Applied Solar Energy最新文献

The thermovoltaic effect, which is the occurrence of an electromotive force (EMF) in a substance during its uniform heating, is a promising phenomenon for the development of effective converters of solar thermal energy into electrical energy. However, the problem of suitable materials and design of the thermovoltaic element remains open. Therefore, this work is devoted to the study of the thermovoltaic effect in n‑GaSb, n-GaAs, and n-GaP binary compounds. The current–voltage characteristic (I–V curve) of the structures Ni–Ag–GaSb–Ag–Ni, Ni–Ag–GaAs–Ag–Ni, Ni–Ag–Sn–GaP–Sn–Ag–Ni, Ni–Ag–Si–Ag–Ni, and Au–Ni–Ag–Au are investigated in the temperature range of 300–500 K. As the temperature increased, shifts in the I–V curves of semiconductor structures are observed towards increasing voltage and current, which indicates the appearance of EMF and current during uniform heating. At 500 K, the points of intersection of the I–V curves with the voltage axis are 10.6 mV for GaP, 6.3 mV for GaSb, 5.3 mV for GaAs, and 0.9 mV for Si, as well as with the current axis, respectively 3.8 μA cm^–2 for GaP, 480 μA cm^–2 for GaSb, 184 μA cm^–2 for GaAs, and 2.7 μA cm^–2 for Si. Uniform heating of the structures under consideration in the dark leads to the occurrence of EMF and current in them. The thermally stimulated EMF of the GaSb and GaAs compounds was almost the same (0.2 mV) and an order of magnitude lower than the EMF of the GaP compound (2.5 mV) at 428 K.

Increasing the efficiency of photovoltaic (PV) solar panels is more and more the quest of many scientists because it is renewable and non-polluting energy. For this purpose, various methods and techniques are used, among which is the Maximum Power Point Tracking (MPPT) method, which has a certain interest because it does not require additional mechanical devices. One of the most used MPPT methods is the Hill Climbing (HC) method which has known a lot of evolution with time. The objective of this work is to scrutinize and present a comprehensive review of the improved Hill Climbing algorithms for tracking the Maximum Power Point (MPP) in PV systems. In-depth descriptions of the many HC techniques, including their algorithms, tracking effectiveness, modeling, mathematical equations, software, and hardware implementations, as well as the most current advancements in the field, are presented in this review study. After this investigation one can conclude that HC MPPT still has good interest and newer improvements are soon to arise.

The drying of fruits, vegetables, ginger, tea, coffee, fish flesh, and herbs can be accomplished with a solar tunnel dryer. It was mathematically modeled for drying ginger products. The solar tunnel dryer comprises of a transparent UV-stabilized plastic-coated chamber and a flat plate solar collector covered in glass. An exhaust fan with solar photovoltaic modules is provided to evacuate the moist air from the dryer. The designed dryer has length, and width area of 8.5, 2 m, and 11 m², respectively. The average daily efficiency of the solar collector over eight hours was about 32%. The dryer can dry 50 kg of ginger per batch. The ginger has a starting moisture content of 90.4% (w.b) and the ultimate moisture level is about 11.8% (w.b). Ginger was selected because it is a major agricultural commodity in Ethiopia, where it is utilized both fresh and dried forms. The dried ginger is utilized for commercial applications. It is used as a local medication and as a flavoring spice in most families. It is quite important in the country’s traditional eating patterns. The ginger was sliced into average length of 9.5 cm, thickness of 1.5–2 mm, and a weight of 7.5–9.2 g pieces. The design improved the Cost of fuel and electricity saved per season. A non-linear regression analysis was used to develop drying models for ginger. The models were compared using the correlation coefficient (R²), the residual sum square (RSS), and standard error of estimates (SEE) analysis to determine the one that best represented the thin layer drying characteristics of ginger. The results show that the Page model satisfactorily described the drying of ginger with R² of 0.995, the Standard error of estimate (SEE) is 0.003 and the residual sum square (RSS) is also 0.006. The drying time of the dryer is 3.33 days. The overall efficiency of the dryer is about 36%.

Partial shading has been shown to negatively affect the power output of solar PV systems. It occurs when part of a PV system is shaded while the rest of the system is fully illuminated. Partial shading disturbs the regular shape of the power curve that has single-power peak and produces power curve with multiple power peaks. Numerous hill-climbing algorithms exist, however they usually miss the operation on the global power peak and instead get stuck in one of the local peaks resulting in power losses. This paper derives a set of simple equations estimating the power peaks of partially shaded modules which are then utilized to develop a method for global power peak tracking. Unlike existing approaches, the proposed approach is very simple for implementation and does not require intricate models or special functions. Extensive verifications and validations are provided through simulations and experimentally. The results show that the proposed method can increase the power generation of solar PV systems through ensuring the global power peak extraction.

It is possible to use low-potential wind energy for the efficient operation of a wind power plant and for increasing the Annual Energy Production for guaranteed power supply to facilities in remote rural areas with a shortage of wind power. Currently in the development of large wind power plants worldwide hydraulic transmission is used to increase reliability and reduce the cost. However, the efficiency of such systems is lower than the efficiency of systems with a mechanical transmission (gearbox). But in regions with a shortage of wind power, wind power plants with a gearbox are not effective, and a hydraulic transmission could provide an increase in the Annual Energy Production of small wind power plants. Proposed is a small multi-unit wind-driven power plant with a hydraulic drive and an accumulator for power supply to remote facilities in rural areas. Methods for calculating the parameters and modes of operation of a multi-unit wind-driven power plant have been developed. The operation of a multi-unit wind-driven power plant was studied in the range of wind speeds of 4–14 m/s. The results of the theoretical analysis of the operation of the multi-unit wind-driven power plant are presented in the form of torque, rotational speed, power and flow rate diagrams. The results showed that the sum of flow rates of several pumps in the hydraulic system can provide the required constant flow rate of the hydraulic motor in a wide range of wind speeds. Thus, even at low wind speeds of 3–4 m/s on a typical day for a region with an average periodic wind speed of 4.3 m/s the total daily flow shortage is 75.2 L/min, while the total daily surplus is 180 L/min. The above calculation methods allow for a comparative analysis of the parameters, as well as the selection of design for the multi-unit wind-driven power plant being developed. The use of a hydraulic system with a hydraulic accumulator and several wind-receiving devices of different parameters, connected in parallel, significantly increases the efficiency of a small wind-driven power plant in a region with low-potential wind energy. In this case, the efficiency of the electric generator of a wind-driven power plant will always be maximum, since a constant rotational speed of the generator shaft is maintained and optimal generator modes are provided.

The paper presents ways to improve the morphology and efficiency of perovskite solar cells synthesized from lead acetate trihydrate and methylammonium iodide. It was found that the quality of nanoscale films of the perovskite absorber depends on the time of precursor solution spinning and conditioning before annealing. The optimal combination of these times made it possible to increase the conversion coefficient and short-circuit current of perovskite solar cells to 10.97% and 18.7 mA/cm², respectively. The results can be used to optimize the optoelectronic characteristics of perovskite depending on a number of kinetic parameters, such as the rotation speed, the acceleration time (acceleration) of the spin-coater, the temperature, and duration of annealing during the formation of solar cells.

Nanoparticle (NP)-based Organic Photovoltaic (OPV) cells have the potential to increase power conversion efficiency (PCE) due to the capacity to excite localized surface plasmon resonances (LSPRs) induced by conductive electron oscillation. Widespread deployment of this technology requires further investigation to find out the most dominant parameters (both optical and electrical) responsible for improving the PCE of NP-based OPV cells. In this work, we primarily investigated the performance of plasmonic NPs (e.g., Ag and Au) based OPV cells using the General-Purpose Photovoltaic Device Model (GPVDM) and Semiconducting Thin Film Optics Simulation (SETFOS) environments and compare them to a reference cell without any NPs. It was discovered that by using the NPs as a distinctive active layer along with P3HT: PCBM, both carrier generation rate, and electric field were significantly enhanced in single-junction OPV cells. Thus, the PCE was increased by 19.5, and 7.35% for Au and Ag NPs-based OPV systems, respectively. This significant increase in PCE can be explained by increased short-circuit current density as a result of enhancing active layer absorption by LSPRs. This analysis will be helpful for basic understating of NP-based OPV cells and optimizing design parameters for realizing highly efficient OPV cells.

In the present work, degradation mechanism in P3HT:PCBM bulk heterojunction photo-voltaic devices has been explored. For this purpose, the JV characteristics of eight P3HT:PCBM solar cell structures fabricated under identical conditions, were studied on hourly basis. Without exception, the power conversion efficiency (PCE) of the solar cells is found to fall off exponentially that saturates within six hours. The decay and rise time of the photo-current in the devices were also studied. The nature of the graphs negates the possibility of surface oxidation and generation of trap centers in the photo-active film. Thus, phase separation of P3HT and PCBM domains is expected to be the root cause of device degradation.

The article presents the results of field experiments to determine the thermal and technical and economic indicators of flat capacitive solar-water heating collectors made of translucent plastics with bottom absorption of solar radiation for seasonal use in the regions of the Republic of Uzbekistan. As follows from the results during the warm season, the seasonal thermal efficiency in the reservoirs under consideration, depending on the thickness of the water layer for the season, respectively, is 17% at 0.05 m and 24% at 0.07 m. At the same time, the specific savings for natural gas from the Shurtan deposit and Angren coal deposit are 488 Nm³ and 910 kg per season, respectively. The reduction of CO₂ emissions during the season during the combustion of natural gas from the Shurtan deposit is 667 kg and Angren coal deposit (depending on the percentage of carbon in the composition of coal) from 3148 to 4814 kg of CO₂, respectively.

The current state of affairs on the Photovoltaic emulator (PVE) is facing two main challenges: complexity in resolving the nonlinear equations of the photovoltaic (PV) and the problem of effective control of the PVE power conversion stage (PCS). In this paper, a new power electronics-based PVE is proposed to emulate the dynamic and static characteristics of the PV cell/module. The nonlinear equations of the PV cell/module are resolved using a new piecewise segmentation technique, involving the splitting of the current-voltage (I–V) curve into twelve linear segments associated with the letters a to m (a–m). Based on input environmental conditions, a trained artificial neural network (ANN) is constructed to assist the linearization process by predicting the current-voltage boundary coordinates of these segments. By the use of simple linear equations with the boundary coordinates, a reference voltage is then generated for the PVE. A nonlinear backstepping controller is designed to exploit the PVE reference voltage and stabilize the PCS. The stability of the controller is verified by Lyapunov laws. Optimal performance and control of the PCS were ensured by resorting to particle swarm optimization (PSO). The overall system has been investigated in the MATLAB environment with major tests including the response to fast-changing irradiance and temperature, the EN 50530 test, and the response to change in the load. The proposed PVE revealed a satisfactory dynamic performances in mimicking the PV characteristics. Furthermore, the accuracy of the PVE as a function of the mean absolute percentage error (MAPE) was found less than 0.5% even for the worst case of environmental conditions. Experimental validation of the proposed PVE under real environmental conditions further validated its good dynamic and static robustness.