sheng Jiang, Daniel Cooper, Gero Corman, Michael Hausmann, Jan-Anders Manson, Timo Schudeleit, Konrad Wegener, Matias Sabelle, Jorge Ramos-Grez, Dusan P. Sekulic

Mechanical Engineering Faculty Publications

We review the process rates and energy intensities of various additive processing technologies and focus on recent progress in improving these metrics for laser powder bed fusion processing of metals, and filament and pellet extrusion processing of polymers and composites. Over the last decade, observed progress in raw build rates has been quite substantial, with laser metal processes improving by about 1 order of magnitude, and polymer extrusion processes by more than 2 orders of magnitude. We develop simple heat transfer models that explain these improvements, point to other possible strategies for improvement, and highlight rate limits. We observe a ...


Hybrid Metal Oxide Cycle Water Splitting, Richard B. Diver Jr., Robert D. Palumbo, Nathan P. Siegel, James E. Miller Jan 2017

Hybrid Metal Oxide Cycle Water Splitting, Richard B. Diver Jr., Robert D. Palumbo, Nathan P. Siegel, James E. Miller

Other Faculty Research and Publications

Hybrid thermochemical water splitting systems are disclosed that thermally reduces metal oxides particles to displace some but not all of the electrical requirements in a water splitting electrolytic cell. In these hybrid systems, the thermal reduction temperature is significantly reduced compared to two-step metal-oxide thermochemical cycles in which only thermal energy is required to produce hydrogen from water. Also, unlike conventional higher temperature systems where the reduction step must be carried out under reduced oxygen pressure, the reduction step in the proposed hybrid systems can be carried out in air, allowing for thermal input by a solar power tower with ...


Evaluating The Performance Of Passive Chilled Beams With Respect To Energy Efficiency And Thermal Comfort, Janghyun Kim Dec 2016

Evaluating The Performance Of Passive Chilled Beams With Respect To Energy Efficiency And Thermal Comfort, Janghyun Kim

Open Access Dissertations

Existing modeling approaches for passive chilled beams determined from tests on individual chilled beams in a laboratory are not adequate for assessing overall energy usage and occupant comfort within building simulation programs. In addition, design guidelines for passive chilled beam systems are needed for identifying appropriate applications and optimal configurations. This thesis includes (i) extensive experimental studies for characterizing the performance of passive chilled beams, in both laboratory settings and in field studies, (ii) development of passive chilled beam performance prediction models, (iii) integration of these models into building simulation models/tools and (iv) use of building simulation for overall ...


Development And Use Of The Energy Model Of A Research And Demonstration House With Advanced Design Features, Nelson Fumo, Vicente Bortone Jun 2016

Development And Use Of The Energy Model Of A Research And Demonstration House With Advanced Design Features, Nelson Fumo, Vicente Bortone

Mechanical Engineering Faculty Publications and Presentations

Advances on manufacturing processes and the use of new materials are increasing the efficiency and reducing the cost of energy efficient and renewable energy technologies to a point that their deployment will reach desired levels for the sake of energy security and environmental concerns. Along these advances, the demonstration of the cost-effectiveness of this technology is vital to educate people and promote deployment of these technologies. In this sense, at the University of Texas at Tyler, two research and demonstration houses were built. House #1 is a conventional design with some advanced features, and House #2 has more advanced design ...


How Can Occupancy Modeling And Occupancy Sensors Reduce Energy Usage In Academic Buildings: An Application Approach To University Of San Francisco, Paloma R. Duong May 2016

How Can Occupancy Modeling And Occupancy Sensors Reduce Energy Usage In Academic Buildings: An Application Approach To University Of San Francisco, Paloma R. Duong

Master's Projects and Capstones

Buildings are amongst the highest energy consumers relative to industry and transportation. They account for 40% of the world’s energy consumption, due to the need for lighting, equipment, heating, cooling and ventilation. Academic buildings are multi-purpose buildings that create a challenge on energy reduction. Most are old and have fixed occupancy schedules, resulting in high energy consumption because these buildings experience significant occupancy variation throughout the day. Five academic buildings were analyzed; their building information, energy consumption data and methods to project energy savings have been analyzed. The case studies presented different strategies on predicting energy savings, but these ...


Hybrid Metal Oxide Cycle Water Splitting, Richard B. Diver Jr, Robert D. Palumbo, Nathan P. Siegel, James E. Miller Jan 2016

Hybrid Metal Oxide Cycle Water Splitting, Richard B. Diver Jr, Robert D. Palumbo, Nathan P. Siegel, James E. Miller

Other Faculty Research and Publications

Hybrid thermochemical water splitting cycles are provided in which thermally reduced metal oxides particles are used to displace some but not all of the electrical requirements in a water splitting electrolytic cell. In these hybrid cycles, the thermal reduction temperature is significantly reduced compared to two-step metal-oxide thermochemical cycles in which only thermal energy is required to produce hydrogen from water. Also, unlike the conventional higher temperature cycles where the reduction step must be carried out under reduced oxygen pressure, the reduction step in the proposed hybrid cycles can be carried out in air, allowing for thermal input by a ...


Operational Planning In Combined Heat And Power Systems, Hariharan Gopalakrishnan Nov 2014

Operational Planning In Combined Heat And Power Systems, Hariharan Gopalakrishnan

Doctoral Dissertations

This dissertation presents methodologies for operational planning in Combined Heat and Power (CHP) systems. The subject of experimentation is the University of Massachusetts CHP system, which is a 22 MWe/640 MBh system for a district energy application. Systems like this have complex energy flow networks due to multiple interconnected thermodynamic components like gas and steam turbines, boilers and heat recovery steam generators and also interconnection with centralized electric grids. In district energy applications, heat and power requirements vary over 24 hour periods (planning horizon) due to changing weather conditions, time-of-day factors and consumer requirements. System thermal performance is highly ...


Improving Indoor Air Quality Through Botanical Air Filtration In Energy Efficient Residences, Daniel William Newkirk Apr 2014

Improving Indoor Air Quality Through Botanical Air Filtration In Energy Efficient Residences, Daniel William Newkirk

Open Access Theses

According to the U.S. EPA, the average American spends 90% of their time indoors where pollutants are two to five times more prevalent than outside. The consequences of these pollutants are estimated to cost the U.S. 125 billion dollars in lost health and productivity. Background literature suggests botanical air filtration may be able to solve this problem by leveraging the natural ability of plants to purify indoor air. By improving indoor air quality, energy consumption can also be reduced by bringing in less outside air to dilute contaminants within the space. A botanical air filter, called the Biowall ...


A Metaevaluation Of Energy Efficiency Evaluations, Brandy Brown Apr 2014

A Metaevaluation Of Energy Efficiency Evaluations, Brandy Brown

Dissertations

This study systematically reviews the methodological characteristics of energy efficiency evaluations and uses metaevaluation to assess its quality. Metaevaluation is used to systematically assess the quality of evaluation products, confirm that evaluations deliver sound findings and conclusions, are useful to the client, are credible, are ethically conducted, and are done as cost-effective as possible. The results of this study show that the ability to accurately assess evaluation for methodological quality using evaluations reports as a primary data source depends on the presence of detailed descriptions of evaluation methods. Furthermore, the study suggests that methodological variations of energy efficiency evaluations coalesce ...


Low Frequency Energy Scavenging Using Sub-Wave Length Scale Acousto-Elastic Metamaterial, Raiz U. Ahmed, Sourav Banerjee Jan 2014

Low Frequency Energy Scavenging Using Sub-Wave Length Scale Acousto-Elastic Metamaterial, Raiz U. Ahmed, Sourav Banerjee

Faculty Publications

This letter presents the possibility of energy scavenging (ES) utilizing the physics of acousto-elastic metamaterial (AEMM) at low frequencies (<∼3KHz). It is proposed to use the AEMM in a dual mode (Acoustic Filter and Energy Harvester), simultaneously. AEMM’s are typically reported for filtering acoustic waves by trapping or guiding the acoustic energy, whereas this letter shows that the dynamic energy trapped inside the soft constituent (matrix) ofmetamaterials can be significantly harvested by strategically embedding piezoelectric wafers in the matrix. With unit cell AEMM model, we experimentally asserted that at lower acoustic frequencies (< ∼3 KHz), maximum power in the micro Watts (∼35µW) range can be generated, whereas, recently reported phononic crystal based metamaterials harvested only nano Watt (∼30nW) power against 10KΩ resistive load. Efficient energy scavengers at low acoustic frequencies are almost absent due to large required size relevant to the acoustic wavelength. Here we report sub wave length scale energy scavengers utilizing the coupled physics of local, structural and matrix resonances. Upon validation of the argument through analytical, numerical and experimental studies, a multi-frequency energy scavenger (ES) with multi-cellmodel is designed with varying geometrical properties capable of scavenging energy (power output from ∼10µW – ∼90µW) between 0.2 KHz and 1.5 KHz acoustic frequencies.


Plasmonics Resonance Enhanced Active Photothermal Effects In Aluminum Nanoenergetics For Propulsion Applications, Jacques Abboud Aug 2013

Plasmonics Resonance Enhanced Active Photothermal Effects In Aluminum Nanoenergetics For Propulsion Applications, Jacques Abboud

Doctoral Dissertations

In this dissertation, aluminum nanoparticles (Al NPs) are shown capable to on-demand enhance and control the local photothermal energy deposition, both spatially and temporally, via active photothermal effects initiated by the localized surface plasmon resonance (LSPR) phenomenon, and amplified by the Al exothermal oxidation reactions. Experiments in dry and wet environments along with computational modeling of the photothermal process are very desirable for gaining fundamental understanding, ignition optimization and parameter exploration.

Combined phenomena of motion and ignition of Al NPs are explored first in this study. Both resulting from exposing a pile of the nanoenergetics in hand to a single ...


Design Of An Energy Efficient Virtual End Node Client Using Openadr2.0a And Smap, Kevin Navero Jun 2013

Design Of An Energy Efficient Virtual End Node Client Using Openadr2.0a And Smap, Kevin Navero

BioResource and Agricultural Engineering

Demand Response (DR) describes the set of actions taken to impose a reduction in electrical loads to stabilize the power grid and decrease costs. It is used when power grid emergencies or extremely high demand and congestion, threaten the electricity supply-demand balance. Automated Demand Response (ADR) describes a web-based control system that triggers DR events automatically by signaling other pre-programmed control systems. This project intends to use the OpenADR2.0 specifications provided by the OpenADR Alliance to construct an open source Virtual End Node (VEN) client to retrieve DR signals. The Simple Measurement and Actuation Profile (sMAP) software is also ...


Investigation Of Peak Load Reduction Strategies In Residential Buildings In Cooling Dominated Climates, Fady Atallah May 2013

Investigation Of Peak Load Reduction Strategies In Residential Buildings In Cooling Dominated Climates, Fady Atallah

UNLV Theses, Dissertations, Professional Papers, and Capstones

This investigation of peak load reduction strategies in residential buildings contributes to the global international efforts in reducing energy consumption and is related directly to energy efficiency in residential and commercial buildings. Work reported here involves computer aided building energy simulation of energy efficient and non-energy efficient residential homes coupled with empirical energy consumption data gathered from monitoring an array of energy efficient residential homes. The latter have been implemented for peak load reduction strategies. In addition non-energy efficient residential homes have been monitored to compare performance to the energy efficient homes. This study demonstrates the crucial importance of energy ...


Synthesis And Growth Kinetics Of Spindly Cuo Nanocrystals Via Pulsed Wire Explosion In Liquid Medium Jan 2013

Synthesis And Growth Kinetics Of Spindly Cuo Nanocrystals Via Pulsed Wire Explosion In Liquid Medium

A.S. Md Abdul Haseeb

One-dimensional CuO nanocrystals with spindly structure were successfully synthesized using pulsed wire explosion technique in deionized water. By modulating the exploding medium temperature spherical Cu nanoparticles and one-dimensional CuO nanocrystals can be selectively synthesized. At low temperature (1 C) the particle growth is governed by Ostwald ripening resulting in formation of equidimensional crystals (spherical). As the exploding temperature increases (60 C), oriented aggregation in a preferential direction resulted in unique spindly nanostructure. A possible crystal growth mechanism for these nanostructures with various morphologies at different exploding temperature is proposed. Particle growth by Ostwald ripening or orientated aggregation is highly dependent ...


Synthesis And Growth Kinetics Of Spindly Cuo Nanocrystals Via Pulsed Wire Explosion In Liquid Medium Jan 2013

Synthesis And Growth Kinetics Of Spindly Cuo Nanocrystals Via Pulsed Wire Explosion In Liquid Medium

A.S. Md Abdul Haseeb

One-dimensional CuO nanocrystals with spindly structure were successfully synthesized using pulsed wire explosion technique in deionized water. By modulating the exploding medium temperature spherical Cu nanoparticles and one-dimensional CuO nanocrystals can be selectively synthesized. At low temperature (1 C) the particle growth is governed by Ostwald ripening resulting in formation of equidimensional crystals (spherical). As the exploding temperature increases (60 C), oriented aggregation in a preferential direction resulted in unique spindly nanostructure. A possible crystal growth mechanism for these nanostructures with various morphologies at different exploding temperature is proposed. Particle growth by Ostwald ripening or orientated aggregation is highly dependent ...


Transient And Quasi-Steady Thermal Behaviour Of A Building Envelope Due To Retrofitted Cavity Wall And Ceiling Insulation, Aimee Byrne, Gerard Byrne, Anna Davies, Anthony Robinson Jan 2013

Transient And Quasi-Steady Thermal Behaviour Of A Building Envelope Due To Retrofitted Cavity Wall And Ceiling Insulation, Aimee Byrne, Gerard Byrne, Anna Davies, Anthony Robinson

Articles

Accurate understanding of the thermal behaviour of building components is essential for predicting heat-ing or cooling needs and facilitates the implementation of more successful energy saving strategies and retrofits. This paper focuses on a specific measure commonly introduced through the residential energy efficiency retrofit programmes in Ireland–insulation. Traditionally, assessments of the performance of building envelopes have been based on assumed thermal resistances of the materials involved, labora-tory tests and computer modelling. The aim of the present work is to investigate the in situ thermal behaviour of a case study building and its components under transient and quasi-steady environmental conditions ...


Development And Implementation Of A Simplified Residential Energy Asset Rating Model, Daire Reilly, Aidan Duffy, David Willis, Michael Conlon Jan 2013

Development And Implementation Of A Simplified Residential Energy Asset Rating Model, Daire Reilly, Aidan Duffy, David Willis, Michael Conlon

Other resources

In accordance with national and European policies, the provision of financial assistance to residential energy consumers has led to a greater awareness of and interest in energy retrofit technologies. However, at present Irish energy consumers have no appropriate advice on the future performance of retrofit options available to them. This is a significant limitation to decision making and technology uptake, since this group need to know whether their investment is likely to be worthwhile.

The asset rating methodology developed for the certification of energy performance of buildings is the current industry standard of prediction of energy demand and post retrofit ...


Reconfigurable Sampling For Enhanced Energy Efficiency In Power-Constrained Wireless Systems, Timothy Kurp Jun 2011

Reconfigurable Sampling For Enhanced Energy Efficiency In Power-Constrained Wireless Systems, Timothy Kurp

Master's Theses

Advancement in microelectronics and wireless communications has nurtured the development of low power and low cost wireless systems such as sensor networks. Each node is typically driven by a battery, which has a limited energy capacity that directly constrains node, and network lifetime. This presents a bottleneck for the widespread exploitation of wireless sensing technology. Therefore, improving the energy efficiency of wireless sensing devices is of critical importance and has attracted the attention of the research community.

In this work, a data-driven method has been proposed and systematically investigated. Specifically, this technique reconfigures, in real time, the rate of data ...


Survey And Sustainability Of Energy Technologies, Joshua Donald Gifford Jan 2011

Survey And Sustainability Of Energy Technologies, Joshua Donald Gifford

Graduate Theses and Dissertations

This thesis is composed of three articles that survey and assess the sustainability of various automotive and power generation technologies.

"Four economies of sustainable automotive transportation" is a journal article has been accepted by Biofuels, Bioproducts, and Biorefining, while "Survey of power generation technologies" is a draft chapter for the upcoming book Handbook of Data Mining for Power Systems, and finally, "Four economies of sustainable power generation" is a draft journal article.

Vehicles fueled by compressed natural gas were found to offer the best overall performance considering operating cost, water usage, energy efficiency, and greenhouse gas emissions for the automotive ...


Nrel: A Year In Clean Energy Innovations: A Review Of Nrel's Feature Stories, National Renewable Energy Laboratory Jan 2010

Nrel: A Year In Clean Energy Innovations: A Review Of Nrel's Feature Stories, National Renewable Energy Laboratory

Publications (E)

The National Renewable Energy Laboratory (NREL) is the nation’s primary laboratory for renewable energy and energy efficiency research and development.

NREL’s mission and strategy are focused on advancing the U.S. Department of Energy’s and our nation’s energy goals. The laboratory’s scientists and researchers support critical market objectives to accelerate research from scientific innovations to market-viable alternative energy solutions. At the core of this strategic direction are NREL’s research and technology development competencies. These areas span from understanding renewable resources for energy, to the conversion of these resources to renewable electricity and fuels, and ...


Reducing Energy Costs By Optimizing Controller Tuning, Aidan O'Dwyer Jan 2006

Reducing Energy Costs By Optimizing Controller Tuning, Aidan O'Dwyer

Conference papers

The proportional integral derivative (PID) controller is the most dominant form of automatic controller in industrial use today. With this technique, it is necessary to adjust the controller parameters according to the nature of the process. This tailoring of controller to process is known as controller tuning. Controller tuning is easily and effectively performed using tuning rules (i.e. formulae for controller tuning, based on process information). Such tuning rules allow the easy set up of controllers to achieve optimum performance at commissioning. Importantly, they allow ease of re-commissioning if the characteristics of the process change. The paper outlines the ...


The Optimized Electrostatic Motor, Christopher Lee Rambin Jul 1998

The Optimized Electrostatic Motor, Christopher Lee Rambin

Doctoral Dissertations

The most common means of electrically activated actuation is the electromagnetic motor. All electromagnetic motors have a low output to weight ratio and low energy efficiency. The motor's weight is due to the coils and magnets used to generate propulsion. The energy loss is mainly the result of Joule heating that is inherent with any current driven device. An electrostatic motor offers the potential of significantly less weight and higher energy efficiency. This lower weight characteristic is due to the epoxide material used to construct the major components of its propulsion unit. Greater efficiency results from the reduced Joule ...