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Photovoltaic Cz Silicon Module Improvements

Description: Work focused on reducing the cost per watt of Cz silicon photovoltaic modules under Phase II of Siemens Solar Industries' DOE/NREL PVMaT 4A subcontract is described in this report. New module designs were deployed in this phase of the contract, improvements in yield of over 10% were realized, and further implementation of Statistical Process Control was achieved during this phase. Module configurations representing a 12% cost reduction per watt were implemented in small scale production under Phase II of this contract. Yield improvements are described in detail, yield sensitivity to wafer thickness is quantified, and the deployment of SPC in critical process steps is reported here.
Date: September 1, 1998
Creator: Jester, T. L.
Partner: UNT Libraries Government Documents Department

High Efficiency Amorphous and Microcrystalline Silicon Based Double-Junction Solar Cells made with Very-High-Frequency Glow Discharge

Description: We have achieved a total-area initial efficiency of 11.47% (active-area efficiency of 12.33%) on a-Si:H/μc-Si:H double-junction structure, where the intrinsic layer bottom cell was made in 50 minutes. On another device in which the bottom cell was made in 30 min, we achieved initial total-area efficiency of 10.58% (active-efficiency of 11.35%). We have shown that the phenomenon of ambient degradation of both μc-Si:H single-junction and a-Si:H/μc-Si:H double-junction cells can be attributed to impurity diffusion after deposition. Optimization of the plasma parameters led to alleviation of the ambient degradation. Appropriate current matching between the top and bottom component cells has resulted in a stable total-area efficiency of 9.7% (active-area efficiency of 10.42%) on an a-Si:H/μc-Si:H double-junction solar cell in which the deposition time for the μc-Si:H intrinsic layer deposition was of 30 min.
Date: October 20, 2004
Creator: Banerjee, Arindam
Partner: UNT Libraries Government Documents Department

PV Charging System for Remote Area Operations

Description: The objective of this project is to provide the public with a study of new as well existing technology to recharge batteries used in the field. A new product(s) will also be built based upon the information ascertained. American Electric Vehicles, Inc. (AEV) developed systems and methods suitable for charging state-of-the-art lithium-ion batteries in remote locations under both ideal and cloudy weather conditions. Conceptual designs are described for existing and next generation technology, particularly as regards solar cells, peak power trackers and batteries. Prototype system tests are reported.
Date: July 31, 2008
Creator: Ilsemann, Frederick & Thompson, Roger
Partner: UNT Libraries Government Documents Department

Ocean Thermal Energy Conversion: An Overall Environmental Assessment

Description: Significant acccrmplishments in Ocean Thermal Energy Conversion (OTEC) technology have increased the probability of producing OTEC-derived power within this decade with subsequent large scale commercialization following by the turn of the century. Under U.S. Department of Energy funding, the Oceanic Engineering Operations of Interstate Electronics Corporation has prepared several OTEC Environmental Assessments over the past years, in particular, the OTEC Programmatic Environmental Assessment. The Programmatic EA considers several technological designs (open- and closed-cycle), plant configuratlons (land-based, moored, and plant-ship), and power usages (baseload electricity, ammonia and aluminum production). Potential environmental impacts, health and safetv issues and a status update of the institutional issues as they influence OTEC deployments, are included.
Date: August 1, 1980
Creator: Sands, M.Dale
Partner: UNT Libraries Government Documents Department

Ocean Thermal Energy Conversion Programmatic Environmental Assessment

Description: Significant achievements in Ocean Thermal Energy Conversion (OTEC) technology have increased the probability of producing OTEC-derived power in this decade with subsequent large-scale commercialization to follow by the turn of the century. Under U.S. Department of Energy funding, Interstate Electronics has prepared an OTEC Programmatic Environmental Assessment (EA) that considers tne development, demonstration, and commercialization of OTEC power systems. The EA considers several tecnnological designs (open cycle and closed cycle), plant configurations (land-based, moored, and plantship), and power usages (baseload electricity and production of ammonia and aluminum). Potencial environmental impacts, health and safety issues, and a status update of international, federal, and state plans and policies, as they may influence OTEC deployments, are included.
Date: August 1, 1980
Creator: Sands, M.Dale
Partner: UNT Libraries Government Documents Department

Ultra Barrier Topsheet (UBT) for Flexible Photovoltaics

Description: This slideshow presents work intended to: Scale-up the Generation -1 UBT to 1+meter width full-scale manufacturing; Develop a Generation-2 UBT on the pilot line, targeting improved performance, longer lifetime and lower cost; Transfer Generation-2 UBT from the pilot line to the full-scale manufacturing line in 2014; and Validate service life of Generation-1 UBT for the 25+ year lifetime. 3M has scaled up UBT for production at 1.2 meter width. 3M is conducting extensive lifetime studies including: –Evaluation of customer processing and installation conditions; –Indoor accelerated testing of UBT film and full CIGS modules; –Outdoor testing of UBT film and CIGS modules. Results have been used to improve ultra barrier film performance for flex module applications.
Date: January 9, 2013
Creator: Schubert, Charlene
Partner: UNT Libraries Government Documents Department

Reducing the Cost of Thermal Energy Storage for Parabolic Trough Solar Power Plants

Description: Thermal energy storage systems using phase change materials were evaluated for trough systems that use oil, steam, and high temperature salts as heat transfer fluids. A variety of eutectic salts and metal alloys were considered as phase change materials in a cascaded arrangement. Literature values of specific heat, latent heat, density, and other thermophysical properties were used in initial analyses. Testing laboratories were contracted to measure properties for candidate materials for comparison to the literature and for updating the models. A TRNSYS model from Phase 1 was further developed for optimizing the system, including a novel control algorithm. A concept for increasing the bulk thermal conductivity of the phase change system was developed using expanded metal sheets. Outside companies were contracted to design and cost systems using platecoil heat exchangers immersed in the phase change material. Laboratory evaluations of the one-dimensional and three-dimensional behavior of expanded metal sheets in a low conductivity medium were used to optimize the amount of thermal conductivity enhancement. The thermal energy storage systems were compared to baseline conventional systems. The best phase change system found in this project, which was for the high temperature plant, had a projected cost of $25.2 per kWhth, The best system also had a cost that was similar to the base case, a direct two-tank molten salt system.
Date: June 25, 2013
Creator: Gawlik, Keith
Partner: UNT Libraries Government Documents Department


Description: The purpose of this project is to provide measurements and analyses of the solar and circumsolar radiation for application to solar energy systems that employ lenses or mirrors to concentrate the incident sunlight. Circumsolar radiation results from the scattering of direct sunlight through small angles by atmospheric aerosols (e.g., dust, water-droplets or ice crystals in thin clouds). Concentrating solar energy systems will typically collect all of the direct solar radiation (that originating from the disk of the sun) plus some fraction of the circumsolar radiation. The exact fraction depends upon many factors, but primarily upon the angular size (field-of-view) of the receiver. A knowledge of the circumsolar radiation is then one factor in predicting or evaluating the performance of concentrating systems. The project employs unique instrument systems (called Circumsolar Telescopes) that were designed and fabricated at LBL. The basic measurements are (1) the "circumsolar scan", the brightness of the sun and circumsolar region as a function of angular distance from the center of the sun and (2) the usual "normal incidence" measurement of a pyrheliometer. Both measurements are made for the entire solar spectrum, and (via colored filters) for eight essentially contiguous wavelength bands. Thus the measurements are applicable to systems in which the receiver is essentially wavelength-insensitive (e.g., central receiver) and to wavelength-sensitive systems (e.g., concentrating photovoltaics). A secondary purpose of the project is to relate the data to the atmospheric processes that attenuate the solar radiation available to terrestrial solar energy systems.
Date: October 1, 1980
Creator: Grether, Donald; Evans, David; Hunt, Arlon & Wahlig, Michael
Partner: UNT Libraries Government Documents Department


Description: Common control strategies used to regulate the flow of liquid through flat-plate solar collectors are discussed and evaluated using a dynamic collector model. Performance of all strategies is compared using different set points, flow rates, insolation levels and patterns (clear and cloudy days), and ambient temperature conditions. The unique characteristic of the dynamic collector model is that it includes effects of collector capacitance. In general, capacitance has a minimal effect on long term collector performance; however, short term temperature response and the energy =storage capability of collector capacitance are shown to play significant roles in comparing on/off and proportional controllers. Inclusion of these effects has produced considerably more realistic simulations than any generated by steady-state models. Simulations indicate relative advantages and disadvantages of both types of controllers, conditions under which each performs better, and the importance of pump cycling and controller set points on total energy collection. Results show that the turn-on set point is not always a critical factor in energy collection since collectors store energy while they warm up and during cycling; and, that proportional flow controllers provide improved energy collection only during periods of interrupted or very low insolation when the maximum possible energy collection is rela= tively low. Although proportional controllers initiate flow ·at lower insolation levels than on/off controllers, proportional controllers produce lower flow rates and higher average collector temperatures resulting in slightly lower instantaneous collection efficiencies.
Date: December 1, 1979
Creator: Schiller, Steven R.; Warren, Mashuri L. & Auslander, David M.
Partner: UNT Libraries Government Documents Department


Description: A new type of reciprocating solar engine utilizing small particles to absorb concentrated sunlight directly within the cylinders is described. The engine operates by drawing an air particle mixture into the cylinder, compressing the mixture, opening an optical valve to allow concentrated sunlight to enter through a window in the top of the cylinder head, absorbing the solar flux with the particles, and converting the heat trapped by the air-particle mixture into mechanical energy with the downward stroke of piston. It differs from other gas driven heat engines using solar energy in three main respects. First, the radiant flux is deposited directly in the working fluid inside the cylinder; second, the heat is directed to the appropriate cylinder by controlling the solar flux by an optical system; third, the gas is heated during a significant portion of the compression stroke. The thermodynamic efficiency of the engine is calculated using an analytical model and is compared to several other engine cycles of interest.
Date: May 1, 1981
Creator: Hull, Patricia G. & Hunt, Arlon J.
Partner: UNT Libraries Government Documents Department


Description: An experimental test facility for solar heating and cooling has been constructed to evaluate the operation and performance of an LBLdeveloped solar controller that has promising commercial potential. The LBL controller was designed to be intermediate in performance between a simple differential thermostat and an on-line microprocessor. The PROM~based controller operates the solar system according to a preprogrammed algorithm that translates operating state conditions (fluid temperatures, switch positions, comparator outputs) into a set of operating instructions (open or close valves, turn pumps on or off). The operating algorithm can be changed by reprogramming or exchanging the plug-in integrated circuit component, or by changing the sensors selected for comparison. The experimental solar heating system can be operated using different control algorithms, input meteorological conditions, and output load demands. In FY 1979 the test facility became operational and initial testing began. Emphasis has been on refinement of system instrumentation and the development of necessary computer software to run the facility and perform data analysis. Preliminary energy balance experiments with the load and collector loops under microcomputer control were successfully completed in November 1979. Experiment modifications have been completed to permit variable-flow and proportional-flow control of the collector loop. A series of experimental comparisons of proportional and on/off collector loop strategies are planned using typical meteorological year data. The evaluation of configurations for combined domestic hot water and heating systems has begun to determine necessary experiment modifications to test one and two tank domestic hot water systems in combination with hydronic space heating systems. Other work has included the application of theoretical models to describe dynamic collector operation and building temperature response. Theoretical analysis of the energy collection performance of on/off and proportional flow control collector loop strategies has been completed. Papers have been presented at the Second System Simulation and Economics Conference ...
Date: March 1, 1980
Creator: Warren, Mashuri L.; Schiller, Steven R. & Wahlig, Michael
Partner: UNT Libraries Government Documents Department


Description: An analytical Detailed Loop Model (DLM) has been developed to analyze the performance of solar thermosiphon water heaters with heat exchangers in storage tanks. The model has been used to study the performance of thermosiphons as a function of heat exchanger characteristics, heat transfer fluids, flow resistances, tank stratification, and tank elevation relative to the collector. The results indicate that good performance can be attained with these systems compared to thermosiphons without heat exchangers.
Date: June 1, 1981
Creator: Mertol, A.; Place, W.; Webster, T. & Greif, R.
Partner: UNT Libraries Government Documents Department


Description: Two methods to assist designers in selecting and evaluating fixed, rectangular shading devices for rectangular wall and roof apertures early in the design process are presented. Both methods are based upon a simple mathematical technique called SHADE. The first method is visual, using graphics prepared in advance by a computer program and the existing Libby-Owens-Ford Sun Angle Calculator to design appropriate shading during early stages of architectural design. The second method uses a Hewlett Packard 41C programmable calculator to refine the design by analysis of shading effects at specific hours, and to generate numerical data for use with detailed hand calculations of building loads. Each method is described, its advantages are noted, and an example of the use of each is given. Possible extensions and potential applications are discussed.
Date: October 1, 1980
Creator: Nawrocki, Dave; Andersson, Brandt & Kammerud, Ronald
Partner: UNT Libraries Government Documents Department

Recovery Act: Novel Kerf-Free PV Wafering that provides a low-cost approach to generate wafers from 150um to 50um in thickness

Description: The technical paper summarizes the project work conducted in the development of Kerf-Free silicon wafering equipment for silicon solar wafering. This new PolyMax technology uses a two step process of implantation and cleaving to exfoliate 50um to 120um wafers with thicknesses ranging from 50um to 120um from a 125mm or 156mm pseudo-squared silicon ingot. No kerf is generated using this method of wafering. This method of wafering contrasts with the current method of making silicon solar wafers using the industry standard wire saw equipment. The report summarizes the activity conducted by Silicon Genesis Corporation in working to develop this technology further and to define the roadmap specifications for the first commercial proto-type equipment for high volume solar wafer manufacturing using the PolyMax technology.
Date: May 6, 2013
Creator: Fong, Theodore E.
Partner: UNT Libraries Government Documents Department

Solar America Initiative State Working Group: Final Scientific/Technical Report

Description: Through the support from the Department of Energy, NARUC has educated thousands of stakeholders, including Public Utility Commissioners, commission staff, and State energy officials on solar energy technology, implementation, and policy. During the lifetime of this grant, NARUC staff engaged stakeholders in policy discussions, technical research, site visits, and educational meetings/webinars/materials that provided valuable education and coordination on solar energy technology and policy among the States. Primary research geared toward State decision-makers enabled stakeholders to be informed on current issues and created new solar energy leaders throughout the United States. Publications including a Frequently Asked Questions guide on feed-in tariffs and a legal analysis of state implementation of feed-in tariffs gave NARUC members the capacity to understand complex issues related to the economic impacts of policies supportive of solar energy, and potential paths for implementation of technology. Technical partnerships with the National Renewable Energy Laboratory (NREL) instructed NARUC members on feed-in tariff policy for four States and solar PV resource assessment in seven States, as well as economic impacts of solar energy implementation in those States. Because many of the States in these technical partnerships had negligible amounts of solar energy installed, this research gave them new capacity to understand how policies and implementation could impact their constituency. This original research produced new data now available, not only to decision-makers, but also to the public at-large including educational institutions, NGOs, consumer groups, and other citizens who have an interest in solar energy adoption in the US. Under this grant, stakeholders engaged in several dialogs. These educational opportunities brought NARUC members and other stakeholders together several times each year, shared best practices with State decision-makers, fostered partnerships and relationships with solar energy experts, and aided in increasing the implementation of smart policies that will foster solar technology deployment. The support from ...
Date: March 30, 2012
Creator: Taylor, Julie
Partner: UNT Libraries Government Documents Department

Purdue Solar Energy Utilization Laboratory

Description: The objective of this project is to establish and set-up a laboratory that will facilitate research and development of new low-cost and high-efficiency solar energy utilization technologies at Purdue University. The outcome will help spur the creation of solar energy start-up companies and eventually a solar energy industry in Indiana that can help fulfill the growing national demand for solar energy.
Date: January 21, 2014
Creator: Agrawal, Rakesh
Partner: UNT Libraries Government Documents Department

Economic Feasibility and Market Readiness of Solar Technologies. Draft Final Report. Volume I.

Description: Systems descriptions, costs, technical and market readiness assessments are reported for ten solar technologies: solar heating and cooling of buildings (SHACOB), passive, agricultural and industrial process heat (A/IPH), biomass, ocean thermal (OTEC), wind (WECS), solar thermal electric, photovoltaics, satellite power station (SPS), and solar total energy systems (STES). Study objectives, scope, and methods. are presented. of Joint Task The cost and market analyses portion 5213/6103 will be used to make commercialization assessments in the conclusions of. the final report.
Date: September 1, 1978
Creator: Flaim, Silvio J.; Buchanan, Deborah L.; Christmas, Susan; Fellhauer, Cheryl; Glenn, Barbara; Ketels, Peter A. et al.
Partner: UNT Libraries Government Documents Department

Cleanable and Hardcoat Coatings for Increased Durability of Silvered Polymeric Mirrors

Description: We have successfully developed coating formulations which significantly increasethe abrasion resistance of mirror films. We have demonstrated manufacturing scale-up of these films to full width andproduction volumes. Implementation of these films in commercial test sites is planned for Q2 2013(Abengoa, Gossamer Space Frames). This slide show outlines the background and objectives of the project, technical approach and results, and key lessons. It also presents the need and opportunity for reduction of costs for CSP and collectors. It also presents an approach for a large aperture parabolic trough collector with reflective film and a high concentration factor, including demonstration and results.
Date: April 1, 2013
Creator: Padiyath, Raghunath
Partner: UNT Libraries Government Documents Department

Adaptive Full-Spectrum Solar Energy Systems Cross-Cutting R&D on adaptive full-spectrum solar energy systems for more efficient and affordable use of solar energy in buildings and hybrid photobioreactors

Description: This RD&D project is a multi-institutional effort to develop a hybrid solar lighting (HSL) system that transports daylight from a paraboloidal dish concentrator to a luminaire via a bundle of polymer fiber optics. The luminaire can be a device to distribute sunlight into a space for the production of algae for CO{sub 2} sequestration or it can be a device that is a combination of daylighting and electric lighting for space/task lighting. In this project, the sunlight is collected using a one-meter paraboloidal concentrator dish with two-axis tracking. For the third generation (beta) system, the secondary mirror is an ellipsoidal mirror that directs the visible light into a bundle of 3 mm diameter fibers. The IR spectrum is filtered out to minimize unnecessary heating at the fiber entrance region. This report describes the major achievements from this research that began in August 2001.
Date: March 30, 2006
Creator: Wood, Byard & Kim, Kwang
Partner: UNT Libraries Government Documents Department

Submission of Final Scientific/Technical Report [Solar Avoided Cost Solution: SunShot 6 Final Report]

Description: The core objectives of this project were two separate but integrated products, collectively providing game-changing Avoided Cost capabilities. • The first was a kit of avoided cost tools and data that any solar provider can use a-lacarte or as a whole. It’s open and easily accessible nature allows the rapid and accurate calculation of avoided cost in whatever context and software that make sense (“Typical and Avoided Cost Tools”). This kit includes a dataset of typical energy rates, costs and usage that can be used for solar prospecting, lead generation and any situation where data about an opportunity is missing or imperfect. • The second is a web application and related APIs specifically built for solar providers to radically streamline their lead-to-sale process (“Solar Provider Module”). The typical and Avoided Cost tools are built directly into this, and allow for solar providers to track their opportunities, collaborate with their installers and financiers, and close more sales faster.
Date: January 29, 2014
Creator: Danziger, Eric
Partner: UNT Libraries Government Documents Department

Photoelectrochemistry, Electronic Structure, and Bandgap Sizes of Semiconducting Cu(I)-Niobates and Cu(I)-Tantalates

Description: Semiconducting metal-oxides have remained of intense research interest owing to their potential for achieving efficient solar-driven photocatalytic reactions in aqueous solutions that occur as a result of their bandgap excitation. The photocatalytic reduction of water or carbon dioxide to generate hydrogen or hydrocarbon fuels, respectively, can be driven on p-type (photocathodic) electrodes with suitable band energies. However, metal-oxide semiconductors are typically difficult to dope as p-type with a high mobility of carriers. The supported research led to the discovery of new p-type Cu(I)-niobate and Cu(I)-tantalate film electrodes that can be prepared on FTO glass. New high-purity flux syntheses and the full structural determination of several Cu(I)-containing niobates and tantalates have been completed, as well as new investigations of their optical and photoelectrochemical properties and electronic structures via density-functional theory calculations. For example, CuNbO3, Cu5Ta11O30 and CuNb3O8 were prepared in high purity and their structures were characterized by both single-crystal and powder X-ray diffraction techniques. These two classes of Cu(I)-containing compounds exhibit optical bandgap sizes ranging from ~1.3 eV to ~2.6 eV. Photoelectrochemical measurements of these compounds show strong photon-driven cathodic currents that confirm the p-type semiconductor behavior of CuNbO3, CuNb3O8, and Cu5Ta11O30. Incident-photon-to-current efficiencies are measured that approach greater than ~1%. Electronic-structure calculations based on density functional theory reveal the visible-light absorption stems from a nearly-direct bandgap transition involving a copper-to-niobium or tantalum (d10 to d0) charge-transfer excitations.
Date: November 14, 2013
Creator: Maggard, Paul A.
Partner: UNT Libraries Government Documents Department


Description: The topic of daylighting, particularly in commercial buildings, is discussed, including economic aspects, control of daylight, fenestration functions, data gathering, design tools and methods, and lighting controls.
Date: August 1, 1980
Creator: Selkowitz, Stephen & Johnson, Richard
Partner: UNT Libraries Government Documents Department

Alternative Energy for Higher Education

Description: This project provides educational opportunities creating both a teaching facility and center for public outreach. The facility is the largest solar array in Nebraska. It was designed to allow students to experience a variety of technologies and provide the public with opportunities for exposure to the implementation of an alternative energy installation designed for an urban setting. The project integrates products from 5 panel manufacturers (including monocrystalline, polycrystalline and thin film technologies) mounted on both fixed and tracking structures. The facility uses both micro and high power inverters. The majority of the system was constructed to serve as an outdoor classroom where panels can be monitored, tested, removed and replaced by students. As an educational facility it primarily serves students in the Creighton University and Metropolitan Community College, but it also provides broader educational opportunities. The project includes a real-time “dashboard” and a historical database of the output of individual inverters and the corresponding meteorological data for researcher and student use. This allows the evaluation of both panel types and the feasibility of installation types in a region of the country subject to significant temperature, wind and precipitation variation.
Date: February 22, 2012
Creator: Michael Cherney, PhD
Partner: UNT Libraries Government Documents Department