Authors:Mathilda Laurensia; Levin Halim Abstract: Energy that can be obtained from natural resources and constantly replenished by nature is called “renewable energy”. To harness solar energy and convert it into electricity, a device known as a solar panel is utilized. However, solar panels encounter certain drawbacks, including reduced efficiency as the panel temperature rises and the partial absorption of sunlight due to its reflection by the top glass layer. This study aims to optimize solar panel efficiency by innovatively integrating a cooling system with water treatments and an aluminum foil reflector to enhance energy output. The study focused on a 700 mm × 510 mm × 30 mm monocrystalline solar panel. Initial efficiency improved significantly after implementing the cooling and reflector system. Based on measurement data, incorporating the reflector, revealed an average temperature of 61.3°C and solar radiation of 871.10 W/m². The cooling duration of 40.64 seconds was achieved with a water pump flow rate of 0.29 lt/s. Notably, the combined approach yielded substantial efficiency enhancements, with the solar panel reaching peak efficiency levels of 10.36%. PubDate: Sun, 30 Jun 2024 00:00:00 +030
Authors:Abdelaziz Zermout; Hadjira Belaıdı, Ahmed Maache Abstract: Numerous approaches and methodologies have been established for online (while the load is supplied) estimation of the State-of-Charge of Lithium-ion cells and batteries. However, as battery load consumption fluctuates in real time because of delivered device operations, obtaining a precise online state of charge estimation remains a challenging task. This work proposes a new technique for online open circuit voltage measurement to estimate state of charge of batteries. This novel technique proposes the addition of an auxiliary regulated load that may be utilized to temporarily force specifically defined forms of the battery's current curve under particular conditions, which results in improving and simplifying online open circuit voltage computations. The effectiveness of the proposed technique was successfully validated through several experimental tests. The acquired findings demonstrated its efficiency with an acceptable online state of charge estimation accuracy. Typically, an estimation error of less than 2% was recorded in most tests, while the error was less than 1% when the battery’s state of charge was high. PubDate: Sun, 30 Jun 2024 00:00:00 +030
Authors:Dmytro Konovalov; Halina Kobalava, Roman Radchenko, Mykola Radchenko, Anatoliy Zubarev, Felix Tsaran, Artem Hrych, Sergey Anastasenko Abstract: This research explores the hydrodynamic processes within the flow section of a low-flow thermopressor as a jet-type heat exchanger that utilizes the instantaneous evaporation of highly dispersed liquid in accelerated superheated gas flow resulting in reducing gas temperature with minimum resistance losses in contrast to conventional surface heat exchanger. The efficiency of thermopressor, as a contact heat exchanger, is highly dependent on the design of the flow section and the water injection nozzle. Geometric characteristics perform a crucial role in shaping gas-dynamic processes along the length of the thermopressor's flow section, influenced by resistance losses and local resistance in the tapering and expanding channel segments. Therefore, the optimum thermopressor design has to ensure minimize pressure losses. Using Computational Fluid Dynamics (CFD), the prototype thermopressor models were simulated and the results were compared with experimental data. The empirical equations for local resistance coefficients of thermopressor diffuser and confuser were received to evaluate the impact of various design parameters. The obtained local resistance coefficients for the confuser ranged from 0.02 to 0.08 and for the diffuser – from 0.08 to 0.32. The practical recommendations on geometric and operating parameters and characteristics for enhancing the efficiency of hydrodynamic processes in thermopressor flow part were given. PubDate: Sun, 30 Jun 2024 00:00:00 +030
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