• KIEAE Journal
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• 제15권2호
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• pp.123-131
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• 2015

Purpose : Improvement of indoor thermal comfort and reduction of the energy consumption in building can be obtained by applying a double skin facade system. In order to achieve effectively this purpose, design team would have to perform easy and appropriate performance analysis for making better design decision during the design process. Method : This paper focus on the natural ventilation performance of a multi-story type double skin facade with main causes which are pressure difference according to the wind and temperature difference between indoor and outdoor (Buoyancy Effect). Using this main causes, the natural ventilation ratio of wind effect-to-buoyancy effect in cavity of multi-story type double skin facade were analyzed through the performance analysis results of CFD (Computational Fluid Dynamics) simulation. Result : When the wind velocity was 2m/s, the ventilation rate in the cavity was highest. If wind velocity was slower than 2m/s wind velocity, buoyancy effect has more influence on the ventilation rate in the cavity, and if wind velocity was faster than 2m/s wind velocity, wind effect has more influence on the ventilation rate in the cavity.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 춘계학술대회 논문집
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• pp.1297-1301
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• 2007

The indoor air quality guideline of public transportation means was prepared recently. therefore we consider a countermeasure for the indoor air quality improvement of public transportation means. In this work, air-cleaner with roll filter system which developed alternative of indoor air quality guideline. The develpoed roll filter system is two function. the first function harmoniously circulated to heating and cooling air through HVAC system and secondary function removed PM(particluatie matters) which re-scatting to passenger's movement and suppled from outdoor air. Filter media of roll filter system select optimum electret mesh filter out of many filter media. Selected filter media was performanced tests of pressure drop, collection efficiency and dust holding capacity. Finally developed roll filter system was performanced bench test.

• 설비공학논문집
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• 제15권7호
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• pp.611-617
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• 2003

The air-side particulate fouling in the heat exchangers of HVAC applications degrades the performance of cooling capacity, pressure drop across a heat exchanger, and indoor air quality. Indoor and outdoor air contaminants foul heat exchangers. The purpose of this study is to investigate the characteristics of the air-side particulate fouling materials in finned-tube heat exchangers of air conditioners. Air conditioners being used in the field such as inns, restaurants, and offices are collected in chronological order in use. Typical fouling materials on the heat exchangers include fibers and dusts ranged from 6.6 to 20.9 ${\mu}{\textrm}{m}$ in mass median diameter.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 춘계학술대회
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• pp.1857-1862
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• 2003

The air-side particulate fouling in the heat exchangers of HVAC applications degrades the performance of cooling capacity, pressure drop across a heat exchanger, and indoor air quality. Indoor and outdoor air contaminants foul heat exchangers. The purpose of this study is to investigate the fouling characteristics trough accelerated tests. The fouling characteristics are analyzed as functions of a dust concentration (1.28 and 3.84 $g/m^3$), a face velocity (0.5, 1.0, and 1.5 m/s), and a surface condition. The cooling capacity in the slitted finned-tube heat exchangers at the face velocity of 1 m/s decreases about 2% and the pressure drop increases up to 57%. The rate of build-up of fouling is observed to be 3 times slower for this three-fold reduction of dust concentration whilst still approaching the same asymptotic level.

• 설비공학논문집
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• 제17권3호
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• pp.262-267
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• 2005

The air-side particulate fouling in the heat exchangers of HVAC applications degrades the performance of cooling capacity, pressure drop across a heat exchanger, and indoor air quality. Indoor and outdoor air contaminants foul heat exchangers. The purpose of this study is to investigate and to model the air-side particulate fouling characteristics of the heat exchangers using accelerated particle loading system. The main variables of the modeling equation are face velocity and dust concentration. The modeling equation shows good agreements with the experimental results at the face velocity of 0.5, 1.0, 1.5 m/s and the dust concentration of 1.28 and $3.84\;g/m^3$. It will be very useful to predict fouling characteristics such as variations of pressure drop and heat transfer capacity in finned-tube heat exchangers of air conditioners.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2005년도 동계학술발표대회 논문집
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• pp.306-310
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• 2005

The air-side particulate fouling in the heat exchangers of HVAC applications degrades the performance of cooling capacity, pressure drop across a heat exchanger, and indoor air quality. Indoor and outdoor air contaminants foul heat exchangers. An empirical modeling equation is derived from the experimental results using accelerated tests and it shows good predictions of the fouling characteristics of the slitted finned tube heat exchangers. However the modeling equation predicts only the fouling characteristics of new heat exchangers and it can not predicts fouling characteristics obtained from actual field data. The purpose of this study is to modify the previous modeling equation using the actual field data Therefore an modified modeling equation is proposed and it shows good predictions of the actual fouling characteristics of finned-tube heat exchangers.

• 한국기계가공학회지
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• 제18권6호
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• pp.69-75
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• 2019

In recent years, the driving performance and exhaust sound quality in automobiles have been recognized as important factors, as they maximize the driving fun to fulfil the demands of customers. Therefore, many automobile manufacturers are studying various exhaust pipe shapes to improve sound quality and optimize exhaust pressure. The objective of the exhaust pipe design is to maximize the engine efficiency using optimal exhaust pressure settings. In this study, an exhaust system was fabricated with different junction shapes, and the results were analyzed through various experiments. The exhaust gas pressure acting inside the exhaust pipe was measured using a pressure transducer. Meanwhile, the vibration generated in the vehicle was measured in three axial directions and analyzed. The ground noise generated in the indoor and outdoor of the vehicle was measured, and the noise generated at the maximum output was measured and analyzed.

• Journal of Electrical Engineering and Technology
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• 제10권6호
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• pp.2434-2441
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• 2015

This paper proposes an exercise recommendation system for treating obesity that provides systematic recommendations for exercise and diet. Five body indices are considered as indicators for recommend exercise and diet. The system also informs users of prohibited foods using health data including blood pressure, blood sugar, and total cholesterol. To maximize the utility of the system, it displays recommendations for both indoor and outdoor activities. The system is equipped with multimode sensors, including a three-axis accelerometer, a laser, a pressure sensor, and a wrist-mounted sensor. To demonstrate the effectiveness of the system, field tests are carried out with three participants over 20 days, which show that the proposed system is effective in treating obesity.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2003년도 유체기계 연구개발 발표회 논문집
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• pp.245-250
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• 2003

In order to control indoor air quality and save energy, it is needed to install a suitable ventilation system equipped with heat exchanger for heat recovery. The purpose of this research is to find the performance of paper heat exchanger for exhaust heat recovery, which exchanges latent heat as well as sensible heat. Experimental apparatus comprises heat exchanger model, constant temperature and humidity chamber, fan and measurement systems for temperature, pressure and flow rate. Thermal performance and pressure loss of the paper heat exchanger are measured and compared at various air velocities and outdoor conditions. Experimental results show that paper heat exchanger can recover $50{\sim}70%$ of the enthalpy difference between supply and exhaust air.

• 태양에너지
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• 제20권1호
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• pp.63-72
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• 2000

In this study, theoretical simulation method for the steady state characteristics of a refrigeration cycle which consists of one condenser and multi-evaporator (Multi-air conditioner) is presented. The simulation was performed for a typical multi-air conditioning system consisted one outdoor unit with air-cooled condenser, compressor, linear electric expansion valve and bypass circuit and connected three-evaporators (three indoor units). The simulation results are good agreement with those of experiments within 5 $\sim$ 10% at the given system operation conditions which are condensing pressure, evaporating pressure, sub-cooled degree of condenser, superheated degree, discharge temperature of compressor and pulse of linear electric expansion valve.