Modeling Joule Heating Effect on Thermal Efficiency of Photovoltaic Thermal (PVT) Collectors with Operation Mode Factor (OMF)

The purpose of the present study is developing the operation mode factor (OMF) by remodeling the thermal efficiency model of a hybrid PVT collector during steady state. Joule heating occurs when the photovoltaic (PV) panel operates at a high current during maximum power point tracking (MPPT) on higher irradiation. Under these conditions, some electrical energy converts to thermal energy within the PV cells. Joule heating contributed to increasing the PVT thermal efficiency. The steps were to construct the OMF by remodeling the thermal efficiency involving the Joule heating effect and to validate the results using the model by comparing the simulation and experiment. The dimensionless OMF was responsible for changes in thermal efficiency for PVT-mode. The conductive heat transfer coefficient from the surface to the absorber was the most decisive component in the OMF. Heat removal factor and OMF might be interrelated at the mass flow rate by decreasing PV temperature to maintain Joule heating. The proposed model with OMF had explained PVT-mode and T-mode with the RMS value of less than 1%. This model complemented the results of the previous studies. The results may contribute from the initial design to the operational monitoring for thermal to electrical energy production.

Inductor Disc CFD Analysis for VAWT

This work shows the computational simulation of the fluid dynamics of inductor discs (patent pending reception number MX/E/2021/002395) applied to vertical axis wind turbines (VAWT). These inductor discs have a unique and innovative design that can be classified as wind concentrators. The purpose of these devices is to increase wind velocity at the wind turbine entrance; this increase in velocity exponentially boosts the mechanical power of the turbine, according to Betz's theory, increasing the electrical energy production of the turbine and, at the same time, reducing its dimensions. The objective of this investigation is to carry out the fluid dynamic simulation (CFD) of two of the inductor disc geometries: an elliptical one and a truncated conical one, varying the entrance wind velocities of the VAWT from 3 m/s to 12 m/s. The proposed methodology consists of employing a CFD software (ANSYS) to model the two inductor disc geometries and extract them from a static control volume. Mesh this volume, establish boundary conditions, and vary wind velocities to carry out the fluid dynamic analysis. Finally, the obtained velocities are compared at different representative points of both geometries.

Optimization of Useful Daylight Illuminance for Vertical Shading Fins Covered by Photovoltaic Panels for a Case Study of an Office Room in the City of Wroclaw, Poland

A building’s facade is its main interface with the external environment, as it controls almost all energy flows in the building—losses and gains. In this context, the most recent invention of adaptive façades allows for the introduction of an optimized system for both daylight management and electrical energy production. The authors of the presented paper propose a novel adaptive façade system that is equipped with vertical shading fins of 1 × 4 m that are covered with PV panels. The fins are kinetic and rotate around a vertical axis in order to optimize solar irradiation for producing electricity. The presented adaptive façade is analyzed in two stages. Firstly, the number of vertical shading fins is optimized in the context of useful daylight illuminance (UDI) and daylight glare probability (DGP) using Radiance-cored software. Next, two scenarios of PV installation are verified for fixed and the Sun-tracking solution. The results show that the Sun-tracking system is more efficient than the fixed one, but electricity production is only increased by 3.21%. The reason for this is the fact that—while following the Sun’s azimuth position—fins shade each other and reduce the effective area of the adjacent PV panels. Based on this, the authors conclude that the Sun-tracking system might be justified due to its protective or decorative function and not because of its improved effectiveness in generating electrical energy.

Exploiting Solar Energy during an Aerial Mapping Mission on a Lightweight UAV

In this study, we present options for extending the endurance of a lightweight unmanned aerial vehicle (UAV), along with their advantages and disadvantages. We present a developed solution based on the use of gallium–arsenide (GaAs) solar modules installed on a UAV and connected to a custom-made maximum power point tracker (MPPT) with an integrated perturb and observe (P&O) algorithm. The mathematical behavior required to calculate the electrical energy production from solar energy on the UAV from known UAV angles of rotation, the position of the sun in the sky, solar irradiance measurements, the solar module area and the solar modules efficiency is presented. A comparison of the calculated and actual measured electrical energy production results during an aerial mapping mission is presented. We perform a number of aerial mapping mission flights and the experimental results confirm an energy efficiency value of more than 96.27% for the MPPT and extended flight endurance by up to 21.25%. In addition, onboard measurements and other data captured during flights confirm the proposed electrical energy production calculation.

Improving the Electrical Efficiency of the PV Panel via Geothermal Heat Exchanger: Mathematical Model, Validation and Parametric Analysis

Silicon based photovoltaic modules (PV) are a wide spread technology and are used for small and large PV power stations. At the moment, the most efficient method which can be used to improve the annual electrical energy production of PVs is solar tracking systems. However, solar tracking systems increase substantially the initial cost of the investment and insert maintenance costs. During the last few decades, alternative improving methods have been investigated. These methods are based on the reduction of the PV cell temperature, which adversely affects the power production. In the present study, a system with water based photovoltaic-thermal (PVT) collector paired with geothermal heat exchanger (GHE) is compared on the electrical energy basis with a conventional PV system. As the first approach on the topic, the aim is to find out in which extent the PVT-GHE system improves the electrical energy generation by cooling down the PV cells and which parameters influence the most its energy performance. With this aim in mind, the model of the system with the PV, PVT, and GHE was formulated in TRNSYS and validated via experimental data. Meteorological data for Athens (Greece) were used and parametric analyses were conducted. The results showed that the PVT based system can increase the generated electricity from 0.61 to 5.5%. The flowrate, the size of the GHE and the number in-series connected PVTs are the parameters which influence the most the energy performance of the system.

Dynamic stability of wind farm multi-machine power system

Since it is difficult to store electrical energy, production, and consumption must be in equilibrium under constant voltage and frequency. The producers, the receivers, and the electrical networks that connect them, have mechanical and electrical inertias which disturb this balance. Faced with a variation in power, the electrical system, after oscillations, returns to a stable state. In some cases, the oscillatory regime may diverge. Studies are being carried out to remedy this problem and ensure the stability of the electricity network. This manuscript focuses on FACTS regulation which helps electrical systems, subjected to strong disturbances, to maintain their stability. Magnetic Energy Storage Superconductor (SMES) contains a short-circuited superconducting coil on itself, which injects or absorbs active and reactive power into the system, thereby improving the stability of electrical systems.

Parametric study of a horizontal axis wind turbine with similar characteristics to those of the Villonaco wind power plant

<p class="JAREAbstract">The present paper focuses on the selection of parameters that maximize electrical energy production of a horizontal axis wind turbine using Python programming language. The study takes as reference turbines of Villonaco wind field in Ecuador. For this aim, the Blade Element Momentum (BEM) theory was implemented, to define rotor geometry and power curve. Furthermore, wind speeds were analyzed using the Weibull probability distribution and the most probable speed was 10.50 m/s. The results were compared with mean annual energy production of a Villonaco’s wind turbine to validate the model. Turbine height, rated wind speed and rotor radius were the selected parameters to determine the influence in generated energy. Individual increment in rotor radius and rated wind speed cause a significant increase in energy produced. While the increment in turbine’s height reduces energy generated by 0.88%.</p>

Technical Performance and Economic Feasibility Simulation of 200kWP Rooftop Solar Photovoltaic On grid on Industrial Estate Factory Building with Helioscope Software

Renewable energy resources are currently being developed by Indonesia. The government is also targeting an energy mix of 23% to achieve renewable energy by 2025. One of the renewable energies is Solar Photovoltaic Generation System. On the other hand, an industrial area is an area filled with factories that are large enough so that it has great potential to develop Rooftop Solar Photovoltaic with the advantage of reducing land investment costs without reducing the operational function of the factory. The purpose of this research is to simulate the technical and economic performance of a 200kWP Solar Photovoltaic On grid on the rooftop of a factory building using Helioscope software in an industrial area in West Java. The simulation result shows that the average values for Global Horizontal Irradiance (GHI), Electrical Energy Production, and Performance Ratio (PR) in one year are 138.2 kWh/m2, 21,977 kWh, and 78.06%. Meanwhile, the total Electrical Energy Production in one year is 263,723.6 kWh. The total investment value of the 200kWP Rooftop Solar Photovoltaic On grid on the factory building is 2,457,850,800 IDR. Based on the economic feasibility study, it can be concluded that the 200kWP Rooftop Solar Photovoltaic On grid on the factory building rooftop is economically feasible as long as the interest rates is less than 12.71% (Internal Rate of Return / IRR).