Showing papers by "Ravishankar Sathyamurthy published in 2023"

A Review on CNTs-Based Electrochemical Sensors and Biosensors: Unique Properties and Potential Applications.

Abstract: Carbon nanotubes (CNTs), are safe, biocompatible, bioactive, and biodegradable materials, and have sparked a lot of attention due to their unique characteristics in a variety of applications, including medical and dye industries, paper manufacturing and water purification. CNTs also have a strong film-forming potential, permitting them to be widely employed in constructing sensors and biosensors. This review concentrates on the application of CNT-based nanocomposites in the production of electrochemical sensors and biosensors. It emphasizes the synthesis and optimization of CNT-based sensors for a range of applications and outlines the benefits of using CNTs for biomolecule immobilization. In addition, the use of molecularly imprinted polymer (MIP)-CNTs in the production of electrochemical sensors is also discussed. The challenges faced by the current CNTs-based sensors, along with some the future perspectives and their future opportunities, are also briefly explained in this paper.

A Review of Different Types of Solar Cell Materials Employed in Bifacial Solar Photovoltaic Panel

Abstract: Conventionally accessible silicon solar cells experience two major drawbacks, such as reduced efficiency and increased fabrication costs. The prospects for the reduction in the cost of the photovoltaic form of energy conversion are bifacial solar cells. Bifacial solar cells show potential opportunity in reducing the cost of solar energy conversion when analyzed with respect to monofacial cells. The bifacial solar cells exploit sunlight occurrence on both sides of the cell more efficiently. Bifacial-based solar photovoltaic (PV) is a technology that increases the generation of electrical energy per square meter of PV module through the utilization of light absorption from the albedo. This technology can generally be categorized based on the type of solar cell material and the fabrication technique. PV devices are classified as a silicon-based, thin film, organic, and advanced nano PV. This paper takes a second look at some recent initiatives and significant issues in enhancing the efficiency of bifacial solar cells from material sciences and chemical composition aspects. From this review, it is concluded that screen-printed solar cells have produced a maximum efficiency of 22%. Additionally, triode structure single-crystalline cells produced a maximum front side efficiency of 21.3% and rear side efficiency of 19.8%. Considering the recycling of solar panels, organic solar panels can be developed.

Performance evaluation of a solar air heater with staggered/longitudinal finned absorber plate integrated with aluminium sponge porous medium

Abstract: Solar air heaters are used to heat air for drying and space heating applications, however, the low heat transfer between air and absorber plate accounts for its low efficiency. In this paper, an experimental study of a staggered/longitudinal finned plate solar air heater (SLFPSAH) with a built-in aluminium sponge porous media as a sensible heat storage material is presented. The fins with the direction of airflow are arranged in a staggered manner by covering a length of 1.25 m, while the remaining 0.75 m is arranged with longitudinal fins. The parameters influencing the performance of the SLFPSAH are investigated with and without using a porous medium. These parameters include solar irradiance, the temperature difference of air through the heater, air temperature ratio, convective heat transfer coefficient, useful heat gain, daily energy efficiency, and exergy efficiency. Experiments are conducted under different air mass flow rates; namely, 0.0078, 0.01, 0.02, and 0.049 kg/s. The results revealed that the implementation of an aluminium sponge porous media over the absorber plate significantly increases the energetic and exergetic performances of the SLFPSAH. It is found that the average air temperature ratio, daily exergetic efficiency, and daily exergy efficiency of the SLFPSAH integrated aluminium sponge porous medium are about 11.52%, 3.97%, and 45.61% greater than that without the aluminium sponge porous medium, at airflow rate of 0.02, 0.049 kg/s, respectively. Moreover, the maximal increase in the convective heat transfer coefficient of the SLFPSAH integrated with aluminium sponge porous medium is more than 1.62 times that obtained with the SLFPSAH without porous media, at the same conditions. Thus, the SLFPSAH with an integrated aluminium sponge porous medium is an effective way to enhance the exergetic and energetic performances of solar air collectors for solar drying applications.

Optimized construction of marble pieces as thermal storage materials for performance improvement of hemispherical solar distiller

Abstract: The present work aims to obtain the optimized construction of marble pieces as thermal energy storage materials that achieves the highest performance of the hemispherical solar distillers. To obtain the optimal construction of the marble pieces as energy storage materials, four different marble pieces (black marble pieces, green marble pieces, red marble pieces, and white marble pieces) were placed on the basin of hemispherical distillers and tested under the same climate conditions. To achieve this goal, three hemispherical distillers were designed, constructed, and tested under the same climatic conditions; the first is the classical hemispherical distiller (CHD) which represents the reference case, the second and third hemispherical distillers contains marble pieces. The experiments were conducted in two stages, in each stage; two types of marble pieces are tested and compared with the reference case. The experimental results showed that the utilization of red marble pieces represents the optimal construction of marble pieces, which led to improving the cumulative productivity of hemispherical solar distillers to 7.75 l/m2 days compared to 4.8 l/m2 day achieved by the CHD, with an improvement of 61.46 %. The accumulative thermal efficiency of CHD reached 39.25 %, while the utilization of red marble pieces improved the accumulative thermal efficiency to 62.98 %. Also, the use of red marble pieces reduced the distillate cost by 35.6 % compared to the reference distiller.

Impact of Solar Energy and Energy Storage on a Still’s Nocturnal Output

Abstract: Solar stills represent one of the effective solutions in remote regions that suffer from the problem of lack of fresh water, but the disadvantage of their type of distillation technologies is the low productivity of pure water per square meter of evaporation surface. During the night, the brine cools down because of the absence of solar radiation, which causes a discontinuity in the operation of the solar still, which no longer produces freshwater. Therefore, the current work aims to achieve the highest performance of solar stills. To achieve these, in the present work, the thermal behavior of a simple greenhouse solar still is coupled to a sensible heat storage tank to ensure the heating of the brine by energy stored and therefore to improve the performance of the solar still by the night production of distilled water. The results obtained are encouraging because the improvement rate was 27.70 % compared to the daily light sentence and the thermal efficiency of our system during the night phase was stable between 60 and 61 %.