Solar Control Research Articles

An innovative approach to assess the limitations of characterizing solar gains in buildings: A Spanish case study

A minimal energy demand should be required in buildings both to optimize the performance of the building façade and to control solar gains. According to the existing studies and national standards, the climate zone classification is usually based on both the degree-days methodology and outdated climate data, thus managing HVAC systems inappropriately or leading to users’ thermal discomfort in indoor spaces. To evaluate the current limitations and to characterize solar gains in the Spanish building stock, an innovative approach is presented. For this purpose, seven clustering algorithms were implemented by distinguishing between winter and summer seasons during the calculation procedures. Solar irradiation from 8,948 locations in Spain were used. Likewise, the control of solar gains was analysed with the regulatory approach of Spain and with those developed through the study. The results of this research revealed that climate zones set by the Spanish Technical Building Code could imply to use values of monthly accumulated solar irradiation with discrepancies between 43.17 and 84.41 kWh/m2, compared to the real values. Hence, an accurate method focused on k-means clustering should be adopted. Furthermore, the results can be used for a more accurate analysis of solar control and improve the energy efficiency of buildings.

Exploring Energy Retrofitting Strategies and Their Effect on Comfort in a Vernacular Building in a Dry Mediterranean Climate

This research explores the energy behaviour of a traditional house on the Mediterranean coast of south-eastern Spain. The objective of the work is to determine the optimal passive strategies for rehabilitating a traditional house, improving its energy savings and comfort, considering the characteristics of the warm semi-arid Mediterranean climate. The main novelty of this article is that it demonstrates that the limits imposed by current regulations, based on globalised climate strategy approaches, undermine the energy efficiency capacity that passive solutions in vernacular architecture already employed. The methodology used consists of a systematised multi-objective study of various energy rehabilitation strategies. Four strategies were studied: raising the thermal insulation of enclosures, improving thermal insulation and solar control glazing with movable shading devices, increasing the size of windows and introducing the use of natural ventilation enhanced by ceiling fans. The results show that simultaneous improvement of these parameters reduces cooling and heating requirements by up to 87%, reducing the energy consumption of air conditioning systems. Indoor temperatures are also maintained within the comfort limits set by regulations for 91% of hours per year without the need for air conditioning systems. This results in a passive energy-efficient and comfortable house almost all year round. This work offers an alternative solution to the comfort standards of current Spanish regulations and demonstrates the need to adapt Fanger’s analytical method for comfort estimation. The research concludes that the comfort criteria of current energy regulations should be modified to better adapt the design criteria to the dry Mediterranean climate.

A comprehensive review of grid-connected solar photovoltaic system: Architecture, control, and ancillary services

The installed capacity of solar photovoltaic (PV) based generating power plants has increased significantly in the last couple of decades compared to the various renewable energy sources (VRES). As a result, the increased penetration of solar PV-based generating units leads to several issues related to power quality, system stability, and reliability. In view of these concerns, various international standards and grid codes have been amended to address such critical issues. Therefore, most solar PV-based generating units have undergone several changes in operational and control structure. Subsequently, varieties of solar PV configurations and control structures have been proposed by several researchers to augment the desired operational features. This paper presents a comprehensive review of various solar PV configurations, control strategies, and ancillary services with multifunctional features within this context. The utilization and benefits of various configurations and their practical aspects have been discussed thoroughly for all the configurations and architectures. Apart from this, the control aspects of grid-connected solar PV systems are categorized into two important segments, namely, a) DC-side control and b) AC-side control. This article covers the important features, utilization, and significant challenges of this controller and summarizes the advanced control techniques available in the literature. Further, the various control techniques have been compared concerning different operational parameters, such as controller gains, duties, and selector quantities in tabular form with ready references. Furthermore, the concerns related to power quality, stability, and reliability of various techniques have been included for understanding the applicability of grid-connected PV systems. In the end, a detailed comparison of some available industrial inverters concerning their power ratings, voltage ratings, configurations, and advanced functions incorporated are also presented, which will help the researchers, academicians, and practicing engineers.

Development of a green and efficient photocatalytic mesh microalgae biorefinery (PMMB) system for sustainable biomass conversion under real solar light

Microalgae biorefinery, which produces carbohydrates, proteins and lipids, is a promising solution for addressing the energy crisis and food shortages. Sunlight-activated photocatalytic reactions have emerged as green strategies for microalgae biorefinery. In this study, a photocatalytic mesh microalgae biorefinery (PMMB) system was developed for the first time, which employed durable photocatalytic meshes to destroy algal cells while maintaining smooth fluid flow and preventing blockages. High efficiency was achieved by stacking photocatalytic meshes using appropriate parameters and providing the suitable temperature and UV irradiance through solar energy control. In addition, the optimal algal concentration of 4 g·L−1, which was used in the PMMB system, maximized biorefinery efficiency. Under actual weather conditions, the PMMB system converted microalgae into carbohydrates (293 mg·L−1), proteins (121 mg·L−1) and lipids (345 mg·L−1) within 60 h, demonstrating its practical feasibility. Compared with traditional microalgae biorefinery methods, PMMB has demonstrated superior economics, practical applicability, and effectiveness. The global applicability evaluation also suggested that the PMMB system could be accessible to all countries. Therefore, the PMMB system could be a green and efficient microalgae biorefinery system to support sustainable global development.

Research on Operation Control Strategy of Wind and Solar Storage Systems Considering High Ratio of New Energy Access

High proportion of distributed new energy generation, DG) Connect to the grid to mitigate problems such as fossil energy shortages and the threat of global climate change. However, distributed new energy has the characteristics of fluctuation and uncertainty of output, so it will bring some difficulties to energy consumption after the high proportion is connected to the power grid. Given the above problem, the uncertainty of wind and solar output is considered in this paper to ensure that accuracy and the stability of the power grid operation after a large amount of distributed energy is accessed, with 8,760 hour-by-hour power generation data throughout the year as an input. Three kinds of wind and solar storage system operation control strategies are compared. Using storage battery energy storage method and multiple energy storage methods on the fly surplus storage, coordinated control of the system, and setting different discharge priorities in the energy storage portion, increase real-time and ordered energy consumption.

Solar Base LED Schlooring Display

The development of solar energy and the LED display, the superiority of the combination of them and software design of the system are discussed in this paper. Hardware design and software design are the key elements of this paper. Solar control circuit, LED display control circuit, etc are described, charge and discharge of the battery and output of the battery is controlled by Arduino IDE. The design of software provides driver to the related hardware circuit. The result of the experiment have achieved anticipate defects and met the design requirements. The aim of this paper is to design a textual display system, based on a light emitting diode (LED) dot matrix array powered by solar energy. The paper involves taking the device from an initial concept, through a design phase, to constructing a prototype of the product. The system consists of the display unit, which is powered from a photovoltaic ( PV) module and a solar sealed lead acid battery.. The self-contained nature of the intended design will allow the display to be mounted almost anywhere it is needed. Therefore, the main purpose of this paper is to utilize the solar energy and a rechargeable battery to power a universal self-contained characters display unit. This display unit is useful for creating attention-getting messages, location identifiers such as maps and address identification display modules.

Prioritization of heat transfer fluids in parabolic trough solar systems using CFD-assisted AHP-VIKOR approach

Parabolic trough solar collectors (PTSCs) are proven technologies and are used in various fields including concentrating solar power, integrated solar combined cycle, industrial process heat, air conditioning, and desalination. The selection of heat transfer fluid (HTF) is a part of the design consideration of concentrating solar technologies (CST) since its technical specifications have a significant effect on the system configuration, operating conditions, and levelized energy cost. Several HTFs including water, thermal oils, molten salts, and gases are already in use for PTSC systems, and others including liquid metals, ionic liquids, and nanofluids are still being tested. Each HTF has pros and cons; thermal and thermodynamic evaluations are practical to compare the performance of an HTF with that of its counterparts however they are insufficient to attribute a parabolic trough CST in terms of design concerns. This study has presented an integrated AHP-VIKOR (Analytical Hierarchy Process - VIekriterijumsko KOmpromisno Rangiranje) multi-criteria decision making (MCDM) approach assisted by computational fluid dynamics (CFD) to prioritize HTFs, particularly for CST and the results are compared to AHP-TOPSIS (Analytical Hierarchy Process - Technique for Order Preference by Similarity to Ideal Solution) for validation. While AHP is chosen to decide the criteria weights in the multi-criteria process, VIKOR is used as decision making to rank and prioritize alternatives. Water, Therminol VP-1, Solar salt, Hitec, Hitec XL, Liquid sodium, Lead-bismuth eutectic, Carbon dioxide, Air, and Helium are evaluated as the HTF inventory and a comprehensive CFD study is conducted to benchmark their thermal and thermodynamic properties in a high concentration PTSC in terms of solidification temperature, upper thermal stability, collector efficiency, pumping power consumption, receiver temperature gradient, and irreversibilities. In addition, other critical design considerations of HTFs including material cost, heat storage capability, material compatibility, operational safety aspects, operational maturity, and solar field control sophistication are taken into account in the MCDM process. Results show that the current parabolic trough CST should have priority for the HTFs of water and molten salt (Hitec) but molten metals and gaseous fluids would gain more insight in near future. This study presents an original perspective for deciding suitable HTFs in PTSC applications where thermal and thermodynamic analyses are limited.

Geometry-based graphical methods for solar control in architecture: A digital framework

The form of a building is among the most critical design aspects concerning building energy consumption. Form-based passive design strategies, like solar control, can significantly reduce heating and cooling demands if implemented early in the design process. In this sense, there is an evident need for tools that can adequately support designers in their decisions. This paper aims to illustrate how geometry-based graphical methods (GGM) can provide effective support in the conceptual design stage. The paper introduces a novel digital framework for designing and analysing shading devices that leverages geometrical models and graphical methods. The digital implementation of GGM allows extending their applicability to three-dimensional and non-planar geometries. A comprehensive review of existing methods and tools for the design of shading devices lays the ground for the proposed digital framework, which is then demonstrated through two case studies. The results show that the diagrammatic nature of GGM facilitates a better and more direct understanding of the relationship between form and performance.

Interrelated Solar and Thermal Plant Autonomous Generation Control Utilizing Metaheuristic Optimization

In this study, the load frequency control of a two-area thermal generation system based on renewable energy sources is considered. When solar generation is used in one of the control areas, the system becomes nonlinear and complicated. Zero deviations in the frequencies and the flow of power through the tie lines are achieved by considering load disturbances. A novel grey wolf optimizer, which is a metaheuristic algorithm motivated by grey wolves is utilized for tuning the controller gains. The proportional, integral, and derivative gains values are optimized for the two-area Solar integrated Thermal Plant (STP). As the load connected to the system varies continuously with time, random load variation is also applied to observe the effectiveness of the proposed optimization method. Sensitivity analyses have also been adopted with the deviation in the time constants of different systems. Inertia constant variations of both areas are considered from −25% to +25%, with or without STP. The proposed algorithm shows good dynamic performance as shown from the simulation results in terms of settling time, overshoot values, and undershoot values. The power in the tie line achieves zero deviation quite rapidly in solar-based cases compared to those without STP.

Design and optimization of thermally responsive autonomous dynamic glazed attachment systems for building solar heat gain control

Design and optimization of thermally responsive autonomous dynamic glazed attachment systems for building solar heat gain control

Optimal control study of solar-air source heat pump coupled heating system operation

With China’s ambitious goals of carbon capping by 2030 and carbon neutrality by 2060, the multi-energy coupled clean heating technology represented by solar-air source heat pumps is developing rapidly. In order to solve the above problems, this paper analyzes the characteristics of the multi-energy coupled heating system by establishing a virtual simulation model and optimizing the system operation and control modes. Technical support is provided for efficiently utilizing multi-energy coupled heating technology in rural buildings.In this paper, the mathematical model of the system is established by analyzing the form and working principle of the solar-air source heat pump coupled heating system. Initially, three operation strategies are constructed: priority utilization of solar energy strategy (Strategy I), air source heat pump fixed temperature switching strategy (Strategy II), and air source heat pump timed switching strategy (Strategy III), laying the foundation for operation strategy optimization.The dynamic load change pattern of the building in winter was calculated using TRNSYS software, based on which equipment selection was carried out, and a simulation model of the solar-air source heat pump coupled heating system was established. The system operation strategy was optimized. A temperature difference control strategy was used for the solar collector cycle control optimization, which increased the solar collector efficiency by 12% compared to the fixed temperature control strategy. Based on typical climate data, the heating season was divided into 10 phases according to a 15-day cycle, and three operation strategies were optimized and compared for each phase with the goal of comprehensive system energy efficiency. After comparison and analysis, strategy 1 and 3 have their advantages in different stages of the heating season. The operation strategies with higher system energy efficiency in each stage were combined in the heating season, called combined operation strategy (strategy 4), and compared with other strategies in the heating season. Compared with strategy 1 and strategy 3 in the whole heating season, the system energy efficiency of strategy 4 was improved by 3%-6%. This indicates that strategy 4 has better operation effect.

Controller Design for Parallel Mechanism Solar Tracker

Solar energy is considered a sustainable solution that has proven its technological competence for electricity generation among renewable energy sources. While green resources provide high energy security, they also reduce environmental pollution and support the use of local resources. In this article, a dual axis solar tracker that can operate with high accuracy in harsh operating conditions is proposed using the Stewart platform. The Stewart platform is designed using linear actuators using direct current (DC) motors. An embedded controller is designed to control the motors and to realize the sun tracking algorithm of the system. An STM32 board is adopted as a real-time controller to implement the decoupled control algorithm. Therefore, the proposed solar tracker panel control system monitors the daily trajectory of the sun by the photovoltaic panel, ensuring that the system’s energy production remains at its maximum throughout the day. First, the Simulink model of the system was created and the proportional derivative integral (PID) control algorithms were simulated. Experimental studies were carried out by producing the system; the experimental results exhibited a better performance, with an increase in the collected energy of about 32% compared with the fixed one.

Solar Control of the Pickup Ion Plume in the Dayside Magnetosheath of Venus

AbstractUsing the 8.5‐year Venus Express measurements, we demonstrate the asymmetric plasma distributions in the Venusian magnetosheath. An escaping plume is formed by pickup oxygen ions in the hemisphere where the motional electric field points outward from Venus, while the velocity of solar wind protons is faster in the opposite hemisphere. The pickup O+ escape rate is estimated to be (3.6 ± 1.4) × 1024 s−1 at solar maximum, which is comparable to the ion loss rate through the magnetotail, and (1.3 ± 0.4) × 1024 s−1 at solar minimum. The increase of O+ fluxes with extreme ultraviolet (EUV) intensity is significant upstream of the bow shock, partially attributed to the increase of exospheric neutral oxygen density. However, the solar wind velocity just has a slight effect on the pickup O+ escape rate in the magnetosheath, while the effect of solar wind density is not observed. Our results suggest the pickup O+ escape rate is mainly controlled by EUV radiation.

The effect of urban geometry on outdoor thermal comfort. Application of the UTCI index in hot and arid climates.

The object of our study is to evaluate the effect of urban geometry on microclimate and outdoor thermal comfort. In this context, “the RayMan pro 2.1” software was adopted to define UTCI index applying in hot and arid climates, exactly, in the urban fabric of the Ksar of The Red Village, El Kantara in Biskra city, Algeria, to define the most efficient urban geometry in term of summer thermal comfort by studying the real impacts of the urban form on the solar control and microclimatic conditions. studying the correlation between the geometry of the street estimated by the ratio H/L, the sky view factor (SVF), its orientation and the evolution of the physical variables (Ta, MRT, Ws) and the values of UTCI index. Significant relationships were found between UTCI index, urban geometry and heat stress in outdoor environments. The results of this research have shown the effect of urban design strategies on modifying the microclimatic conditions in hot summer for outdoor spaces in hot-arid climate.

The Effect of Solar Control Elements on Building Energy Consumption in Hot Dry Climate Regions The Case of Diyarbakır

The Effect of Solar Control Elements on Building Energy Consumption in Hot Dry Climate Regions The Case of Diyarbakır

Determining the optimal visible light transmittance of semi-transparent photovoltaic considering energy performance and occupants’ satisfaction

With the increasing use of front windows such as curtain walls, the application of semi-transparent photovoltaic (STPV) systems is effective in producing renewable energy, reducing cooling load via solar radiation control, and improving visual comfort. However, in STPV, the visibility of the view from a window decreases, and this can have a negative impact on the occupants' satisfaction (i.e., psychological satisfaction, task performance, and task load). Therefore, this study sought to present the optimal visible light transmittance (VLT) of STPV that simultaneously considers energy performance and the occupants' satisfaction according to the azimuth of a building. To this end, a residential building in South Korea was selected, and energy performance according to the VLT of STPV (amorphous Si thin film PV) was analyzed using DesignBuilder and EnergyPlus for STPV with three VLTs (i.e., 10%, 20%, and 30%). In order to analyze the occupants' satisfaction according to the VLT of STPV, 31 participants were recruited, and an experiment using virtual reality (VR) was carried out. Multi-objective optimization was performed using the energy performance, psychological satisfaction, and task load. The results showed that as the weight of energy performance was adjusted to 0.33, 0.5, and 0.6, the optimal VLT of STPV was 25.53%, 22.65%, and 20.85% on average, respectively. It is expected that the findings of this study can allow the building owner or building designer to predict the energy performance, the occupants’ psychological satisfaction and task load according to the VLT of STPV.

An Artificial Neural Network for Solar Energy Prediction and Control Using Jaya-SMC

In recent years, researchers have focused on improving the efficiency of photovoltaic systems, as they have an extremely low efficiency compared to fossil fuels. An obvious issue associated with photovoltaic systems (PVS) is the interruption of power generation caused by changes in solar radiation and temperature. As a means of improving the energy efficiency performance of such a system, it is necessary to predict the meteorological conditions that affect PV modules. As part of the proposed research, artificial neural networks (ANNs) will be used for the purpose of predicting the PV system’s current and voltage by predicting the PV system’s operating temperature and radiation, as well as using JAYA-SMC hybrid control in the search for the MPP and duty cycle single-ended primary-inductor converter (SEPIC) that supplies a DC motor. Data sets of size 60538 were used to predict temperature and solar radiation. The data set had been collected from the Department of Systems Engineering and Automation at the Vitoria School of Engineering of the University of the Basque Country. Analyses and numerical simulations showed that the technique was highly effective. In combination with JAYA-SMC hybrid control, the proposed method enabled an accurate estimation of maximum power and robustness with reasonable generality and accuracy (regression (R) = 0.971, mean squared error (MSE) = 0.003). Consequently, this study provides support for energy monitoring and control.

Passive Satellite Solar Panel Thermal Control with Long-Wave Cut-Off Filter-Coated Solar Cells

Satellite performance and capability have increased dramatically, particularly for micro- and nanosatellites, requiring more power supply and higher thermal conditions. Problems worth considering include how to provide more power with little or no weight increase, and how to reduce satellite thermal control difficulties. A new way to decrease the temperature of the solar panels on a satellite was proposed. Firstly, the model of solar cells is presented, and the relationship between solar irradiation and the electricity generated explained. Based on this, a new method to reduce the temperature of the solar cell is proposed. Details about current generation and temperature rise calculations for various types of solar cells are also provided. Finally, an experiment was conducted on original and proposed solar cells. While the experiment showed some degree of effectiveness, further experiments are needed.

Solar Hydrogen Variable Speed Control of Induction Motor Based on Chaotic Billiards Optimization Technique

This paper introduces a brand-new, inspired optimization algorithm (the chaotic billiards optimization (C-BO) approach) to effectively develop the optimal parameters for fuzzy PID techniques to enhance the dynamic response of the solar–hydrogen drive of an induction motor. This study compares fuzzy-PID-based C-BO regulators to fuzzy PID regulators based on particle swarm optimization (PSO) and PI-based PSO regulators to provide speed control in solar–hydrogen, induction-motor drive systems. The model is implemented to simulate the production and storage of hydrogen while powering an induction-motor drive which provides a great solution for the renewable energy storage problem in the case of solar pumping systems. MATLAB/Simulink 2021a is used to simulate and analyze the entire operation. The laboratory prototype is implemented in real time using a DSP-DS1104 board. Based on the simulation and experimental results, the proposed fuzzy-PID-based C-BO has reduced speed peak overshoot by 45.3% when compared to a fuzzy PID based PSO speed regulator and by 68.13% when compared to a PI-based PSO speed controller in the case of a large-scale motor. Additionally, the proposed speed regulator has a 6.1% faster speed rising time than a fuzzy-PID-based PSO and a 9.5% faster speed rising time than a PI–PSO speed controller. It has an excellent dynamic responsiveness value when compared to the other speed regulators.

Climate change influence on buildings dynamic thermal behavior during summer overheating periods: An in-depth sensitivity analysis

Climate change is increasing heatwaves occurrence, which consequently impact buildings indoor overheating during summers. While indoor overheating in free-running buildings during future typical summers has been quantified by many researchers, its intensification during future heatwaves remains relatively under-researched. Furthermore, analyzing the dynamic thermal response of free-running buildings to these varying local climate changes is current lacking. This paper objective and novelty is to understand the building dynamic thermal change during different indoor overheating periods induced by several hot outdoor sequences during present and future climates. Two sensitivity analysis methods are used for this analysis, applied to a free-running top floor apartment of a collective building: the Morris method, which allows to quickly select the most influential parameters and the Sobol method, which allows to conduct an in-depth temporal uncertainty and sensitivity analysis. Results show that in the semi-oceanic climate of the French capital Paris, while the indoor overheating is projected to drastically increase, the building dynamic thermal behavior is greatly modified amongst the three climate sequences under study: present and future typical summers, and future heatwave of the mid-century. During the future heatwave in Paris, the building response is projected to behave more similarly as it would in a French Mediterranean city. Static design parameters such as thermal mass, albedo and emissivity or glazing percentage, as well as dynamic design parameters such as the operation of the ventilative cooling and solar control strategies all play an important role in regulating the building indoor overheating, with a different ranking depending on the outdoor local climate conditions. These results are of foremost importance to provide guidance in the design of adapted buildings to climate change, which can withstand future extreme heat periods.