• 한국우주과학회:학술대회논문집(한국우주과학회보)
• /
• 한국우주과학회 2005년도 한국우주과학회보 제14권1호
• /
• pp.129-132
• /
• 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
• /
• 제12권7호
• /
• pp.632-641
• /
• 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.

• International Journal of Air-Conditioning and Refrigeration
• /
• 제9권3호
• /
• pp.46-56
• /
• 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
• /
• 제11권1호
• /
• pp.10-16
• /
• 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.

• Journal of Astronomy and Space Sciences
• /
• 제29권1호
• /
• pp.23-31
• /
• 2012

Thermal analysis and control design are prerequisite essential to design the satellite. In the space environment, it makes satellite survive from extreme hot and cold conditions. In recent years CubeSat mission is developed for many kinds of purpose. Triplet Ionospheric Observatory (TRIO)-CubeSat for Ion, Neutral, Electron, MAgnetic fields (CINEMA) is required to weigh less than 3 kg and operate on minimal 3 W power. In this paper we describe the thermal analysis and control design for TRIO-CINEMA mission. For this thermal analysis, we made a thermal model of the CubeSat with finite element method and NX6.0 TMG software is used to simulate this analysis model. Based on this result, passive thermal control method has been applied to thermal design of CINEMA. In order to get the better conduction between solar panel and chassis, we choose aluminum 6061-T6 for the material property of standoff. We can increase the average temperature of top and bottom solar panels from $-70^{\circ}C$ to $-40^{\circ}C $ and decrease the average temperature of the magnetometer from $+93^{\circ}C$ to $-4^{\circ}C$ using black paint on the surface of the chassis, inside of top & bottom solar panels, and magnetometer.

• 설비공학논문집
• /
• 제14권2호
• /
• pp.91-97
• /
• 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.

• 한국복합재료학회:학술대회논문집
• /
• 한국복합재료학회 2002년도 춘계학술발표대회 논문집
• /
• pp.77-80
• /
• 2002

Thermal analysis has been performed to evaluate the thermal effect on composite antenna (Ka-band) structure in space environment. The concepts of thermal control are also presented to maintain the antenna components within respective temperature limits. A steady-state algorithm of I-DEAS' thermal analysis software was utilized to predict both maximum and minimum temperature, maximum gradient temperature, and temperature distribution on each antenna component.

• International Journal of Aeronautical and Space Sciences
• /
• 제17권4호
• /
• pp.526-534
• /
• 2016

A MEMS solid propellant thruster array shall be operated within an allowable range of operating temperatures to avoid ignition failure by incomplete combustion due to a time delay in ignition. The structural safety of the MEMS thruster array under severe on-orbit thermal conditions can also be guaranteed by a suitable thermal control. In this study, we propose a thermal control strategy to perform on-orbit verification of a MEMS thruster module, which is expected to be the primary payload of the STEP Cube Lab mission. The strategy involves, the use of micro-igniters as heaters and temperature sensors for active thermal control because an additional heater cannot be implemented in the current design. In addition, we made efforts to reduce the launch loads transmitted to the MEMS thruster module at the system level structural design. The effectiveness of the proposed thermo-mechanical design strategy has been demonstrated by numerical analysis.

• 대한원격탐사학회:학술대회논문집
• /
• 대한원격탐사학회 2002년도 Proceedings of International Symposium on Remote Sensing
• /
• pp.229-234
• /
• 2002

Under the hostile influence of the extreme space environmental conditions due to the deep space and direct solar flux, the thermal control in space applications is especially of major importance. There are tight temperature range restrictions for electro-optical elements while on the other hand there are low power consumption requirements due to the limited energy sources on the spacecraft. So, we usually have strong requirement of thermal and power control module in space applications. In this paper, the design concept of a thermal and power control module in the MSC(Multi-Spectral Camera) system which will be a payload on KOMPSATII is described in terms of H/W & S/W. This thermal and power control module, called THTM(Thermal and Telemetry Module) in MSC, resides inside the PMU(Payload Management Unit) which is responsible for the proper management of the MSC payload for controlling and monitoring the temperature insides the EOS(Electro-Optic System) and gathering all the analog telemetry from all the MSC sub-units, etc. Particularly, the designed heater controller has the special mode of "duty cycle" in addition to normal closed loop control mode as usual. THTM controls heaters in open loop according to on/off set time designed through analysis in duty cycle mode in case of all thermistor failure whereas it controls heaters by comparing the thermistor value to temperature based on closed loop in normal mode. And a designed THTM provides a checking and protection method against the failure in thermal control command using the test pulse in command itself.

• 한국항공우주학회지
• /
• 제36권12호
• /
• pp.1222-1228
• /
• 2008

㈜쎄트렉아이는 UAE의 EIAST와 함께 2008년 발사를 목표로 SI-200 표준버스시스템을 기반으로 하는 DubaiSat-1 비행모델을 개발하였다. DubaiSat-1 비행모델의 열제어계는 전력 소비의 최소화를 위해 수동 열제어를 기반으로 하되, 주요 부품에는 히터를 이용한 능동 열제어가 이뤄지도록 설계되었다. 또한 열해석 모델을 작성하여 DubaiSat-1의 임무궤도에 대해 열해석을 수행하였으며, 해석 결과를 토대로 모든 구성품이 설계 요구조건을 만족시킬 수 있도록 설계 보정 작업을 진행하였다. 또한 우주환경을 모사한 열진공시험을 수행하여 DubaiSat-1 비행모델의 열제어 성능에 대해 검토하였으며, 시험 결과와 해석 결과의 비교를 통한 열해석 모델의 보정 작업을 완료하였다.