• Energy Research

By only producing electricity and contributing to the provision of electricity, photovoltaic cells are limited in their function. There are numerous ways to evaluate the performance of photovoltaic cells. The electrical and thermal performance of such cells must typically be examined for cells that utilize thermal energy as well. The performance of a photovoltaic cell has been examined and assessed in this article from an energy and exergy standpoint. For modeling and calculating the electrical attributes of the system, such as open-circuit voltage, short circuit current, system resistances, maximum power point qualities, and characteristic curves, a computer code has been developed. The model’s results have been compared with data provided by the manufacturer and other sources in order to validate the model. This panel’s daytime energy efficiency is typically 13.19%. The instantaneous energy efficiency during the experiment ranged from 11.22% to 13.94%, with 13.94% being the highest number.

The current work describes the synthesis of Nano magnetic catalysts, oil extraction from fish waste and processing of biodiesel. The first-order thermodynamic equations are considered to determine its kinetic and thermodynamic parameters involved in extraction process. The study has considered the rate constant (k), activation energy (Ea), frequency factor (A), entropy (ΔS), enthalpy (ΔH), and Gibb's free energy (ΔG) as variables at different temperatures. The maximum activation energy, rate constant, enthalpy and entropy are 59.31 kJ mol−1, 27.15 s−1, 65.87kJmol-1 and 27.63kJmol-1k−1 respectively. The important parameters affecting the process of biodiesel production is reaction temperature and catalyst concentration. Here, the nano magnetic catalysts accelerate the production of biodiesel from fish waste. So, the biodiesel yield is high at 55 °C reaction temperature (95 wt%) than 32 °C reaction temperature (65 wt%). The resulting biodiesel was tested according to ASTM standards and obtained the closer values as per ASTM D6751 specification.

Abstract In this work, a square pyramid solar still is designed, fabricated and tested during recommended days at the four seasons of Al Kufa climatic conditions (elevation is 30 m and location is 32° North and 44° East), Iraq. The proposed design of the still can be used at any remote location in Iraq where is no electricity and high solar intensity. Designing the affordable solar still was mainly due to simplicity in its operation process, long life and low cost. Data obtained from an advanced simulation modeling of multi-shaped solar stills are used to determine the temperature gradient and the heat flux distributions during unsteady-state conditions. The procedure of the modelling is included: volumetric properties of the solid and fluid regions, thermal loads on the still, mesh generation, grid convergence index and grid refinery processes. The experiments were measured during the four seasons to investigate the temperatures of water, glass, ambient, water production and solar intensity. The results show that the maximum daily water production of the designed still is 2.2 L/m2 in 17th of July with a low cost of 15 US dollars. The numerical model is predicted the thermal behavior of triangle, pyramid and pentagon types of solar stills. The results also show that the efficiency of the designed still is significantly improved to 60% compared with other experimental solar stills. The results also demonstrate that the manufacturing and transferring of the portable solar still during 20 years has a reasonable effect on the environment in terms of air acidification and water eutrophication.

Solar still owns low distillate productivity. Many researchers enhanced the performance of solar still by variable the design of its components. The combination of internal/external reflectors, absorber materials (fins, sponge, pebbles), and external condensers had a substantial impact on the absorption, evaporation, and condensation processes of the classic basin type solar still. This paper is showing how existing methods for increasing solar still absorption, evaporation, and condensation may be used to improve solar still absorption, evaporation, and condensation. From this review, it is found that for solar still, that adjusting the internal/external reflectors might increase daily distillate yield by 70% to 100%. Added Absorbent materials improve the thermal performance of a still by increasing production by over 20%. In addition, the external condensers enhanced still freshwater yield by 62% more than the regular still.

In this paper, the thermal conductivity (knf) of cerium oxide/ethylene glycol nanofluid is extracted for different temperatures (T = 25, 30, 35, 40, 45, and 50 °C) and the volume fraction of nanoparticles ( φ = 0, 0.25, 0.5, 0.75, 1, 1.5, 2 and 2.5%) and then knf is predicted by two methods including Artificial Neural Network (ANN) and fitting method. For both methods, the results have been presented and compared. The experiments showed that with increasing φ and temperature, the thermal conductivity ratio (TCR) of nanofluid increases. It was also observed that when the experiments are performed at high temperatures, the rate of increase in knf is much higher than the change in the same amount of φ change at low temperatures. An ANN with 7 neurons has a correlation coefficient very close to 1 and this proves that the outputs are compatible with experimental results. Also, it can be seen that the ANN could predict the thermal behavior of cerium oxide/ethylene glycol nanofluid more accurately.

Phase change material (PCM) is a material that has a specific melting point, and its latent heat of melting is large enough that it can be used to store thermal energy. This study investigated the effect of size (4–8 Å), and the number of layers (3–10 layers) of iron nanoparticles (NPs) channel on thermal behavior (TB) and phase change (PC) process of sodium sulfate/calcium chloride hexahydrate (Na2SO4/MgCl2·6H2O) PCM molecular dynamics (MD) simulation. By increasing the number of layers from 3 to 5, the maximum temperature and heat flux (HF) increased from 406 and 1471 W/m2 to 451.51 K and 1496 W/m2. By increasing the number of layers from 3 to 7 layers, the charging time (CT) and discharge time (DT) of atomic samples decreased from 4.01 ns and 4.25 ns to 3.88 ns and 4.17 ns. By adding the iron NPs with a radius of 4, 5, 6, and 8 Å, the maximum temperature increased to 420, 429, 458, and 503 K, respectively. By adding the iron NPs with different radii from 4 to 8 Å, the HF increased from 1566 W/m2 to 1657 W/m2. By adding the iron NPs into the Na2SO4/MgCl2·6H2O, the received HF increased, and the maximum temperature increased. By adding the iron NPs with different radii, the CT decreased from 3.95 ns to 3.73 ns. The DT increased from 4.33 ns to 4.36 ns by increasing the radius from 4 to 8 Å. According to the TB of this PCM, it should be used in refrigerants instead of toxic and dangerous refrigerants, such as ammonia and chlorofluorocarbon. Moreover, they were used for construction purposes for double-glazed windows.