• KIEAE Journal
• /
• v.9 no.4
• /
• pp.17-22
• /
• 2009

It is common to design the duct branches where to supply the required air flow for individual room in residential apartment house. However it is difficult to adjust the air volume adequately in small air duct branches in residential ventilation system. The purpose of this study is to figure out the performance of Multidrop chamber coupling system for the residential ventilation system. The experiments were designed to simulate apartment of $84m^2$ and established multidrop chamber duct and general duct on the ceiling of the apartment. Distribution performance of air supply rate were evaluated in this experiments. As a result, distribution performance of air supply rate in the general duct is different from designed air supply rate by about 35% ~ 50% and about 10% in the multidrop chamber system. In additional the sound insulation performance of the multidrop chamber system decreased about 20% compared with general duct system. Therefore, the multidrop chamber system is considered to satisfy proper air supply rate of each room and to improve the sound insulation performance in apartment Houses.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.10 no.1
• /
• pp.66-78
• /
• 1998

Adequate ventilation with the proper amount of air to the right place is important factor to achieve a good Indoor air climate. Thus it is of prime importance that the ventilation system is working properly. This requires reliable pressure loss calculation to balance the air flow through duct systems. So a computer program for balancing CAV duct system is developed In this study. The results of CAV duct system is compared with the "Balans" code developed by Larsen from Norway. To obtain the pressure drop characteristics of damper at duct terminal, some experiments are performed using DPM(Dual Pressure Measurement) system. To adjust the resistance of damper, present study suggests that some special diffusers should be designed and damper producers should give the data of air flow vs. pressure drop to the customs when they manufacture the damper. One of the results concludes that the working time can be reduced from several minutes to several seconds per damper in the present experimental site, if the DPM system and the air volume adjusting process are used.

• Journal of the Society of Naval Architects of Korea
• /
• v.41 no.6
• /
• pp.24-32
• /
• 2004

The effects of guide vanes and tip clearances on the characteristics nf axial flow fans are investigated both computationally and experimentally. Performance test of fans carried out in full scale shows considerable effects of tip clearance between rotor tip and duct on the characteristics of fans. The tested results are compared with the computation based on the finite volume method to solve the Navier-Stoke equations with $textsc{k}$-$\varepsilon$ turbulence model. The comparison shows good agreements between experimental and computational results. In addition, the effects of shape of guide vanes are numerically studied. The results show that increased volume of separated region around the guide vane reduces the recovery of tangential component of kinetic energy in the wake, resulting in loss of efficiency

• 한국생물공학회:학술대회논문집
• /
• 2000.11a
• /
• pp.473-474
• /
• 2000

Ozone has a potency for disinfection, deodorization, decolorization and decomposition of organic materials by strong oxidation. therefore we used the ozonizer to disinfection and deoderization of a piggery. CFU of the ozonated piggery was lower than the others. And the of ozonizer was redesigned from open-type to close-type to obtain high ozone concentration. We was also investigated the effect of air velocity to ozone concentration.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.28 no.10
• /
• pp.414-419
• /
• 2016

Air flow measurement is a fundamental and important task for testing, adjusting, and balancing of HVAC system. However, it is difficult to carry out in the field due to the large size and weight of the flow meter. In this study, for the purpose of developing a small and portable flow meter, we proposed a different method of static pressure measurement and verified it experimentally. In the proposed method, static pressure difference was measured by inserting a tube inside the chamber before and after the nozzles. The results were compared with measurements according to the ANSI/ASHRAE standard. The results were in good agreement, indicating that the inserted tube method could be used for static pressure measurement of a portable flow meter. The proposed method eliminates the pressure tubes that are attached outside, which results in smaller size and easy handling.

• Journal of Advanced Navigation Technology
• /
• v.13 no.6
• /
• pp.813-819
• /
• 2009

Designing actuator controllers of aircraft, which control aileron, flap, elevator and so on, is quiet difficult, because they have time variant nonlinear mechanical structures and also have many kinds of disturbances which are not been able to model easily. This paper reports about the performance of Fuzzy Auto gain tuning Control algorithm applied unmaned aerial vehicle. Fuzzy Auto gain tuning PID control uses PID control and Fuzzy control, therefore It can be applied very easily and it also has advances of PID control. It can control a unmaned aerial vehicle actuators adaptively even though the designer does not have enough information of plant.

• Journal of Power System Engineering
• /
• v.9 no.4
• /
• pp.11-17
• /
• 2005

This paper reports an experimental study on the performance evaluation of air-to-air heat exchanger with rotary type newly developed in this study. Air flow rate is varied from 10 to 120 m3/h. The range of RPM of the porous rotating discs mounted inside the heat exchanger unit is 0 to 50. The temperature of the return air side is set by adjusting heat supply at heater. The material of the porous rotating discs is cooper and its thickness is 1.0 mm. The heat transfer rate increased with the increase in air flow rate. It was found that the heat transfer rate, as the temperature of the return air side was increased, was improved due to higher temperature difference. The heat exchange performance increased with the increase in the temperature of the return air side at the conditions of the same RPM. The sensible heat exchange efficiency was maximum 68 to 76 percent, and enthalpy exchange efficiency 64 to 74 percent.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
• /
• 1998.11a
• /
• pp.94-98
• /
• 1998

최근 온열 환경에서 인간의 쾌적감에 대한 관심이 커지고 있다. 온열쾌적감에 영향을 주는 요인들로는 온도, 습도, 기류 둥의 물리적 요인과 성별이나 체질 둥의 개인적인 요인들 뿐만 아니라 온열환경에서 느끼는 인간의 감성적인 측면도 요인으로 작용하게 된다. 본 연구에서는 여러가지 온열 환경 중에서 기류환경에 따른 인간의 온열 쾌적감을 평가하기 위해 생체반응의 변화 및 감성의 변화에 따른 생리신호를 분석을 통해 살펴보았다. 기류환경은 기존에 사용되고 있는 풍향변화기류 및 풍량변화기류와 새롭게 개발되어진 감성기류의 3가지 기류 조건을 제시하였고, 이에 따른 인체의 자율신경계의 반응과 감성 상태를 관찰하기 위해 심전도(ECG)와 뇌파(EEC)를 측정하여 HRV(Heart Rate Variability) 분석과 EEG 주파수 스펙트럼 분석을 시행하였다. 생리신호 분석결과 심전도의 HRV 분석에서는 감성기류가 풍향변화 기류와 풍속변화기류에 비해 HF/LF 비가 높게 나타났고, 뇌파의 주파수 스펙트럼 분석에서도 $\beta$파에 대한 뇌파의 상대 전력비가 감성기류에서 높게 나타나 감성기류가 제시된 다른 기류인 풍향변화기류나 풍속변화기류에 비해 쾌적한 온열환경 제시를 위한 기류조건이라고 평가되었다. 결론적으로 심전도의 HRV분석과 뇌파의 주파수 분석이 .제시된 기류환경의 온열쾌적감 평가에서 서로 유의한 결과를 나타냄으로써, 이들 생리신호의 분석이 온열환경에 따른 인간의 감성 변화를 객관적으로 나타내고 온열 쾌적감을 평가하는데 있어 유용한 정보가 될 수 있음을 제시하였다.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.13 no.10
• /
• pp.947-959
• /
• 2001

We propose a control scheme to control the indoor zone temperature via variable air volume (VAV) unit. To control the room temperature, state space model of the conditioned zone which is partitioned into nine artificial sectional regions is derived. The nonlinearity of the damper motion and actuator are considered for the practical use in the state space system description. The temperature control of the room temperature is performed by manipulating the degree of openness of the damper in relation to the local room temperature and the supplied air flow rate. In general, since a local temperature in the conditioned zone is measured, it is required to estimate the temperature values in each regions for the precise temperature control. We thus design a state observer to estimate the regional temperature, and use these values in the controller. The overall control system consists of the state observer based state feedback with the integral control. We compared the control results of the proposed scheme with those of cascade proportional and integral (PI) control, and showed that the scheme achieved precise control of the conditioned system.

• Journal of IKEEE
• /
• v.19 no.4
• /
• pp.603-609
• /
• 2015

Thermal comfort is one of the fundamental aspects of indoor environmental quality and it is strongly related to occupant satisfaction and energy used in building. In this paper, we proposes smart comfort algorithm that save energy and provide a pleasant and comfortable environment for workers by the indoor comfort conditions(Predictive Mean Vote) detection and controlling the temperature and humidity, air flow. Simulation results, heating and cooling control of the thermal comfort control can be compared with the existing general air conditioners reduces the power of 0.5kW and indoor comfort can be maintained. Also, It showed a 49.2% improvement in the light by lighting control algorithm.