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Go to Editorial ManagerThe conventional open sun drying is not efficient, it is slow and contaminated and there is a necessity to develop highly advanced technologies in solar drying. The review looks critically at solar dryers that are improved with concentrator, optical, thermal energy storage (TES) or phase-change materials (PCM). The incorporation of parabolic trough or compound parabolic concentrators leads to a high temperature of over 100-115 oC and a thermal efficiency of up to 88 %. Reflective walls are also made to enhance optical capturing by up to 37.6 %, and shorten drying time by 15-20 %. TES/PCM systems increase the operation of TES systems beyond the sunset, nano-enhanced PCMs reduce drying time by 40% and enhance thermal efficiency by more than 48%. These systems demonstrate short payback periods (0.43-5.14 years) with regard to economics. They minimise the emission of CO2 by 2-44 tons/ lifetime of systems. These combined technologies have addressed intermittency and low efficiency and enabled solar drying to be a reliable and cost-effective and sustainable solution, as the UN Sustainable Development Goals of clean energy and climate action suggest.
In this research paper, it has been studied the influence of the temperature of the cell on the performance and behavior of two types of modules, which are mono-crystalline silicon (mc-Si) and poly-crystalline silicon (pc-Si) solar modules. The experimental work has been achieved under the outdoor conditions, where the range of cell temperature is between 20 and 60 °C. It was applied three different values of solar radiation [500, 750, and 1000W/m2 (standard condition, where cell temperature of 25 °C, solar irradiance of 1000 W/m², and air mass AM 1.5)]. All tests are achieved under the Iraqi weather conditions in the city of Baghdad city. It was computed the temperature coefficients for each module and during any time during the experiment. It was found that the open circuit voltage decreased with -0.0912 V/ºC and -0.07 V/ºC when using the pc-Si module and mc-Si, respectively. While, the short circuit current increased slightly with 4.4 mA/ºC and 0.3 mA/ºC corresponding to the pc-Si and mc-Si, respectively. Finally, the lowest drop in output power was found when using the pc-Si module (-0.0915 W/ ºC), and the highest drop when using the mc-Si module (-0.1353 W/ ºC).
Shadows dramatically reduce solar panel output because individual cells are wired in chains (series). Blocking one cell chokes the current for the entire chain. While bypass diodes bypass shaded sections, severe shadows can still cause "hot spots", which permanently damage panels. The proposed work presents an experimental measurements on the impact of shading on monocrystalline power losses. The solar module is exposed under the real environment conditions for direct solar radiation of 500 W/m2 and 80 W/m2 solar radiation at penumbra shading of shaded area with operating solar module temperature 25oC at ambient temperature 18oC. The Solar Module Analyzer simulator was used in this study, where 10 pattern of shading are tested. The photovoltaic solar module performance in terms of outlet power and fill factor with its corresponding efficiency are greatly affected by shadow. The maximum output power drops drastically, often much more than the shaded area percentage would suggest ; 25% shading can lead to 60% power loss and also 50% shading can lead to 60% power loss. It is noticeable that there is a sudden change in the behavior of the I-V and P-V characteristic curves at a certain range of open circuit voltage 9-9.5V.
The worldwide evolution towards cleaner and more sustainable energy infrastructures has fostered intense research on Hybrid Renewable Energy Systems (HRES) that combine two or more energy sources that are complementary to each other to tackle the limitations of individual renewables. This paper reviews the optimization, control, and energy management strategies used for the HRES and provides a critical short review of the same. This paper covers system classification, component modeling, classical and metaheuristic optimization techniques, AI-based energy management, and techno-economic assessment. The review also highlights key current challenges and offers directions for future research, including AI-based smart systems, hydrogen integration, digital twins, and blockchain-based energy trading.