ReflecTech® Polymer Mirror Film Advancements in Technology and Durability Testing

2011 ◽  
Author(s):  
Michael J. DiGrazia ◽  
Gary Jorgensen ◽  
Randy Gee ◽  
Carl Bingham ◽  
Christa Loux
Keyword(s):  
Uv Light ◽  
Water Immersion ◽  
Accelerated Weathering ◽  
Production Environment ◽  
Cooperative Research ◽  
Curved Glass ◽  
Durability Testing ◽  
Cleaning Methods ◽  
The Cost ◽  
Utility Scale

One of the most promising developments for lowering the cost of utility scale concentrating solar power (CSP) is the emergence of durable reflective polymer films as an alternative to conventional curved glass mirrors. The broad adoption of wide web polymer film reflectors has been slowed by the lack of long-term weathering data. With the advent of the Ultra Accelerated Weathering System (UAWS), testing and development can proceed at a faster pace, and ReflecTech® Mirror Film has recently exceeded the equivalent terrestrial UV cumulative dosage of 25 years. ReflecTech® Mirror Film was developed through earlier collaborations between ReflecTech, Inc. (a subsidiary of SkyFuel, Inc.) and the National Renewable Energy Laboratory (NREL). More recently, through a Cooperative Research and Development Agreement (CRADA), ReflecTech, Inc. and NREL have developed an abrasion resistant coating (ARC) appropriate for application to polymer based mirror film. This hardcoat was developed to address the need for reflectors that are low in cost, high in performance and durable to mechanical cleaning methods sometimes used in the CSP environment. The combined impact of these two developments has the potential to significantly change the preferred supply choice for solar reflectors in new utility scale CSP projects. ReflecTech® Mirror Film samples prepared with and without the ARC hardcoat were subjected to accelerated exposure conditions more extreme than actual conditions. Both the uncoated and ARC films exhibit excellent weatherability with no loss in reflectance after highly accelerated exposure of over 25 years equivalent terrestrial UV. The ARC coated samples also exhibited outstanding initial abrasion resistance and adhesion to ReflecTech® Mirror Film, properties that were retained after exposure to various accelerated stress conditions including condensation cycling, thermal cycling, water immersion, and accelerated exposure to UV light. ReflecTech® Mirror Film is a commercially available product. The ARC-coated ReflecTech® Mirror Film has been successfully manufactured as a 1.5 m (5 ft) wide roll-to-roll construction in a commercial production environment and after further testing is expected to be commercially available in late 2011.

ReflecTech® Mirror Film Attributes and Durability for CSP Applications

2009 ◽  
Author(s):  
Michael DiGrazia ◽  
Randy Gee ◽  
Gary Jorgensen
Keyword(s):  
Elevated Temperatures ◽  
Solar Power ◽  
Mechanical Stability ◽  
Uv Light ◽  
Water Immersion ◽  
Accelerated Testing ◽  
Mechanical Resistance ◽  
Test Results ◽  
Concentrating Solar Power ◽  
Utility Scale

Reflectors are an essential part of parabolic trough solar electric and other concentrating solar power (CSP) systems. Reflectors in CSP systems require a high reflectance over the solar wavelength spectrum and they must be durable to outdoor exposure and resist all forms of degradation over time. All utility-scale CSP systems installed to date use glass reflectors. Glass mirrors have maintained their reflectance very well in CSP environments, but they are susceptible to wind-related breakage and are expensive to transport and install. Alternative lower-cost reflectors are needed to reduce the cost of CSP systems [1]. ReflecTech® Mirror Film is a highly reflective polymer-based film co-developed with the National Renewable Energy Laboratory (NREL) for concentrating solar energy applications. The attributes of ReflecTech® Mirror Film and test results for weatherability are described herein. This paper discusses field and lab test results and properties of ReflecTech® Mirror Film, specifically: 1. Stability under ultraviolet (UV) light through accelerated testing and outdoor real-time testing. 2. Mechanical stability and resistance to moisture through water immersion tests for delamination and “tunneling”. 3. Mechanical resistance to high wind events common in utility-scale concentrating solar power applications. 4. Lighter weight and resistance to breakage that reduces transportation and installation costs, and allows greater design flexibility of concentrator geometries. 5. Lower initial cost compared with curved glass mirrors. To test for weatherability, reflector samples were subjected to controlled conditions more extreme than actual outdoor environments. NREL maintains a world-class testing capability for solar reflectors that includes a Solar Simulator (SS), QUV (an accelerated exposure chamber manufactured by Q-Lab Corp. that subjects materials to alternating cycles of light and condensation at elevated temperatures), and several WeatherOmeter® (WOM) exposure chambers that allow accelerated testing of reflector samples. In addition, samples of ReflecTech® Mirror Film have been subjected to ACUVEX® accelerated outdoor weathering tests (natural sunlight in Phoenix, AZ, concentrated 7 to 8 times with a Fresnel-reflector while the samples are cooled with a fan to near ambient conditions and sprayed with de-ionized water 8 min per natural sun hour). Immersion tests were also performed to test the resistance of ReflecTech® Mirror Film to extreme moisture. Test results compared ReflecTech® film performance to past film products like 3M’s ECP-300 and ECP-305+ which suffered from “tunneling” [2], a problem whereby the silver reflective layer delaminates from the polymer film in the presence of moisture.

Inorganic-Organic Hybrid Nanocomposites for Photovoltaic Applications

2012 ◽  
Vol 571 ◽  
pp. 120-124
Author(s):  
Liang Min Zhang
Keyword(s):  
Solar Cells ◽  
Uv Light ◽  
Solar Spectrum ◽  
Wide Band ◽  
Hybrid Nanocomposites ◽  
Wide Band Gap ◽  
Inorganic Semiconductors ◽  
The Cost ◽  
Ruthenium Dye ◽  
Photovoltaic Characteristics

Hybrid photovoltaic concepts based on a nanoscale combination of organic and inorganic semiconductors are promising way to enhance the cost efficiency of solar cells through a better use of the solar spectrum, a higher ratio of interface-to-volume, and the flexible processability of polymers. In this work, two types of thin film solar cells have been developed. In both types of solar cells, poly-N-vinylcarbazole (PVK) is used as electron donor, cadmium sulfide (CdS) and titanium dioxide (TiO2) nanocrystals are used as electron acceptors, respectively. Since TiO2 has a wide band gap and can only absorb UV light, in the second type of solar cell, ruthenium dye is used as photo-sensitizer. The preliminary results of photoconductive and photovoltaic characteristics of these two inorganic-organic composites are presented.

A Very Low-Cost, Labor-Efficient, and Simple Method to Block Scattered Ultraviolet Light in PDMS Microfluidic Devices by Inserting Aluminum Foil Strips

2018 ◽  
Vol 11 (1) ◽  
Author(s):  
Shuo Wang ◽  
Peter Shankles ◽  
Scott Retterer ◽  
Yong Tae Kang ◽  
Chang Kyoung Choi
Keyword(s):  
Soft Lithography ◽  
Uv Light ◽  
Low Cost ◽  
Microfluidic Devices ◽  
Aluminum Foil ◽  
Material Synthesis ◽  
Simple Method ◽  
Micro Particles ◽  
Complex Shapes ◽  
The Cost

Abstract Opto-microfluidic methods have advantages for manufacturing complex shapes or structures of micro particles/hydrogels. Most of these microfluidic devices are made of polydimethylsiloxane (PDMS) by soft lithography because of its flexibility of designing and manufacturing. However, PDMS scatters ultraviolet (UV) light, which polymerizes the photocrosslinkable materials at undesirable locations and clogs the microfluidic devices. A fluorescent dye has previously been employed to absorb the scattered UV light and shift its wavelength to effectively solve this issue. However, this method is limited due to the cost of the materials (tens of dollars per microchip), the time consumed on synthesizing the fluorescent material and verifying its quality (two to three days). More importantly, significant expertise on material synthesis and characterization is required for users of the opto-microfluidic technique. The cost of preliminary testing on multiple iterations of different microfluidic chip designs would also be excessive. Alternatively, with a delicate microchannel design, we simply inserted aluminum foil strips (AFS) inside the PDMS device to block the scattered UV light. By using this method, the UV light was limited to the exposure region so that the opto-microfluidic device could consistently generate microgels longer than 6 h. This is a nearly cost- and labor-free method to solve this issue.

scholarly journals A Review of Conventional and Innovative- Sustainable Methods for Cleaning Reflectors in Concentrating Solar Power Plants

2018 ◽  
Vol 10 (11) ◽  
pp. 3937 ◽  
Author(s):  
Sahar Bouaddi ◽  
Aránzazu Fernández-García ◽  
Chris Sansom ◽  
Jon Sarasua ◽  
Fabian Wolfertstetter ◽  
...  
Keyword(s):  
Power Plants ◽  
Solar Power ◽  
Alternative Methods ◽  
Concentrating Solar Power ◽  
Water Based ◽  
Solar Power Plants ◽  
Cleaning Methods ◽  
The Cost ◽  
Solar Field ◽  
High Reflectance

The severe soiling of reflectors deployed in arid and semi arid locations decreases their reflectance and drives down the yield of the concentrating solar power (CSP) plants. To alleviate this issue, various sets of methods are available. The operation and maintenance (O&M) staff should opt for sustainable cleaning methods that are safe and environmentally friendly. To restore high reflectance, the cleaning vehicles of CSP plants must adapt to the constraints of each technology and to the layout of reflectors in the solar field. Water based methods are currently the most commonly used in CSP plants but they are not sustainable due to water scarcity and high soiling rates. The recovery and reuse of washing water can compensate for these methods and make them a more reasonable option for mediterranean and desert environments. Dry methods, on the other hand, are gaining more attraction as they are more suitable for desert regions. Some of these methods rely on ultrasonic wave or vibration for detaching the dust bonding from the reflectors surface, while other methods, known as preventive methods, focus on reducing the soiling by modifying the reflectors surface and incorporating self cleaning features using special coatings. Since the CSP plants operators aim to achieve the highest profit by minimizing the cost of cleaning while maintaining a high reflectance, optimizing the cleaning parameters and strategies is of great interest. This work presents the conventional water-based methods that are currently used in CSP plants in addition to sustainable alternative methods for dust removal and soiling prevention. Also, the cleaning effectiveness, the environmental impacts and the economic aspects of each technology are discussed.

scholarly journals A mathematical model for production routing of mechanical engineering products

2021 ◽  
Vol 25 (3) ◽  
pp. 332-341
Author(s):  
I. V. Fokin ◽  
A. N. Smirnov
Keyword(s):  
Mathematical Model ◽  
Mechanical Engineering ◽  
Complex Geometry ◽  
3D Models ◽  
Point Of View ◽  
Structural Elements ◽  
Production Environment ◽  
Automatic Mode ◽  
The Cost ◽  
Production Routing

The aim was to create a mathematical model describing the development of a production (shop-to-shop) routing of mechanical engineering products based on a 3D model and allowing the cost of the final product to be reduced. The developed mathematical model was simulated based on 3D models designed in the Siemens NX system, which were subsequently imported into the *stp format and recognized by a designed module written in the Phyton programming language. The factors of the production environment affecting the formation of the production routing of mechanical engineering products were determined. A diagram of the algorithm for the “constructive element - technological operation - means of technological equipment (equipment-tool)” relationship was developed. Based on the results of testing the developed mathematical model, the use of neural networks as a tool for the implementation and automation of the work was found advantageous as compared to the standard scheme of work of a process engineer when developing a production routing of mechanical engineering products. These advantages include a decrease in the time for the development of a routing and the cost of the final product. The developed model has a practical limitation consisting in a rather complex geometry of some structural elements of a unit, which impedes the development of an algorithm for recognizing their structure. The use of a neural network prototype in automatic mode is advisable for relatively simple parts (including a flange, hole, chamfer and rounding). However, since the number of simple units from the recognition point of view amounts to about 40% among the nomenclature of manufactured units, the reduction in the development time of the technological process in comparison with the conventional approach comprises only 10–25% of the total time of technological preparation.

Current and Future Economics of Parabolic Trough Technology

2007 ◽  
Author(s):  
Henry Price ◽  
Mark Mehos ◽  
Chuck Kutscher ◽  
Nate Blair
Keyword(s):  
Natural Gas ◽  
Power Systems ◽  
Power Plants ◽  
Solar Power ◽  
Power Market ◽  
Parabolic Trough ◽  
Cost Of Electricity ◽  
Near Term ◽  
The Cost ◽  
Utility Scale

Solar energy is the largest energy resource on the planet. Unfortunately, it is largely untapped at present, in part because sunlight is a very diffuse energy source. Concentrating solar power (CSP) systems use low cost reflectors to concentrate the sun’s energy to allow it to be used more effectively. Concentrating solar power systems are also well suited for large solar power plants that can be connected into the existing utility infrastructure. These two facts mean that CSP systems can be used to make a meaningful difference in energy supply in a relatively short period. CSP plants are best suited for the arid climates in the Southwestern United States, Northern Mexico, and many desert regions around the globe. A recent Western Governors’ Association siting study [1] found that the solar potential in the U.S. Southwest is at least 4 times the total U.S. electric demand even after eliminating urban areas, environmentally sensitive areas, and all regions with a ground slope greater than 1%.While it is currently not practical to power the whole county from the desert southwest, only a small portion of this area is needed to make a substantial contribution to future U.S. electric needs. Many of the best sites are near existing high-voltage transmission lines and close to major power load centers in the Southwest (Los Angeles, Las Vegas, and Phoenix). In addition, the power provided by CSP technologies has strong coincidence with peak electric demand, especially in the Southwest where peak demand corresponds in large part to air conditioning loads. Parabolic troughs currently represent the most cost-effective CSP technology for developing large utility-scale solar electric power systems. These systems are also one of the most mature solar technologies, with commercial utility-scale plants that have been operating for over 20 years. In addition, substantial improvements have been made to the technology in recent years including improved efficiency and the addition of thermal energy storage. The main issue for parabolic trough technology is that the cost of electricity is still higher than the cost of electricity from conventional natural gas-fired power plants. Although higher natural gas prices are helping to substantially reduce the difference between the cost of electricity from solar and natural gas plants, in the near-term increased incentives such as the 30% Investment Tax Credit (ITC) are needed to make CSP technology approach competitiveness with natural gas power on a financial basis. In the longer term, additional reductions in the cost of the technology will be necessary. This paper looks at the near-term potential for parabolic trough technology to compete with conventional fossil power resources in the firm, intermediate load power market and at the longer term potential to compete in the baseload power market. The paper will consider the potential impact of a reduced carbon emissions future.

scholarly journals An Ultraviolet Sensor and Indicator Module Based on p–i–n Photodiodes

Sensors ◽  
2019 ◽  
Vol 19 (22) ◽  
pp. 4938 ◽  
Author(s):  
Yu-Chieh Chiu ◽  
Pinghui Sophia Yeh ◽  
Tzu-Hsun Wang ◽  
Tzu-Chieh Chou ◽  
Cheng-You Wu ◽  
...  
Keyword(s):  
Indium Tin Oxide ◽  
Uv Light ◽  
Collection Efficiency ◽  
Light Emitting ◽  
Pin Photodiode ◽  
Structural Details ◽  
The Cost ◽  
Pin Photodiodes ◽  
Conversion Efficiencies ◽  
Ultraviolet Sensor

The monolithic integration of an ultraviolet (UV) sensor and warning lamp would reduce the cost, volume, and footprint, in comparison to a hybrid combination of discrete components. We constructed a module comprising a monolithic sensor indicator device based on basic p–i–n (PIN) photodiodes and a transimpedance amplifier. GaN-based light-emitting diodes (LEDs) with an indium-tin oxide (ITO) current-spreading layer and PIN photodiodes without ITO deposition on the light-receiving area, were simultaneously fabricated. The resultant incident photon-to-electron conversion efficiencies of the PIN photodiodes at UV wavelengths were significantly higher than those of the reverse-biased LEDs. The photocurrent signals of the PIN photodiode were then converted to voltage signals to drive an integrated visible LED, which functioned as an indicator. The more the ambient UV-light intensity exceeded a specified level, the brighter the glow of the LED. The responsivities of 0.20 and 0.16 A/W were obtained at 381 and 350 nm, respectively, under a bias voltage of 5 V. We also addressed the epitaxial structural details that can affect the collection efficiency of the photocurrent generated by UV light absorption. The crosstalk between the PIN photodiode and LEDs (of various center-to-center distances) was measured.

scholarly journals Improved Weathering Performance of Poly(Lactic Acid) through Carbon Nanotubes Addition: Thermal, Microstructural, and Nanomechanical Analyses

Biomimetics ◽  
2020 ◽  
Vol 5 (4) ◽  
pp. 61
Author(s):  
Thevu Vu ◽  
Peyman Nikaeen ◽  
William Chirdon ◽  
Ahmed Khattab ◽  
Dilip Depan
Keyword(s):  
Carbon Nanotubes ◽  
Lactic Acid ◽  
Uv Light ◽  
Degradation Mechanism ◽  
Decomposition Temperature ◽  
Poly Lactic Acid ◽  
Accelerated Weathering ◽  
Degradation Behavior ◽  
Scanning Calorimetry ◽  
Norrish Type

To understand the interrelationship between the microstructure and degradation behavior of poly(lactic acid) (PLA), single-walled carbon nanotubes (CNTs) were introduced into PLA as nucleating agents. The degradation behavior of PLA-CNT nanocomposites was examined under accelerated weathering conditions with exposure to UV light, heat, and moisture. The degradation mechanism proceeded via the Norrish type II mechanism of carbonyl polyester. Differential scanning calorimetry (DSC) studies showed an increase in glass transition temperature, melting temperature, and crystallinity as a result of the degradation. However, pure PLA showed higher degradation as evidenced by increased crystallinity, lower onset decomposition temperature, embrittlement, and a higher number of micro-voids which became broader and deeper during degradation. In the PLA-CNT nanocomposites, CNTs created a tortuous pathway which inhibits the penetration of water molecules deeper into the polymer matrix, making PLA thermally stable by increasing the initial temperature of mass loss. CNTs appear to retard PLA degradation by impeding mass transfer. Our study will facilitate designing environmentally friendly packaging materials that display greater resistance to degradation in the presence of moisture and UV light.

Optical Durability of Candidate Solar Reflectors

2005 ◽  
Vol 127 (2) ◽  
pp. 262-269 ◽  
Author(s):  
C. E. Kennedy ◽  
K. Terwilliger
Keyword(s):  
Cone Angle ◽  
Front Surface ◽  
Advanced Materials ◽  
Accelerated Weathering ◽  
Thin Glass ◽  
Specular Reflectance ◽  
Outdoor Environments ◽  
Exposure Testing ◽  
Durability Testing ◽  
Main Activity

Concentrating solar power (CSP) technologies use large mirrors to collect sunlight to convert thermal energy to electricity. The viability of CSP systems requires the development of advanced reflector materials that are low in cost and maintain high specular reflectance for extended lifetimes under severe outdoor environments. The long-standing goals for a solar reflector are specular reflectance above 90% into a 4 mrad half-cone angle for at least 10 years outdoors with a cost of less than $13.8/m2 (the 1992 $10.8/m2 goal corrected for inflation to 2002 dollars) when manufactured in large volumes. Durability testing of a variety of candidate solar reflector materials at outdoor test sites and in laboratory accelerated weathering chambers is the main activity within the Advanced Materials task of the CSP Program at the National Renewable Energy Laboratory (NREL) in Golden, Colorado. Test results to date for several candidate solar reflector materials will be presented. These include the optical durability of thin glass, thick glass, aluminized reflectors, front-surface mirrors, and silvered polymer mirrors. The development, performance, and durability of these materials will be discussed. Based on accelerated exposure testing the glass, silvered polymer, and front-surface mirrors may meet the 10 year lifetime goals, but at this time because of significant process changes none of the commercially available solar reflectors and advanced solar reflectors have demonstrated the 10 year or more aggressive 20 year lifetime goal.

An Investigation of the Results of the Annual Review of Ineligibles and Non-Rehabilitants

1979 ◽  
Vol 10 (1) ◽  
pp. 32-34
Author(s):  
Paul Cooper ◽  
Reed Greenwood ◽  
Stephanie Davis
Keyword(s):  
Vocational Rehabilitation ◽  
Review Process ◽  
Research Effort ◽  
Fiscal Year ◽  
Annual Review ◽  
Cooperative Research ◽  
Ready Access ◽  
Time Required ◽  
The Cost

The annual review of ineligibles and non-rehabilitants is a mandatory study for all public vocational rehabilitation agencies to insure that all individuals are given ready access to the benefits of the program. In a cooperative research effort, three vocational rehabilitation agencies provided the data necessary for a study of the cost and effectiveness of the annual review process. As part of this study, the participating agencies provided data for each of their clients reviewed in Fiscal Year 1977. This data consisted of information· regarding the type of review, the outcome of the review process, and the amount of counselor time required to complete the review. The results of the study indicated that the annual review was not only ineffective but extremely costly in terms of counselor time as a technique for insuring benefits to eligible individuals.

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