Wireless body area network (WBAN) has evolved from Wireless personal area network (WPAN), a prominent area of research with vast applications in last decade. In WBAN, various wirelessly interconnected body node (BN) are implanted in or around the human body. Also due to advancement in technology a miniature low power device/BN is developed. The main challenge in WBAN body node is to maintain finite size of battery as well as to increase its capacity. Hence this issue can be resolved by using energy harvesting. Generally researchers have used piezoelectric, electromagnetic or solar harvester only. But, in this research energy harvesting using the hybrid optimization of Piezoelectric and Peltier sensors by controlling on-off timing of body nodes is introduced. A hybrid optimized algorithm is developed using MATLAB 2015b platform and extensive simulation is performed considering four different human gestures (relaxing, walking, running and fast running) which in turn improves overall Quality of Service (QoS) including average (packet loss, end to end delay, throughput) and overall detection efficiency.
The aim of this study was an assessment of feasibility of conversion of sewage holding (SH) tanks to rainwater harvesting (RWH) tanks in Poland. Such a conversion may partly solve the problem of water scarcity for irrigation of plants in individual small gardens and reduce tap water consumption. Seven methods of RWH tanks sizing were applied to an example of a small harvesting system of the roof area equal to the garden irrigation area of 100 m2 for three different irrigation doses. A new criterion was introduced to optimize the tank capacity. Economic optimization was provided for new RWH tanks and for the tanks adapted from abandoned SH tanks. Results obtained for a system sited in west-central Poland in an average year have shown that design capacity of RWH tanks varied markedly between sizing methods. The conversion of SH tanks to RWH tanks is profitable, especially for irrigation due to scarcity of water in relatively dry west-central regions. Conversion of individual SH tanks in a good technical state to RWH tanks is relatively simple and cheap. The potential increase in storage volume due to the conversion of individual SH tanks to RWH tanks could reach all over Poland 215–350 dam3 per year, and individually can save up to 18–25% of total annual water use.
The paper presents a circuit structure that can be used for powering an IoT (Internet of Things) sensor node and that can use energy just from its surroundings. The main advantage of the presented solution is its very low cost that allows mass applicability e.g. in the IoT smart grids and ubiquitous sensors. It is intended for energy sources that can provide enough voltage but that can provide only low currents such as piezoelectric transducers or small photovoltaic panels (PV) under indoor light conditions. The circuit is able to accumulate energy in a capacitor until a certain level and then to pass it to the load. The presented circuit exhibits similar functionality to a commercially available EH300 energy harvester (EH). The paper compares electrical properties of the presented circuit and the EH300 device, their form factors and costs. The EH circuit’s performance is tested together with an LTC3531 buck-boost DC/DC converter which can provide constant voltage for the following electronics. The paper provides guidelines for selecting an optimal capacity of the storage capacitor. The functionality of the solution presented is demonstrated in a sensor node that periodically transmits measured data to the base station using just the power from the PV panel or the piezoelectric generator. The presented harvester and powering circuit are compact part of the sensor node’s electronics but they can be also realized as an external powering module to be added to existing solutions.
The paper presents the analysis of the magnetic sensor’s applicability to the energy harvesting operations. The general scheme and technical advancement of the energy extraction from the electric vehicle (such as a tram or a train) is presented. The proposed methodology of applying the magnetic sensor to the energy harvesting is provided. The experimental scheme for the sensor characteristics and measurement results is discussed. Conclusions and future prospects regarding the practical implementation of the energy harvesting system are provided.
In this paper, an autonomous wearable sensor node is developed for long-term continuous healthcare monitoring. This node is used to monitor the body temperature and heart rate of a human through a mobile application. Thus, it includes a temperature sensor, a heart pulse sensor, a low-power microcontroller, and a Bluetooth low energy (BLE) module. The power supply of the node is a lithium-ion rechargeable battery, but this battery has a limited lifetime. Therefore, a photovoltaic (PV) energy harvesting system is proposed to prolong the battery lifetime of the sensor node. The PV energy harvesting system consists of a flexible photovoltaic panel, and a charging controller. This PV energy harvesting system is practically tested outdoor under lighting intensity of 1000 W/m2. Experimentally, the overall power consumption of the node is 4.97 mW and its lifetime about 246 hours in active-sleep mode. Finally, the experimental results demonstrate long-term and sustainable operation for the wearable sensor node.
The main drawback of vibration-based energy harvesting is its poor efficiency due to small amplitudes of vibration and low sensitivity at frequencies far from resonant frequency. The performance of electromagnetic energy harvester can be improved by using mechanical enhancements such as mechanical amplifiers or spring bumpers. The mechanical amplifiers increase range of movement and velocity, improving also significantly harvester efficiency for the same level of excitation. As a result of this amplitude of motion is much larger comparing to the size of the electromagnetic coil. This in turn imposes the need for modelling of electromagnetic circuit parameters as the function of the moving magnet displacement. Moreover, high velocities achieved by the moving magnet reveal nonlinear dynamics in the electromagnetic circuit of the energy harvester. Another source of nonlinearity is the collision effect between magnet and spring bumpers. It has been shown that this effect should be carefully considered during design process of the energy harvesting device. The present paper investigates the influence of the above-mentioned nonlinearities on power level generated by the energy harvester. A rigorous model of the electromagnetic circuit, derived with aid of the Hamilton’s principle of the least action, has been proposed. It includes inductance of the electromagnetic coil as the function of the moving magnet position. Additionally, nonlinear behaviour of the overall electromagnetic device has been tested numerically for the case of energy harvester attached to the quarter car model moving on random road profiles. Such a source of excitation provides wide band of excitation frequencies, which occur in variety of real-life applications.
Scarcity of freshwater is one of the major issues which hinders nourishment in large portion of the countries like Ethio-pia. The communities in the Dawe River watershed are facing acute water shortage where water harvesting is vital means of survival. The purpose of this study was to identify optimal water harvesting areas by considering socioeconomic and biophysical factors. This was performed through the integration of soil and water assessment tool (SWAT) model, remote sensing (RS) and Geographic Information System (GIS) technique based on multi-criteria evaluation (MCE). The parame-ters used for the selection of optimal sites for rainwater harvesting were surface runoff, soil texture, land use land cover, slope gradient and stakeholders’ priority. Rainfall data was acquired from the neighbouring weather stations while infor-mation about the soil was attained from laboratory analysis using pipette method. Runoff depth was estimated using SWAT model. The statistical performance of the model in estimating the runoff was revealed with coefficient of determination (R2) of 0.81 and Nash–Sutcliffe Efficiency (NSE) of 0.76 for monthly calibration and R2 of 0.79 and NSE of 0.72 for monthly validation periods. The result implied that there's adequate runoff water to be conserved. Combination of hydrological model with GIS and RS was found to be a vital tool in estimating rainfall runoff and mapping suitable water harvest home sites.