Periodic Reporting for period 1 - WiPTherm (Innovative Wireless Power Devices Using micro-Thermoelectric Generators arrays)
Periodo di rendicontazione: 2019-11-01 al 2020-10-31
In an Era when sensing, monitoring and interconnectivity are crucial for improving our society, Micro and Nanosatellites (often referred to as CubeSats) are revolutionizing the paradigm of space exploration and engineering in the last years. Several areas, such as weather information and climatic research, multimedia communications, telephone and television, data distribution, transportation and logistics, navigation, safety, security, and rescue, are resorting to this technology. One of the problems stems from the fact that they comply with several conditions, including dimensions and weight. Weight is one of the significant barriers of CubeSat technology. For instance, nanosatellites could require batteries and/or substantial solar panels that significantly increase nanosatellites' value (1-10 kg).
So finding a way to bring electrical energy to CubeSats to reduce weight and recharge batteries efficiently is one of the biggest challenges that this industry faces.
The WiPTherm project responds to this challenge by developing an innovative energy transfer system, using a laser as an energy source and a thermoplasmic hybrid convert. This project has as the main objective, through the developed system, it aims to obtain an efficiency of 5% of transmission at a distance of 500 meters.
So finding a way to bring electrical energy to CubeSats to reduce weight and recharge batteries efficiently is one of the biggest challenges that this industry faces.
The WiPTherm project responds to this challenge by developing an innovative energy transfer system, using a laser as an energy source and a thermoplasmic hybrid convert. This project has as the main objective, through the developed system, it aims to obtain an efficiency of 5% of transmission at a distance of 500 meters.
During the first year of the WiPTherm project, several scientific developments were underway to achieve the main project's goal.
In the first phase, the team's knowledge was achieved across the various multidisciplinary areas such as Energy Harvesting, optics & Cubsats. In the first six months of the project, a bibliographic review (WP3, WP4, WP5 and WP6) made contributes significatively to this transversal knowledge to the WiPtherm team.
Concerning the developed research, several batches of Bi2Te3 (n-type and p-type) microparticles were prepared by solid state or by using available commercial solutions in terms of materials. The microparticles were then used to prepare different types of paints based on commercial polymers or polymers prepared at the laboratory level. By using screen printing or stencil printing, different prototypes were designed and printed. Thermoplasmonics materials were being examined and identified that could be highly absorbed in the wavelength range to be used (1500 nm). This task is currently underway, preparing by chemical methods or by physical vapor deposition, as is Sputtering's case. finally the numerical simulations conducted on thermoelectric design and thermoplamosnic are optimized,
On lasers, the state-of-the-art study conducted encompassing high-power fiber laser technologies, rare earth doping ions as well as laser beam propagation through the atmosphere. Afterward, two specific rare-earth doping ions were retained: Erbium-doped fibers for their emission at 1550 nm and Thulium-doped fibers for their emission at 2000 nm. In a first approach, Erbium-doped fiber was selected due to the large commercial availability of optical and fiber components around 1500 nm. A double-clad fiber design was selected since it offers the possibility to reach high average power while maintaining a transverse single-mode propagation, two key parameters for the objectives of the project. Afterward, two silica doped materials with adequate doping concentrations were ordered in order to realize the Er-doped double-clad fiber. The manufacturing process used is based on a powder technique, which is one of the newest technological processes for the fabrication of doped material with a high control on the refractive index profile (value and homogeneity).
Concerning the developments that have been carried out among the CubeSat field, those were focused not only in a review of the state of the art but also on setting the different system requirements that should fulfil the CubeSat Structure, which were classified in: (i) general, (ii) mechanical, (iii) electrical and (iv) operational requirements.
Along the second half of the first year, special attention has been set to perform the thermal analysis of the platform. The key challenge for the thermal control subsystem is to assure thermal gradients in the HPTP device while maintaining temperatures of the different spacecraft components within its operational range. That includes also the study of the duty cycle, to avoid overheating the structure maximizing the power generated. To develop the analysis, several thermal models of increasing complexity (all of them based on commercial CubeSat components) were implemented.
In the first phase, the team's knowledge was achieved across the various multidisciplinary areas such as Energy Harvesting, optics & Cubsats. In the first six months of the project, a bibliographic review (WP3, WP4, WP5 and WP6) made contributes significatively to this transversal knowledge to the WiPtherm team.
Concerning the developed research, several batches of Bi2Te3 (n-type and p-type) microparticles were prepared by solid state or by using available commercial solutions in terms of materials. The microparticles were then used to prepare different types of paints based on commercial polymers or polymers prepared at the laboratory level. By using screen printing or stencil printing, different prototypes were designed and printed. Thermoplasmonics materials were being examined and identified that could be highly absorbed in the wavelength range to be used (1500 nm). This task is currently underway, preparing by chemical methods or by physical vapor deposition, as is Sputtering's case. finally the numerical simulations conducted on thermoelectric design and thermoplamosnic are optimized,
On lasers, the state-of-the-art study conducted encompassing high-power fiber laser technologies, rare earth doping ions as well as laser beam propagation through the atmosphere. Afterward, two specific rare-earth doping ions were retained: Erbium-doped fibers for their emission at 1550 nm and Thulium-doped fibers for their emission at 2000 nm. In a first approach, Erbium-doped fiber was selected due to the large commercial availability of optical and fiber components around 1500 nm. A double-clad fiber design was selected since it offers the possibility to reach high average power while maintaining a transverse single-mode propagation, two key parameters for the objectives of the project. Afterward, two silica doped materials with adequate doping concentrations were ordered in order to realize the Er-doped double-clad fiber. The manufacturing process used is based on a powder technique, which is one of the newest technological processes for the fabrication of doped material with a high control on the refractive index profile (value and homogeneity).
Concerning the developments that have been carried out among the CubeSat field, those were focused not only in a review of the state of the art but also on setting the different system requirements that should fulfil the CubeSat Structure, which were classified in: (i) general, (ii) mechanical, (iii) electrical and (iv) operational requirements.
Along the second half of the first year, special attention has been set to perform the thermal analysis of the platform. The key challenge for the thermal control subsystem is to assure thermal gradients in the HPTP device while maintaining temperatures of the different spacecraft components within its operational range. That includes also the study of the duty cycle, to avoid overheating the structure maximizing the power generated. To develop the analysis, several thermal models of increasing complexity (all of them based on commercial CubeSat components) were implemented.
High thermoelectric performing inks are expected on thermoelectrics, namely by optimizing the figure-of-merit inks to approach their materials bulk counterparts. Moreover, innovative nanoparticle synthesis will be performed since dimensional confinement will affect the phonons' free average path, not acting on the electronic transport properties. The absorption system's optimization for such long wavelengths (1500 nm, Near-ultraviolet) is not the most usual since it is typically sought to absorb for wavelengths in the visible area of ultraviolet.
By the end of the project, the fiber laser source will have to meet the required specifications defined for the final demonstrator of the Wiptherm project, i.e. an efficient Erbium-doped fiber laser source potentially able to deliver more than 100 W of average output power in a continuous-wave operation. The laser emission has to be centered around 1.5 µm regarding the atmospheric transmission and diffraction-limited (Singlemode to minimize the beam divergence and its size after long-distance propagation. Concerning the potential to go beyond the state-of-the-art, achieving such a high average power at a 1550nm wavelength with a diffraction-limited beam using an Erbium-doped double-clad fiber which would be a world first to the best of our knowledge. A study on the impact on beam characteristics (shape, deviation…) of climatic conditions such as rain, fog, the density of polluting particles, and thermal gradients inducing refractive index variations will also be conducted. Finally, multiple solutions will be investigated to divide the power at the fiber laser source's output into multiple Gaussian beams centered on each of the 27 thermoelectric generators incorporated on 3U Cubesat, used for the final demonstrator.
The WiPTHERM project aims to integrate the HTPT generator on a CubeSat of 3 Standard Units of 10 x 10 cm. In conjunction with the used energy-gathering solutions for this type of satellite, namely solar cells, the satellite power supply will be improved in a novel way in situations where environmental obstacles like the orbit shadow period don’t allow for energy reception.
A derived ultimate goal to be reached is to use the energy generation solution in situations where scarce energy sources are available,, i.e. deep space missions. A WiPTHERM HTPT generator receiving energy from a LASER source located on a master satellite which has a different, more accessible, or long-term energy source (large solar panels, HTPT generator for charging from Earth, etc.), could represent a promising goal of achieving energy in a deep space mission and thus assuring its continuity. For that, simulations within a developed Concept of Operations will be considered in the case when a CubeSat “slave” satellite orbits another planet from our galaxy and a “master” satellite orbiting Earth, with a primary LASER source, will feed energy to it.
By the end of the project, the fiber laser source will have to meet the required specifications defined for the final demonstrator of the Wiptherm project, i.e. an efficient Erbium-doped fiber laser source potentially able to deliver more than 100 W of average output power in a continuous-wave operation. The laser emission has to be centered around 1.5 µm regarding the atmospheric transmission and diffraction-limited (Singlemode to minimize the beam divergence and its size after long-distance propagation. Concerning the potential to go beyond the state-of-the-art, achieving such a high average power at a 1550nm wavelength with a diffraction-limited beam using an Erbium-doped double-clad fiber which would be a world first to the best of our knowledge. A study on the impact on beam characteristics (shape, deviation…) of climatic conditions such as rain, fog, the density of polluting particles, and thermal gradients inducing refractive index variations will also be conducted. Finally, multiple solutions will be investigated to divide the power at the fiber laser source's output into multiple Gaussian beams centered on each of the 27 thermoelectric generators incorporated on 3U Cubesat, used for the final demonstrator.
The WiPTHERM project aims to integrate the HTPT generator on a CubeSat of 3 Standard Units of 10 x 10 cm. In conjunction with the used energy-gathering solutions for this type of satellite, namely solar cells, the satellite power supply will be improved in a novel way in situations where environmental obstacles like the orbit shadow period don’t allow for energy reception.
A derived ultimate goal to be reached is to use the energy generation solution in situations where scarce energy sources are available,, i.e. deep space missions. A WiPTHERM HTPT generator receiving energy from a LASER source located on a master satellite which has a different, more accessible, or long-term energy source (large solar panels, HTPT generator for charging from Earth, etc.), could represent a promising goal of achieving energy in a deep space mission and thus assuring its continuity. For that, simulations within a developed Concept of Operations will be considered in the case when a CubeSat “slave” satellite orbits another planet from our galaxy and a “master” satellite orbiting Earth, with a primary LASER source, will feed energy to it.