NTU Journal of Renewable Energy

Development of Compound Parabolic Concentrator based on Flat Plate Receiver Solar Air Heater and Phase Change Material

2023-09-27T13:05:20+00:00

This work involves an experimental investigation of a Compound
Parabolic Concentrator (CPC) solar air flat plate collector with adding
Phase Change Material (PCM). To explore the best model performance,
the structure of CPC has two symmetric giant parabolic mirror reflectors,
a concentration ratio of 1.7, similar flat plate receiver with 12 tubes filled
with paraffin wax PCM. The tests were performed in April and May 2023
in Mosul City/Iraq under standard conditions for around 11 hours during
the day. The outcomes indicated that a rise in air mass flowrate leads to a
rise in the receiver performance. The findings confirm the thermal
efficiency of 64.3% for 0.0174kg/s. For constant air flowrate, the
performance of involute shape by A significant inlet temperature change
has been found in CPC. It is demonstrated that phase change material and
the position of the receiver have considerable influence on the model
performance. The current work provides important information for
evaluating the CPC model performance for Mosul/city.

Characterizing Biochar Derived from Palm Kernel Shell Biomass via Slow Pyrolysis for Adsorption Applications

2023-10-27T19:28:23+00:00

This comprehensive study delves into the thorough characterization of biochar derived from palm kernel shells, with a focus on its potential as an environmentally friendly solution to tackle waste management challenges within Malaysia's agro-industry. Employing the (BET) method, the current investigation unveils an impressive specific surface area of 299.7565 m²/g, complemented by a pore size of 2.17783 nm and a substantial pore volume of 0.1632 cm³/g, attesting to its extraordinary adsorption capacity. Assessment of thermal stability through (FESEM) imaging underscores its resilience, FTIR spectroscopy unravels distinct peaks within the stretching region. XRD analysis introduces a characteristic pattern for palm kernel shell-derived biochar (PKSBC), marked by a prominent, broad peak observed at approximately 2? = 20-30º and 2? = 40-50º, indicative of crystalline and semi-crystalline phases, respectively. Elemental analysis assumes a pivotal role in assessing biochar quality, with a particular emphasis on carbon content, instrumental in identifying potential impurities or contaminants that could compromise its effectiveness in critical applications, including water treatment, air purification, and gas adsorption. This study not only underscores the substantial promise of palm kernel shell-derived biochar in addressing environmental challenges but also provides invaluable insights into its exceptional properties. These findings have the potential to redefine sustainable practices and drive environmental stewardship, offering innovative solutions to the pressing issues of our time.

Analysis of the performance of a 25-level inverter with a minimum number of switches and reduced harmonics for an environment solar energy

2024-02-26T03:59:51+00:00

A multilevel inverter is a type of electrical equipment that converts a DC voltage to a higher AC value by creating a stepped waveform using several voltage levels. Multilevel inverters may create waveforms with three or more voltage levels, although regular inverters cannot. This separation results in lower harmonic distortion, decreased electromagnetic interference, and higher efficiency. An innovative MLI design that makes use of fewer switches and PV sources solves this problem. The Perturbation and Observation (P&O) approach is used to derive the Maximum Power Point Tracking (MPPT) from these PVs. The MC-SPWM technique was used in the design, simulation, and construction of single-phase and three-phase multilevel inverters with inverter levels ranging from three to twenty-five. The technique's cornerstones are phase disposition (PD-PWM) and power quality improvement. The main goal of the paper objectively analyzing the issue of power-system harmonics, providing information on causes, effects, and useful harmonic mitigation strategy.

The Effective Parameters on the Performance of Finned Heat Sinks Used for Light Emitting Diode Application: A Review

2024-03-04T15:46:58+00:00

The increasing demand for high-performance LED applications has led to the development of thermal management systems to reduce heat generation. This review paper examines finned heat sinks for LED applications, examining the impact of fin number, height, thickness, shape, type, direction, and materials used. The study concludes that creating holes in the fins improves heat sink performance, while shape, size, and number also affect heat transfer rate and temperature drop along the fins. This research highlights the importance of efficient thermal management systems in LED applications. This review paper examines the impact of various parameters on the performance of finned heat sinks used for LED applications. It explores the influence of fin number, height, thickness, shape, type, direction, and materials on heat transfer rate and temperature drop along the fins. The study emphasizes the importance of efficient thermal management systems in LED applications. From the beginning of March until the end of August 2022, tests will be conducted to determine the sensitivity of single-glass solar modules to environmental changes.

Estimation of annual evaporation losses for the Makhoul Dam reservoir (under construction)

2024-03-16T12:22:47+00:00

The Evaporation problem is considered one of the most important problems that dam reservoirs suffer from because of the economic losses and costs of treating. Makhoul Dam, which is a dam under construction in Iraq. In this research, a study was conducted to estimate the evaporation losses from the dam’s reservoir. The type A pan was used to measure daily evaporation for a full year, starting from July 2022 until June 2023. The GES program was used to estimate the shape of the reservoir based on Based on the information available for the dam and DEM satellite images of the area with a resolution of 30 meters. Two sites were chosen to measure evaporation, one in the city of Al-Zab, approximately in the center of the reservoir, and the other in the village of Tal Ali, about 30 km from the dam. The results showed that the cumulative total of annual evaporation from the Al-Zab measuring station reached 1547 mm/year, and the cumulative total of annual evaporation from Tal Ali station reached 1766 mm/year. The evaporation rate from the two stations was taken to calculate the annual rate of evaporation from the reservoir, which amounted to 1656 mm/year. Two hypotheses were imposed for the method of evaporation from the reservoir. The first assumed that the reservoir was full throughout the year. In this case, the evaporation losses from the reservoir would be 380,631,600 cubic meters/year, or the equivalent of 15% of the volume of the storage. As for the second hypothesis, it assumed that the reservoir is variable throughout the year, starting with the highest level in the spring and then decreasing. Gradually until the end of autumn, then it increases again in winter. In this hypothesis, the annual losses will be 288,175,555 cubic meters / year, or the equivalent of 11% of the volume of the storage

An analysis of the productivity of an active solar still vs. a passive solar still over the autumn and winter seasons in the city of Kirkuk, Iraq

2024-03-22T19:13:07+00:00

Solar distillation is seen as a sustainable and practical way to solve water shortages in rural regions, which are experiencing an increase in demand for clean water. Over the course of four months in the autumn and winter, experiments were carried out in Kirkuk, Iraq, located at 35.4666° N, 44.3799° E. We directly inserted eight vacuum tubes into the solar still to boost the passive still's production. The area of it is 1 square meter. The productivity recorded in each month was as follows: 1208 ml in November, 2653 ml in December, 2541 ml in January, and 1794 ml in February. In comparison to the passive still, productivity rose by 277.5%, 237.5%, 245.7%, and 233%, respectively. In comparison to the passive still, which achieved an efficiency of 16%, the thermal efficiency increased to 18.6%, 18.8%, 24.8%, and 36%, respectively.

Effect of square and perforated fins on improving the efficiency of the classic pyramidal solar still

2024-03-23T16:11:13+00:00

A practical study was conducted to improve the performance of traditional pyramidal solar stills by using fins with square shapes and a circular diameter on the inside, as well as an internal mirror with a pyramid angle of 55 degrees for the improved and 45 degrees for the traditional. The fins were inserted into the base of the solar still, and a glass mirror was installed on each of the still's four sides to compare its performance to that of a typical device. The experimental findings acquired from the pyramidal and enhanced solar systems revealed the following for the first system: Combining the classic pyramidal with the inner-mirror pyramidal demonstrated the results of traditional distillation at 1250 ml/hour with a 47.6% efficiency. Regarding the modified pyramidal still, distillation data revealed an increase of up to 1500 ml/hour with an efficiency of 56.9%. The second system consisted of a traditional pyramid with a 45-degree angle and an enhanced one with a 55-degree angle, square fins, and an internal mirror, which generated more distillate products than the traditional one under all conditions tested. The daily productivity of the enhanced pyramid was 2200 ml/hour, with a 90% efficiency, whereas the original pyramid's daily output was 1675 ml/hour, with a 59.5% efficiency. Furthermore, the use of fins enhanced daily distillate production.