21 research outputs found
Rancang Bangun Sistem Pengukuran Alat Thermobath sebagai Alat Kalibrasi Temperatur dengan Sistem Arduino Uno
No full textA thermobath cooler is a device that contains water or other liquid as a coolant that can maintain a constant temperature. The control system designed in this study uses a K-type thermocouple temperature sensor and pressure transmitter microcontroller-based, namely Arduino Uno to be able to produce temperature and pressure measurement data on the thermobath through the software PLX-DAQ. This system thermobath requires a K-type thermocouple component and apressure transmitter JYB-KO-H. Before being placed in the system thermobath, the K-type thermocouple and pressure transmitter are required to calibrate. Based on the results of the temperature and pressure calibration equation, the coefficient of determination (R2) on the K-type thermocouple ranges from 0.9986 to 0.9998 and the coefficient of determination (R2) at the pressure transmitter is 0.9994. With the calibration results, the design of measuring thetool thermobath as a temperature calibration tool with the Arduino system can be applied to thecooling system thermobath.</jats:p
Performance Evaluation of Ammonia Refrigeration Systems in a Texturizing Plant
No full textThis study evaluates the performance of an ammonia refrigeration system used as a cooling medium in a texturizing plant. The analysis was conducted over a 10-day period, focusing on key performance indicators such as compressor work, condenser exhaust heat, refrigeration effect, mass flow rate, Coefficient of Performance (COP), and overall system efficiency. The data revealed that the system performed optimally on Day 5, achieving a peak efficiency of 91%, with compressor work at 304.1 kJ/kg and condenser exhaust heat at 1414.6 kJ/kg. In contrast, the lowest efficiency was recorded on Day 3, at 77%. The refrigeration effect reached its highest value of 491.3 kJ/kg on Day 3, highlighting efficient heat absorption despite lower overall system efficiency. On Day 4, the mass flow rate was 0.001049929 kg/s, with an actual COP of 1.39, while the ideal COP peaked on Day 10 at 1.69, reflecting the system’s theoretical maximum efficiency under optimal conditions. The study emphasizes the critical role of the condenser in the system’s performance. Optimizing the condenser’s operation by controlling temperature, pressure, and flow rates, alongside regular maintenance, significantly impacts system efficiency. The findings suggest that careful monitoring of operational parameters, including compressor work and refrigerant flow, can enhance the overall efficiency and reliability of ammonia refrigeration systems in industrial settings. This research provides practical insights into improving the cooling performance, reducing energy consumption, and ensuring consistent production quality in texturizing plants
Design and Analysis of a Vertical Axis Ocean Current Turbine Tunnel Using SolidWorks Computational Fluid Dynamics
No full textThe development of renewable energy in the marine power generation sector presents a promising approach to producing electrical energy in a sustainable and environmentally friendly manner. Indonesia, with its vast oceanic territory, holds significant potential for harnessing marine energy. However, the relatively slow speed of ocean currents in the region, typically ranging from 0.1 m/s to 1.5 m/s, poses a challenge to the efficiency of marine power generation. To overcome this limitation, this research focuses on the design and analysis of a vertical-axis ocean current turbine tunnel aimed at increasing the speed of ocean currents, thereby enhancing the overall efficiency of energy production. The study combines a thorough literature review with experimental research methods, utilizing SolidWorks Computational Fluid Dynamics (CFD) software to simulate the tunnel's impact on ocean current velocity. The simulations reveal that the tunnel construction significantly boosts current speeds, increasing them from 1.0 m/s to 1.7 m/s, and from 1.5 m/s to 2.6 m/s. This increase in velocity directly translates to higher kinetic energy available for conversion into electrical power by the turbine. Moreover, the study shows that the tunnel construction contributes to a more uniform flow of ocean currents, as evidenced by the Reynolds numbers obtained—100.250 at a current speed of 1.0 m/s and 150.375 at 1.5 m/s. These values, being below 2000, indicate laminar flow conditions within the tunnel, which are beneficial for optimizing turbine performance by reducing turbulence and ensuring a stable energy output. The findings underscore the effectiveness of the tunnel design in improving the efficiency of vertical-axis ocean current turbines, making it a viable solution for enhancing renewable energy production in regions with low ocean current speeds
Heat transfer coefficient of near boiling single phase flow with propane in horizontal circular micro channel
No full textPerformance Evaluation of a Condenser at a Combined Cycle Power Plant Using the LMTD Method
No full textThis study evaluates the performance of the condenser at the Cilegon Combined Cycle Power Plant (CCPP) using the Logarithmic Mean Temperature Difference (LMTD) method to measure the heat transfer rate. Routine maintenance carried out on the condenser in the form of cleaning the condenser water box and condenser tube from garbage and crust on the condenser tube wall. Currently, condenser maintenance follows a routine schedule that is tied to steam turbine maintenance, without taking actual condenser performance into account. This can lead to inefficiencies and unnecessary downtime. The goal of this research is to assess the heat transfer rate of the condenser before and after maintenance to judge its effectiveness. Data on temperature changes were gathered in June 2023, before maintenance, and again in July 2023, after an overhaul. The analysis shows that the heat transfer rate increased from 51,362,294.48 kcal/h to 127,246,219.7 kcal/h, while the LMTD value rose from 0.76°C to 1.86°C. Based on these results, the study suggests a new approach to maintenance that focuses on performance. Specifically, maintenance should be done when the heat transfer rate drops below 110,000,000 kcal/h. This approach will help ensure the condenser works at its best, improve the plant's overall efficiency, and prevent the need for unnecessary maintenance. By aligning maintenance with performance data, the plant can boost output while lowering costs and downtime
RANCANG BANGUN THERMOBATH UNTUK KALIBRASI SUHU DENGAN TERMOKOPEL TIPE-K MENGGUNAKAN REFRIGERAN HFC-134
No full textThermobath adalah alat laboratorium yang berisikan air ataupun cairan lainnya sebagai beban pendingin yang dapat mempertahankan temperatur tersebut agar tetap konstan dalam waktu tertentu. Dalam perancangan thermobath penulis menggunakan kompresor 1/6 PK, pipa tembaga ¼ inch, katup ekspansi berupa ball valve, refrigeran HFC-134, dan fluida berupa air dengan volume 2 Liter. Perancangan didasarkan akibat mesin pemanas atau pendingin pada perindustrian dan perusahaan masih banyak memakai refrigeran yang memiliki potensi kerusakan lapisan ozon, penggunaan gas refrigeran semakin banyak untuk menjalankan suatu kerja pada sistem kompresi uap. Alat kalibrasi thermobath menghasilkan panas yang sesuai dengan yang terbaca pada alat ukur dengan bantuan termokopel yang sudah terkalibrasi. Penggunaan termokopel tipe-K ini dirancang menggunakan modul Arduino Max 6675 sebagai safety control agar thermobath tidak melebihi temperatur yang sudah diatur. Uji coba thermobath dilakukan hingga temperatur fluida mencapai 12°C dan 5°C, dengan nilai rata-rata pressure gauge sebelum dan sudah katup ekspansi berturut-turut 2,8 MPa dan 0,4 MPa serta 3,1 MPa dan 0,35 MPa. Laju pendinginan pada temperatur 12°C membutuhkan waktu 35 menit sementara laju pendinginan temperatur 5°C didapatkan dalam waktu 60 menit, laju pendinginan temperatur 5°C lebih lama sekitar 5 menit dan memiliki selisih paling besar 14,32% untuk mencapai suhu 12°C. Nilai COPaktual tertinggi ada pada pengujian temperatur 12°C dengan nilai 1,9 dan penyerapan kalor evaporator sebesar 78,403 kJ, dibandingkan uji temperatur 5°C dengan nilai 1,5 dan kalor serap evaporator 68,570 kJ
Heat transfer coefficient on two-phase flow in small tube with propane iso-butane mixture refrigerant
No full textEffect of Liquid Reynolds Number on Pressure Drop of Evaporative R-290 in 500µm Circular Tube
No full textDue to certain advantages, natural refrigerants have
recently become more popular. Environmental issues motivate this study, focused
on the characteristics of propane (R-290) as a replacement for conventional
refrigerants. The aim of the present research is to characterize the pressure
drop of evaporative R-290 in a microchannel
of 500µm diameter and 0.5 m
length. The variables of the experimental conditions are mass flux between 155 and
1071 kg/m2s and vapor quality between
0 and unity. The results show a laminar flow for liquid R-290 and a turbulence flow
for vapor. Some existing correlations of two-phase flow viscosity were used to predict the pressure drop. For
homogeneous model, Dukler et al.’s (1964) prediction viscosity correlation best
predicted the present experimental pressure drop
