Solar Panel Array Research Articles

Solar assisted desiccant evaporative cooling system for office buildings in Iran: a yearly simulation model

In this research, the feasibility of solar assisted desiccant evaporative cooling system for office buildings was studied. An office building in Chabahar, Iran, as a high cooling load demanding region was considered as the case study. Different configurations as the desiccant based cooling systems were examined to determine the most appropriate configuration in terms of established indoor air conditions and required cooling energy. The configurations were simulated hourly and the monthly mean values were determined. TRNSYS software was used for this purpose. The results indicated that the desiccant based cooling system operating in the recirculation cycle with pre-cooling, Config. E has the potential to keep the indoor air conditions within the standard recommendations. In addition, it was shown that Config. E is the superior configuration in terms of the energy performance and could meet the cooling energy requirements of the space. The potential of providing the desiccant regeneration heat by the solar energy was also investigated. Three standard solar thermal panels were explored to propose the most proper array plant. The study showed that an array of solar panels consists of two rows of four unglazed solar thermal collectors could meet the heat energy requirement by the regenerating process.

Thermal Cycle and Combustion Analysis of a Solar-Assisted Micro Gas Turbine

The authors discuss in this paper the potential of two power plant concepts for distributed generation, based on the integration of a cogenerating micro gas turbine with a solar panel array. The first one relies on the adoption of a parabolic trough network with an intermediate thermal carrier, while the second one considers the direct heating of the working air in a solar tower system. The first solution also includes a bottoming organic Rankine cycle (ORC) plant, so that it is mainly addressed to the power output increase. The second one involves a relevant temperature increase of the air entering the combustor, so allowing a direct fuel energy saving, whose amount is strongly variable with both the solar irradiance and the eventual part-load operation. In addition, the latter solar-assisted scheme involves noticeable variations in the conditions for the combustion development. This suggested the authors to proceed with a detailed CFD analysis of the combustion, after a preliminary thermal cycle study for highlighting the main benefits from the solar integration of the power plant.

Detecting photovoltaic solar panels using hyperspectral imagery and estimating solar power production

Remote sensing platforms have consistently demonstrated the ability to detect, and in some cases identify, specific targets of interest, and photovoltaic solar panels are shown to have a unique spectral signature that is consistent across multiple manufacturers and construction methods. Solar panels are proven to be detectable in hyperspectral imagery using common statistical target detection methods such as the adaptive cosine estimator, and false alarms can be mitigated through the use of a spectral verification process that eliminates pixels that do not have the key spectral features of photovoltaic solar panel reflectance spectrum. The normalized solar panel index is described and is a key component in the false-alarm mitigation process. After spectral verification, these solar panel arrays are confirmed on openly available literal imagery and can be measured using numerous open-source algorithms and tools. The measurements allow for the assessment of overall solar power generation capacity using an equation that accounts for solar insolation, the area of solar panels, and the efficiency of the solar panels conversion of solar energy to power. Using a known location with readily available information, the methods outlined in this paper estimate the power generation capabilities within 6% of the rated power.

Batteries that breathe air

Last year, zinc-air battery start-up Fluidic Energy installed backup batteries for an array of solar panels in Welay Selatan, a tiny village on the Indonesian island of Alor. The location is remote, a 77-hour drive from Jakarta, including intermittent ferry voyages. The new solar power setup can bring electricity to 52 homes not currently connected to the grid. The scene isn’t unique. So far, the Scottsdale, Ariz., firm has deployed 22 MWh of battery storage for 96 rural solar electrification projects on some of the Indonesian archipelago’s remoter islands, providing power to 110,000 people. The company signed an agreement with the Indonesian government to provide backup power for a total of 1.2 million inhabitants. Ramkumar Krishnan, Fluidic’s chief technology officer, says many people from the world’s most underdeveloped regions are getting power for the first time from the sun, photovoltaic cells, and batteries locally rather than waiting for long-distance transmission

Optimization of energy distribution in solar panel array configurations by graphs and Minkowski’s paths

Nowadays, the development of the photovoltaic (PV) technology is consolidated as a source of renewable energy. The research in the topic of maximum improvement on the energy efficiency of the PV plants is today a major challenge. The main requirement for this purpose is to know in real-time the working point of each of the PV modules that integrate the PV field and improve their performance.For this purpose, a Power Line Communications (PLC) based Smart Monitoring and Communications Module, which is able to monitor at PV level their operating parameters, has been developed at the University of Málaga. This device can check if any of the panels is suffering any type of overriding performance, due to a malfunction or partial shadowing of its surface.In this paper, the data acquisition system is described and subsequently the solution of the most energy-efficient path was arised from information acquired in real-time. Through graph theory and Minkoski’s paths have been possible to deduce the recursive programming algorithm that generate a dynamic reconfiguration to solve this problem.

The Grace Follow-On Quiet Electrical Power System

This paper provides and overview of the GRACE-FO Electrical System and an in depth discussion of the Electrical Power System (EPS). The EPS elements are presented and their features described by their key parameters. These components are inclusive of the body-mounted Solar Array Panels for Power Generation, the Power Control Unit (PCU) and Power Distribution Unit (PDU), a Li-Ion Battery and the Thermal Control System’s Heater Control Electronics (HCE’s) acting as active current control front-ends. The latter is explained more in detail with respect to its purpose and implementation. The GRACE-FO EPS has been given the designation of “quiet” EPS due to the function of the HCE within the thermal control Subsystem.The final portion of the paper provides information about the power and energy budgeting and operational aspects of the EPS such as undervoltage and overcurrent H/W features of the PCU/PDU design, and the EPS related On-board Software and On-Board Control Procedures. Finally, the system level power analysis is provided to provide the reader with a better understanding of the expected behaviour of the electrical power parameters.

An Energy Supply Chain from Large Scale Photovoltaic Power Generation from Asian Cities to End Users in Japan

This study proposes four possible energy supply chains from the megawatt class of photovoltaics (PV) installation in Kuala Lumpur, Kolkata, Beijing or Ulan Bator to end users in Tokyo Japan. In the proposed chains, the electricity generated from solar PV panels would be used to generate H2 through water electrolyzer. The H2 is then liquefied (or converted into organic hydride) and transported by tank truck for land as well as tanker for marine to Japan and finally supplied to fuel cells (FC) for power generation purpose. This study investigates the energy efficiencies of the proposed energy supply chain and the amount of CO2 emission in the transportation process from the four locations. As a result, it is found the largest amount of power could be generated in Ulan Batorthan in other cities with the same size of solar panel array, while it also emitted the largest amount of CO2 in the transportation process. The best energy efficiency is obtained in the case of Beijing. This study also revealed that the ratio of total energy consumption to calorific value of H2 after transportation in the case of H2 liquefaction is smaller than that in the case of organic hydride.

Wind loads on solar panels mounted parallel to pitched roofs, and acting on the underlying roof

This paper describes an investigation of the net wind loads on solar panels and wind loads on the underlying roof surface for panels mounted parallel to pitched roofs of domestic buildings. Typical solar panel array configurations were studied in a wind tunnel and the aerodynamic shape factors on the panels were put in a form appropriate for the Australian/New Zealand Wind Actions Standard AS/NZS 1170.2:2011. The results can also be used to obtain more refined design data on individual panels within an array. They also suggest values for the aerodynamic shape factors on the roof surface under the panels, based on a gust wind speed at roof height, of ± 0.5 for wind blowing parallel to the ridge, and ± 0.6 for wind blowing perpendicular to the ridge. The net loads on solar arrays in the middle portion of the roof are larger than those on the same portion of the roof without any solar panels, thus resulting in increased loads on the underlying roof structure.

光ファイバセンサを用いた太陽電池パネルの健全性評価手法の開発

There is a concern that a thermal stress in a solar array panel under cryogenic environment would damage a solar cell and its interconnector, which might result in a drop of electrical power. Therefore it is important to perform the verification test on the ground to assure the healthiness of solar cells in orbit. In this study, we have developed the health monitoring method for solar array panel using Fiber Bragg Grating (FBG) sensor which is one of optical fiber sensors. In this paper, to reveal the thermal deformation behavior of the substrate composed of very thin Carbon Fiber Reinforced Plastics (CFRP) faceskin and aluminum honeycomb core in cryogenic environment, we measured the strain of CFRP faceskin near the center of honeycomb cell and showed that the depth of dimple increased linearly as temperature lowered. In addition, to confirm the effectiveness of our health monitoring method, we measured the internal strain of solar array panel and showed that we could detect its internal damage by strain change, and we observed the cross section of the damaged area and identified the damage point.

Using Spectral Decomposition to Detect Dirty Solar Panels and Minimize Impact on Energy Production

Dirt and dust deposits on the surface of a solar panel array obstruct the amount of light that can reach the photovoltaic cells, reducing the amount of electricity produced. Solar panels are cleaned when the energy drop has already occurred and is detected. This work presents an algorithm designed to detect dirty solar panels. It is based on the spectral decomposition of the scattered light reflected off the panels' surface by analyzing color images of the surface obtained using digital cameras. It applies the statistical classification method of Mahalanobis distance to separate images where it detects the excess reflected light, classifying them as having a high probability of representing dirty solar panels. It aims to minimize the loss of energy by warning solar plants operators to clean panels before the energy drop becomes significant.

Arcing Test on an Aged Grouted Solar Cell Coupon With a Realistic Flashover Simulator

We have performed arcing tests on an aged grouted solar cell coupon provided by Kyutu Institute of technology (Japan) under New Energy and Industrial Development Organization (Japan) grant. Aging is simulated by electrons, protons, and UV irradiations combined with thermal cycling, corresponding to 10 years in the geostationary orbit. Arcing tests are performed with a European standard setup implemented with two different flashover simulators. Instead of using a large capacitance corresponding to the missing solar panel surface, we have implemented two more realistic devices: 1) a 2.4- $\text{m}^{2}$ Kapton surface charged in an inverted potential gradient mode, which releases an average flashover current of 6-A peak at 200 $\mu \text{s}$ and 2) RLC circuit, deduced from the European Etude et Modelisation des Arcs sur Generateur Solaire study (large flashover on an 8- $\text{m}^{2}$ solar array panel). This circuit is connected between the solar array simulator (SAS) line and the surrounding environment with a ring-shape electrode, which releases an adaptable flashover current of 5-A peak during 600 $\mu \text{s}$ (average values). The results present the occurrence of different arc types versus current/voltage SAS values. A comparison is made with other tests, on a similar coupon, performed by U.S. and Japanese laboratories and also with comparable coupons without grouting.

CFD simulation and validation of self-cleaning on solar panel surfaces with superhydrophilic coating

Solar panel conversion efficiency, typically in the twenty percent range, is reduced by dust, grime, pollen, and other particulates that accumulate on the solar panel. Cleaning dirty panels to maintain peak efficiency, which is especially hard to do for large solar-panel arrays. To develop a transparent, anti-soiling Nano-TiO₂ coating to minimize the need for occasional cleaning is the purpose of this study. In our study, a 2D rainwater runoff model along tilted solar panel surface based on the Nusselt solution was established to have better understanding and predicting the behavior of runoff rain water, especially in contact with solar-panel surfaces with Nano-TiO₂ coating. Our simulation results demonstrate that solar-panel surfaces with Nano-TiO₂ coating create a superhydrophilic surface which cannot hold water, showing features of more pronounced in increasing runoff water film velocity comparing to the uncoated surfaces during raining event resulting in better effect of self-cleaning. Validation of our model was performed on titled solar panels for real time outdoor exposure testing in Switzerland. It is found that the dust particles are not easy to adhere to the coated surfaces of the slides comparing with uncoated surfaces, showing great potential for its use in harsh environmental conditions. This study suggests that superhydrophilic self-cleaning solar panel coating maximize energy collection and increases the solar panel’s energy efficiency.

Reliability Model for Designing Solar-Powered Center-Pivot Irrigation Systems

<abstract> <b><sc>Abstract.</sc></b> Due to the energy-intensive nature of sprinkler irrigation and limited availability of conventional energy resources, viable alternative energy sources are becoming increasingly important. The use of solar photovoltaic (PV) technology in irrigated agriculture is particularly appealing because of the mutual dependence of crop evapotranspiration and potential energy production on incoming solar radiation. However, successful implementation of a PV irrigation system depends on appropriately sizing the PV system components (solar panel array, battery capacity, etc.) under highly variable and site-specific influencing factors, which include the inter-annual variability of the local climate, the crop water requirement, the soil water holding capacity of the field, the irrigation management practice, and the capacity of the irrigation system itself. The objective of this research was to develop a model for assessing the reliability of a PV-powered center-pivot irrigation system. A numerical simulation tool was developed by combining sub-models of the solar power production, battery storage, and irrigation system power requirement, which can be used to evaluate the system performance under variable operating and meteorological conditions. Given the required input variables, the model determines the reliability of the PV system by analyzing the time of irrigation for which the power both produced by the PV array and stored in the batteries is sufficient to fulfill the load demands. The model was validated by comparing the simulated results to field measurements of a small (1.4 ha) solar-powered center-pivot irrigation system installed near Outlook, Saskatchewan, Canada. The utility of the model was demonstrated by simulating the system performance over five years. It was shown that a PV system that has a reliability of greater than 90% is required to avoid moisture stress during dry years for the selected irrigation management strategy. It was further demonstrated how the model may be used to explore different combinations of PV sizing for achieving the desired reliability. This modeling approach is presented as an effective tool to ensure the technical feasibility of a PV irrigation system before the system is built.

White butterflies as solar photovoltaic concentrators.

Man’s harvesting of photovoltaic energy requires the deployment of extensive arrays of solar panels. To improve both the gathering of thermal and photovoltaic energy from the sun we have examined the concept of biomimicry in white butterflies of the family Pieridae. We tested the hypothesis that the V-shaped posture of basking white butterflies mimics the V-trough concentrator which is designed to increase solar input to photovoltaic cells. These solar concentrators improve harvesting efficiency but are both heavy and bulky, severely limiting their deployment. Here, we show that the attachment of butterfly wings to a solar cell increases its output power by 42.3%, proving that the wings are indeed highly reflective. Importantly, and relative to current concentrators, the wings improve the power to weight ratio of the overall structure 17-fold, vastly expanding their potential application. Moreover, a single mono-layer of scale cells removed from the butterflies’ wings maintained this high reflectivity showing that a single layer of scale cell-like structures can also form a useful coating. As predicted, the wings increased the temperature of the butterflies’ thorax dramatically, showing that the V-shaped basking posture of white butterflies has indeed evolved to increase the temperature of their flight muscles prior to take-off.

Effect of roof-mounted solar panels on the wind energy exploitation on high-rise buildings

The analysis of the wind flow around buildings is of great interest in the field of renewable energies. This work presents an investigation of the effects of roof-mounted solar panels on the wind flow on building roofs, from the point of view of the wind energy exploitation. CFD simulations of the wind flow around an isolated building are performed with OpenFOAM. The simulations are compared with two wind tunnel experiments for validation: an isolated building and an array of solar panels. The wind flow on an empty roof is compared with roof-mounted solar panels cases. The solar panels are tested with tilt angles of 10° and 30°, the most adequate inclination for solar panels in the Mediterranean region. The analysis is carried out both quantitatively and qualitatively. The full-scale building results are compared with a reduced-scale model and scaling issues are reported. The most adequate wind turbine for each roof region is suggested.

A107 無人移動ロボットの電源制御システムにおける最大電力追従装置の開発と評価(OS2 宇宙機・宇宙ロボットのダイナミクスと制御2)

Unmanned Ground Vechiles (UGV) are required to be operated in extreme environment where the UGV should manage its electric power by itself. A typical approach for the power generation in such scenario is to use Solar Array Panels (SAP). However, the power generation with the SAP on the UGV is different from that used for static system relative to the sun such as for house or satellite. This study focuses on a development of the power generation system for the UGV; in particular, the Maximum Power Point Tracker (MPPT), a core device in the power generation system is developed. Three tracking methods were implemented in the MPPT and each of them was experimentally evaluated.

Coupled Navier–Stokes/Direct Simulation Monte Carlo Simulation of Multicomponent Mixture Plume Flows

A coupled particle-continuum simulation method is presented to compute the multicomponent mixture plume flow from the attitude-control engines of a satellite through the use of the Navier–Stokes solver and direct simulation Monte Carlo method. In this study, the implicit hybrid flux iteration scheme for the axisymmetric compressible Navier–Stokes equations is constructed to solve the inner flowfield of the nozzle. The Navier–Stokes computing technique is implemented considering slip boundary theory for the near-continuum slip flow near the nozzle exit. Direct simulation Monte Carlo methods for the axisymmetric core plume and three-dimensional far-field plume flows of multispecies mixture gas are developed by using a radial weighted factor, by tracking the molecular motion trajectory, and with secondary Cartesian and unstructured cell processing techniques. A multiregion decomposition and hybrid Navier–Stokes/direct simulation Monte Carlo algorithm with two-way and one-way coupling is established to solve the internal and external flow of the thruster, including the near-field, far-field, backflow, and gas-surface contaminated regions. After constructing the coupled Navier–Stokes/DSMC simulation scheme, the present method is applied to solve the plume flowfield and impinging contamination effects from the satellite attitude-control engine and solar array panel; the simulation results correspond well with the experimental measurements from the low-density wind tunnel and the theoretical predictions. To study the contamination effects produced by the multicomponent mixture plume, the current method is employed to simulate a five-component mixture plume flowfield of tens of meters from two representative attitude-control engines installed in different locations of a satellite in orbit. The results of the nonreacting multicomponent flow with equivalent mole fractions can be achieved with a one-component gas simulation if the species is assigned the properties of the mixture. The deposition rate of the plume flows produced by the two teamwork engines can be superimposed on each other. This method can be used to efficiently predict the impingement contamination effects of the gas-fired mixture plume flow on the satellite and solar array panels.

A compact non-explosive separation device for high preload and low shock

In this paper, we present a compact non-explosive actuator device (NEA) that is activated with a thermal cutting method using Ni-Cr wire. Practical applications include the deployment of satellite appendages such as solar array panels and antennae. The pyrotechnic based separation device generates high shock and chemical contaminants, which cause malfunctions of components such as optic cameras and other sensors. The proposed NEA device is designed to generate low shock using unspool mechanism characteristic, and to have compact dimensions and a light mass. In the design process, we formulated equations based on a static analysis to verify that it satisfied the basic requirements. Then we fabricated the device based on a theoretical analysis and carried out pre-tests such as maximum preload and response time tests to verify the results of the theoretical analysis. The pre-test results showed an average maximum preload of 1,000 kgf and a response time of 600 ms. Consequently, we verified the feasibility of an NEA that could be activated within 600 ms under high preload. In order to develop a qualification model for the NEA, various additional tests are planned, including launching and space environment tests based on the European Satellite Agency standard test manual.

Economical evaluation of large-scale photovoltaic systems using Universal Generating Function techniques

Solar energy plays an important role in the global energy framework for future. Comparing with con- ventional generation systems using fossil fuels, the cost structure of photovoltaic (PV) systems is different: the capital cost is higher while the operation cost is negligible. Reliabilities of the PV system can also influence the cost for producing electricity. Investors, planners and regulators require deep insight into the return and cost of a PV pro- ject. A reliability based economical assessment of large- scale PV systems has been conducted utilizing Universal Generating Function (UGF) techniques. The reliability models of solar panel arrays, PV inverters and energy production units (EPUs) are represented as the corre- sponding UGFs. The expected energy production models for different PV system configurations have also been developed. The expected unit cost of electricity has been calculated to provide informative metrics for making optimal decisions. The proposed method has been applied to determine the PV system configuration which provides electricity for a water purification process.

Measurement of the “IBUKI” Solar Array Panel's Behavior Using High Precision Image Processing

Generally, many space satellites have large solar array panels for power generation and large antennas for observation and communication. The panels and antennas must be lightweight because of the payload weight limit of the launch vehicle. So, they are very flexible, with little damping ability. This results in vibrations cause serious problems. When the thermal environment around a flexible structure on orbit such as a solar array panel changes to cold or hot, the flexible structure produces its own deformation or vibration. These occur most often during rapid temperature changes called thermal snap or thermally-induced vibration, which has been known to cause attitude disturbance in Low Earth Orbit (LEO) satellites. Thermal snap vibration occurring on a flexible solar array panel is very slow. It is very difficult to measure thermal snap motion by sensors such as accelerometer. The behavior of a space structure affected by thermal snap has never been observed directly in space so far. This report presents the measurement results of “IBUKI” solar array panel's behavior using monitor camera.