• ICROS
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• v.5 no.1
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• pp.41-44
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• 1999

• The KSFM Journal of Fluid Machinery
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• v.11 no.2
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• pp.64-68
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• 2008

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.17 no.5
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• pp.444-451
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• 2005

The fault detection and diagnosis technology may be applied in order to decrease the energy consumption and the maintenance cost of an air-conditioning system. In this study, partial faults for fans, coils, dampers, and sensors of a constant volume air handling unit were considered. A fuzzy algorithm was developed to detect and diagnose these faults. Diagnostic results by the fuzzy algorithm were compared with those by the model reference algorithm. The fuzzy algorithm showed better results in diagnostic accuracies.

• The KSFM Journal of Fluid Machinery
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• v.15 no.2
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• pp.57-62
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• 2012

The constant air volume flow fan can maintain constant flow rate to the wide range of exit pressure. Therefore, the use of this fan is increasing recently for ventilation of high building. Brushless DC motor is adopted to this fan because that has advantages of compactness and performance. But this type of motor protrude from impeller hub side to fan inlet. The Impeller inlet flow is influenced by size of this obstacle called hub. In this paper, the influence of hub shape on the fan performance characteristics are experimentally and numerically analyzed. CFX 12.0 is used to perform the fan internal flow analysis and numerical results are compared with the experiments. Depending on hub shape, internal loss is generated and the performance and efficiency are reduced. The best performance is occurred around $h/b_1$ = 0.25. The results of this study will be contribute to initial design of constant air volume flow fan development.

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

• Proceedings of the SAREK Conference
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• 2006.11a
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• pp.48-48
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• 2006

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.25 no.11
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• pp.612-616
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• 2013

A circular CAV damper has been developed, based on the investigation of the pressure loss, and the flow-resisting moment by the damper blade. When a torsional spring is attached to the damper axle, and the setting angle is adjusted to around $82^{\circ}$, the volume rate across the damper is almost independent of the static pressure. Such a CAV characteristic appears at an opening angle between $40^{\circ}$ and $60^{\circ}$, where the normalized moment decreases linearly with the angle. In addition, by adjusting the setting angle, the volume rate can be controlled to within 10% error, regardless of the pressure loss.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.16 no.2
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• pp.184-193
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• 2004

The purpose of this study is to evaluate the performance of various control strategies in commercial buildings which have been operated by the variable air volume (VAV) system. Two buildings in Seoul were chosen for the field study. The one (D building) combined by LonWorks has the constant airflow of supply fan and the proportional control of VAV units (damper type). The other (S building) combined by DDC has the PI control mode of the supply fan and the floating control of VAV units (venturi type). In estimating thermal comfort and energy performance through control modes of PI, PID, and CAV in the supply fan, we could identify several energy efficient operating control strategies for the VAV system.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.16 no.9
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• pp.872-880
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• 2004

The fault detection and diagnosis technology may be applied in order to decrease the energy consumption and the maintenance cost of the air-conditioning system. In this study, an air handling unit fault test apparatus was built and fault diagnosis algorithms were applied to diagnose various faults of an air handling unit. Test results showed the good diagnosis for applied faults. Therefore, these algorithms may be effectively used to develope the real time fault detection and diagnosis system for the air handling unit.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.9 no.1
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• pp.1-13
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• 1997

This paper reports the dynamic analysis of energy consumption for an office building by heat resistance-capacitance method. If a building is divided into several wall components and the wall components is replaced by one thermal capacitance and several thermal resistances, the building becomes an electric circuit. By solving the simultaneous equations of the circuit, the dynamic heat transfer characteristics and the energy consumption rate of the building were predicted. Accuracy of modified BIN method was evaluated by the present resistance-capacitance method. The result shows that modified BIN method overpredicts the heating load of the office building 15%. Annual energy consumptions of equipments(fan, boiler, chiller) for various ventilating control system(CAV, VAV, FCU+VAV, FCU+CAV) were compared. FCU+CAV shows the minimum annual energy consumption.