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The design of an optimized thermal management system for Li-ion batteries has challenges because of their stringent operating temperature limit and thermal runaway, which may lead to an explosion. In this paper, an optimized cooling system is proposed for kW scale Li-ion battery stack. A comparative study of the existing cooling systems; air cooling and liquid cooling respectively, has been carried out on three cell stack 70Ah LiFePO4 battery at a high discharging rate of 2C. It has been found that the liquid cooling is more efficient than air cooling as the peak temperature of the battery stack gets reduced by 30.62% using air cooling whereas using the liquid cooling method it gets reduced by 38.40%. The performance of the liquid cooling system can further be improved if the contact area between the coolant and battery stack is increased. Therefore, in this work, an immersion-based liquid cooling system has been designed to ensure the maximum heat dissipation. The battery stack having a peak temperature of 49.76 °C at 2C discharging rate is reduced by 44.87% to 27.43 °C after using the immersion-based cooling technique. The proposed thermal management scheme is generalized and thus can be very useful for scalable Li-ion battery storage applications also.

•A detailed comprehensive review of photovoltaic panel cooling techniques.•Original classification system for cooling methods applied to photovoltaic panels.•Valuable guidance for future research and insights into improving efficiency.•Automatic spray cooling has the shortest payback period at 1.279 years.•Phase change materials have varying payback periods between 2.828 and 3.772 years. Solar photovoltaic (PV) cells have emerged as the primary technology for producing green electricity. This innovation harnesses direct sunlight to generate power and its flexibility of installation has drawn significant investment in PV panels. Despite numerous benefits, these cells are hindered by a decline in efficiency caused by elevated cell temperature. As such, researchers have undertaken extensive investigations into possible solutions aimed at enhancing the performance of photovoltaic cells using diverse techniques. This review paper provides a thorough analysis of cooling techniques for photovoltaic panels. It encompasses both passive and active cooling methods, including water and air cooling, phase-change materials, and various diverse approaches. Within each category, it delves into detailed sub-categories, such as evaporative cooling, water immersion, floating systems, water pipes, cooling channels, water sprayers, jet impingement, geothermal cooling, and natural convection enhanced by PV designs. It also covers forced convection using cooling ducts, heat sinks, and air collectors, alongside the integration of Phase Change Materials (PCMs), nanofluids, radiative cooling, thermoelectric methods, heat pipes, heat pumps, and other innovative techniques. Each of these approaches is illustrated with specific schematics and thoroughly discussed and compared. Furthermore, this paper introduces an original classification system for these cooling methods applied to photovoltaic panels, offering valuable guidance for future research and insights into improving efficiency. [Display omitted]

Photovoltaic panels play a pivotal role in the renewable energy sector, serving as a crucial component for generating environmentally friendly electricity from sunlight. However, a persistent challenge lies in the adverse effects of rising temperatures resulting from prolonged exposure to solar radiation. Consequently, this elevated temperature hinders the efficiency of photovoltaic panels and reduces power production, primarily due to changes in semiconductor properties within the solar cells. Given the depletion of limited fossil fuel resources and the urgent need to reduce carbon gas emissions, scientists and researchers are actively exploring innovative strategies to enhance photovoltaic panel efficiency through advanced cooling methods. This paper conducts a comprehensive review of various cooling technologies employed to enhance the performance of PV panels, encompassing water-based, air-based, and phase-change materials, alongside novel cooling approaches. This study collects and assesses data from recent studies on cooling the PV panel, considering both environmental and economic factors, illustrating the importance of cooling methods on photovoltaic panel efficiency. Among the investigated cooling methods, the thermoelectric cooling method emerges as a promising solution, demonstrating noteworthy improvements in energy efficiency and a positive environmental footprint while maintaining economic viability. As future work, studies should be made at the level of different periods of time throughout the years and for longer periods. This research contributes to the ongoing effort to identify effective cooling strategies, ultimately advancing electricity generation from photovoltaic panels and promoting the adoption of sustainable energy systems.

The self-heating effect can be considered as a catastrophic phenomenon that occurs in polymers and polymer–matrix composites (PMCs) subjected to fatigue loading or vibrations. This phenomenon appears in the form of temperature growth in such structures due to their relatively low thermal conductivities. The appearance of thermal stress resulting from temperature growth and the coefficient of thermal expansion (CTE) mismatch between fibers and neighboring polymer matrix initiates and/or accelerates structural degradation and consequently provokes sudden fatigue failure in the structures. Therefore, it is of primary significance for a number of practical applications to first characterize the degradation mechanism at the nano-, micro- and macroscales caused by the self-heating phenomenon and then minimize it through the implementation of numerous approaches. One viable solution is to cool the surfaces of considered structures using various cooling scenarios, such as environmental and operational factors, linked with convection, contributing to enhancing heat removal through convection. Furthermore, if materials are appropriately selected regarding their thermomechanical properties involving thermal conductivity, structural degradation may be prevented or at least minimized. This article presents a benchmarking survey of the conducted research studies associated with the fatigue performance of cyclically loaded PMC structures and an analysis of possible solutions to avoid structural degradation caused by the self-heating effect.

Cooling techniques following thermal treatments and related microcracking are a hot spot in rock mechanics and must be precisely studied. Hence, this research performed systematic experiments on the influences of rapid cooling on the behavior of thermally treated granodiorite at different temperatures. Furthermore, using the optical microscope, a comparison between rapid and slow cooling methods was studied to investigate how the cooling process affected the microstructure of the Egyptian granodiorite. The granodiorite samples were heated to 200, 400, 600, and 800 °C and then cooled slowly by air and rapidly by the water. According to the experimental results, the changes in examined properties occurred in three distinct temperature stages: zone I (25–200 °C), zone II (200–400 °C), and zone III (400–800 °C). Zone II was a conspicuous transition region for the rapid cooling approach, distinguished by a significant increase in porosity, thermal damage, crack density, and a substantial decrease in wave velocities, uniaxial compressive strength, and elastic modulus. Microcrack densities and widths increased with temperature for both cooling methods. According to microscopic analyses of granodiorite samples, boundary cracks were formed at the boundaries of quartz and feldspar first due to their minimal lattice energy, followed by biotite of high lattice energy. However, due to the thermal shock induced, the intragranular microcracks of the rapid cooling technique began to form at lower temperatures (200 °C). The physical and mechanical properties of rapidly cooled granodiorite significantly dropped between 200 and 400 °C, and the failure mode altered from axial splitting to shear modes. Consequently, over 600 °C, longitudinal waves could not penetrate rock samples due to the thermal fusion of inter and transgranular fissures, which turned into macrocracks. Hence, the elastic modulus measurements and wave velocity at 800 °C were challenging with an extremely low UCS and complex failure mode.

The cutting process of difficult materials to machine has a common problem that affects tool life and workpiece quality, which is the high temperature in the cutting zone; that is why cooling technology plays a large role in the manufacturing industry. The combination of cooling techniques with microtextured tools can be one of the best solutions for this problem due to the synergistic effect; as the microtexture provides pathways for the coolant to proceed into the tool surface to the cutting zone, the cooling approach is enhanced, which results in a reduction in friction and heat. This paper comprehensively summarizes and simplifies the most recent research on microtextured tools with cooling technology and the coupling effect of microtextured tools with cooling techniques on heat and friction reduction in the cutting zone.

In buildings, air conditioning and mechanical ventilation (ACMV) systems are the major shareholders of overall energy consumption. Energy-efficient designs for ACMV systems in building applications are therefore needed. While designing an efficient ACMV system, consideration must be given to the growing concerns of enhanced thermal comfort and improved indoor air quality. The variable refrigerant flow (VRF) air-conditioning system is a widely adopted alternative to the existing building cooling systems due to the higher energy efficiency and individualized temperature control feature. However, it still suffers from shortcomings such as no outdoor air induction for ventilation and higher initial cost. Therefore, this paper reviewed the variable refrigerant flow and mechanical ventilation/air distribution systems, their integrated designs for non-residential buildings, performance evaluation and control optimization of the integrated systems, VRF systems’ faults detection and diagnosis, current application of the VRF systems, and associated challenges. Together with these all, some advanced buildings’ cooling techniques and improvements toward nearly/net-zero energy buildings are briefly discussed. Indoor thermal comfort models and criteria for different climates are also presented for an in-depth understanding of the VRF integrated mechanical ventilation designs. The literature survey shows that the supply air temperature and airflow rate are foremost in parameters that can be optimized in VRF integrated ventilation design as they greatly reduce the energy consumption. Further, policies on elevated indoor temperatures in air-conditioned buildings to mitigate their carbon footprint are strictly being implemented. Therefore, this review provides an insight to the researchers for further improvement in the integrated design and control optimization of the parameters involved. A paradigm shifts from the conventional compression-based electric-powered air conditioning systems to the renewable energy driven advanced air conditioning technologies which is also an emerging research area to be focused on achieving the target of nearly/net-zero energy buildings.

Personal cooling garments (PCGs) have gained increasing attention as a promising solution to alleviate heat stress and enhance thermal comfort in hot and humid conditions. However, limited attention has been paid to the influence of clothing design on cooling performance. This review highlights the influence of design factors and provides a quantitative comparison in cooling performance for different types of PCGs, including air cooling garments, evaporative cooling garments, phase-change cooling garments, and liquid cooling garments. A detailed discussion about the relationship between design factors and the cooling performance of each cooling technique is provided based on the available literature. Furthermore, potential improvements and challenges in PCG design are explored. This review aims to offer a comprehensive insight into the attributes of various PCGs and promote interdisciplinary collaboration for improving PCGs in both cooling efficiency and garment comfort, which is valuable for further research and innovation.

The degradation performance of solar photovoltaic (SPV) panels, is a critical issue for its adoption. The current study introduces a novel dual-cooling technique to enhance the performance of the SPV panels under conditions of contamination from bird droppings. The front and backside temperatures, output power, and efficiency of the cooled SPV panels were evaluated and compared. Results showed that the cooling process reduced the front and backside temperatures by 24–47% and 34–48% respectively, compared to contaminated SPV panels. The cooled SPV module exhibited an output current increase of 8–9% and an output voltage increase of 7–9% compared to both contaminated and controlled modules. Consequently, output power for the cooled SPV module increased by 12–33% and 7–12% compared to bird droppings and controlled modules, respectively. Moreover, the overall efficiency of the SPV module dropped to 15% in the presence of bird droppings, compared to 20% with the cooling process was applied. These findings suggest significant potential benefits for large-scale SPV installations, enhancing performance and efficiency.

The development of zero-energy buildings (ZEBs) is a critical pillar for designing the sustainable cities of the future. Photovoltaics (PVs) play a significant role in the design of ZEBs, especially in cases with fully electrified buildings. The goal of this analysis was to investigate different advanced PVs with integrated cell cooling techniques that can be incorporated into buildings aiming to transform them into ZEBs. Specifically, the examined cooling techniques were radiative PV cells, externally finned PVs and the combination of PVs with phase-change materials. These ideas were compared with the conventional PV design for the climate conditions of Athens, Barcelona, Munich and Stockholm. At every location, two different building typologies, B1 (a five-story building) and B2 (a two-story building), were investigated and the goal was to design zero-energy buildings. In the cases that the roof PVs could not cover the total yearly electrical load, building-integrated photovoltaics (BIPVs) were also added in the south part of every building. It was found that in all the cases, it is possible to design ZEB with the use of roof PVs, except for the cases of B1 buildings in Munich and Stockholm, there is also a need to exploit BIPVs. Moreover, a significant electricity surplus was reported, especially at the warmest locations (Athens and Barcelona). Among the examined cooling techniques, the application of the fins in the back side of the PVs was determined to be the most effective technique, with radiative cooling to follow with a slightly lower performance enhancement. The application of PCM was found to be beneficial only in hot climate conditions.