Cooling systems using colling towers are often an important element in a production process and always involve water or energy consumption. Therefore, increasing the efficiency of the colling tower will reduce water and / or energy consumption. In order to increase the efficiency of colling tower energy consumption, the most studied part is the fills, where heat transfer occurs. However, there are no studies on the use of vortex generators in colling tower fills. Hence the aim of this study was to evaluate the performance improvement in a forced draught cooling tower using a vortex generator. It was conducted on a laboratory scale using single fill as a trial medium. The fill was made of 3-mm acrylic with dimensions of 30 × 30 × 1950 mm. A three-unit vortex generator was placed inside the fill. The rectangular vortex generator was made of 0.5-mm thick aluminium and had a size of 50 × 10 mm. Data were retrieved for the fills with and without a vortex generator. Water and air discharge of 1 L/minute and an inlet water temperature of 60°C were maintained. The results indicated that the effectiveness of the fill with a vortex generator was increased by 90.72% compared to the fill without a vortex generator.

The geometry of a solar still determines the convection constants C and n, which in turn affect the convection heat transfer coefficient’s value and mass. A method for determining the value of convection heat transfer constants C and n has already been developed by the researchers. Therefore, this study aimed to use several methods and theories to find the value of convection heat transfer constants C and n. The results are then compared with the results of the study. The solar still used in this study has one slope. To reduce variables that cannot be controlled, the data collection was conducted indoors using a halogen lamp that can be regulated as a heat source for 24 hours nonstop. The sea surface height in the solar still was maintained at a height of 20 mm, using a height regulator. Temperature was measured using a data logger set to enter data every hour. The desalinised clean water was stored in bottles placed on scales that were recorded every one hour. Room temperature was maintained in the range of 35 to 36 oC. The data in this study were used to calculate the heat transfer constants C and n to obtain the value of the convection heat transfer coefficient and mass calculation. This study compares the calculation models of Tiwari, Dunkle and Power. The following calculation model results: Tiwari model, C = 0.082 and n = 0.612; Dunkle model, C = 0.075 and n = 1/3; Power model, C = 0.815 and n = 0.611. The C and n values obtained with these four approaches reveal that the results from the Power model calculation are the closest to the actual mass, showing a percentage deviation of 1.63%.

Consumption of electrical energy continues to increase along with population growth. As a result, various sources of electrical energy are utilised to meet these needs, especially in areas that have not been reached by the national electricity network. In countries with hilly geography and irrigation canals, pico hydro energy is often considered an alternative. One of the tools used to convert water flow energy into electrical energy is the Dethridge wheel. The Dethridge wheel is a simple waterwheel that is easy to manufacture and suitable for irrigation canals with very low water head heights. This study aims to increase the performance of the Dethridge wheel by changing the shape of the wheel blades and examine the effect of the variation of water flow rate in the channel. Experimental and numerical methods were used to investigate the potential of the developed wheel. The Dethridge wheel and its development were tested using an artificial irrigation canal with flow rates of 20, 30, 60, 90 and 120 m3/h. Furthermore, a three-dimensional numerical model of the Dethridge wheel was simulated using Ansys Fluent 18.2 software. The highest efficiency of the experimental Dethridge wheel, 55.6%, was achieved when the flow rate was 30 m3/h. The developed Dethridge wheel efficiency increased to 71.72%. These results are also in agreement with the simulated model.

Telah dilakukan perhitungan  ketebalan bahan komposit karet alam timbal oksida sebagai pelindung radiasi sinar-x 100 Kev. Perhitungan bertujuan untuk memperoleh ketebalan bahan proteksi radiasi yang aman bagi lingkungan atau pekerja dilingkungan medan radiasi. Perhitungan kemampuan daya serap bahan komposit karet alam timbal oksida dilakukan pada energy 100 Kev. Dasar perhitungan daya serap komposit karet alam timbal oksida sebasar 50 pphr (part per hundred rubber) sampai dengan 1000 pphr. Tebal komposit karet alam timbal oksida yang akan diukur setebal 2,5 mm. hasil perhitungan menunjukan bahwa ketebalan bahan komposit karet alam timbal oksida yang aman bagi pengguna atau para pekerja dimedan radiasi, apabila karet alam dicampur dengan timbal oksida sebanyak 550 pphr, nilai daya serap pada 550 pphr telah memenuhi standart yang diizinkan.

Cooling tower is needed right now in the context of efficiency and energy conventions for cooling circulation. The type of cooling tower used depends on the level of performance. One type of cooling tower used in this study is forced draft. Cooling tower in this study was added by a rectangular winglet generator vortex with the aim to increase the effectiveness of performance by reducing the value of the approach. This is because forced tower cooling draft on its utilization results in performance that is not commensurate with the costs incurred. The results obtained in this study are a comparison of the value of the forced draft cooling tower approach with the addition of a vortex generator and without the addition of a vortex generator. This research was conducted in the workshop and laboratory of Mechanical Engineering, Faculty of Engineering UHAMKA with stages: designing tools, making prototypes, assembling, and testing. Based on the results of the study it was found that the approach value obtained on cooling towers that use 0.86% lower than without a vortex generator.