• Energy Research

One of the disadvantages of solar systems is their low efficiency due to weather conditions such as dust and clouds that reduce their performance. Therefore, this article examines the impact of cloudy weather on the performance of the PV/solar chimney to demonstrate the performance of these solar systems under overcast weather conditions. The PV/solar chimney system was designed and built, and two days in December were chosen for testing: 27 December with clear weather without clouds and 28 December with cloudy weather.The results showed that cloudy weather has a clear effect on the performance of the PV/solar chimney where the intensity of solar radiation is low. Clouds act as a barrier preventing access to sunlight, as the electrical power generated on a clear weather day reached 341.92 W, while on a cloudy weather day, 187.88 Watts at noon. The kinetic energy on a clear weather day reached 17.212 mW, while on a cloudy weather day, it reached 9.47 mW at noon. The electrical efficiency on a clear weather day reached 15.96 %. In contrast, on a cloudy weather day, it reached 13.2 % when the test started at 9 a.m., after which the efficiency decreased with the increase in the intensity of solar radiation to become 13.574 % in clear weather while 12.12 % in cloudy weather at noon, and the thermal efficiency on a clear weather day reached 56.06 %. In contrast, on a cloudy weather day, 42 % at noon. The total efficiency in clear weather reached 69.65 %, while on a clear weather day cloudy by 54.12 % at noon.

The provision of electricity and hot water is among the most significant human requirements at present. A photovoltaic/Trombe wall (PV/TW) system concurrently provides warm water, hot air, and electrical power for domestic usage. To optimize the amount of incident solar radiation, reflective mirrors were put on each side of the front face of the PV/TW system. The current article aims to determine the optimal angle for these mirrors that improve the thermal and electrical efficiency of the system.The findings indicated the utilization of DC fans, reflecting mirrors and water flowing across a heat exchanger improves thermal and electrical performance. The best angle for the impact of reflective mirrors to enhance electrical efficiency is the angle (30°) when using water cooling, which led to a decrease in the temperature of the photovoltaic panel and thus raised the electrical efficiency to reach (13.86 %). Also, the results confirmed that the system’s thermal efficiency that uses two cooling fluids is the highest relative to the other cases, and the system’s thermal efficiency that contains mirrors at 30° was higher than the other two angles. Finally, the addition of reflective mirrors is a favorable option for obtaining higher energy compared to the system without mirrors.

Renewable energy sources, especially solar energy, can meet part of the global energy needs, especially for domestic uses at present. The combination of Trombe walls and solar cells is currently one of the most extensive research topics and this system is named a Photovoltaic/Trombe wall (PV/TW). A PV/Trombe wall system can simultaneously generate electricity, heat water, and heat homes. The current article discusses studies that have been conducted on this system in several countries over the past few decades. The current review covers the effect of operational parameters including a DC fan that can assist in cooling the solar cells and raising the interior temperature, air gap thickness, and thermal insulation effect. The use of double glazing reduces the temperature of photovoltaic cells and enhances the efficiency of the system. The efficiency of the PV/TW can be improved using porous media, binary fluids, nano-fluids, and phase change materials.

The current article studies the effect of dusty weather conditions on the performance of PV/Trombe wall Photovoltaic. Two experimental models were built to study the impact of climatic changes and operating conditions on the PV/Trombe wall, one with DC fans and the other without DC fans. The operating conditions for dusty and non-dusty days were tested to show their impact on system efficiency. In the case of the model using DC fans on a clear day, the electrical and thermic efficiency of the model reached 10.2% and 17.6%, respectively. While in the case of the model without DC fans and on a clear day, the electrical and thermic efficiency of the model reached 8.4% and 40.1%, respectively. In the case of the model using DC fans on a dusty day, the electrical and thermic efficiency of the model reached 6.6% and 11.9%, respectively. While in the case of the model without DC fans and on a dusty day, the electrical and thermic efficiency of the model reached 3.5% and 34.1%, respectively. Dusty weather conditions reduce the electrical efficiency of the PV/TW system; the average daily electrical efficiency increase was 2.4% under clear weather conditions compared to dusty weather conditions. Also, the dusty weather conditions lead to an apparent decrease in the temperatures of the solar panel and air in the room. The decrease was 12% compared to a clear day.

The world is currently suffering from the careless usage of fossil fuels, which is primarily responsible for global warming and pollution. As a result, researchers have looked into alternate techniques to alleviate this issue and limit the dependence on fossil fuels. Renewable energy, particularly solar energy, offers a promising and sustainable future for energy markets. Over time, researchers have discovered various novel techniques to harness solar energy, including solar water heaters (SWHs), which are made up of absorber surfaces, pipelines, storage, and other mechanical components such as pumps. Recently, there has been a significant increase in interest in SWH as a means to save expenses and enhance thermal efficiency by canceling the connecting pipes. Pipe cancellation was the result of merging the absorber and storage into a single unit. This cancellation led to the creation of a new type of solar collector called integrated collector storage (ICS). These collectors are geometric shapes filled with water and painted black to optimize solar radiation absorption. This article examines the approaches for improving storage solar collectors, specifically integrated solar water heaters (ISWHs). The study focuses on structural design improvements, PV cells, evacuated pipelines, and phase change materials (PCMs). Furthermore, the study examines the performance of ICSSWH. These improvements demonstrated that the integrated solar heater provides good and promising efficiency at a reasonable cost, in addition to meeting the desired goal of lowering polluting emissions.

The performance of solar panels is significantly affected by high temperatures, leading to various cooling methods being employed to enhance their efficiency. This study utilizes comprehensive computational fluid dynamics (CFD) simulations with Ansys Fluent 2023 R1 software to evaluate the effectiveness of cooling photovoltaic (PV) panels using ground source energy in Kirkuk city, northern Iraq (35° 28′ N - E. 44.39). A 3-D model was employed to analyze the thermal behavior of the PV panel over 10 h (8:00 a.m. to 5:00 p.m.). The simulation demonstrates that the proposed cooling method achieved an impressive temperature reduction of approximately 28 % compared to conventional cooling methods. Moreover, the PV panel with ground-source cooling consistently outperformed the PV-only setup, showing a noteworthy improvement of approximately 6.5 % in power output, reaching a maximum of around 88 W. Examination of velocity and temperature distribution contours revealed that ambient air drawn in as hot air gradually dissipated its heat to the surrounding soil and bricks as it traversed through underground pipes, resulting in a significant reduction in temperature. This cooling process effectively enhanced the overall performance of the PV panel.

Hybrid solar collector (PV/T) is designed to produce electricity, hot water, or hot air at the same time as they operate solar cells and solar heaters in one system. This system is designed to increase the electrical efficiency of solar cells by absorbing heat from these cells. The fuzzy logic (FL) is a tool usually used to optimize the operation of the systems. In this paper, the FL is to monitor and correct the mainsystem parameters to remain optimization efficiency at a better level. Three affected variables were studied: Effect of reflective mirrors, the effect of the glass cover, and the effect of the lower reflector angle on the performance of the PV / T hybrid solar system. These three parameters are traveled to be inputs for the FL, and the PV temperature in addition to system efficiency is the output for it. The effect of solar radiation was found to have a great effect on the efficiency of the hybrid solar collector. The thermal efficiency was 82% for the given value of the PV and mirrors, while the efficiency down to 50 for another angle. By using the artificial intelligent the system behavior depends on its output, which called feedback close loop control, at a real-time process that optimizes the system efficiency and its output. 

This article introduces a new design of solar storage collectors integrated with a PV panel for domestic applications. Two identical practical models were built to test the performance of the collectors by analyzing and comparing them with the classical storage solar collector. In the first model, the solar cells were mounted on the tank’s front inclined surface to act as a black absorber surface, while in the second model, the absorbent plate was metallic and dyed in a pale black color.A number of experiments have been conducted on both models to validate and assess their performance. For the no-load conditions, the maximum storage temperature was about 77 °C and 81 °C for the new and conventional models respectively. For the load conditions, the mean storage temperature recorded the maximum value of 77 °C and 74 °C for the new model and conventional models respectively. Electrical efficiency increased as a result of removing warm water from the model. The highest electrical efficiency recorded for the new system was 15% at 9 a.m., with a water flow rate of 0.085 liters/min. On the other hand, the thermal efficiency of the new system is lower than the traditional system. The highest thermal efficiency recorded for the new system was 69% at 10 a.m., with a water flow rate of 0.085 liters/min. At the same time, the highest thermal efficiency for the conventional system was 88% at 11 a.m., with a water flow rate of 0.085 liters/min. It was also found that increasing the mass flow of the fluid drawn from the collector increases the thermal efficiency of the old and new designs.