• International Journal of Air-Conditioning and Refrigeration
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• 제9권3호
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• pp.46-56
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• 2001

The present study concerns the numerical simulation of a supply airflow control in a variable air volume (VAY) system. A stratified thermal model (multi-zone model) is suggested to predict a local thermal response of an air-conditioned space. The effects of various thermal parameters such as the cooling system capacity, the thermal mass of an air-conditioned space, the time delay of thermal effect, and the building envelope heat transmission are investigated. Further, the influence of control parameters such as the supply air temperature, the PI control factor and the thermostat location on a VAV system is quantitatively delineated. The results obtained show that the previous homogeneous lumped thermal model (single zone model) may overestimate the time taken to the set point temperature. It is also found that there exist the appropriate ranges of the control parameters for the optimal airflow control of the VAV system.

• International Journal of Air-Conditioning and Refrigeration
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• 제11권1호
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• pp.10-16
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• 2003

The present study performs an experimental measurement on transient thermal response of an air-conditioned space by a variable air volume (VAV) system with a PI(pro-portional-integral) control logic. A thermal chamber with a PI controlled VAV unit is constructed to verify the previously suggested stratified multi-zone model. The effects of thermal parameters and control parameters such as supply air temperature and PI control factor are investigated by implementing the thermal chamber test. The experimental results obtained show that transient behavior of the air-conditioned space-temperature is in good accordance with the simulation results of the stratified thermal model.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.168-168
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• 2000

In this paper, a boiler control system for thermal power plant is configured. The boiler control system for thermal power plant is largely composed of an ABC(Automatic Boiler Control) system and a MBC(Mill Burner Control) system. ABC system controls analog process values, so almost all analog control logic is dealt with in ABC system. On the other hand, MBC system relates to sequence control logic such as MFT logic, Furnace Purge, Safety related logic. Advanced control systems made from advanced countries deal with an ABC system and MBC system in a distributed control system. In this paper, we adopt a DCS as an ABC system and adopt a PLC system as a MBC system to configure a boiler control system for thermal power plant using domestic control system. Finally the validity of the configured boiler control system is shown via simulation using digital simulator for boiler system in thermal power plant.

• 한국우주과학회:학술대회논문집(한국우주과학회보)
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• 한국우주과학회 2005년도 한국우주과학회보 제14권1호
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• pp.129-132
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• 2005

본 논문에서는 HAUSAT-2의 궤도 열 해석과 열 제어계의 예비설계를 살펴본다. HAUSAT-2의 열 제어계를 설계하기 위해서 우선 열 제어의 기본 이론 및 열 평형 방정식을 바탕으로 능동 및 수동의 각종 열 제어 방법을 고려하여 HAUSAT-2에 적합한 열 제어 방법 및 재질을 선정하였다(Karam 1998). 또한, 예상궤도인 고도 650km, 경사각 $98^{\circ}$의 태양동기궤도에서 HAUSAT-2가 처해지는 열 환경에 대한 분석 및 위성체의 각 면에 가해지는 은도 분포 및 범위를 예측하여 이를 바탕으로 열 제어계를 설계하였다. 열 해석은 기본적으로 시스템레벨의 해석, 부품레벨의 해석, 보드레벨의 해석 차순으로 진행되었으며, 현재 HAUSAT-2의 열 해석은 발열이 비교적 많은 보드의 해석까지 진행된 상태이며, 이러한 열 해석을 통해서 얻은 결과는 요구조건을 만족하지 못하는 부분에 대해 설계 변경 등을 통해서 모든 부품이 허용온도 범위를 유지하도록 HAUSAT-2의 열 제어계를 설계하였다. 향후 구조-열 모델(STM; Structure & Thermal Model)을 제작한 후 열 진공시험을 통해 열 해석 결과에 대한 검증을 수행할 것이다.

• 설비공학논문집
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• 제23권6호
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• pp.430-440
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• 2011

The purpose of this study was to investigate the interactions between the thermal factors in existing thermal control methods and to find out the control logic that can create more comfortable thermal conditions. For it, four thermal control logics were developed：conventional temperature-based control; temperature-based and humidity-based control; PMV-based control; and TS-based control. Their performance was comparatively tested in the U.S. typical 5-story office building in two climate zones (Detroit, Michigan and Miami, Florida) for two seasons (winter and summer) incorporating IBPT (International Building Physics Toolbox) and Matlab/Simulink. Analysis on the thermal conditions and energy efficiency revealed that each control logic created comfortable conditions for their respective target, i.e., temperature, humidity, PMV or TS, but uncomfortable for others (e.g., temperature-based control logic maintained PMV or TS uncomfortably or vise versa). In addition, energy efficiency was significantly different by logics. In conclusion, it can be said that the overall thermal comfort can be improved by the adoption of the PMV and TS as a target variable and their economical benefits are expected in the hotter climate zones with the reduced cooling and dehumidifying energy consumptions.

• 설비공학논문집
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• 제14권2호
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• pp.91-97
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• 2002

The present study concerns an experiment on the supply-air control in variable air volume (VAV) system with a Pl control logic. A thermal chamber with a Pl control logic is constructed to verify the previously suggested multi-zone model. The stratified thermal model is adopted in the control logic for a thermal chamber cooling test. The effects of taler- mal parameters and control parameters such as supply air temperature and Pl control factor are investigated by implementing the thermal chamber cooling test. The experimental results obtained show that the transient behavior of the air-conditioned space temperature are in good agreement with the simulation results of the stratified thermal model.

• 설비공학논문집
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• 제12권7호
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• pp.632-641
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• 2000

The present study concerns the simulation of supply-air control in a variable air volume (VAV) system. A stratified lumped thermal model (multi-zone model) is suggested to predict local thermal response of an air-conditioned space. The effects of various thermal parameters such as the cooling system capacity, the thermal mass of air-conditioned space, the time delay of thermal effect, and the building envelope heat transmission are investigated in detail. Further, the influence of control parameters, PI control factor and the sensor location on a VAV system is quantitatively delineated. The results obtained show that the previous homogeneous lumped thermal model (1-zone model) may predict a significantly different thermal response in the air-conditioned space according to the sensor location.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1990년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 26-27 Oct. 1990
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• pp.333-338
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• 1990

Most verification of improvements for adaptive control schemes are. dependent on computer simulations, but these computer simulations have much limitation, because (if complex actual conditions of system. This paper is concerned with the constructions of a thermal process system for experiments with various control schemes. This thermal process system is composed of a water tank, PC-XT, AD/DA converters power supply and thermal sensors. We estimate. the algorithms of pole-assignment adaptive control in the manifold disturbances and environments, changing system dynamics. The system equations for thermal press are included.

• Journal of Mechanical Science and Technology
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• 제19권4호
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• pp.958-967
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• 2005

The mathematical model for tension behaviors of a moving web by Shin (2000) is extended to the tension model considering the thermal strain due to temperature variation in furnace. The extended model includes the terms that take into account the effect of the change of the Young's Modulus, the thermal coefficient, and the thermal strain on the variation of strip tension. Computer simulation study proved that the extended tension model could be used to analyze tension behaviors even when the strip goes through temperature variation. By using the extended tension model, a new tension control method is suggested in this paper. The key factors of suggested tension control method include that the thermal strain of strip could be compensated by using the velocity adjustment of the helper-rollers. The computer simulation was carried out to confirm the performance of the suggested tension control method. Simulation results show that the suggested tension control logic not only overcomes the problem of the traditional tension control logic, but also improves the performance of tension control in a furnace of the CAL (Continuous Annealing Line).

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.358-358
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• 2000

An iterative learning control technique based on a linear quadratic optimal criterion is proposed for temperature uniformity control of a silicon wafer in rapid thermal processing.