53 research outputs found
Bifacial thermophotovoltaic energy conversion
Thermophotovoltaic (TPV) energy conversion efficiency has recently surpassed
30%. The key behind such high efficiency is the inclusion of a highly efficient
mirror in the rear of the TPV cell that turns back to the thermal emitter the
outband energy photons. Efficiencies over 50% could be theoretically attainable
by approaching a mirror reflectance of 100%. However, the very few percent of
outband absorption significantly deteriorate the conversion efficiency. Thus,
current research focuses on developing advance mirror designs able to reach an
extreme high outband reflectance over 95%. In this article I propose a bifacial
TPV cell that enables very efficient photon recycling without using mirrors and
that is less sensitive to outband optical losses. The key to this design is
that the cell is introduced in a thermal emitter enclosure where it is
irradiated from both sides. Then, outband photons transmit through the cell and
are re-absorbed in the emitter. Therefore, the optical losses linked to the
mirror/cell interface are eliminated, potentially enabling higher photon
recycling efficiencies. This article presents a detailed balance simulation of
an edge-cooled bifacial TPV cell to demonstrate that bifacial configuration
enables higher conversion efficiencies and twice much as power density than
monofacial designs, the latter being a remarkable advantage for moderate
temperature and low-cost TPV power generation. Therefore, bifacial TPV cells
are appealing for developing practical high-efficient and low-cost TPV devices
for power generation in an extended range of heat source temperatures
Demonstration of the operation principles of intermediate band solar cells at room temperature
In this work we report, for the first time at room temperature, experimental results that prove, simultaneously in the same device, the two main physical principles involved in the operation of intermediate band solar cells: (1) the production of sub-bandgap photocurrent by two optical transitions through the intermediate band; (2) the generation of an output voltage which is not limited by the photon energy absorption threshold. These principles, which had always required cryogenic temperatures to be evidenced all together, are now demonstrated at room temperature on an intermediate band solar cell based on InAs quantum dots with Al0.3Ga0.7As barriers
Defectos del cierre del neuroporo anterior: anencefalias en mortinatos
El objetivo general del presente trabajo consiste en demostrar la incidencia de estas patologías en fetos que no han llegado a término pertenecientes a la Cátedra “A” de Anatomía y servicios de patología de hospitales zonales.Facultad de Ciencias Médica
Defectos del cierre del neuroporo anterior: anencefalias en mortinatos
El objetivo general del presente trabajo consiste en demostrar la incidencia de estas patologías en fetos que no han llegado a término pertenecientes a la Cátedra “A” de Anatomía y servicios de patología de hospitales zonales.Facultad de Ciencias Médica
NGCPV: a new generation of concentrator photovoltaic cells, modules and systems
Starting on June 2011, NGCPV is the first project funded jointly between the European Commission (EC) and the New Energy and Industrial Technology Development Organization (NEDO) of Japan to research on new generation concentration photovoltaics (CPV). The Project, through a collaborative research between seven European and nine Japanese leading research centers in the field of CPV, aims at lowering the cost of the CPVproduced photovoltaic kWh down to 5 ?cents. The main objective of the project is to improve the present concentrator cell, module and system efficiency, as well as developing advanced characterization tools for CPV components and systems. As particular targets, the project aims at achieving a cell efficiency of at least 45% and a CPV module with an efficiency greater than 35%. This paper describes the R&D activities that are being carried out within the NGCPV project and summarizes some of the most relevant results that have already been attained, for instance: the manufacturing of a 44.4% world record efficiency triple junction solar cell (by Sharp Corp.) and the installation of a 50 kWp experimental CPV plant in Spain, which will be used to obtain accurate forecasts of the energy produced at system level
Large-Diameter Single-Wall Carbon Nanotubes Formed Alongside Small-Diameter Double-Walled Carbon Nanotubes
Samples containing a majority of either single-wall carbon nanotubes (SWCNTs) or double-walled carbon nanotubes (DWCNTs) are prepared in the same catalytic chemical vapor deposition conditions but using slightly different catalytic materials, based on alumina impregnated with iron and molybdenum salts. There is a sharp SWCNTs-to-DWCNTs transition. By contrast to the usual findings, the selectivity is not correlated to the size of the iron-based catalyst nanoparticles, nor does the transition occur upon a decreasing carbon/catalyst ratio. The result is attributed to the increasing MoO3 concentration inducing modifications of the gas atmosphere, such as the formation of more reactive C2 species through C2H4 dissociation, which thus favors the nucleation and growth of a DWCNT. In the DWCNT sample, the average diameter of the SWCNTs is higher than the average outer diameter of the DWCNTs, which is uncommon, as many authors stress that SWCNTs show a lower diameter than DWCNTs. The study could provide guidelines for the synthesis of very small diameter DWCNTs
AMADEUS: Next generation materials and solid state devices for ultra high temperature energy storage and conversion
<p>Promotional poster</p
AMADEUS project: ultra high temperature energy storage and conversion
<p>AMADEUS Project Presentation given at the CIC Energigune, Vitoria‐Gasteiz, 8th Nov. 2017</p
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