Defense laboratories continue to explore and advance solar energy technology with new designs and applications.
How long it takes for these solar energy technologies to be seen in use depends on how quickly they are licensed and developed by solar energy companies.
This Navy solar energy technology is a passive cooling system for CPV solar, but it can also be used with conventional photovoltaic solar systems. A passive system requires no electricity to power fans or pumps to cool the solar system. At the same time, the waste heat is an asset that can be used for other applications. Ideal settings for this technology include small- to medium-sized solar farms, urban and city solar projects, and co-generation energy systems.
Navy researchers have developed an electrical system controller that can be quickly set up and connected to available power sources, sensors, storage devices, and end users. Power sources can include those installed and operational, or temporary sources such as generators. Sensors monitor load and available supply on the temporary micro grid, as well as a plethora of other data including weather and the status of assets. Storage devices may include batteries and other systems which can be charged through the power conditioner. End users can include homes, standalone machines, computer or communications networks, or any other electricity demanding unit.
Many solar collectors rest on fixed mounts, fewer use a solar tracking system that tilts or turns collectors to follow the sun to improve electrical generation because of costs. The Navy has invented a mounting system that can be used with most solar arrays, which is simple and inexpensive and constructed of lightweight, commonly available materials, therefore reducing cost and setup time.
Air Force researchers have developed a process to make uniform thin films with micron-size perovskite grains, by using a controlled amount of metal ions in a precursor solution. In one example of this process, large organo-lead halide-based perovskite grains are formed during low-temperature thin film growth by adding sodium ions to the precursor solution in a two-step interdiffusion process. This generates films with improved power conversion efficiencies compared with non-sodium thin films.
Navy researchers have developed organic PV materials with tunable energy levels, improved oxidation stability, thermal stabilities, solubility, and processability. The improvements are provided by a derivatized poly-benzo-isimidazobenzo phenanthroline (Py-BBL) which yields organic PV modules that are air stable and more soluble in environmentally benign solvents for large area fabrication of thin films. Other related circuit component devices including field effect transistors, capacitors, and simple inverters, are also demonstrated with materials.
Navy researchers have developed a low bandgap, oxidation-resistant, conductive polymer which will significantly extend the lifetime of equipment and enable new flexible electronics. Bandgap is defined as the energetic separation between the filled valence and empty conduction bands of bulk solid-state material and is traditionally reported in units of electron volts (1 eV = 1240 nm). As the bandgap corresponds to energy between the HOMO (highest occupied molecular orbital) and LUMO (lowest unoccupied molecular orbital) of the material, it determines the onset of absorbance or the energy of any potential emission. Smaller bandgaps result in greater thermal population of the conduction band, thus contributing to enhanced conductivity.
The Navy has figured out how to generate hydrogen fuel by using electrolysis powered by PV cells. Since the construction of the device is based on semiconductor processes, the invention is scalable in size and production, with equivalent cost reduction. MEMS actuators can be added to allow for hydrogen storage and release. The concept is that a large number of these devices can be placed in a liquid medium such as a body of water. The sun provides the fuel from the PV modules, and the system creates hydrogen. The amount of hydrogen produced by each device is small, but when a large number of devices are working in unison the system can produce significant amounts of fuel.
This Navy innovation builds on existing solar technology by storing the emission source inside the solar cell. Instead of using the sun’s radiation, the technology uses reactive material at its core. Single-junction solar cell materials encase a core consisting of X-ray isotopes that convert the radiation to electricity. The technology may find utility in backup power systems, primary power system for isolated areas, micro-scale battery systems, consumer products, aviation, and automotive applications.
The Air Force Research Laboratory has developed a pseudomorphic glass (PMG) protective covering for solar cells that is applied as a sheet over the solar cell array. PMG is composed of ceria doped borosilicate or fused silica beads incorporated in a variety of polymer matrices. The glass beads provide radiation shielding and the matrix provides the mechanical integrity. PMG is in use with several recent satellites that are currently in orbit and will continue to be used in upcoming launches. PMG is flexible which allows a larger variety of uses including as a covering for flexible solar cells. PMG research and development is continuing with a variety of goals. Conductivity across the covering and the ability to adjust the optical forward scattering of a solar cell will provide increased capabilities.
This Navy invention provides a solar energy concentrating reflection system comprising multiple arrays of solar reflectors arranged adjacent to one another on a generally planar support structure where each of the reflector arrays configured into a first Fresnel array in a first dimension. Each of the first Fresnel array of reflectors are in turn arrayed and supported in a support frame in a configuration of second Fresnel arrays in a second dimension such that solar energy from the sun is reflected and concentrated to a predetermined focal line. A solar receiver is disposed in the focal line of the configured solar reflectors such that the first and second Fresnel arrays uniformly reflect and concentrate solar energy from the sun onto the solar receiver within the first and second dimensions with a uniform solar intensity profile.
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