Efficiency Of Energy Harvesting Systems Research Articles

Unlocking the Power of Reconfigurable Intelligent Surfaces: From Wireless Communication to Energy Efficiency and Beyond

Reconfigurable Intelligent Surfaces (RISs) are a class of metamaterials that have gained significant attention in recent years due to their potential to revolutionize wireless communication, sensing, and imaging technologies. RISs consist of a planar array of closely spaced, subwavelengthsized elements that can manipulate electromagnetic waves in a controllable manner. By reconfiguring the geometry, material properties, or phases of the individual elements on the RIS, the surface can be customized to meet specific application requirements. RISs can improve wireless communication by creating virtual channels, reducing interference, and improving overall quality. They can also enhance the efficiency of energy harvesting systems and improve sensing and imaging technologies by manipulating the propagation and scattering of electromagnetic waves. Additionally, RISs could be used to increase privacy and security by selectively blocking or allowing specific frequencies of electromagnetic waves. In this editorial, we provide a brief history of the development of RISs and discuss the design and fabrication of RIS structures. We also discuss RIS technology’s potential applications and benefits, including improved wireless communication, enhanced energy efficiency, advanced sensing and imaging, and increased privacy and security. Finally, we highlight some current research challenges and future directions for RIS technology. Overall, RISs hold great promise for advancing a wide range of technologies and applications, and we expect to see many exciting developments in this area.

Thermodynamic limits for simultaneous energy harvesting from the hot sun and cold outer space

The sun and outer space are two of the most important fundamental thermodynamic resources for renewable energy harvesting. A significant amount of work has focused on understanding the fundamental limit of energy harvesting from the sun. More recently, there have been several theoretical analyses of the fundamental limit of energy harvesting from outer space. However, far less is understood about the fundamental limits of simultaneous energy harvesting from both the sun and outer space. Here, we consider and introduce various schemes that are capable of simultaneous energy harvesting and elucidate the fundamental thermodynamic limits of these schemes. We show that the theoretical limits can far exceed the previously established limit associated with utilizing only one thermodynamic resource. Our results highlight the significant potential of simultaneous energy harvesting and indicate new fundamental opportunities for improving the efficiency of energy harvesting systems.

Low-temperature (70 °C) ambient air plasma-fabrication of inkjet-printed mesoporous TiO2 flexible photoanodes

Titania/silica electron-generating and -transporting nanocomposite 300 nm layers of high porosity were deposited onto ITO/PET flexible foils using inkjet printing. Prior to printing, the ITO surface had been modified by novel low-temperature ambient air roll-to-roll plasma in order to enhance its surface properties by removing carbon and oxygen contaminants, a process that led to rapid improvement of surface energy. Consequently the ITO work function, an important parameter involving charge injection efficiency in energy harvesting systems, increased by 1 eV. Afterwards, the TiO2/methyl-silica ink exhibited excellent wetting on a 2 s plasma-treated ITO surface. The coating was further processed/mineralized by an additional low-temperature ambient air plasma treatment step. The plasma processing of raw photoanodes led to the mineralization of the methyl-silica binder which resulted in the formation of a fully inorganic TiO2/SiO2 mesoporous structure and significantly increased electrophotocatalytic activity, leading to increased photocurrents. The entire two-step plasma process was performed at low-temperature (70 °C) and high speeds, enabling practical applications of such a procedure for large-area fabrication of flexible photoanodes.

PIEZOELECTRIC SYSTEMS AS AN ALTERNATIVE ENERGY SOURCE / PJEZOELEKTRINIŲ ENERGIJOS SURINKIMO SISTEMŲ APŽVALGA

The article gives an overview of the problems and solutions related to energy harvesting systems used for power supply of low power electronics systems. Power density is the main parameter describing the efficiency of energy harvesting systems. Piezoelectric energy harvesting systems demonstrate a high value of power density, and therefore the article presents an overview of piezoelectric energy harvesting systems and their components. Also, a summary of the terms that affect the efficiency of piezoelectric energy harvesting systems has been presented. Straipsnyje apžvelgiamos problemos ir sprendimai, susiję su elektrinės energijos tiekimu mažos galios elektronikos sistemoms, taikant energijos surinkimo iš aplinkos technologijas. Vienas iš pagrindinių energijos surinkimo sistemas apibūdinančių parametrų yra galios tankis. Pjezoelektrinė energijos surinkimo technologija pasižymi vienu iš didžiausių galios tankiu, todėl straipsnyje išsamiai nagrinėjami pjezoelektriniai kinetinės energijos keitikliai, apžvelgiamos keitiklių konstrukcijos, jų sudedamosios dalys, išskiriamos technologinės sąlygos, darančios įtaką keitiklių efektyvumui.

Piezoelectric Energy Harvesting Improvement with Complex Conjugate Impedance Matching

One way to enhance the efficiency of energy harvesting systems is complex conjugate impedance matching of its electrical impedance. In Piezoelectric energy Harvesting systems the match is done to increment the energy flows from a vibration energy source to an energy storage electrical circuit. In this article, we compare the power generated using the modulus impedance matching with the power generated using the complex conjugate impedance matching. We present the power ratio between both types of matching methods. The novelty of this article consists of a piezoelectric transducer completely adapted with a complex conjugate impedance match. The theory developed is validated on a commercial piezoelectric transducer QP40w from Midé Technology. The transducer model is first identified by means of a system identification step based on a novel two-port Lumped-Electromechanical Model. The QP40w is complex conjugate matched at its fourth resonant mode increasing the generated power by up to 20% more compared with the modulus match.