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Efficiency

Sandia National Laboratory

High Voltage Re-grown GaN P-N Diodes Enabled by Defect and Doping Control

Vertical transistors based on bulk gallium nitride (GaN) have emerged as promising candidates for future high efficiency, high power applications. However, they have been plagued by poor electrical performance attributed to the existing selective doping processes. Sandia National Laboratories will develop patterned epitaxial regrowth of GaN as a selective area doping processes to fabricate diodes with electronic performance equivalent to as-grown state-of-the-art GaN diodes. The team's research will provide a better understanding of which particular defects resulting from impurities and etch damage during the epitaxial regrowth process limit device performance, how those defects specifically impact the junction electronic properties, and ultimately how to control and mitigate the defects. The improved mechanistic understanding developed under the project will help the team design specific approaches to controlling impurity contamination and defect incorporation at regrowth interfaces and include development of in-chamber cleans and regrowth initiation processes to recover a high-quality epitaxial surfaces immediately prior to crystal regrowth.

Sandia National Laboratory

Multi-Modal Monitoring of Plant Roots for Drought & Heat Tolerance in the US Southwest

Sandia National Laboratories will develop novel, field-deployable sensor technologies for monitoring soil, root, and plant systems. First, the team will develop microneedles similar and shape and function to hypodermic needles used in transdermal drug delivery and wearable sensors. The minimally invasive needles will be used to report on sugar concentrations and water stress in leaves, stems, and large roots in real-time. Continuously monitoring the sugar concentrations at multiple locations will be transformative in understanding whole plant carbon dynamics and the function of the vascular tissues that conduct sugars and other metabolic products downward from the leaves. The second key technology are gas chromatographs deployed in the soil and near plants in order to monitor volatile organic compounds (VOC). Plants synthesize and release volatile organic compounds both aboveground and belowground that act as chemical signals or in response to biotic stress (damage from insects, bacteria, etc.) or abiotic stress (such as drought, flooding, and extreme temperatures). VOCs modulate biomass uptake and the team hopes to better understand soil composition by measuring VOC transport. The team's integrated microsensor technologies will be deployed in arid environments in both natural and agricultural lands to characterize whole plant function in both environments. Applying these sensors to plants in arid environments could assist in re-greening arid ecosystems with new specially bred plants developed and selected to improve soil function with less water and nutrient requirements while depositing more soil carbon.

Scanalytics

Floor Sensors for Occupancy Counting in Commercial Buildings

Scanalytics will develop pressure-sensitive flooring underlayers capable of sensing large areas of commercial buildings with a high-resolution and fast response time. This technology will enable the precise counting of people in commercial environments like stores, offices, and convention centers. The floor sensors will consist of a material which changes electrical resistance when compressed. Conductive elements above and below the material will measure the resistance at a grid of points within the floor mat, and electronics will control the switching between sensors, cache the results for transmission, and transmit the readings to a local gateway for analysis. The team's system and data processing algorithms will be developed to resolve multiple people in close proximity, as well as account for non-typical travel methods such as wheelchairs and crutches. This occupancy information may be passed directly to HVAC control, or combined with occupancy information from other sensors to manage the heating, cooling and air flow in order to maximize building energy efficiency and provide optimal human comfort. Energy costs of heating and cooling can be reduced by up to 30% by training the building management system to deliver the right temperature air when and where it is needed.

Sheetak, Inc.

Non-Equilibrium Asymmetic Thermoelectric (NEAT) Devices

Sheetak is developing a thermoelectric-based solid state cooling system that is more efficient, more reliable, and more affordable than today's best systems. Many air conditioners are based on vapor compression, in which a liquid refrigerant circulates within the air conditioner, absorbs heat, and then pumps it out into the external environment. Sheetak's system, by contrast, relies on an electrical current passing through the junction of two different conducting materials to change temperature. Sheetak's design uses proprietary thermoelectric materials to achieve significant energy efficiency and, unlike vapor compression systems, contains no noisy moving parts or polluting refrigerants. Additionally, Sheetak's air conditioner would be made with some of the same manufacturing processes used to produce semiconductor chips, which could lead to less material use and facilitate more affordable production.

SiCLAB, Rutgers University, NJ

First In-Class Demonstration of a Completely New Type of SiC Bipolar Switch (15kV-20kV)

The Rutgers University SiCLAB is developing a new power switch for utility-scale PV inverters that would improve the performance and significantly reduce the size, weight, and energy loss of PV systems. A power switch controls the electrical energy flowing through an inverter, which takes the electrical current from a PV solar panel and converts it into the type and amount of electricity that is compatible with the electric grid. SiCLAB is using silicon carbide (SiC) semiconductors in its new power switches, which are more efficient than the silicon semiconductors used to conduct electricity in most conventional power switches today. Switches with SiC semiconductors can operate at much higher temperatures, as well as higher voltage and power levels than silicon switches. SiC-based power switches are also smaller than those made with silicon alone, so they result in much smaller and lighter electrical devices. In addition to their use in utility-scale PV inverters, SiCLAB's new power switches can also be used in wind turbines, railways, and other smart grid applications.

Signetron Inc.

Using a Smart-Phone for Fast, Automated Energy Audit of Buildings

Signetron is developing a technology that will enable fast, cost effective, and accurate energy audits without the need for expensive, skilled labor to collect data manually. Signetron's innovation integrates low-cost visible and infrared optical cameras into a handheld scanner with depth sensing. This enables the operator to capture indoor 3D maps of building geometry and energy-relevant features as they traverse a building. Captured data is uploaded to the cloud where it is analyzed by Signetron software to generate an energy model and provide actionable energy audit information. If successful, this technology will reduce the time and cost associated with today's energy audits by a factor of 5 and 10 respectively, while offering actionable energy-saving recommendations. This technology could lower the cost barrier for building energy audits, thereby enabling property owners and facility managers to better understand the sources of energy loss in their buildings and where to optimally target retrofits to improve energy savings.

SixPoint Materials, Inc.

GaN Homoepitaxial Wafers by Vapor Phase Epitaxy on Low-Cost, High-Quality Ammonothermal GaN Substrates

SixPoint Materials will create low-cost, high-quality vertical gallium nitride (GaN) substrates for use in high-power electronic devices. In its two-phase project, SixPoint Materials will first focus on developing a high-quality GaN substrate and then on expanding the substrate's size. Substrates are thin wafers of semiconducting material used to power devices like transistors and integrated circuits. SixPoint Materials will use a two-phase production approach that employs both hydride vapor phase epitaxy technology and ammonothermal growth techniques to create its high-quality, low-cost GaN substrates.

SolarBridge Technologies, Inc.

Scalable Submodule Power Conversion for Utility-Scale Photovoltaics

SolarBridge Technologies is developing a new power conversion technique to improve the energy output of PV power plants. This new technique is specifically aimed at large plants where many solar panels are connected together. SolarBridge is correcting for the inefficiencies that occur when two solar panels that encounter different amounts of sun are connected together. In most conventional PV system, the weakest panel limits the energy production of the entire system. That's because all of the energy collected by the PV system feeds into a single collection point where a central inverter then converts it into useable energy for the grid. SolarBridge has found a more efficient and cost-effective way to convert solar energy, correcting these power differences before they reach the grid.

Sonrisa Research, Inc.

A New Class of SiC Power MOSFETs with Record-Low Resistance

Sonrisa Research will develop a new class of SiC power transistors using a simple three-dimensional architectural modification to reduce the channel resistance by up to a factor of nine. To accomplish this, Sonrisa will etch trenches into the basic planar MOSFET, increasing its effective channel width without increasing its overall area. This is similar to the fin-type field-effect transistor (FinFET) geometry popular in advanced Si integrated circuits, but in a configuration that meets high-power application needs. A different structural modification will be used to reduce the substrate resistance. The combination of lower channel and substrate resistance will enable SiC MOSFETs to displace silicon MOSFETs and insulated-gate bipolar transistors (IGBTs) in the blocking voltage regime below 1200V broadening the useful application space and furthering their adoption.

Soraa, Inc.

High-Pressure Ammonothermal Process for Bulk Gallium Nitride Crystal Growth for Energy Efficient Commercially Competitive Lighting

Soraa's new GaN crystal growth method is adapted from that used to grow quartz crystals, which are very inexpensive and represent the second-largest market for single crystals for electronic applications (after silicon). More extreme conditions are required to grow GaN crystals and therefore a new type of chemical growth chamber was invented that is suitable for large-scale manufacturing. A new process was developed that grows GaN crystals at a rate that is more than double that of current processes. The new technology will enable GaN substrates with best-in-world quality at lowest-in-world prices, which in turn will enable new generations of white LEDs, lasers for full-color displays, and high-performance power electronics.

Soraa, Inc.

Large-Area, Low-Cost Bulk GaN Substrates for Power Electronics

Soraa will develop a cost-effective technique to manufacture high-quality, high-performance gallium nitride (GaN) crystal substrates that have fewer defects by several orders of magnitude than conventional GaN substrates and cost about 10 times less. Substrates are thin wafers of semiconducting material needed to power devices like transistors and integrated circuits. Most GaN-based electronics today suffer from very high defect levels and, in turn, reduced performance. In addition to reducing defects, Soraa will also develop methods capable of producing large-area GaN substrates--3 to 4 times larger in diameter than conventional GaN substrates--that can handle high-power switching applications.

SRI International

Direct Low-Cost Production of Titanium Alloys

SRI International is developing a reactor that is able to either convert titanium tetrachloride to titanium powder or convert multiple metal chlorides to titanium alloy powder in a single step. Conventional titanium extraction and conversion processes involve expensive and energy intensive melting steps. SRI is examining the reaction between hydrogen and metal chlorides, which could produce titanium alloys without multiple complicated steps. Using titanium powder for transportation applications has not been practical until now because of the high cost of producing powder from titanium ingots. SRI's reactor requires less material because it produces powder directly rather than converting it from intermediate materials such as sponge or ingot. Transforming titanium production into a direct process could reduce costs and energy consumption by eliminating energy intensive steps and decreasing material inputs.

SRI International

Window Retrofit Applique Using Phonon Engineering (WRAP)

SRI International, in collaboration with its partners will develop a transparent, adhesive film that can be easily applied to single-pane windows to reduce heat loss from warm rooms during cold weather. The team proposes an entirely new approach to thermal barriers and will develop a new class of non-porous materials that use nanoparticles to reflect heat and provide superior thermal insulation. Moreover, the transparent film does not block visible light, meaning that the coating allows light to transmit through the window and brighten the interior. The film could also improve the soundproofing of the window.

SRI International

STATIC Radiative Cooling for Cold Storage

SRI International and PPG Industries are integrating SRI's proprietary Spectrally Tuned All-Polymer Technology for Inducing Cooling (STATIC) technology into a novel structure for use as a radiative cooling system that can provide supplemental cooling for power plant water during the daytime or nighttime. The two-layer polymer structure covers a pool holding power plant condenser discharge water. The cover prevents sunlight from penetrating it and warming the water, while allowing thermal energy to radiate to the sky, even during the day. The STATIC structure provides an insulating air gap to prevent conductive and convective heating, and both layers work in concert to reject solar energy. Specifically, the bottom layer acts as an emitter at the water temperature and radiates heat to the sky, while the top layer and key component, produced using STATIC technology, enables transmittance of the thermal radiation. The cooling power can achieve greater than 100 W/m2 without evaporation. All materials are inexpensive and amenable to scalable manufacturing techniques, which could lower the cost of the system.

SRI International

Wearable Electroactive Textile for Physiology-based Thermoregulation

SRI International will develop a highly efficient, wearable thermal regulation system that leverages the human body's natural thermal regulation areas such as the palms of the hands, soles of feet, and upper facial area. This innovative "active textile" technology is enabled by a novel combination of low-cost electroactive and passive polymer materials and structures to efficiently manage heat transfer while being quiet and comfortable. SRI's electronically controllable active textile technology is versatile - allowing the wearer to continue to use their existing wardrobe. We believe that these features will allow for products that augment wearable technologies and thus achieve the widespread adoption needed to save energy on a large scale.

Stanford University

Large-Scale Energy Reductions through Sensors, Feedback, and Information Technology

A team of researchers from more than 10 departments at Stanford University is collaborating to transform the way Americans interact with our energy-use data. The team built a web-based platform that collects historical electricity data, which it uses to perform a variety of experiments to learn what triggers people to respond. Experiments include new financial incentives, a calculator to understand the potential savings of efficient appliances, new Facebook interface designs, communication studies using Twitter, and educational programs with the Girl Scouts. Economic modeling is underway to better understand how results from the San Francisco Bay Area can be broadened to other parts of the country.

Stanford University

Utilizing CO2 for Commodity Polymer Synthesis

Stanford University will develop a new process to produce furan-2,5-dicarboxylic acid (FDCA), a potential replacement for purified terephthalic acid (PTA). PTA is produced from petroleum on the scale of 60 million tons per year and used to make synthetic polymers like polyester. The production of PTA is associated with 90 million tons of greenhouse gas emissions annually. FDCA, on the other hand, can be made from biomass and its polymers boast superior physical properties for high-volume applications such as beverage bottles. Current technologies produce FDCA from food sources (fructose) and have not demonstrated economic competitiveness with PTA. The Stanford technology produces FDCA from CO2 and furfural, a feedstock chemical produced industrially from waste biomass. The use of CO2 avoids challenging oxidation reactions required for fructose-based syntheses, which provides a potential advantage for commercial production. Packed-bed reactors utilizing the technology have achieved high FDCA yields but require reaction times that are too long for industrial application. This project will transition the process to a fluidized bed reactor, where reactants are suspended in flowing CO2, to achieve industrially viable synthesis rates. If optimized, the process could enable the production of FDCA with negative greenhouse gas emissions.

Stanford University

Exploring the Limits of Cooling for Extreme Heat Flux Applications: Data Centers and Power Electronics

Stanford will develop an innovative cooling technology, the Extreme Heat Flux Micro- (EHF?-) Cooler, to improve reliability and performance in power electronics by offering improved chip thermal management. The cooler employs a novel liquid wicking, thin-film evaporator, with microchannels to route liquid and the resulting vapor, with the net effect of improved heat removal rates at manageable pressure drops. This significantly increases heat flux thereby reducing the device (chip) temperature. The design could increase heat transfer rates by an order of magnitude compared with today's corresponding state-of-the-art cooling technologies. Improved cooling devices could greatly increase efficiency, reliability, and performance for microprocessors and power electronics.

Stanford University

High Efficiency Wafer-Scale Thermionic Energy Converters

By leveraging advanced microfabrication processes, the team led by Stanford University will develop a scalable heat-to-electricity conversion device with higher performance at a lower manufacturing cost than is presently available to industry. The team's solid-state conversion device is based on a 20th century thermionic converter design, where an electric current is produced by heating up an electrode to eject electrons across a vacuum gap for collection by a cooler electrode. Historically, thermionic energy converters are limited by heat losses and are costly to manufacture due to the high precision used in their construction. However, by utilizing wafer-based fabrication processes to create a much smaller vacuum gap and enhanced thermal isolation structures, Stanford's thermionic converter will result in improved device performance, lower manufacturing cost, and a scalability for systems producing Watts to Megawatts of power. The team's initial focus is on the residential Combined Heat and Power (CHP) applications, but their innovative microfabricated thermionic device could also be used to improve efficiency in high-temperature solar thermal systems as well as convert waste heat from factory equipment, power plants, and vehicles to useful power.

Stanford University

Photonic Structure Textiles for Localized Thermal Management

Stanford University will develop transformative methods for integrating photonic, or radiant energy structures into textiles. Controlling the thermal photonic properties of textiles can significantly influence the heat dissipation rate of the human body, which loses a significant amount of heat through thermal radiation. To achieve heating, the team utilizes metallic nanowire embedded in textiles to enhance reflection of body heat. To achieve cooling, the team utilizes visibly opaque yet infrared transmissivity (IR) transparent textile. These techniques for heating and cooling have not yet been achieved to date. The team will leverage advances in photonic structures to build textiles with varying amounts of infrared transparency and reflectivity to enable a wearer to achieve comfort in a wider temperature range, and therefore generate a substantial reduction of energy consumption for both heating and cooling.

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