Investigate and analysis the efficiency of photovoltaic system with active cooling based on numerical method

<p style="margin: 0in 0in 10.6pt 0.5pt; text-align: justify; text-indent: -0.5pt;">The aim of this research is to establish a simulation model to examine the performance and working efficiency of a solar cell system by using computational fluid dynamics (CFD). The proposed model consists of a water feed tube and an absorber plate, as well as a convection heat transfer system, the ansys fluent system simulation program was used. The electrical output of the panel and its efficiency have been investigated and the effect of changes in the intensity of solar radiation on the temperature of the liquid and the absorption plate on the performance of the system have been studied. A dynamic analysis of the thermal hybrid system was performed with a circulation pump. Calculations were performed using a detailed mathematical model. The analysis was performed in three cases, the first case when the system has no cooling, in the second case with constant flow, and in the third case when the pump was optimized. Finally, numerical results were compared with the practical reference results. Both results are in good agreement. The results obtained showed that the system with optimization case give a good improvement in efficiency with low reduction of the thermal efficiency compared to a constant flow.</p>

Heating up a lantern with a tealight candle

This paper provided physics principles and a method to heating up a lantern with a tealight candle, so it reaches 2.5 m within the shortest time. The experiments aimed to determine optimal parameters in filling paper lanterns with hot air and the ideal shape of lanterns that would travel most quickly in a vertical direction. Hot air from burning a 28-wick candle was directed through a heat transfer system to fill the lanterns. The small ellipsoid lantern required the shortest time. This problem is suitable as a platform for STEM education approach on topics of convection, buoyancy and drag force.

Modeling and Simulation of Human Body Heat Transfer System Based on Air Space Values in 3D Clothing Model

Comfort can be considered as subjective feeling, which could be affected by the external ambient, by the physical activity, and by clothing. Considering the human body heat transfer system, it mainly depends on various parameters including clothing materials, external and internal environment, etc. The purpose of the current paper is to study and establish a quantitative relationship between one of the clothing parameters, ease allowance (air gap values) and the heat transfer through the human body to clothing materials and then to the environment. The study considered clothing which is integrated with the 3D ease allowance from the anthropometric and morphological data. Such incorporating of the clothing’s 3D ease control was essential to properly manage the air space between the body and the proposed clothing thermal regulation model. In the context of thermal comfort, a clothing system consisting of the human body, an ease allowance under clothing, a layer of textile materials, and a peripheral layer adjacent to the textile material was used. For the complete system, the heat transfer from the skin to the environment, which is influenced by thermoregulation of the human body, air gap, tissue, and environmental conditions were also considered. To model and predict the heat transfer between the human body and the temperature of skin and clothes, a 3D adaptive garment which could be adjusted with ease allowance was used. In the paper, a thermoregulatory model was developed and proposed to predict the temperature and heat within clothing material, skin, and air space. Based on the result, in general the main difference in the temperature of clothing and skin from segment to segment is due to the uneven distribution of air layers under the clothing.