• Particle and aerosol research
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• v.8 no.4
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• pp.133-141
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• 2012

A new depth filter media was designed and samples of flat sheet as well as cartridge assembly were prepared and tested to evaluate the filtration performance and compare with the commercial product. The arrangement of the depth filter media layers is important to reach the optimal filtration parameters like filter pressure drop, particle collection efficiency and dust holding capacity. Initially, both flat sheet samples of new media and commercial product have been tested using standard test units. Tests with new depth filter media cartridges of various pleat count were conducted in order to find the optimal pleat count which would represent the lowest pressure drop. These tests give an insight on how the pleat count and the assembly configuration affect the performance of the depth filter media cartridge. By comparing the samples with a commercial product we could confirm relatively high filtration performance of the sample cartridge with pleat count 150 made of new depth filter media. The cartridge with the same pleat count exhibits better performance without the outer mesh.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.15 no.5
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• pp.439-445
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• 2003

The purpose of this study is to suggest the improvement strategies for exhaust performance in composite kitchen hoods. The Exhaust only hood, the 2-way compensating hood and the 3-way compensating hood were selected, and the laboratory experiments were performed to compare the local exhaust efficiency and the indoor temperature distributions according to the variations of the hood type and supply/exhaust air velocity. The results of this study can be summarized as follows. The compensating hood has better performance than exhaust only hood in the aspect of local exhaust efficiency and temperature distribution. The 3-way compensating hood shows the best performance when the supply air velocity is about 2.7 m/s, and the 2-way compensating hood at the supply air velocity of 3.5 w/s. In the same exhaust rate condition, if the exhaust area of the hood is increased and therefore the exhaust velocity is lowered, the supply air velocity is also lowered to get the optimum performance. The optimum exhaust velocity range of the commercial kitchen hood which derived from this study is 0.48 ∼ 0.55 m/s.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.8 no.2
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• pp.61-69
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• 2012

Geothermal heat pump(GHP) systems have been shown to be an environmentally-friendly, efficient alternative to traditional cooling and heating systems in both residential and commercial applications. Although some experimental work related to performance evaluation of GHP systems with vertical borehole ground heat exchangers for commercial buildings has been done, relatively little has been reported on the performance simulation of these systems. The aim of this study is to evaluate the cooling and heating performance of the GHP system with 30 borehole ground heat exchangers applied to an commercial building($1,210m^2$) in Seoul. For this purpose, a typical design procedure was involved with a combination of design parameters such as building loads, heat pump capacity, circulating pump, borehole diameter, and ground effective thermal properties, etc. The cooling and heating performance prediction of the system was conducted with different prediction methods and then each result is compared.

• Fire Science and Engineering
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• v.32 no.6
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• pp.55-62
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• 2018

To improve the prediction result with enhanced reliability of domestic Performance-Based Design (PBD), actual scale fire tests were carried out on products made of plastics from sales facility combustibles. The commercial buildings were separated into single and multiple combustibles for the experimentation of fire spread caused by the sales shelves where the various combustible materials are displayed. A according to the maximum heat release rate, exposed area and weight of the combustible material, the results revealed a linear relationship of as 93% and 89%. In addition, analysis of the gas concentrations for various combustibles showed that $CO_2$ has a linear relationship, whereas the CO concentration indicated exponential function. These results can be applied to reliable fire source information in PBD of plastic fire source in commercial buildings. This may be applied as fire source information representative of a plastic fire in commercial buildings through additional experiment using the area of the shelf in actual commercial buildings.

• Membrane Journal
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• v.32 no.6
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• pp.496-513
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• 2022

In this study, we sought to verify the applicability of anion exchange membrane water electrolysis system using FAA-3-50, Neosepta-ASE, Sustainion grade T, and Fujifilm type 10, which are commercial anion exchange membranes. The morphology of the commercial membranes and the elements on the surface were analyzed using SEM/EDX to confirm the distribution of functional groups included in the commercial membranes. In addition, mechanical strength and decomposition temperature were measured using UTM and TGA to check whether the driving conditions of the water electrolyte were satisfied. The ion exchange capacity and ion conductivity were measured to understand the performance of anion exchange membranes, and the alkaline resistance of each commercial membrane was checked and durability test was performed because they were driven in an alkaline environment. Finally, a membrane-electrode assembly was manufactured and a water electrolysis single cell test was performed to confirm cell performance at 60℃, 70℃, and 80℃. The long-term cell test was measured 20 cycles at other temperatures to compare water electrolysis performance.

• Journal of Mechanical Science and Technology
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• v.15 no.6
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• pp.776-787
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• 2001

The turbofan engine performance analysis for a medium scale commercial aircraft was carried out and the LQR control scheme for performance optimization was studied. By using scaled component maps from well-known CF6 engine characteristics, the steady-state performance analysis result was compared with BR715-56 engine performance data. The transient performance analysis was performed with four fuel schedules. The linear simulation was done at the maximum take-off condition. The real time linear simulation was performed by interpolation of the system matrices, which used the least square method as the function of LPC rotational speed. By using linear system matrices of design point, the LQR controller which used control variables for the fuel flow and the LPC bleed air was designed.

• 유체기계공업학회:학술대회논문집
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• 2005.12a
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• pp.331-337
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• 2005

This study aims at evaluation of component performance of a commercial micro gas turbine by detailed measurements of various system parameters. A test facility to measure performance of a micro gas turbine was set up. Performance parameters such as turbine exit temperature, exhaust gas temperature, engine inlet temperature, compressor discharge pressure and fuel flow rate were measured. Variations in measured data and estimated performance parameters were analyzed. In addition to overall engine performance, component characteristic parameters including the turbine inlet temperature, the compressor efficiency, the turbine efficiency, the recuperator effectiveness were estimated. Behaviors of the estimated characteristic parameters with operating condition change were examined.

• Journal of Positioning, Navigation, and Timing
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• v.7 no.4
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• pp.205-215
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• 2018

The recent emergence of new Global Navigation Satellite Systems (GNSS) has resulted in a gradual improvement in the performance of positioning services. This paper verifies the degree of improvement in positioning performance of Assisted-GNSS (A-GNSS) receivers using assistance information compared to standalone-GNSS receivers that do not use assistance information in various urban environments in Korea. For this purpose, field tests are performed in various urban and indoor environments in Korea. The assistance information is provided by u-blox's AssistNow Online and low-cost commercial receivers are used for mobile station receivers. Through experiments, the Time to First Fix (TTFF), acquisition sensitivity, and position accuracy performance improvement are analyzed. The results of the experiments show that using assistance data improved the performance in all experiment locations, and, in particular, a significant performance improvement in terms of TTFF.

• Journal of Auto-vehicle Safety Association
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• v.7 no.2
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• pp.32-38
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• 2015

A sine with dwell test is well known as a test scenario for evaluation of performance of electronic stability control(ESC) on passenger vehicles and heavy commercial vehicles. However, when it comes to ESC for medium commercial vehicles, the test scenario has not been established yet. In this paper, the sine with dwell test was modified considering characteristics of medium commercial vehicles. The three main modifications of the original test scenario are the steering angle level, steering frequency, and loading condition of the vehicle. These modifications are derived from simulation study for different medium commercial vehicles. From simulation study, it was shown that the ESC system for medium commercial vehicle is objectively evaluated by the proposed test scenario. A clear improvement on vehicle stability was seen in the results when ESC system was used.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.2018-2023
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• 2003

An experiment is conducted for measuring the performance of an air tool, which is operated at 100,000 RPM at the unloaded state with the low torque. An experimental apparatus is developed as the power absorption type dynamometer. Inlet static pressure, flow rate, RPM and force are measured simultaneously. Torque, output power and specific output power are obtained. Those experimental results are compared with the experimental results obtained on a commercial dynamometer. However, no commercial dynamometers are available for measuring the torque above 30,000RPM. In order to use the commercial dynamometer, a reduction gear is applied to the shaft of dynamometer. Torque and power obtained on the commercial dynamometer show 50% lower than those obtained on a power absorption type dynamometer, because the inertia force is added to the air tool rotor for the braking system. Moreover, the starting RPM on the commercial dynamometer is less than 40,000RPM. From the compared results, they show that the power absorption type dynamometer should be applied for measuring the performance of an air tool operating at low torque and high RPM.