Energy Generation Performance Research Articles

Remotely controlled self-powering electrical stimulators for osteogenic differentiation using bone inspired bioactive piezoelectric whitlockite nanoparticles

Endogenous electric fields naturally exist in our body and plays a vital role especially in the development and regeneration of bones. Therefore, piezoelectric bone implants are gaining ample attention due to its inherent electrical signal generation, but generally they lack bioactivity, resorption, and ECM like composition. To address this, we evoke ‘piezoelectricity’ in whitlockite (Ca 18 Mg 2 (HPO 4 ) 2 (PO 4 ) 12 ) nanoparticles (WH NPs) for the first time in literature. WH NPs are the second most-abundant inorganic bone mineral and reported for intermediate resorption compared to hydroxyapatite and tricalcium phosphate. Systematic electrical studies reveal that WH NPs annealed at 750 °C (PWH-750) exhibit superior ferroelectric and dielectric characteristics and produce electrical signals analogous to native tissues when triggered using FDA approved low-intensity pulsed ultrasound (LIPUS) noninvasively. The energy generation performance of Piezoelectric WH based self powered nanogenerators are analyzed and demonstrated to power the commercial LED upon LIPUS stimulation. The in vitro studies with pre-osteoblast MC3T3-E1 cells co-cultured with piezoelectric WH NPs exhibit increased ALP activity, calcium mineralization, and osteogenic gene expression along with significant upregulation of Piezo1, and TRPV4 expressions. This confirms the enhanced osteogenic differentiation compared to the control WH nanoparticles due to the remotely activated self powering capacity of piezoelectric WH NPs and thereby produce bioelectric signals analogous to native tissues. Thus, the study evidences the development of a potential bioactive piezoelectric ceramic with extensive applicability for future clinical translation. • Development of piezoelectric whitlockite nanoparticles for self-powered electrical cell stimulation. • The study also reports the development of the unique piezoelectric nanogenerator (PENG) based on biocompatible WH NPs. • LIPUS mediated electric field produced by the piezoelectric WH NPs promotes osteoblast proliferation and differentiation. • The study confirms the enhanced osteogenic differentiation via Piezo1 and TRPV4 mechanosensitive ion channels. • A new perspective in the field of regenerative medicine through self-powered electrical stimulation to cells.

A lever-type piezoelectric energy harvester with deformation-guiding mechanism for electric vehicle charging station on smart road

To meet the increasing demand for electric vehicles, this paper presents a novel concept to enhance the energy generation performance of piezoelectric energy harvesters used as charging stations on roads. A lever-type piezoelectric energy harvester with a deformation-guiding mechanism was designed and fabricated to overcome the existing limitations of low electrical output and low durability of piezoelectricity under extremely low road displacement conditions of 1 mm. The proposed harvester achieved a maximum output power of 60.3 mW at a load resistance of 50 kΩ under an input displacement of 1 mm. Thus, the module’s electrical performance was significantly higher than that obtained in previous similar studies. The proposed harvester had 467% higher output power than the previously proposed vibration type road energy harvester. For the energy storage test, a 0.08 F supercapacitor was charged up to 5.09 V (1 J) in 170 min. The results prove that the energy generated by the proposed harvester can be potentially used as a power source for electric vehicles on smart roads beyond the power supply of various sensor systems on the road.

Multidisciplinary design optimization of distributed energy generation systems: The trade-offs between life cycle environmental and economic impacts

Distributed energy systems (DES) are the focus of increasing attention because they have the potential to enhance the sustainability performance of energy generation. Previous DES researches evaluated various distributed energy technologies and systems from different aspects. However, there is still a research gap to evaluate and compare the multiple technology combinations and sizes for finding optimal energy solutions under various scenarios. This study aims to determine the best combination of technologies and their corresponding sizes for DES for various building types and climate zones in terms of life cycle environmental and economic impact. We developed parametric models (which considers dynamic hour by hour energy demand) for six commercially available distributed energy technologies and simulated the performance of them under various conditions. Then, we used a novel approach – multidisciplinary design optimization (MDO) to examine the billions of options (e.g., technologies, sizes, climate zone, Etc.) and identified the Pareto front with the optimal environmental and economic impact. According to MDO simulations, the microturbine-solar PVs-lithium ion battery and solid oxide fuel cells-solar PVs-lithium ion battery are two optimal combinations of technologies for three commercial building types for five climate zones. The DES can primarily reduce the environmental impact compared to conventional centralized energy production (CCEP) by 16–61% in all scenarios. However, the life cycle cost of DES is higher than CCEP, especially for SOFC-based DES. The microturbine-based DES is more cost-competitive and economical (about 65%, 32%, and 64% lower than SOFC-based DES for the small, medium, and large office, respectively).

Energy Generation Performance of Window-Type Dye-Sensitized Solar Cells by Color and Transmittance

Previous research has shown Dye-Sensitized Solar Cells (DSSCs) to have excellent applicability for building exterior materials and windows, because they can be controlled in terms of Visible Light Transmittance (VLT) and color, and thus have good variability. However, windows with solar cells may not show ideal energy generation efficiency. This depends on a variety of factors, such as window composition, shadow, and light scattering. In this paper, through mock-up tests, the energy generation of DSSCs with various transmittances and colors was measured. Red, Green, and Blue (RGB)-based DSSCs of 7, 10, and 20% VLT were used, and Pmax values were measured for solar radiation for comparison. As a result of the comparison, performance estimates were made for each color and VLT when used as a window. In this study, the electrical energy generated by DSSCs was measured in an environment applied to a real window, not a virtual environment. Therefore, the study is meaningful, in that data that can estimate performance when applying various types of DSSCs in a real-world window environment were created.

A Broadband Multiplex Living Solar Cell.

Developing renewable and sustainable energy sources is a compelling goal in materials science and engineering. In particular, natural photosynthesis with its infinite energy reservoir provides profound inspiration for energy conversion and storage systems. Here, we report a multiplex living solar cell that offers a drastic power enhancement by harnessing the broadband spectra of the visible wavelength range for photosynthesis. Cyanobacteria are embedded into a nanostructural complex composed of Au nanoparticles (NPs) and ZnO nanorods (NRs). This nanocomposite system is capable of not only generating excitons but also amplifying the photosynthetic performance of the cell via a far-field scattering effect in the broadband region of the light, resulting in multiplex energy harvesting with a peak power density of 6.15 mW/m2. We envision that this study will provide a strategic way to enhance the performance of biophotovoltaics, enabling efficient and durable energy generation.

Enhanced energy-generation performance of a landfilled road-capable piezoelectric harvester to scavenge energy from passing vehicles

We demonstrate the use of a road-capable piezoelectric harvester (RCPH) with improved maintenance and power-generation characteristics. The RCPH obtained its ingress and moisture protection system rating (IP 66) through a new housing system used to evaluate its waterproof performance. Finite element simulations were performed to identify the proper depth (1, 3, or 5 cm) under an actual road for its placement to achieve increased output power. The highest von Mises stress value was measured by the 1 cm landfilled module (1LFM). The RCPH was installed under a test road and was tested with the use of the exposed and landfilled method to compare output power levels. Correspondingly, the output voltage and output power of the 1LFM were higher the exposed module. When a minivan drove over the 1LFM at 90 km/h, an output voltage of 18 Vmax and an output power of 1150 mWmax (power density: 1.15 mW/cm2) were measured at a load resistance level of 910 Ω. In a test road environment, the electrical energy generated by the 1LFM was sufficient to illuminate four delineators for 40 s. This system could be used on actual roads by connecting the piezoelectric modules to an emergency lighting that can be powered by the electricity generated by the module.

Experimental analysis of flexible thermoelectric generators used for self-powered devices

Thermoelectric generators are becoming a promising power source for wearable electronics and microtechnology. By creating energy from waste heat or a temperature gradient between dissimilar materials, thermoelectric generator provides an alternative to wired power that restricts movement and to batteries that challenge waste disposal. This study is an experimental evaluation of a flexible thermoelectric generator to determine how the energy generation performance is affected by varying several physical and operational parameters. The test parameters included the contact pressure between the generator and the temperature plates, several thermal interface materials, the device temperature, the temperature gradient between the hot and cold plates, and the bend radius of the flexible generator itself. The results showed that the most influential parameters were the contact pressure, which could affect the generation by 10–20 mW (increased by up to 83.3%), and the choice of thermal interface material (increased by up to 51.9%).

사무소 건물 적용 DSSC BIPV 창호의 환경 및 에너지성능 분석

Purpose: This study aimed at analyzing the building indoor environment conditions and energy performance when DSSC BIPV windows are applied, and building a database to suggest the appropriate performance level of DSSC BIPV windows in future buildings. Method: The DesignBuilder, a building energy analysis program, was used to evaluate indoor illuminance, room temperature, cooling and heating energy, lighting energy, and power generation performance. Result: Simulation results demonstrate that the current characteristics of DSSC BIPVs exhibit an improved U-value but low visible light transmission (VLT) performance in comparison with low-emissivity double glazing windows. Thus, heating energy consumption was reduced, while as the electricity consumption for lighting was significantly increase. This increasement influenced the increase of the cooling energy consumption due to the higher indoor cooling load from lighting fixtures. To satisfy the 13% power generation efficiency suggested by the National Renewable Energy Laboratory, a VLT of 30% is required, which will produce energy savings of 4,861.44 ㎾h/year. For VLTs of ＞50%, energy saving is possible in combination with any generation efficiency.

Analyzing long-term empirical interactions between renewable energy generation, energy use, human capital, and economic performance in Pakistan

BackgroundThe current research attempts to systematically investigate the causal interactions between renewable energy generation, aggregated energy use, human capital, and economic performance in Pakistan both in a short-term and long-term test for the period of 1990–2016.MethodsAs a primary step, a unit root analysis was conducted employing, among others, an augmented Dickey-Fuller-generalized least squares (ADF-GLS) test. Based on the order of integration I(1), the Johansen and Juselius (JJ) co-integration testing was employed to confirm a long-term causality analysis, which was followed by a vector error correction model (VECM) to calculate the short-run Granger causality analysis. Furthermore, the vector autoregressive (VAR)-based Cholesky test allowed the standard deviation impulse response functions to be generated to explain the responses of variables to arbitrary shocks in the data series under analysis.ResultsThe empirical findings unearthed the bilateral causal connection between aggregated energy use and economic performance, renewable energy generation and economic performance, and human capital and economic performance. Thus, it confirmed the existence of feedback effects for aggregated energy use, renewable energy generation, and human capital in their relation to economic performance. Likewise, a unilateral positive causal connection was revealed running from renewable energy generation and human capital to aggregated energy use, and from human capital to renewable energy generation in both a long-term and short-term test. Additionally, the causal association running from aggregated energy use and renewable energy generation to economic performance was exposed in a long-term as well as short-term test, hence supporting the growth hypothesis.ConclusionsThe findings signified the importance of an enhanced generation of renewable energy along with the promotion of an aggregated energy use for the economic performance in Pakistan.

Piezoelectric Flexible Energy Harvester Based on BaTiO3 Thin Film Enabled by Exfoliating the Mica Substrate

Flexible piezoelectric energy harvesters (f‐PEHs) have exhibited significant potential as long‐lasting self‐powered sources or sensor devices, as they can generate reliable and repeatable electricity under harsh and tiny mechanical bending cycles without restraints anywhere and anytime. Herein, a new approach for transferring piezoelectric ceramic thin films onto a single flexible substrate via piecemeal elimination of the sacrificial mica substrates is proposed. The crystallized piezoelectric BaTiO3 thin film on a rigid mica substrate with electrodes and passivation layers is peeled off by means of a physical delamination process using sticky tape as the remover. The film is then transferred onto a flexible polyimide substrate using a polymer elastomer as a support. The fabricated BaTiO3 thin‐film f‐PEH successfully converts an open‐circuit voltage of ≈0.5 V and a short‐circuit current of ≈30 nA from repeated mechanical bending deformations. The energy generation mechanism and performance of the perovskite BaTiO3 thin‐film f‐PEH is supported using finite‐element analysis (FEA) with multiphysics simulations. The novel transfer techniques adopting the removal of sacrificial mica layers opens the door to various high‐performance flexible and wearable applications based on all‐inorganic materials.

Investigation energy, exergy and electricity production performance of an integrated system based on a low-temperature geothermal resource and solar energy

In this work, energy, exergy and electricity generation performance of an integrated system was conceptually investigated by using Engineering Equation Solver (EES) under 200–1000 W/m2 solar irradiation interval. The system comprises evacuated tube solar collectors (EVTSCs) with the surface area of 100 m2, an organic Rankine cycle (ORC) and a low-grade geothermal resource. The EVTSCs were used to enhance the temperature of the low-grade water coming from the geothermal source. The calculations were carried out for three geothermal sources in Kula (63 °C), Saraycık (74 °C) and Turgutlu (86 °C), respectively. N-hexane, n-pentane and n-butane were selected as a working fluid in the ORC. It was determined that the selection of the working fluid affected the performance of the ORC. And also, the waste heat is extracted from the ORC were used efficiently for space heating. As a result, the overall energy and exergy efficiencies of the system and power generation of the ORC were seriously affected by enhancing the water temperature of the geothermal resources by EVTSCs. The maximum overall energy and exergy efficiencies of the system were calculated as to be 6.92% and 21.06% by using n-butane for the source in Turgutlu, respectively. The minimum overall energy and exergy efficiencies of the system were calculated as 0.32% and 2.19% by using n-hexane for the source in Kula, respectively. The maximum and minimum generated electricity were calculated as to be 19.46 kW and 0.6168 kW for the sources in Turgutlu and Kula, respectively. It was seen that the best performance of the system was found for n-butane compared to n-pentane and n-hexane.

Optimal Battery Capacity for Residential Rooftop PVs With Consideration of Net-Metering Scheme Compensation Period

With the significant increase of the prosumers in the world, the battery energy storage system (BESS) has become an important device to enhance the performance of renewable energy generation. By focusing on residential scale of rooftop PVs, BESS has been developed and applied in many aspects especially in terms of electricity charge saving. Many papers propose the methodology to control the operation of BESS, while many papers propose the methodology to determine the battery capacity. As f or this paper, the proposed methodology will simultaneously determine the operation schedule and battery capacity of BESS for rooftop PVs under a net-metering scheme (NMS). The main objective is to maximize the net present value (NPV) of the prosumers. The battery capacity will be constrained by the period of the NMS compensation which will be effective for only one year of each electricity bill. The numerical results show that , for the TOU structure without demand charge, an appropriate BESS should have C NOM,DC as high as possible to increase the revenue from BESS and have P NOM,DC as low as possible to reduce the total investment cost (TTC). Also, by considering the limit period of the NMS compensation, an appropriate battery capacity should not be higher than monthly residential load consumption. Lastly, the sensitivity of electricity tariff shows that the NPV will increase proportionally by the increment of electricity price, which will reduce the break-even year of the investment.

Transient self-templating assembly of M13 bacteriophage for enhanced biopiezoelectric devices

Many biogenic materials are hierarchically structured across several length scales. Attaining similar control over bottom-up assembly would allow for efficient synthesis of materials for enhanced electrical or energy generating devices. Here we developed a transient self-templating assembly process inspired by nature for the synthesis of enhanced biopiezoelectric devices. We used M13 bacteriophage (phage) as a piezoelectric nanofiber building block and created hierarchically organized nano- and micro-structures for enhanced piezoelectric devices. We controlled the self-assembly of M13 phage by exploiting transiently forming, periodic menisci. Each micron-sized meniscus directed the local formation of hexagonally packed nanostructures that further assembled into macroscopic, hierarchical structures. By tuning deposition parameters during the transient self-templating assembly process, we created diverse array of phage nanostructures. The resulting hierarchically organized phage nanostructure exhibited enhanced piezoelectric energy generation performance. Our transient self-templating assembly process can assemble many other energy generating colloidal nanoparticles into ordered nanostructures for the development of optical, mechanical, and electrical materials in the future in an energy efficient manner.

Monitoring investigation of solar diffuse fraction in Taiwan

Global solar radiation, which passes through the atmosphere and arrives on earth’s ground, is composed of two constituents, that is, beam and diffuse radiation. It is agreed that the beam radiation is the only effective part for use of solar energy in concentrating either photovoltaic or solar thermal energy application, which concentrates the incident sunlight to attain high performance of either electrical power or high-temperature thermal energy generation, respectively. Information of beam radiation quantity incident upon an absorbing surface is, thus, a prerequisite for the performance evaluation of concentrating optic device. However, very few data of diffuse fraction, defined as the ratio of diffuse radiation to global radiation, is available in Taiwan. A long-time monitoring investigation in the main island (Taiwan proper) and one offshore islet (Penghu) were conducted over recent years. It was found that the annually averaged diffuse fractions, calculated with the time duration from sunrise to sunset, in the east (Taitung) and west (Tainan) sides of the main island were about 0.49 and 0.53, respectively, while about 0.50 in the offshore islet (Penghu). Seasonal variations due to geographical/topographical effects on diffuse fraction are also reported and discussed. It is found that Northeast Monsoon has remarkable effects on increment of diffuse fraction in Taitung and Penghu, while insignificant effect in Tainan.

Effect of ions (K+, Mg2+, Ca2+ and SO42−) and temperature on energy generation performance of reverse electrodialysis stack

For investigating the influence of coexisting ions (K+, Mg2+, Ca2+ and SO42−), temperature and their synergistic effect on energy generation by reverse electrodialysis, two series of cells dividing with Yadeshi membranes are fed with different solutions at 10 °C, 25 °C and 40 °C. The presence of K+, Mg2+, Ca2+ and SO42− results in lower open circuit voltage, higher internal resistance and lower maximum power density, and the influence order of ions coexisting with NaCl is Ca2+ > Mg2+ (>SO42−) > K+. With the temperature risen, the open circuit voltage and the internal resistance show a trend of increase and decrease respectively, resulting in a bigger power density. Based on the synergistic effect of coexisting ions and temperature, the maximum power density of the pure NaCl system shows a greater increment (0.15 W m−2) than that of NaCl-CaCl2 (0.10 W m−2) and NaCl-MgCl2 (0.11 W m−2) systems when temperature increases from 10 °C to 40 °C. Furthermore, the transport quantities of ions in each system increased with temperature at different degrees, and the uphill of Ca2+ and Mg2+ was more obvious, which can reasonably explain the different effects of temperature on the maximum power density. Moreover, these results are further verified when simulated concentrated seawater is used for both the Yadeshi- and Fujifilm membranes, and the Fujifilm shows better energy generation performance mainly due to a lower internal resistance.

Design and Simulation of a Novel Thermoelectric Micro-Device with Electrodeposited Bi-Te Alloys

A novel thermoelectric micro-device was designed with n-type and p-type Bi-Te materials alloys via a template electrodeposition process. The glass template including 250 holes in 10×10 mm2with a thickness of 200~ 400 µm. The diameter of the holes is 50~ 80 µm and the distance of adjacent centers of the holes is 200 µm. According to the design, the performance of heat transference and thermoelectric energy generation are simulated by COMSOL Multiphysics. In order to simplify model, there are 16 units in total, and each unit is made up of 16 (4 × 4) pillars. In the simulation, the largest temperature difference is 7.8K on the conditions of 500 W/m2K in convection heat transfer coefficients and the maximum output potential of the module is 21.7 mV. The maximum output power achieved 96.9 µW under 500 W/m2K of heat transfer coefficient and 10 mA of current. Under ideal conditions, the value of open circuit voltage and maximum output power increases to nine times as the model, but short circuit current remains the same. When the heat transfer coefficient is 500 W/m2K and the current density is 10 mA, the maximum output power of the actual product achieved 871.7 µW.

Modeling, Control Design, and Combined Plant/Controller Optimization for an Energy-Harvesting Tethered Wing

This paper presents a combined plant and controller performance analysis and optimization for a tethered rigid wing with on-board rotors, flying in crosswind patterns. Specifically, we use a 3-D model of the tethered wing to assess the influence of critical design parameters on both quality of flight and energy-generation performance, as quantified by the “Loyd Factor,” which compares energy-generation performance to a theoretical upper bound. Recognizing that the optimal performance occurs when the system is on the verge of closed-loop instability, we demonstrate how a combined optimization of the plant and controller can aid in further pushing the boundaries of the system. The results of this combined optimization show a critical tradeoff between robustness and energy-generation performance. We demonstrate that attaining maximum energy-generation performance requires operating on the verge of closed-loop instability and also results in a reduced set of parameters for which the system is stable.

Spectrally-Selective Energy-Harvesting Solar Windows for Public Infrastructure Applications

A study of photovoltaic solar window technologies is reported and it focuses on their structural features, functional materials, system development, and suitability for use in practical field applications including public infrastructures and agricultural installations. Energy generation performance characteristics are summarized and compared to theory-limit predictions. Working examples of pilot-trial solar window-based installations are described. We also report on achieving electric power outputs of about 25 Wp/m2 from clear and transparent large-area glass-based solar windows.

Fuzzy Logic System for Intermixed Biogas and Photovoltaics Measurement and Control

This study develops a new integrated measurement and control system for intermixed biogas and photovoltaic systems to achieve safe and optimal energy usage. Literature and field studies show that existing control methods on small- to medium-scale systems fall short of comprehensive system optimization and fault diagnosis, hence the need to revisit these control methods. The control strategy developed in this study is intelligent as it is wholly based on fuzzy logic algorithms. Fuzzy logic controllers due to their superior nonlinear problem solving capabilities to classical controllers considerably simplify controller design. The mathematical models that define classical controllers are difficult or impossible to realize in biogas and photovoltaic generation process. A microcontroller centered fuzzy logic measurement and control embedded system is designed and developed on the existing hybrid biogas and photovoltaic installations. The designed system is able to accurately predict digester stability, quantify biogas output, and carry out biogas fault detection and control. Optimized battery charging and photovoltaic fault detection and control are also successfully implemented. The system is able to optimize the operation and performance of biogas and photovoltaic energy generation.

Energy Payback Time (EPBT) and Energy Return on Energy Invested (EROI) of Perovskite Tandem Photovoltaic Solar Cells

Two-terminal tandem perovskite (PK) cells are considered a promising option for future photovoltaic (PV) market due to the rapid improvements in their power conversion efficiencies. However, their large-scale adoption requires a better understanding on the energy performance of these PVs. In this paper, the life-cycle energy consumptions of two-terminal tandem solar cells consisting of lead-based PK top cells prepared on bottom cells of copper indium gallium selenide, copper zinc tin selenide, and monocrystalline silicon are evaluated. The energy payback time (EPBT) and the energy return on invested (EROI) are the two useful metrics for examining the energy generation performance of PV systems. EPBTs of the current state-of-the-art devices range from 7 months to 12 months, while the EROI of the cells is in the reverse order as the EPBT and ranged between 5.2 and 9.2. These two energy indicators of tandem devices are expected to improve as the tandem PV technologies mature, with an EBPT as low as ∼27 day (0.9 month) and the EROI as high as 105 for high-efficiency long-lifetime devices.