Energy Harvesting Techniques Research Articles

Enhanced Power Extraction with Sediment Microbial Fuel Cells by Anode Alternation

Sediment microbial fuel cells (SMFCs) are energy harvesting devices where the anode is buried inside marine sediment, while the cathode stays in an aerobic environment on the surface of the water. To apply this SCMFC as a power source, it is crucial to have an efficient power management system, leading to development of an effective energy harvesting technique suitable for such biological devices. In this work, we demonstrate an effective method to improve power extraction with SMFCs based on anodes alternation. We have altered the setup of a traditional SMFC to include two anodes working with the same cathode. This setup is compared with a traditional setup (control) and a setup that undergoes intermittent energy harvesting, establishing the improvement of energy collection using the anodes alternation technique. Control SMFC produced an average power density of 6.3 mW/m2 and SMFC operating intermittently produced 8.1 mW/m2. On the other hand, SMFC operating using the anodes alternation technique produced an average power density of 23.5 mW/m2. These results indicate the utility of the proposed anodes alternation method over both the control and intermittent energy harvesting techniques. The Anode Alternation can also be viewed as an advancement of the intermittent energy harvesting method.

Energy-Efficient Power Allocation and Splitting for mmWave Beamspace MIMO-NOMA With SWIPT

Non-orthogonal multiple access (NOMA) has recently been employed into millimeter wave (mmWave) beamspace MIMO to further improve connection density and spectrum efficiency for the emerging cellular internet of things (IoT) with massive IoT sensors and devices. Meanwhile, to achieve energy-efficient green communication, an advanced energy harvesting technique named simultaneous wireless information and power transfer (SWIPT) has been regarded as a promising solution. In this paper, we study the integration of SWIPT in mmWave beamspace MIMO-NOMA system. To improve the energy efficiency while guaranteeing the minimum rate and harvested energy requirements at each IoT node, we analyse the energy efficiency maximization via power allocation at the base station and power splitting at each IoT node. The challenge is that this joint optimization problem is non-convex and intractable due to the presence of intra-beam and inter-beam interference. To tackle it, we propose a two-layer iterative algorithm by leveraging Dinkelbach method and alternating optimization (AO) framework. Specifically, the original fractional objective function is transformed to an equivalent subtractive one via Dinkelbach method at the outer layer, whereas in the inner layer, AO is adopted to address the transformed optimization problem. Numerical results indicate that: 1) the proposed joint power allocation and splitting algorithm can converge within five iterations; 2) the proposed scheme can achieve higher energy efficiency and achievable sum rate compared with the existing scheme and conventional beamspace MIMO with SWIPT.

A Review of Piezoelectric Vibration Energy Harvesting with Magnetic Coupling Based on Different Structural Characteristics.

Piezoelectric vibration energy harvesting technologies have attracted a lot of attention in recent decades, and the harvesters have been applied successfully in various fields, such as buildings, biomechanical and human motions. One important challenge is that the narrow frequency bandwidth of linear energy harvesting is inadequate to adapt the ambient vibrations, which are often random and broadband. Therefore, researchers have concentrated on developing efficient energy harvesters to realize broadband energy harvesting and improve energy-harvesting efficiency. Particularly, among these approaches, different types of energy harvesters adopting magnetic force have been designed with nonlinear characteristics for effective energy harvesting. This paper aims to review the main piezoelectric vibration energy harvesting technologies with magnetic coupling, and determine the potential benefits of magnetic force on energy-harvesting techniques. They are classified into five categories according to their different structural characteristics: monostable, bistable, multistable, magnetic plucking, and hybrid piezoelectric–electromagnetic energy harvesters. The operating principles and representative designs of each type are provided. Finally, a summary of practical applications is also shown. This review contributes to the widespread understanding of the role of magnetic force on piezoelectric vibration energy harvesting. It also provides a meaningful perspective on designing piezoelectric harvesters for improving energy-harvesting efficiency.

A novel energy harvesting with middle-order weighted probability (EHMoWP) for performance improvement in wireless sensor network (WSN)

Wireless sensor network (WSN) has been a promising technology and widely involved in environmental monitoring. The limited energy supply associated with WSNs impacts the lifetime of the network and the energy constraints make it difficult for sensor nodes to harvest environmental energy. This drawback on the performance of WSN is improved through routing and clustering techniques for environmental energy harvesting and termed as harvesting wireless sensor network (EH-WSN). As a result of the unique characteristics of EH-WSN, the performance of typical clustering and routing protocols of WSN are ineffective in EH-WSN. A novel energy harvesting middle-order weighted probability (EHMoWP) is proposed in this paper for the static and dynamic operation of WSN nodes. The proposed EHMoWP approach is based on the integration of cluster head selection and routing, with the utilization of a distributed–centralized approach which cogitates the energy of nodes, harvested energy, clustering process, and neighbor nodes. Simulation outcomes showed that this proposed EHMoWP outperforms significantly the conventional techniques concerning residual energy and the number of alive and dead nodes. The proposed EHMoWP exhibits almost 10% higher residual energy with improved network lifetime which is measured in terms of alive node and dead node count. Based on the analysis of dead node and alive node estimation, it was observed that the number of alive nodes was 10% higher and the number of dead nodes was 10% fewer than in the conventional technique. This is because the proposed EHMoWP exhibits 2 dead nodes less and 2 alive nodes higher than the existing technique.

Rotational energy harvesting systems using piezoelectric materials: A review.

In the past few decades, rotary energy harvesting has received more and more attention and made great progress. The energy harvesting device aims to collect environmental energy around electronic equipment and convert it into usable electrical energy, developing self-powered equipment that does not require replaceable power supplies. This paper provides a holistic review of energy harvesting techniques from rotary motion using piezoelectric materials. It introduces the basic principles of piezoelectric energy harvesting, the vibrational modes of piezoelectric elements, and the materials of piezoelectric elements. There are four types of rotational energy harvesting technologies: inertial excitation, contact execution, magnetic coupling, and hybrid systems. An overview of each technology is made, and then, a detailed analysis is carried out. Different types of rotating energy harvesting technologies are compared, and the advantages and disadvantages of each technology are analyzed. Finally, this paper discusses the future direction and goals of improving energy harvesting technology. This Review will help researchers understand piezoelectric energy harvesting to effectively convert rotational energy into electrical energy.

Performance Analysis of a SWIPT Enabled UAV-Assisted Relaying

In the recent era, unmanned aerial vehicle (UAV) plays an important role in numerous application fields related to the wireless communication system. Due to its precise control, efficient deployment, and affordable cost, UAV-assisted communication attracts significant attention to all the sectors including the defense sector, agriculture sector, and security purpose, and so on. Though UAVassisted relaying has enormous advantages but there are potential challenges while UAV deploys as a relay. For example, deploying UAV in the wireless communication field, its battery life is the main concern due to its limited battery size and storage capacity. To get significant benefits from UAV while deployed in the cooperative communication network, the battery status of the UAV is an unavoidable issue. To minimize the aforementioned problem, energy harvesting (EH) techniques can be an efficient solution. The UAV can harvest energy from the transmitted power by the source and with the help of this harvested energy UAV can retransmit the signal to the destination. However, there are several parameters that also significantly influence the UAV-based cooperative system performance such as UAV’s position, time allocation factor and power allocation factor, and UAV’s height. Considering the importance of the aforementioned parameters, in this paper, we have considered simultaneous wireless information and power transfer (SWIPT) enabled UAV-assisted relaying network and evaluate the system outage performance with different parameters aspects. We have provided some insight about the parameters such as the UAV’s position, the power allocation factor and the time allocation factor and the UAV’s height by providing simulation results such as the outage probability versus transmit power in the different urban scenario, the outage probability versus time allocation factor and power allocation factor and the outage probability versus UAV’s height. These simulation results clearly show the significance of the abovementioned parameters in wireless-powered UAVassisted cooperative communication. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium provided the original work is properly cited.

Potential of subdermal solar energy harvesting for medical device applications based on worldwide meteorological data.

.Significance: Active implants require batteries as power supply. Their lifetime is limited and may require a second surgical intervention for replacement. Intracorporal energy harvesting techniques generate power within the body and supply the implant. Solar cells below the skin can be used to harvest energy from light.Aim: To investigate the potential of subdermal solar energy harvesting.Approach: We evaluated global radiation data for defined time slots and calculated the output power of a subdermal solar module based on skin and solar cell characteristics. We assumed solar exposure profiles based on daily habits for an implanted solar cell. The output power was calculated for skin types VI and I/II.Results: We show that the yearly mean power in most locations on Earth is sufficient to power modern cardiac pacemakers if 10 min midday solar irradiation is assumed. All skin types are suitable for solar harvesting. Moreover, we provide a software tool to predict patient-specific output power.Conclusions: Subdermal solar energy harvesting is a viable alternative to primary batteries. The comparison to a human case study showed a good agreement of the results. The developed code is available open source to enable researchers to investigate further applications of subdermal solar harvesting.

A Concurrent Plantar Stress Sensing and Energy Harvesting Technique by Piezoelectric Insole Device and Rectifying Circuitry

Concurrent high force detection accuracy and extended battery lifetime are strongly expected in wearable gait monitoring systems, which are essential for many Internet of Health Things (IoHT) applications. In this article, a piezoelectric insole device and a rectifying circuitry-based technique is presented to achieve these two ultimate goals. Here, walking induced positive and negative charges are separated for plantar stress detecting and energy harvesting, respectively; these two functions are realized concurrently. Experimental results demonstrate that first, the high detection sensitivity of 55 mN and responsivity of 231 mV/N are achieved, satisfying the need for diagnosing various diseases; second, the electric energy of 9.6 pJ (2.67×10-15 W·hr) is stored during a walking cycle, showing the potential of extending the battery lifetime. The developed technique enhances the development of gait monitoring in IoHT.

Experimental investigation of an Organic Rankine cycle system using an oil-free scroll expander for low grade heat recovery

ABSTRACT Organic Rankine cycle (ORC) has become a promising energy harvesting technique to recover thermal energy from low-grade heat sources. In this study, a lab-scale ORC system has been designed, constructed, and tested to investigate the potential of utilizing the heat from hot water, which is used to simulate the jacket water of internal combustion engines. The ORC system employs an oil-free scroll expander with R245fa as working fluid. A wide range of operating conditions has been studied by adjusting the pump frequency, the load and the mass flow rate of cooling water. Effect of the superheat degree at the expander inlet was investigated and the results showed that the ORC system presented better performance with superheat of 0. It is concluded that the system should be controlled to maintain the least possible superheat degree to obtain higher power output and better efficiency. The maximum electric power output and the maximum thermal efficiency are 0.61 kW and 4.09%, respectively, when the heat source is 96.8°C. The power consumed by the pump ranges from 0.07 to 0.18 kW, which accounts for 22 to 39% of the power output of ORC.

On Architecture of Self-Sustainable Wearable Sensor Node for IoT Healthcare Applications

In healthcare applications, the remote monitoring of moving patients depends on wearable nodes that should be mobile. Thus, wearable nodes should be power mains-disconnected most of the time to enable natural wandering of patients in the area. Thus, easy-to-use models are utilized in a seamless way. From this perspective, it becomes necessary to develop a generation of wearable nodes that are energy self-sustainable with minimal dependency on fixed power sources and also more safe in light of world health organization recommendations. In this paper, a solar energy harvesting technique is proposed to provide a mains power supply for an independent continuous operation of a patient monitoring node in sunny environments. A case study is built experimentally whereas the proposed designed node is architected as a combined node that enables parallel measurements of heart rate, blood oxygen saturation (SpO2), and body temperature. The experimental results show that the wearable node can survive more than 28 h without battery recharging from the mains. While the charging time of the battery from the solar energy harvesting is approximately 2 h.

Wearable and Implantable Electroceuticals for Therapeutic Electrostimulations.

Wearable and implantable electroceuticals (WIEs) for therapeutic electrostimulation (ES) have become indispensable medical devices in modern healthcare. In addition to functionality, device miniaturization, conformability, biocompatibility, and/or biodegradability are the main engineering targets for the development and clinical translation of WIEs. Recent innovations are mainly focused on wearable/implantable power sources, advanced conformable electrodes, and efficient ES on targeted organs and tissues. Herein, nanogenerators as a hotspot wearable/implantable energy‐harvesting technique suitable for powering WIEs are reviewed. Then, electrodes for comfortable attachment and efficient delivery of electrical signals to targeted tissue/organ are introduced and compared. A few promising application directions of ES are discussed, including heart stimulation, nerve modulation, skin regeneration, muscle activation, and assistance to other therapeutic modalities.

Radio frequency energy harvesting circuits design for the applications of low power electronics

ABSTRACT Radio frequency (RF) energy harvesting, a new demanding area of research during last decade promises to be a source of generating a small amount of electrical power to drive low power consumable electronics devices. This paper presents different RF energy harvesting circuits and techniques to improve the performance of RF energy harvesting technology. A multiport Wilkinson power combiner circuit followed by Villard voltage multiplier circuit has been achieved to combine output power from multiple RF input sources. The performance of a multiport Schottky diode-based energy harvesting circuit is also studied. Experimentally RF power is captured at different frequencies. A Monte Carlo simulation along with worst case analysis has been carried out and results show close proximity to the nominal or actual outcome. A multiport NMOS-based Dickson’s charge pump is also designed compatible with MOS fabrication technology which shows remarkable results.

Lifetime enhancement of wireless sensor network using solar energy harvesting technique

The finite energy of batteries associated with wireless sensor networks is a major constraint, which limits its lifetime. One of the methods to overcome this major limitation is the energy harvesting (EH) systems. There are many energy sources available nowadays, but solar energy is flexible, mature and is an external power source; so, it is broadly utilised for EH in the wireless sensor network to enhance the life of the network. The solar EH technique along with the low energy adaptive clustering hierarchy protocol is applied. The charging and discharging curves of the battery and energy status of the nodes are propounded. The simulation results demonstrate that the lifetime of the battery and the network gets augmented after applying the solar EH technique.

Cross-Shaped Titanium Resonators Based Metasurface for Ultra-Broadband Solar Absorption

We propose a scheme for ultra-broadband and polarization-insensitive metamaterial perfect absorber (PA) by utilizing a thin metal-insulator-metal (MIM) stack, which is comprised of an array of cross-shaped titanium resonators, a silica dielectric spacer, and an opaque titanium slab. The bandwidth of absorption (A) > 90% is up to 2100 nm, ranging from the visible to near infrared region. At the wavelength range of 400-2500 nm, this metamaterial absorber shows strong absorption of electromagnetic waves. The spectral average absorptivity reaches 93.8% and the maximal absorptivity is up to 99.8%. In addition, the simulations show that the absorption remains high over a broad range of incident angles. Additionally, we have investigated the influences of geometries, structural parameters and material features on the absorption properties. The utilization of titanium rather than the noble metals efficiently lowers the fabrication cost and enhances the thermal stability and biocompatibility, thus paving a way to numerous applications such as solar energy harvesting, imaging, infrared detection and bio-medical techniques.

Environment-resisted flexible high performance triboelectric nanogenerators based on ultrafast self-healing non-drying conductive organohydrogel

Triboelectric nanogenerator (TENG), a promising energy harvesting technique, has attracted intense research interests in recent years for its applicability in portable and wearable electronics. Self-powered sensors with high sensitivity based on TENG have been widely reported. However, for practical applications, the survivability of TENG in harsh working environments is a vital issue which must be addressed. Herein, we report a hydrophobic, icephobic, and ultrafast self-healing TENG with outstanding non-drying and non-freezing properties for energy harvesting and self-powered sensor. Due to the excellent environment resistance and conductive capability of organohydrogel, the TENG shows much better electrical output stability in a wide temperature range than conventional hydrogel-based TENG which suffers from being frozen at low temperature and dried at high temperature. Moreover, the ultrafast self-healing function enables the electrical output performance of the TENG rapidly restore without delay. The TENG in this work demonstrates an open-circuit voltage of 157 V, a short-circuit current of 16 µA, and a short-circuit charge of 29 nC. The maximum output power density reaches up to 710 mW m−2. This research might pave a new road for novel applications of TENG in harsh environments with reliable output performance and self-healing capability for practical applications.

Energy Harvesting Techniques for Internet of Things (IoT)

The rapid growth of the Internet of Things (IoT) has accelerated strong interests in the development of low-power wireless sensors. Today, wireless sensors are integrated within IoT systems to gather information in a reliable and practical manner to monitor processes and control activities in areas such as transportation, energy, civil infrastructure, smart buildings, environment monitoring, healthcare, defense, manufacturing, and production. The long-term and self-sustainable operation of these IoT devices must be considered early on when they are designed and implemented. Traditionally, wireless sensors have often been powered by batteries, which, despite allowing low overall system costs, can negatively impact the lifespan and the performance of the entire network they are used in. Energy Harvesting (EH) technology is a promising environment-friendly solution that extends the lifetime of these sensors, and, in some cases completely replaces the use of battery power. In addition, energy harvesting offers economic and practical advantages through the optimal use of energy, and the provisioning of lower network maintenance costs. We review recent advances in energy harvesting techniques for IoT. We demonstrate two energy harvesting techniques using case studies. Finally, we discuss some future research challenges that must be addressed to enable the large-scale deployment of energy harvesting solutions for IoT environments.

Green Communication for Next‐Generation Wireless Systems: Optimization Strategies, Challenges, Solutions, and Future Aspects

Wireless sensor networks (WSNs) have emerged as a backbone technology for the wireless communication era. The demand for WSN is rapidly increasing due to their major role in various applications with a wider deployment and omnipresent nature. The WSN is rapidly integrated into a large number of applications such as industrial, security, monitoring, tracking, and applications in home automation. The widespread use in many different areas attracts research interest in WSNs. Therefore, researchers are taking initiatives in exploring innovation day by day particularly towards the Internet of Things (IoT). But, WSN is having lots of challenging issues that need to be addressed, and the inherent characteristics of WSN severely affect the performance. Energy constraints are one of the primary issues that require urgent attention from the research community. Optimal energy optimization strategies are needed to counter the issue of energy constraints. Although one of the most appropriate schemes for handling energy constraints issues is the appropriate energy harvesting technique, the optimal energy optimization strategies should be coupled together for effectively utilizing the harvested energy. In this high‐level systematic and taxonomical survey, we have organized the energy optimization strategies for EH‐WSNs into eleven factors, namely, radio optimization schemes, optimizing the energy harvesting process, data reduction schemes, schemes based on cross‐layer optimization, schemes based on cross‐layer optimization, sleep/wake‐up policies, schemes based on load balancing, schemes based on optimization of power requirement, optimization of communication mechanism, schemes based on optimization of battery operations, mobility‐based schemes, and finally energy balancing schemes. We have also prepared the summarized view of various protocols/algorithms with their remarkable details. This systematic and taxonomy survey also provides a progressive detailed overview and classification of various optimization challenges for the EH‐WSNs that require attention from the researcher followed by a survey of corresponding solutions for corresponding optimization issues. Further, this systematic and taxonomical survey also provides a deep analysis of various emerging energy harvesting technologies in the last twenty years of the era.

A Survey on Non-Orthogonal Multiple Access with Energy Harvesting for Underwater Acoustic Sensor Networks

Underwater sensor networks play a key role for unique applications such as naval surveillance, underwater multimedia, internet of underwater things, aided navigation and so on. Mainly, acoustic waves play an important role in underwater communications between sensor nodes, buoys and autonomous underwater vehicles (AUVs). As a result, the available bandwidth of underwater acoustic sensor networks (UASNs) is limited to a few kHz. On the other hand, the sensor node batteries can be neither rechargeable nor replaceable when the node battery is running out. Hence, there is a great need for UASNs to simultaneously enhance the channel capacity and energy efficiency. In this paper, we study the various energy harvesting techniques proposed for UASNs to improve the energy efficiency and non-orthogonal multiple access (NOMA) techniques to improve the channel capacity. Firstly, we will discuss various NOMA techniques used in the papers to improve data rate and channel capacity, we can use any one or combination of techniques discussed in the papers to improve data rate, channel capacity and connectivity. Secondly, we will discuss various energy harvesting techniques used in the papers, we can use any one or hybrid combination of two or more techniques discussed in the papers to improve energy efficiency.

Electron-Ion Coupling Mechanism to Construct Stable Output Performance Nanogenerator.

Recently, triboelectric nanogenerators (TENGs) have been promoted as an effective technique for ambient energy harvesting, given their large power density and high energy conversion efficiency. However, traditional TENGs based on the combination of triboelectrification effect and electrostatic induction have proven susceptible to environmental influence, which intensively restricts their application range. Herein, a new coupling mechanism based on electrostatic induction and ion conduction is proposed to construct flexible stable output performance TENGs (SOP-TENGs). The calcium chloride doped-cellulose nanofibril (CaCl2-CNF) film made of natural carrots was successfully introduced to realize this coupling, resulting from its intrinsic properties as natural nanofibril hydrogel serving as both triboelectric layer and electrode. The coupling of two conductive mechanisms of SOP-TENG was comprehensively investigated through electrical measurements, including the effects of moisture content, relative humidity, and electrode size. In contrast to the conventional hydrogel ionotronic TENGs that require moisture as the carrier for ion transfer and use a hydrogel layer as the electrode, the use of a CaCl2-CNF film (i.e., ion-doped natural hydrogel layer) as a friction layer in the proposed SOP-TENG effectively realizes a superstable electrical output under varying moisture contents and relative humidity due to the compound transfer mechanism of ions and electrons. This new working principle based on the coupling of electrostatic induction and ion conduction opens a wider range of applications for the hydrogel ionotronic TENGs, as the superstable electrical output enables them to be more widely applied in various complex environments to supply energy for low-power electronic devices.

A Review of Metasurfaces for Microwave Energy Transmission and Harvesting in Wireless Powered Networks

Wireless energy transmission and harvesting techniques have recently emerged as attractive solutions to realize wireless powered networks. By eliminating fundamental power constraints arising from the use of conventionally battery sources, wireless modes of energy transmission provide viable means to power wireless network devices away from the grid. Metasurfaces have emerged as key enablers for the use of microwave energy as a power source. Their unique abilities to tailor electromagnetic waves have motivated significant research interest into their use for power-focused microwave systems. This article provides an overview of progress in the development of metasurface implementations for microwave energy transmitters and energy harvesters. First, the paper provides a basic introduction to metasurfaces, after which it reviews research progress in metasurfaces for microwave energy transmission and harvesting. Also highlighted are key parameters by which the performance of such metasurface designs are characterized. In addition, an overview of studies on metasurfaces as reconfigurable intelligent surfaces in wireless networks supporting the simultaneous transmission of information and energy is presented. Finally, the paper highlights existing challenges, and explores future directions, including opportunities to control radio environments through ambiently energized reconfigurable intelligent surfaces in next-generation wireless networks.