Periodic Reporting for period 1 - METATHERM (Meta-Antenna and Energy harvesting/storage modules development for autarkic sensors arrays)
Reporting period: 2022-04-01 to 2023-03-31
METATHERM aims at the demonstration of a versatile energy harvesting and communication system for environment sensors arrays allowing the development of autarkic operation devices without any maintenance. The novelty builds up from several different innovations, the main one being the antenna, based on epsilon engineering using metamaterials, allowing the antenna to show extremely high gain and an extreme compactness. The energy efficiency of the antenna and the general principle of operation allows the electrical power need to be drastically decreased, which allows the consideration of novel energy harvesting technologies to be used to power the system.
EXCELLENCE:
In METATHERM, the thermal energy of the sun is harvested using a novel ionic thermoelectric (iTE) device. This technology is based on ion migration under a thermal gradient and show higher Seebeck coefficient than usual Tellurium based semiconductors without the use of rare or toxic elements: a significant advantage in the context of the rapidly growing energy demand for IoT and nomad electronic systems.
Used in addition to a supercapacitor to store the electrical energy and a thermal energy storage device, the METATHERM platform will allow continuous operation of the device day and night. Moreover, due to the similarity in device structure between the iTE device and the supercapacitor, METATHERM will benefit from manufacturing know how of the latter. A substantial maturity level increase is then expected for the iTE devices.
Finally, the project aims at the development of a platform integrating all these technology in a single device, and exploration of its potential applications. Main applications consist in the use of the MW emitted or reflected signal to probe the environment for natural event monitoring (avalanche, landslide, earthquakes…), for infrastructure and building monitoring (bridges, industrial site…) and for airport ground traffic monitoring.
OBJECTIVES:
The general objective of the project is the development of a communication platform and energy harvesting power source for autarkic sensors arrays. Potential application is outdoor sensing, for which the heat provided by sunlight absorption will be converted to electrical power using iTE devices and stored in a supercapacitor. In addition, a heat storage module will be used to further allow the iTE device to continue working during the night. The harvested power will be used to produce an RF signal thanks to the metamaterial antenna and its superior gain and compactness.
Two potential application families are identified: either the use of the METATHERM system to power and transmit data from sensors integrated in the platform (temperature, humidity, gas sensing etc..) or the use of the RF signal emitted by the system as an environment sensing signal for an additional receiving antenna.
More generally, the METATHERM technology can find numerous applications in the IoT field, for which an autarkic energy harvesting platform using no rare or toxic element could represent a breakthrough for a wide deployment and hence could address large size markets.
Distributed sensor systems are the very key example for the "Internet of Things". Some are remotely operating, mobile sensors and tiny storages that are running on a battery and being read out and recharged at the end of a 'journey'. Other examples are distributed locally and connected to some kind of supply and communicate either wirelessly or via cable, too. The best solution would be a sensor that operates independently, does not require recharging, and communicates 100% wirelessly, making it perfectly autarkic. The promise: Such a sensor solution is not far from reality; all building block of it are already either reality or on the verge of implementation. The goal of METATHERM is exactly to prove this promise to be true.
EXCELLENCE:
In METATHERM, the thermal energy of the sun is harvested using a novel ionic thermoelectric (iTE) device. This technology is based on ion migration under a thermal gradient and show higher Seebeck coefficient than usual Tellurium based semiconductors without the use of rare or toxic elements: a significant advantage in the context of the rapidly growing energy demand for IoT and nomad electronic systems.
Used in addition to a supercapacitor to store the electrical energy and a thermal energy storage device, the METATHERM platform will allow continuous operation of the device day and night. Moreover, due to the similarity in device structure between the iTE device and the supercapacitor, METATHERM will benefit from manufacturing know how of the latter. A substantial maturity level increase is then expected for the iTE devices.
Finally, the project aims at the development of a platform integrating all these technology in a single device, and exploration of its potential applications. Main applications consist in the use of the MW emitted or reflected signal to probe the environment for natural event monitoring (avalanche, landslide, earthquakes…), for infrastructure and building monitoring (bridges, industrial site…) and for airport ground traffic monitoring.
OBJECTIVES:
The general objective of the project is the development of a communication platform and energy harvesting power source for autarkic sensors arrays. Potential application is outdoor sensing, for which the heat provided by sunlight absorption will be converted to electrical power using iTE devices and stored in a supercapacitor. In addition, a heat storage module will be used to further allow the iTE device to continue working during the night. The harvested power will be used to produce an RF signal thanks to the metamaterial antenna and its superior gain and compactness.
Two potential application families are identified: either the use of the METATHERM system to power and transmit data from sensors integrated in the platform (temperature, humidity, gas sensing etc..) or the use of the RF signal emitted by the system as an environment sensing signal for an additional receiving antenna.
More generally, the METATHERM technology can find numerous applications in the IoT field, for which an autarkic energy harvesting platform using no rare or toxic element could represent a breakthrough for a wide deployment and hence could address large size markets.
Distributed sensor systems are the very key example for the "Internet of Things". Some are remotely operating, mobile sensors and tiny storages that are running on a battery and being read out and recharged at the end of a 'journey'. Other examples are distributed locally and connected to some kind of supply and communicate either wirelessly or via cable, too. The best solution would be a sensor that operates independently, does not require recharging, and communicates 100% wirelessly, making it perfectly autarkic. The promise: Such a sensor solution is not far from reality; all building block of it are already either reality or on the verge of implementation. The goal of METATHERM is exactly to prove this promise to be true.
METATHERM has two main innovations.
1. META-Innovation - Communication module, which is on metamaterial-based antenna and
2. THERM-Innovation - Energy harvesting and storage module, which consists of three sub-innovations:
a. thermo-electrical module,
b. heat storage module, and
c. supercapacitor.
The main achievement for these innovations and sub-innovations within the first year of the project can be summarized as following:
- Antenna module: The frequency range required for the antenna is the key parameter deciding the type of technology to be used for the antenna fabrication. The two alternatives are:
o PCB level antenna and
o Integrated antenna.
To meet the requirement of the project user cases two antennas have been designed. A PCB level antenna for a frequency range 100MHzto 3000 MHz and an integrated antenna for 10GHz frequency.
- Energy harvesting and storage module: main parameters for the performance of the subsystems were identified. A first simple semi-analytical model for the determination of the performances of the energy harvesting module was built. The model allows the study of the influence of the system’s main parameters values on its overall efficiency. The model was used to validate the order of magnitude of the power production of the therm platform using simple sunlight and air temperature variation curves through several days.
- Thermo-electrical module: After choosing the thermogalvanic technology rather than the ionic thermoelectric supercapacitors, we formulated redox electrolyte, fabricated thermogalvanic cells and also made thermogalvanic modules. As redox electrolyte for the thermogalvanic cells, we chose 0.4 M of Fe(CN)x-6 dissolved in to a highly concentrated solution of “polyacrylate potassium PAAK: water” of weigh ratio = 1:2. As electrode, we chose porous carbon electrodes made by Ligna Energy. We then varied the concentration of PAAK in this redox electrolyte and measured the Seebeck coefficient, ionic conductivity, cell conductivity. NANOTEST measured the thermal conductivity. Beside the development and optimization of the thermogalvanic electrolytes and cells, we also spend some effort in the manufacturing process and design of thermogalvanic modules made of various numbers of TGC cells.
- Heat storage module: New PCM materials were studied. The literature study allowed the selection of advanced PCM formulation showing enhanced performances in terms of energy storage, thermal conductivity and expected reliability. Two strategies were studied and tested:
o The first one relies on the use of expanded graphite as filler for the organic PCM.
o A second study was conducted to obtain polymeric PCM materials.
The conclusions of the study are that these strategies are effective to enhance the thermal conductivity of the PCM and develop cured formulations, satisfying the targets of the phase change materials development for the fabrication of the heat storage module of METATHERM.
- Supercapacitor: Ligna has developed an organic electrolyte based on a non-flammable propylene carbonate, which is a low toxicity, biodegradable, non-corrosive solvent with a low vapour pressure, and EPA VOC exemption, and hence is classified as a “green'' sustainable alternative. In the project we will also adapt the size and shape of the supercapacitor to fit the needs from the Therm Module and the rest of the system
1. META-Innovation - Communication module, which is on metamaterial-based antenna and
2. THERM-Innovation - Energy harvesting and storage module, which consists of three sub-innovations:
a. thermo-electrical module,
b. heat storage module, and
c. supercapacitor.
The main achievement for these innovations and sub-innovations within the first year of the project can be summarized as following:
- Antenna module: The frequency range required for the antenna is the key parameter deciding the type of technology to be used for the antenna fabrication. The two alternatives are:
o PCB level antenna and
o Integrated antenna.
To meet the requirement of the project user cases two antennas have been designed. A PCB level antenna for a frequency range 100MHzto 3000 MHz and an integrated antenna for 10GHz frequency.
- Energy harvesting and storage module: main parameters for the performance of the subsystems were identified. A first simple semi-analytical model for the determination of the performances of the energy harvesting module was built. The model allows the study of the influence of the system’s main parameters values on its overall efficiency. The model was used to validate the order of magnitude of the power production of the therm platform using simple sunlight and air temperature variation curves through several days.
- Thermo-electrical module: After choosing the thermogalvanic technology rather than the ionic thermoelectric supercapacitors, we formulated redox electrolyte, fabricated thermogalvanic cells and also made thermogalvanic modules. As redox electrolyte for the thermogalvanic cells, we chose 0.4 M of Fe(CN)x-6 dissolved in to a highly concentrated solution of “polyacrylate potassium PAAK: water” of weigh ratio = 1:2. As electrode, we chose porous carbon electrodes made by Ligna Energy. We then varied the concentration of PAAK in this redox electrolyte and measured the Seebeck coefficient, ionic conductivity, cell conductivity. NANOTEST measured the thermal conductivity. Beside the development and optimization of the thermogalvanic electrolytes and cells, we also spend some effort in the manufacturing process and design of thermogalvanic modules made of various numbers of TGC cells.
- Heat storage module: New PCM materials were studied. The literature study allowed the selection of advanced PCM formulation showing enhanced performances in terms of energy storage, thermal conductivity and expected reliability. Two strategies were studied and tested:
o The first one relies on the use of expanded graphite as filler for the organic PCM.
o A second study was conducted to obtain polymeric PCM materials.
The conclusions of the study are that these strategies are effective to enhance the thermal conductivity of the PCM and develop cured formulations, satisfying the targets of the phase change materials development for the fabrication of the heat storage module of METATHERM.
- Supercapacitor: Ligna has developed an organic electrolyte based on a non-flammable propylene carbonate, which is a low toxicity, biodegradable, non-corrosive solvent with a low vapour pressure, and EPA VOC exemption, and hence is classified as a “green'' sustainable alternative. In the project we will also adapt the size and shape of the supercapacitor to fit the needs from the Therm Module and the rest of the system