With the inception of high voltage (HV), requisites on the insulating permanence of HV equipment is becoming increasingly crucial. Mineral/synthetic oil liquid insulation—together with solid insulation materials (paper, pressboard)—is the fundamental insulation constituent in HV apparatuses; their insulation attributes perform a substantial part in a reliable and steady performance. Meanwhile, implications on the environment, scarcity of petroleum oil supplies and discarding complications with waste oil have stimulated investigators to steer their attention towards sustainable, renewable, biodegradable and environmentally friendly insulating substances. The contemporary insulating constituent’s evolution is driven by numerous dynamics—in particular, environmental obligations and other security and economic issues. Consequently, HV equipment manufacturers must address novel specifications concerning to these new standards. Renewable, sustainable and environmentally friendly insulating materials are continuously substituting conventional insulating items in the market place. These are favorable to traditional insulating materials, due to their superior functionality. The also offer explicit security and eco-friendly advantages. This article discusses cutting-edge technology of environmentally friendly insulating materials, including their fabrication, processing and characterization. The new renewable, insulating systems used in HV equipment are submitted and their fundamental gains stated in comparison with conventional insulating materials. Several experimental efforts carried out in various parts of the world are presented, offering an outline of the existing research conducted on renewable insulating systems. The significance of this article lies in summarizing prior investigations, classifying research essence, inducements and predicting forthcoming research trends. Furthermore, opportunities and constraints being experienced in the field of exploration are evidently reported. Last but not least, imminent research proposals and applications are recommended.

Thermal management of electronic components is critical for long-term reliability and continuous operation, as the over-heating of electronic equipment leads to decrement in performance. The novelty of the current experimental study is to investigate the passive cooling of electronic equipment, by using nano-enriched phase change material (NEPCM) with copper foam having porosity of 97$\%$. The phase change material of PT-58 was used with graphene nanoplatelets (GNPs) and magnesium oxide (MgO) nanoparticles (NPs), having concentrations of 0.01 wt.% and 0.02 wt.%. Three power levels of 8 W, 16 W, and 24 W, with corresponding heating inputs of 0.77 kW/${\mathrm{m}}^2$, 1.54 kW/${\mathrm{m}}^2$ and 2.3 kW/${\mathrm{m}}^2$, respectively, were used to simulate the heating input to heat sink for thermal characterization. According to results, at 0.77 kW/${\mathrm{m}}^2$ heating input the maximum base temperature declined by 13.03% in 0.02 wt.% GNPs-NEPCM/copper foam case. At heating input of 1.54 kW/${\mathrm{m}}^2$, the maximum base temperature reduction of 16% was observed in case of 0.02 wt.% GNPs-NEPCM/copper foam and 13.1% in case of 0.02 wt.% MgO-NEPCM/copper foam. Similarly, at heating input of 2.3 kW/${\mathrm{m}}^2$, the maximum temperature of base lessened by 12.58% in case of 0.02 wt.% GNPs-NEPCM/copper foam. The highest time to reach the set point temperature of 50 $°$C, 60 $°$C, and 70 $°$C was in case of GNPs-NEPCM/copper foam composites, while at all power levels MgO-NEPCM/copper foam gave comparable performance to GNPs based composite. Similar trend was observed in the study of enhancement ratio in operation time. From the results, it is concluded that the copper foam incorporation in NEPCM is an effective measure to mitigate the heat sink base temperature and can provide best cooling efficiency at low and higher heating loads.

The demand for high-performance and compact electronic devices has been increasing day by day. Due to their compactness, excessive heat is generated, causing a decrease in efficiency and life. Thermal management of electronic components is crucial for maintaining excessive heat within the limit. This experimental research focuses on the combined effect of nano-enhanced phase-change material (NePCM) with different configurations of heat sinks for cooling electronic devices. Multi-walled carbon nanotubes (MWCNTs) are used as nanoparticles with concentrations of 3 wt% and 6 wt%, RT-42 as the phase-change material (PCM), and aluminum as the pin fin heat sink material. Different configurations of the heat sink, such as circular, square, and triangular pin fins, are used against the fixed volume fraction of the fins. It is found that the square configuration has the highest heat transfer with and without PCM. A maximum base temperature reduction of 24.01% was observed in square pin fins with RT-42 as PCM. At 6 wt% of NePCM, the maximum base temperature lessened by 25.83% in the case of a circular pin fin. It is concluded from the results that a circular pin fin with NePCM is effective for base temperature reduction, and all fin configurations with NePCM collectively reduce the heat sink base temperature.

Cool roof coatings are being applied on rooftops to reflect solar irradiance back into the atmosphere. Bifacial photovoltaic modules can receive solar irradiance from the front and rear side. The purpose of this study is to investigate the impact of reflected irradiance caused by cool roof coating (CRC) on the performance of bifacial photovoltaic (bPV) modules and monofacial photovoltaic (mPV) modules. According to the experiments, cool roof coating is an efficient way to increase the output and efficiency of solar modules. Experimental results show that for cool roof coating based on TiO₂ and FC resin with an average albedo of 0.63, the peak power output of the bifacial photovoltaic module is increased by 3.29% and its highest peak power efficiency is 18.1%. A peak power bifacial gain of 15.6% is seen. Due to a 1.3 °C decrease in temperature, the monofacial photovoltaic module power output also increased by 0.24%.

Due to high heat generation within closely packed smart electronic devices, some efficient thermal management systems are required for their reliable performance, avoid overheating, long lifecycle and safety. In this study, a novel thermal management system based on forced air cooling having three airflow configurations is developed to explore the thermal characteristics of each configuration. A customized cavity is designed to have provision for three airflow configurations (axial, cross, and reverse flow) and temperature profiles are investigated within the cavity for each configuration. The experiments are performed at three heat generation rates, i.e., 10 W, 20 W, and 30 W to analyze the cooling effectiveness at a variable heat generation rate. It was observed that the maximum temperature within the setup increases with the increase in heat generation rate. In axial flow air configuration, cavity temperature has been reduced remarkably by 69 and 82.4% at 10 W and 30 W, respectively. Second to axial flow, cross flow configuration performs better than reverse flow and an overall 65.7~78.6% temperature drop is obtained compared with enclosed cavity from 10 W to 30 W, respectively. Furthermore, a similar cooling rate trend in the cavity is obtained for an increased heat generation rate in the cavity.