Borobudur Engineering Review

Komparasi Kinerja AC Kendaraan dengan Menggunakan Refrigeran R-134a, dan R-290

Dimas Bayu Hindratmo — 2023-05-17

The development of vapor compression refrigeration systems currently depends on the issue of environmental problems related to ozone layer depletion (ODP) and global warming potential (GWP). In addition to environmental issues, low energy use is also in the spotlight of researchers. To solve the problem of refrigeration development, natural refrigeration, especially hydrocarbons, is the focus of attention. Hydrocarbons are refrigerants that have excellent properties to be natural refrigerants. This study aims to compare the performance of refrigerant R-134a with R-290. The research used a standard vapor compression refrigeration system with a TEV-type expansion valve. The system performance is seen through compression, refrigeration effect, and COP with variations in compressor rotational speed of 1000 rpm, 1500 rpm, and 2000 rpm. The results showed that the compression work, refrigeration effect, and coefficient of performance (COP) of R-290 had a more excellent value. R-290 produces the highest compression work at a 2000 rpm compressor speed of 33.34 kJ/kg for the refrigeration effect at 1000 rpm of 353.33 kJ/kg and COP at 1500 rpm 12.32.

Effect of Heat Loss on the Working Index of Electric Arc Furnace (EAF)

Iliyasu Okediran — 2023-05-19

Day in day out of human life the use of metal is inevitable, metals are needed for different purposes such as in construction of bridges houses, roads etc. but despite the availability of huge amount of metal, it does not meet the global demand thus this paper investigate the effect of reduction of power of heat loss on the cost of production of electric arc furnace. In order to achieve maximum precision during production, getting product at relatively reduced price has remained a major challenge to the scientists. The experiment was conducted at industrial scale whereby power of heat loss was varied from 7.707- 4.624 MW while energy consumption fell from 0.5463 to 0.5317 MW-Hour per ton and productivity q tremendously increased from 253.0 ton to 254.0 ton per hour . Data used were collected from active furnace in Zerepaves Metallurgical plant, Russia and further analyzed with software package for accuracy

Solar-powered seawater desalination: A contribution to provide energy-efficient clean water

Widjonarko Widjonarko — 2023-05-21

This study focuses on developing a prototype for a seawater desalination system powered by solar
panel. The desalination process is heated by a solar collector and 150 WP solar panel. The primary
objective is to design, develop, and evaluate the prototype's efficacy, affordability, and scalability.
The efficiency was measured by the quantity of freshwater produced per unit of solar energy. Of
the three distillation tests, it was determined that the addition of a heater enhanced the
performance of the system. However, the overall efficiency was limited due to the solar panel and
collector's low heat output. A positive correlation was observed between irradiance and
temperature, but incomplete evaporation indicated the need for additional research to optimize
the process. The system consisted of a solar collector, a heater, and a distillation apparatus. Three
distillation tests revealed that the addition of a heater improved the system's performance,
resulting in a maximum achievable efficiency of 0.99% and the production of 16 ml of fresh water.
This study demonstrates the potential for renewable energy sources to power seawater
desalination and lays the groundwork for future sustainable desalination technologies despite its
limitations.

Improved Engine Performance Using Ozone Generator

Herlang Anantama — 2023-05-27

An increase in the number of vehicles today will result in an increase in fuel oil consumption and emission pollution. Therefore, it is necessary to optimize for fuel oil economy and emission reduction by improving engine performance. Improving engine performance can be done through several factors, including; with compression ratio, volumetric efficiency and fuel quality. The purpose of this study is to prove that with the addition of ozone (O₃) the combustion process will be more reactive than oxygen (O₂) so that it can produce faster and more complete combustion, This study will convert oxygen (O₂) into more reactive ozone (O₃) by using a 15 g/h plasma plasma generator ozone installed on an air filter. Engine performance testing includes engine power and torque using a 50L super dyno type dynamometer chassis. The test results showed, with ozone generator engine torque increased from 0 – 0.5 Nm and increased engine power from 0 – 0.4 KW compared to without using an ozone generator. Nevertheless, the use of ozone (O₃) at a high equivalent ratio can lead to knocking