• Transactions of the Korean hydrogen and new energy society
• /
• v.28 no.2
• /
• pp.225-230
• /
• 2017

Coal oil is widely used as a home heating fuel for portable and installed coal oil heaters. Today, Coal oil is widely used as fuel for jet engines and some rocket engines in several grades. This paper describes the performance characteristics according to the compression ratio of spark ignition engine fuelled with coal oil. As a result, the following knowledge is obtained: As the compression ratio is decreased, there is an increase in torque, indicated mean effective pressure (IMEP), heat release rate, and brake thermal efficiency. Higher compression ratio of the engine decreases the ignition delay period, combustion period, and cooling loss.

• Journal of Environmental Policy
• /
• v.14 no.2
• /
• pp.133-148
• /
• 2015

The number of used oil refining companies has been increased and it causes shortage of the volume of used oil per recycling company. In addition, the number of used oil collecting companies has been increased and it caused excessive competition among companies with excessive costs. Companies use not only proper used oil but also low quality used oil because of shortage of supply. It is the reason of environmental pollution. Also excessive competition brings high cost of refined oil and it becomes a burden on the consumer. Therefore, the recycling improvement plans of used oil is needed because of these causes. First of all, importing used oil from the developed countries of OECD is the one of solution to secure a used oil supply. However, imported used oil should meet the international quality standards and it is examined twice by international authority institute such as K-petro in both exporting and importing countries. Second, the cost would be reduced with the relaxation on regulations of used oil refinement. However, regulation to sediment and water should be separated. Sediment should be kept within 2% and water should be kept within 5%. It is the way to relax the regulations of used oil refinement with preventing environmental pollutions. Finally, the standard of used oil for heater should be regulated strictly. To prevent pollutions, used oil for heater is limited to high quality waste lubricating oil. Also the air pollution prevention device has to be installed on heater.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.21 no.6
• /
• pp.998-1002
• /
• 2012

This paper investigates the behavior of bubbles trapped in the in-mold coating (IMC) process. Silicon oil with different viscosity, 100, 150, 200, 300 and 400cps, was selected instead of the coating materials. To observe the flow front inside, a special mold was designed, where front plate was made of transparent material (acrylate). The overall size of front plate was $150mm{\times}120mm$. Mold gate location can be changed from up to down. Four heaters were used to investigate the effectiveness of temperature. The results show that silicon viscosity, mold gate location and mold temperature play an important role on the appearance of bubbles trapped in IMC process.

• Journal of Biosystems Engineering
• /
• v.34 no.5
• /
• pp.363-370
• /
• 2009

Hot air heater with light oil combustion is used as the most common heater for greenhouse heating in the winter season. Hot air heaters of 256,246 units have been supplied as main greenhouse heating equipment until 2008 and greenhouse heating cost has reached to 620 billions won in Korea. In order to improve the thermal efficiency of the hot air heater and to reduce the expenses for greenhouse heating, prototype hot air heater was manufactured and tested in this experiment. The heat exchanger of tested prototype hot air heater was circular and hexagonal pipe type and inline and stagger arrangement type. Capacity of the heating was 43,062 kJ/h and total heat transfer area of the heat exchanger was $10.728\;m^2$. According to the performance test, it could supply heat of 38,240 to 35,100 kJ/h depending on the fan motor speed of 1,740~1,220 rpm, respectively. Thermal efficiency of hot air heater was 87.0% to 80.8% in the same conditions. As a result, thermal efficiency of hot air heater with hexagonal pipe-stagger arrangement heat exchanger developed in this study was higher 10.2% than that of conventional hot air heater and heating energy saving rate of 14.3% increased.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.37 no.10
• /
• pp.919-926
• /
• 2013

Experiments were conducted to determine the operating characteristics of a small-scale ORC (organic Rankine cycle) system for various low-temperature heat sources. A small-scale ORC power generation system adopting R-245fa as a working fluid was designed and manufactured. Hot water was used as the heat source, and the temperature was controlled using 110-kW electric resistance heaters that provided temperatures of up to $150^{\circ}C$. An open-drive oil-free scroll expander directly connected to a synchronous generator was installed in the ORC unit. Experiments were conducted by varying the rotational speed of the expander under the same heat source temperature conditions. The factors that influence the performance of the small-scale ORC system were analyzed and discussed.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.39 no.3
• /
• pp.237-243
• /
• 2015

In this study, the effects of the mixing ratio of emulsified fuel on the droplet evaporation and spray behavior characteristics were analyzed. A surfactant comprising span 80 and tween 80 mixed at a 9:1 ratio was used for the emulsified fuel. The fuel and surfactant were mixed at a ratio of 3:1 for the emulsified fuel. In addition, considering the mixing ratio of the surfactant, the mixing ratio of $H_2O_2$ in the emulsified fuel was set as EF (emulsified fuel)0, EF2, EF12, EF22, EF32, and EF42. To observe the evaporation characteristics, droplets of the emulsified fuel were dropped on a heating plate and observed using scattered light and a Schlieren system. In addition, to analyze the effect of the $H_2O_2$ mixing ratio, the behavior characteristics of the evaporative free spray were investigated in the mixing ratio range of EF0 to EF22 using a constant volume chamber with heaters. Consequentially, it was found that in the case of EF22, the free spray development of the emulsified fuel was faster than that of EF0 (diesel only) because of the promotion of the evaporation due to the phase change in the peroxide contained in the emulsion fuel.