This short concept article discusses four specific ways to eradicate respiratory pandemics once and for all. These include: Protecting the nose, mouth, throat and lungs; New hygiene regimens; Clearing the air; and Biophysical interventions. Technical breakthoughs in all four of these areas would not only protect people from life-threatening pathogens, but also take the dread out of respiratory disease outbreaks.
Spectrum splitting is an optical technique that can increase conversion efficiency or add energy storage capability to a photovoltaic (PV) energy system. In this Sandia National Laboratory Campus Executive project, two distinct types of Diffractive Optical Elements (DOEs) for spectrum splitting were developed, fabricated and measured. The first DOE was an algorithmically-designed freeform surface relief structure. A parametric study of the Broadband Gerchberg-Saxton algorithm was performed to show the effect of design variables on device performance. Two DOE designs were fabricated using a grayscale Maskless Lithography Tool (MLT) and measured. The second DOE was a volume holographic lens. This concept was explored in the context of hybrid PV/biofuel implementation, and was later applied to a multiple-bandgap PV module. A design process was developed to ensure diffraction into a single order across the lens and to enable spectral tuning of diffracted light. A proof-of-concept off-axis holographic lens was fabricated and measured. The report concludes with a summary of spectrum splitting performance and discussion of areas for improvement and future work.
A unique, micro-scale architecture is proposed to create a novel hybrid concentrated photovoltaic system. Micro-scale (sub-millimeter wide), multi-junction cells are attached to a large-area silicon cell backplane (several inches wide) that can optimally collect both direct and diffuse light. By using multi- junction III-V cells, we can get the highest possible efficiency of the direct light input. In addition, by collecting the diffuse light in the large-area silicon cell, we can produce power on cloudy days when the concentrating cells would have minimal output. Through the use of micro-scale cells and lenses, the overall assembly will provide higher efficiency than conventional concentrators and flat plates, while keeping the form factor of a flat plate module. This report describes the hybrid concept, the design of a prototype, including the PV cells and optics, and the experimental results.
The goal of this SAND report is to provide guidance for other groups hosting workshops and peerto-peer learning events at Sandia. Thus this SAND report provides detail about our team structure, how we brainstormed workshop topics and developed the workshop structure. A Workshop “Nuts and Bolts” section provides our timeline and check-list for workshop activities. The survey section provides examples of the questions we asked and how we adapted the workshop in response to the feedback.
To fill a major knowledge gap, Sandia National Laboratories (SNL) and the Electric Power Research Institute (EPRI) are jointly engaged in a multi-year research effort, supported by the Department of Energy’s SunShot Program, to examine real-world photovoltaic (PV) plant reliability and performance. Findings and analyses, derived from field data documented in the PV Reliability Operations Maintenance (PVROM) database tool as well as from convened workshops and working group discussions, are intended to inform industry best practices around the optimal operations and maintenance (O&M) of solar PV assets. To improve upon and evolve existing solar PV O&M approaches, this report: 1. Provides perspective on the concept of PV “system” reliability and how it can inform plant design, operations, and maintenance decisions that produce better long-term outcomes; 2. Describes the PVROM data collection tool, its technical capabilities, and results generated from database content in 2014; 3. Presents ongoing research efforts that are meant to drive the solar industry toward PV O&M best practice protocols and standards; and 4. Reflects on future areas of inquiry that can help better forecast plant health (e.g., system component availability, component wear out, etc.) and associated lifecycle costs. Ultimately, this report adds to the knowledge base of improving PV system O&M activities by discussing data collection and analysis techniques that can be used to better understand and enhance the reliability, availability, and performance of a photovoltaic system.
Microsystems Enabled Photovoltaics (MEPV) is a relatively new field that uses microsystems tools and manufacturing techniques familiar to the semiconductor industry to produce microscale photovoltaic cells. The miniaturization of these PV cells creates new possibilities in system designs that can be used to reduce costs, enhance functionality, improve reliability, or some combination of all three. In this article, we introduce analytical tools and techniques to estimate the costs associated with a hybrid concentrating photovoltaic system that uses multi-junction microscale photovoltaic cells and miniaturized concentrating optics for harnessing direct sunlight, and an active c-Si substrate for collecting diffuse sunlight. The overall model comprises components representing costs and profit margin associated with the PV cells, concentrating optics, balance of systems, installation, and operation. This article concludes with an analysis of the component costs with particular emphasis on the microscale PV cell costs and the associated tradeoffs between cost and performance for the hybrid CPV design.