Propane R-290 as hydrocarbon refrigerant has more benefits from the aspect of thermophysical properties, but the only weakness from this refrigerant is flammable. The distribution prediction of R-290 leakage to an air-conditioned room. The study using numerical simulation of CFD ANSYS FLUENT V.13. The distribution of R-290 with a leakage rate of 0,001kg/s and an airflow of 0,1m/s will run out after 600s, with 0,002kg/s will run out after 300s and with 0,005kg/s and 0,5m/s will run out after 120s. The mass flow rate can influence the refrigerant distribution of leakage effect flowrate. Airflow can increase the dispersion of refrigerant gas and decrease the level of the refrigerant amount at any certain point in the room after the refrigerant charge is empty. This momentum effect was due to the impact of supply air initial velocity. The buoyancy effect was due to R-290 density is greater than the air makes the refrigerant flows downward, accumulated, and stagnant. Make sure that the contactor relays and other electrical tools have the position, x=0 m ≤ x ≤ 1 m on y=0 m ≤ x ≤ 26 m and then y=1 m, x=0 m ≤ x ≤ 4 m.
<p><em>Mini freezer</em> yang terdapat di pasaran umumnya memiliki temperatur kabin hanya sampai -20<sup>o</sup>C. Penelitian ini bertujuan menampilkan metode perhitungan panjang pipa evaporator sehingga dapat mencapai temperatur kabin hingga -40<sup>o</sup>C dengan menggunakan refrigeran R404A. Refrigeran R404A selain relatif lebih ramah lingkungan dibandingkan dengan R22, juga memiliki temperatur N<em>ormal Boiling Point</em> (NBP) lebih rendah dari R22. Kapasitas kompresor yang digunakan adalah 250 W yang khusus dirancang untuk refrigeran R404A. Berdasarkan pengujian didapatkan bahwa temperatur kabin dapat mencapai -40<sup>o</sup>C setelah 120 menit mesin pendingin dioperasikan. Selama beroperasi, tekanan kerja, yaitu tekanan <em>suction</em> dan <em>discharge</em> kompresor, <em>mini freezer</em> hampir sama dengan hasil perhitungan. Ini artinya metode yang digunakan pada penelitian ini dengan desain dan pengembangan (R&D). Namun untuk mendapatkan <em>freezing time</em> yang lebih singkat masih diperlukan optimasi panjang pipa evaporator masih diperlukan, supaya temperatur kabin -40<sup>o</sup>C dapat dicapai lebih singkat. Perbedaan hasil perancangan, yaitu: tekanan <em>suction</em>, tekanan <em>discharge</em> dan temperatur <em>discharge</em>, dengan hasil pengujian tidak lebih dari 10%.</p>
The Kuningan West Java Vocational Training Center (BLK) is ready to create manpower to fill the world of work or independent businesses, to reduce unemployment rates. The condition of work training centers that have new buildings but are not yet supported with adequate equipment and human resources and according to needs still require support from stakeholders to improve their quality. Bandung State Polytechnic, especially the Department of Refrigeration and Air Conditioning Engineering, is experienced enough and feels the need to contribute to the development program of the BLK Kuningan, especially in the field of Facilities Development and Instructor Training in the Field of Maintenance and Repair of Display Cases at BLK Kuningan Regency. This program aims to increase the role of the BLK in increasing the competence of Human Resources according to the needs of the labor market. The method implemented is through the Facility Development and Instructor Training Program in the Field of Maintenance and Repair of Display Cases. This activity has been carried out in theory and practice with a ratio of 20% theory and 80% practice in the field which was held at BLK Kuningan. The outputs that have been achieved include training participants having sufficient competence as instructors in the field of refrigeration and air conditioning engineering, especially regarding maintenance and repair of display case machines, availability of job sheets and theory and practice modules on basic refrigeration, especially for display case machines, a set training unit display case and its service equipment.
Thermoelectrics can convert electrical energy to thermal energy. The generated thermal energy can be used in various cooling systems (TEC) applications. Improvement of TEC performance influenced by hot-side heat dissipation method, working fluid, and multi-thermoelectric. This study aims to investigate the relation between multi-thermoelectric configuration and the cooling behaviors. The experiment was conducted on the devices equipped with two modules of TEC arranged in series and parallel with variations of input voltage, working fluid mass flow, and temperature. The result reveals variations in cooling behaviors between the two configurations. Parallel configuration TEC gives the highest cooling capacity with a value of 66.62 W, 100% bigger than the series configuration. Meanwhile, the series configuration provides a delta temperature of 11.03 K, 2% higher than the parallel one. The parallel modules cooling performance is the biggest among the two arrangement, with a value of 2.57, which is 147% higher than series one.
The utilization of condensate water as a compressor-discharge cooler results in subcooling on the condenser outlet. On the other hand, a split-type air conditioner (A/C) with R32 as working fluid can provide higher compressor-discharge temperatures than other refrigerants used in the same A/C. Therefore, A/C working with R32, equipped with a heat exchanger by utilizing waste-condensate water as the compressor-discharge cooler, has promising potential to produce the largest subcooling effect in air-conditioning systems. The aim of this study is to investigate the effect of condensate water as the compressor-discharge cooler on the performance of an A/C using R32 as the working fluid with different sizes of heat exchanger. The experimental study was carried out on the A/C with a compressor capacity of 1.1 kW, using three different heat-exchanger lengths, i.e., 18, 20 and 22 cm. The results indicated that longer heat exchangers produced higher degrees of subcooling; the heat exchangers with lengths of 18, 20 and 22 cm produced average degrees of subcooling of 0.9, 1.5 and 4.5 K, respectively. Therefore, increments in the degree of subcooling generate improvements in cooling capacity, lowering the compressor-input power, and enhance the COP of the A/C. The average COP improvement of the A/C with heat-exchanger lengths of 18, 20 and 22 cm were 9.1, 14.4 and 27.3%, respectively.
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