Energy Harvesting Technologies for Achieving Self-Powered Wireless Sensor Networks in Machine Condition Monitoring: A Review <s> Potential Energy Harvesting Sources in Machines <s> The potential of electric power generation from marine tidal currents is enormous. Tidal currents are being recognized as a resource to be exploited for the sustainable generation of electrical power. The high load factors resulting from the fluid properties and the predictable resource characteristics make marine currents particularly attractive for power generation and advantageous when compared to other renewable energies. Moreover, international treaties related to climate control have triggered resurgence in development of renewable ocean energy technology. Therefore, several demonstration projects in tidal power are scheduled to capture the tidal generated coastal currents. Regarding this emerging and promising area of research, this paper reviews marine tidal power fundamental concepts and main projects around the world. It also report issues regarding electrical generator topologies associated to tidal turbines. Moreover, attempts are made to highlight future issues so as to index some emerging technologies mainly according to relevant works that have been carried out on wind turbines and on ship propellers. <s> BIB001 </s> Energy Harvesting Technologies for Achieving Self-Powered Wireless Sensor Networks in Machine Condition Monitoring: A Review <s> Potential Energy Harvesting Sources in Machines <s> Solar Energy Harvesting Introduction I-V Characteristics of Photovoltaic (PV) Systems PV Models and Equivalent Circuits Sun Tracking Systems MPPT Techniques Shading Effects on PV Cells Power Electronic Interfaces for PV Systems Sizing the PV Panel and Battery Pack for Stand-Alone PV Applications Modern Solar Energy Applications Wind Energy Harvesting Introduction Winds History of Wind Energy Harvesting Fundamentals of Wind Energy Harvesting Wind Turbine Systems Wind Turbines Different Electrical Machines in Wind Turbines Synchronous Generators Wind Harvesting Research and Development Tidal Energy Harvesting Introduction Categories of Tidal Power and Corresponding Generation Technology Turbine and Generator's Control Tidal Energy Conversion Systems Grid Connection Interfaces for Tidal Energy Harvesting Applications Potential Resources Environmental Impacts Ocean Wave Energy Harvesting Introduction to Ocean Wave Energy Harvesting The Power of Ocean Waves Wave Energy Harvesting Technologies Wave Energy Applications Wave Energy in Future Ocean Thermal Energy Harvesting History Classification of Ocean Thermal Energy Conversions (OTECs) Technical Obstacles of Closed-Cycle OTEC Systems Components of an OTEC System Control of an OTEC Power Plant Control of a Steam Turbine Potential Resources Multipurpose Utilization of OTEC Systems Impact on Environment Index A Summary and References appear at the end of each chapter. <s> BIB002 </s> Energy Harvesting Technologies for Achieving Self-Powered Wireless Sensor Networks in Machine Condition Monitoring: A Review <s> Potential Energy Harvesting Sources in Machines <s> This book comprehensively covers the fundamentals of design and the methodology for evaluating innovative systems and components. <s> BIB003 </s> Energy Harvesting Technologies for Achieving Self-Powered Wireless Sensor Networks in Machine Condition Monitoring: A Review <s> Potential Energy Harvesting Sources in Machines <s> Current progress in wearable and implanted health monitoring technologies has strong potential to alter the future of healthcare services by enabling ubiquitous monitoring of patients. A typical health monitoring system consists of a network of wearable or implanted sensors that constantly monitor physiological parameters. Collected data are relayed using existing wireless communication protocols to a base station for additional processing. This article provides researchers with information to compare the existing low-power communication technologies that can potentially support the rapid development and deployment of WBAN systems, and mainly focuses on remote monitoring of elderly or chronically ill patients in residential environments. <s> BIB004 </s> Energy Harvesting Technologies for Achieving Self-Powered Wireless Sensor Networks in Machine Condition Monitoring: A Review <s> Potential Energy Harvesting Sources in Machines <s> Energy is regarded as one of the most critical challenges for static and mobile pervasive sensor networks. It not only limits a network's operating lifetime but also causes a performance bottleneck. Traditional techniques for overcoming energy constraints include replacing batteries or using a constant electrical source for wired recharging. These might not always be feasible solutions, however, and in some cases, could even prove prohibitive. Fortunately, due to recent technological advancements, several prominent techniques now exist to viably address such energy constraints. Among these, energy harvesting is gaining significant attention in academia and industry due to its potential to enable perpetual operation without the need for external power cables or periodic battery replacements. Energy can be harnessed from a diverse set of nonelectrical ubiquitous sources whenever required. This article presents a review of several potential energy-harvesting sources for wireless body area networks (WBAN). The authors examine sources' characteristics, usefulness in enhancing service availability and minimizing performance bottleneck, current challenges, and possible future research directions. They discuss how recent developments in energy-harvesting technologies have raveled self-sustainable operation for low-power body sensor networks. <s> BIB005 </s> Energy Harvesting Technologies for Achieving Self-Powered Wireless Sensor Networks in Machine Condition Monitoring: A Review <s> Potential Energy Harvesting Sources in Machines <s> Condition monitoring (CM) of gearbox is a crucial activity due to its importance in power transmission for many industrial applications. Monitoring temperature is an effective mean to collect useful information about the healthy conditions of the gearbox. This study investigates the use of a novel wireless temperature node to monitor and diagnose different faults on a gearbox transmission system under different conditions. The wireless temperature node was fabricated with a novel feature that it is supplied by a thermoelectric generator module mounted on the gearbox house to be monitored so that the measurement system avoids the shortage of using a wired power sources or the requirement for recharging or changing batteries. Moreover, the temperatures from lubricating oils and housing are modelled empirically to implement a model based detection. The results show that this monitoring approach allows a number of common faults: tooth breakage, oil shortage, and shaft misalignment to be separated under different loads, which demonstrates the outstanding performance of the proposed system and thus suitable for online and automated condition monitoring. <s> BIB006 </s> Energy Harvesting Technologies for Achieving Self-Powered Wireless Sensor Networks in Machine Condition Monitoring: A Review <s> Potential Energy Harvesting Sources in Machines <s> Due to recent abrupt climate change and the environmental contamination, the interest in the renewable energy increases, and various types of renewable energy generation systems have been replacing the existing old ones using fossil fuels. Hydroelectric power generation is traditionally one of those clean energy solutions. Recently, new hydroelectric power generation from municipal water systems has been developed and regarded as a new or replaceable water system of new and old cities. In this paper, basic architecture of hydroelectric power generation from water pipes and information modeling is proposed in terms of management. <s> BIB007 </s> Energy Harvesting Technologies for Achieving Self-Powered Wireless Sensor Networks in Machine Condition Monitoring: A Review <s> Potential Energy Harvesting Sources in Machines <s> Conventional internal combustion engines exhibit efficiency in the range of 30%-40%. A significant portion of the remaining energy is dissipated as exhaust heat, some of which can be recovered using thermoelectric generators to reduce fuel consumption and CO2 emissions. The current study evaluates the benefits of using thermoelectric electric generators in hybrid electric vehicles over a prescribed drive-cycle. Specifically, a hybrid electric bus was first modeled over a realistic urban drive-cycle. Engine operating parameters such as torque and speed were extracted and provided as inputs to an engine simulation model. A virtual thermoelectric generator was then modeled using the Matlab/Simulink architecture to evaluate the quantity of energy that can be recovered based on inputs from the engine simulation model. Simulations were carried out to accurately assess the amount of fuel savings achieved due to the use of the thermoelectric generators system. From the analysis, it was observed that a fuel saving of 7.2% and 6.5% can be achieved with the use of Skutterudite and Silicon Germanium-based thermoelectric generator systems, respectively. It was also observed that the additional weight of the thermoelectric generator system had a negligible effect on the fuel consumption. (C) 2018 Elsevier Ltd. All rights reserved. <s> BIB008 </s> Energy Harvesting Technologies for Achieving Self-Powered Wireless Sensor Networks in Machine Condition Monitoring: A Review <s> Potential Energy Harvesting Sources in Machines <s> Abstract The impact of design and external parameters on the intrinsic output properties and load characteristics of hybrid energy harvesting generator is significant in both designing the generator and power management circuit and achieving high energy conversion efficiency. In this work, the intrinsic output characteristics of a hybrid triboelectric and piezoelectric generator is investigated, where the impacts of design parameters on the output properties and load characteristics under resistive and capacitive load conditions are demonstrated using a wide-ranging setting of the design parameters and compared with the theoretical calculations using a parallel hybrid model. The regularities concluded from the experimental results reflect the actual output behavior of a typical hybrid generator and provide evidence that the parameters have significant impacts on the intrinsic output properties, resistive load behavior and charging behavior. The outcomes of this study can be used as guidance toward designing effective structures and power management as well as in future simulation of a wide range of hybrid generators. <s> BIB009
To provide sufficient power for self-powered WSNs, the potential energy harvesting resources in or around mechanical systems can be analyzed as shown in Figure 2 . In general, these sources can be split into internal and external energy sources representing the energy coming from mechanical systems or their surroundings. Then, they are further classified into light, electricity, heat and motion based on the forms of energy. data processing and data transmission in algorithm design and network optimization. In general, power at the milliwatt level or watt level is required to process and transmit large amounts of rapidly varying signals at a wireless sensor node for remote and real-time machine condition monitoring. To provide sufficient power for self-powered WSNs, the potential energy harvesting resources in or around mechanical systems can be analyzed as shown in Figure 2 . In general, these sources can be split into internal and external energy sources representing the energy coming from mechanical systems or their surroundings. Then, they are further classified into light, electricity, heat and motion based on the forms of energy. Solar energy is a green, renewable and efficient source in the environment where most mechanical systems are located. Solar radiation at a high level can be harvested and stored. However, sunlight is crucially affected by the region, weather and length of day. Artificial light has little correlation with these factors, but its illumination level is several orders of magnitude lower than that of sunlight. Electromagnetic waves, such as RF radiation, are another energy source mainly existing in the surroundings due to the wide usage of radio transmitters. Both light and RF radiation energy can be harvested to use for wireless body area networks BIB004 BIB005 . The force generated by fluid flows (like wind and tidal current BIB002 ) is an effective source of kinetic energy. For example, marine tidal energy [44] can be harvested for large-scale equipment on the seashore or ships. External energy sources are greatly influenced by the environment, and the corresponding generators may be difficult to adapt to condition monitoring systems. Their common applications are power generation for the power plants BIB001 BIB003 BIB007 . Solar energy is a green, renewable and efficient source in the environment where most mechanical systems are located. Solar radiation at a high level can be harvested and stored. However, sunlight is crucially affected by the region, weather and length of day. Artificial light has little correlation with these factors, but its illumination level is several orders of magnitude lower than that of sunlight. Electromagnetic waves, such as RF radiation, are another energy source mainly existing in the surroundings due to the wide usage of radio transmitters. Both light and RF radiation energy can be harvested to use for wireless body area networks BIB004 BIB005 . The force generated by fluid flows (like wind and tidal current BIB002 ) is an effective source of kinetic energy. For example, marine tidal energy [44] can be harvested for large-scale equipment on the seashore or ships. External energy sources are greatly influenced by the environment, and the corresponding generators may be difficult to adapt to condition monitoring systems. Their common applications are power generation for the power plants BIB001 BIB003 BIB007 . In contrast, the internal energy of machines is relatively reliable and steady. Efficiency of the power machines (usually IC engines and motors) is less than 50%. The wasted energy gives a chance to be harvested and then used to power the WSN for monitoring the working conditions. For example, the efficiency of a conventional combustion engine can only reach a range of 30% to 40% BIB008 . The wasted energy can be the source of power for maintenance-free wireless sensor nodes. The available energy for harvesting is thermal and kinetic energy. Figure 3a presents the energy audit of a traditional diesel engine using a pie chart  . It is understood that energy loss is inevitable during the operation of an engine resulting with the fuel efficiency being less than 50%. Most of the wasted energy is in the forms of heat and kinetic energy. For typical diesel engines in tested in 2009, the heat lost with the exhaust is approximately a quarter of the fuel energy. Meanwhile, exhaust emission is also a process in which gas flow may be used to generate force. Therefore, both thermal and kinetic energies can be harvested from the machine exhaust. Another form of the wasted energy is heat rejection (heat releasing into the environment with the coolant) with the energy supplied being slightly more than the exhaust. It is mainly a result of a significant increase in the temperature of the environment and components of the mechanical system, this provides an opportunity for powering WSN if there are effective and efficient thermal energy harvesting technologies. Although the development of technologies improved higher fuel efficiency for engines to around 50% in recent years (for example, Wärtsilä engine fuel efficiency increases year-over-year as shown in Figure 3b [50] ), a mass of fuel energy still dissipates in the form of heat and kinetic energy. Nevertheless, since the transmission efficiency of machines is always less than 100%, most of the lost energy being used is due to overcoming friction and generated heat. Interestingly, researchers at the University of Huddersfield have analyzed the thermodynamics of an industrial helical gearbox of 10kW by thermography signals to obtain the heat distribution of the gearbox as shown in Figure 4b . It shows the thermal energy at the motor drive end and gearbox housing is relatively high and the temperature near the cooling system (in this case a fan) is much lower than shown in Figure 4a , this can be utilized to assemble a thermoelectric generator to power the gearbox monitor BIB006 . In addition, the cooling system of a machine can also generate useful kinetic energy while cooling the mechanical system. These examples illustrate that these different forms of wasted energy can be effectively harvested to power the wireless condition monitoring systems with little effect on the overall mechanical efficiency. the operation of an engine resulting with the fuel efficiency being less than 50%. Most of the wasted energy is in the forms of heat and kinetic energy. For typical diesel engines in tested in 2009, the heat lost with the exhaust is approximately a quarter of the fuel energy. Meanwhile, exhaust emission is also a process in which gas flow may be used to generate force. Therefore, both thermal and kinetic energies can be harvested from the machine exhaust. Another form of the wasted energy is heat rejection (heat releasing into the environment with the coolant) with the energy supplied being slightly more than the exhaust. It is mainly a result of a significant increase in the temperature of the environment and components of the mechanical system, this provides an opportunity for powering WSN if there are effective and efficient thermal energy harvesting technologies. Although the development of technologies improved higher fuel efficiency for engines to around 50% in recent years (for example, Wärtsilä engine fuel efficiency increases year-over-year as shown in Figure 3b [50] ), a mass of fuel energy still dissipates in the form of heat and kinetic energy. Nevertheless, since the transmission efficiency of machines is always less than 100%, most of the lost energy being used is due to overcoming friction and generated heat. Interestingly, researchers at the University of Huddersfield have analyzed the thermodynamics of an industrial helical gearbox of 10kW by thermography signals to obtain the heat distribution of the gearbox as shown in Figure 4b . It shows the thermal energy at the motor drive end and gearbox housing is relatively high and the temperature near the cooling system (in this case a fan) is much lower than shown in Figure 4a , this can be utilized to assemble a thermoelectric generator to power the gearbox monitor BIB006 . In addition, the cooling system of a machine can also generate useful kinetic energy while cooling the mechanical system. These examples illustrate that these different forms of wasted energy can be effectively harvested to power the wireless condition monitoring systems with little effect on the overall mechanical efficiency. In summary, internal and external energy resources can be employed separately or simultaneously using various energy harvesting technologies or hybrid energy harvesters, such as a hybrid triboelectric-piezoelectric generator BIB009 . Solar energy can be scavenged to supply power for WSNs applied in the outdoor machine condition monitoring because of its abundance. Moreover, because of a considerable quantity of waste thermal and kinetic energy in mechanical systems, most machines have sufficient power resources for harvesting to achieve a WSN-based maintenance-free condition monitoring system. In summary, internal and external energy resources can be employed separately or simultaneously using various energy harvesting technologies or hybrid energy harvesters, such as a hybrid triboelectric-piezoelectric generator BIB009 . Solar energy can be scavenged to supply power for WSNs applied in the outdoor machine condition monitoring because of its abundance. Moreover, because of a considerable quantity of waste thermal and kinetic energy in mechanical systems, most machines have sufficient power resources for harvesting to achieve a WSN-based maintenance-free condition monitoring system.