• Journal of the Institute of Convergence Signal Processing
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• v.23 no.3
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• pp.123-128
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• 2022

A lot of research is being done to develop a high-efficiency heat pump to save energy, and research to reduce or eliminate the phenomenon of frost occurring in the outdoor unit coil is also being conducted at the same time. In order to conduct a study that does not cause frost on the outdoor unit of the heat pump regardless of the season, a constant temperature chamber like a general room that can be tested under the same conditions as in the natural state was built. The experiment was conducted by providing an environment similar to the natural state to the outdoor unit of the heat pump installed in the constant temperature chamber. As a result, the lower the outdoor temperature, the lower the efficiency of the heat pump. It wat confirmed that the lower the value, the longer it is.

• Journal of the Institute of Convergence Signal Processing
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• v.24 no.3
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• pp.140-146
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• 2023

A lot of research is being done to develop a high-efficiency heat pump to save energy. Among them, research to reduce or eliminate the phenomenon of frost occurring in the outdoor unit coil are being conducted at the same time. A constant temperature chamber that can be tested under the same conditions as natural conditions was constructed to conduct research that does not cause frost on the outdoor unit of the heat pump regardless of the season. The outdoor unit of the heat pump installed in the constant temperature chamber was simulated under the same natural conditions. As a result, it was confirmed that the mass flow rate of the refrigerant decreased as the outdoor temperature decreased, and the dryness of the refrigerant also increased linearly with the outdoor temperature.

• Journal of the Institute of Convergence Signal Processing
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• v.22 no.3
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• pp.116-121
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• 2021

A lot of research is being done to develop a high-efficiency heat pump to save energy, and research to reduce or eliminate the phenomenon of frost occurring in the outdoor unit coil is also being conducted at the same time. A curved constant temperature chamber was constructed that can be tested under the same conditions as in the natural state so that the research can be conducted in which frost does not occur on the outdoor unit of the heat pump regardless of the season. Simulations were performed to verity whether such a curved constant temperature chamber has feasibility as an experimental device. For CFD conditions, the length of the straight duct in front of the outdoor unit located in the duct-type constant temperature chamber was 1, 5, 10 and 15 times the diameter of the duct. As a result, it was found that a straight space must be secured 10 times the diameter of the duct.

• Journal of the Korean Applied Science and Technology
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• v.37 no.5
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• pp.1402-1408
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• 2020

In order to save energy, a lot of research has been conducted to develop a high-efficiency heat pump. Research to reduce or eliminate the occurrence of frost in the outdoor unit coil is also being conducted at the same time. A constant temperature chamber was constructed that allows experimentation under the same conditions as in the natural state so that frost does not occur in the outdoor unit of the heat pump regardless of the season. In order to verify the validity of the experimental apparatus, a simulation was conducted by dividing the straight length of the duct in front of the outdoor unit in the constant temperature chamber, which is the experimental apparatus, into three conditions. As a result, it was found that a straight space must be secured 10 times the diameter of the duct.

• Journal of Korean Society of Archives and Records Management
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• v.13 no.1
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• pp.35-58
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• 2013

The archives preservation chamber is an equipment that is able to store important archives with air-cleaning and isothermal-isohumidity control functions to permanently store archives in a highly safe environment. The chamber can only store small amounts of archives but it is crucial for organizations preserving archives to economically store a variety of archives, be it a medium or a small amount of documents. An arm of this study researches the current preservation status of the local record center to determine the need for such a chamber. In addition, in order to improve the air-cleaning and isothermal-isohumidity functions, the researchers of this study have conducted analyses to design the core parts. The preservation chamber that had been designed includes an archives preservation area, air-cleaning equipment, and environment measurement equipment. A preservation chamber is used to preserve small amounts of important archives safely. Thus, when a local record center is preserving various types of archives in small or medium quantities in a stack room, the preservation chamber can be used to aid their long-term preservation.

• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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• 2003.04a
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• pp.141-141
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• 2003

신선농산물의 호홉속도를 측정하는 방법 중 하나인 개방계(open system) 호흡속도 측정시스템은 소정의 농도로 조정된 혼합기체를 측정대상시료에 흘려 보내며 측정하는 방법이다. 개방계 측정법의 장점은 혼합 기체조성 영역에서 정확한 호흡속도를 얻을 수 있으며 방치시간이 필요 없으므로 반복 측정이 용이한 것 등이다. 그러나 개방계 측정법은 공급되는 혼합기체의 농도와 유속이 일정하여야 하며 연속으로 호흡속도 측정용 챔버의 혼합기체 공급측과 배기측에서 기체시료를 수집하여 매우 미세한 기체농도의 차이를 측정할 수 있어야 하고 기체 시료 수집에 상당한 주의가 요구된다. 이러한 문제를 개선하기 위하여 개방계 호흡속도 측정 시스템을 자동화하였다. 자동화된 호흡속도 측정 시스템은 혼합기체 발생장치, 온도조절이 가능한 기체기밀용 챔버와 G.C로 구성되어 있다. 환경기체조성을 위한 혼합기체발생장치는 $N_2$, $O_2$, $CO_2$ 압축 실린더에서 공급되는 기체를 압력 조절기를 통해서 일차압력을 조정하고 정밀 압력 조절기를 이용하여 0.1~0.2 kg/$\textrm{cm}^2$의 정압을 유지시켰다. 압력이 일정해진 기체는 metering valve를 이용하여 각 기체의 유량을 소정의 비율로 제어할 수 있도록 하였으며 각각의 기체는 gas mixed cell에서 실험 농도의 환경기체조성으로 혼합되어 항온기내의 호흡속도 측정 챔버($25^{\circ}C$)로 공급될 수 있도록 하였다. 호흡속도 측정용 챔버는 개스킷이 장착된 아크릴 재질이며 온도 조절이 가능한 항온기로 구성되어 있다. 호흡속도 측정용 챔버와 G.C간의 기체흐름은 three way solenoid valve에 의하여 제어되며 전원의 on/off에 따라 공급측의 가스와 배기측의 가스가 선택적으로 G.C에 공급될 수 있도록 구성하였다. 측정 대상 챔버의 기체는 제어된 유로를 따라 multi-position valve를 통과하여 G.C에서 분석되도록 하였다. 본 연구에서 개발된 개방계 호흡속도 자동 측정 시스템의 성능 실험에서 혼합기체발생장치에서 조제된 혼합 기체의 농도를 설정치와 비교한 결과 $O_2$와 $CO_2$의 농도에서 평균오차 0.2%로 정밀한 것으로 나타났으며 호흡속도 측정용 챔버의 혼합기체 공급측과 배기측의 가스 농도를 3회 반복 측정한 결과 재현성에서는 0.1%이하의 편차로 나타났다. 개방계 호흡속도 자동 측정 시스템을 이용하여 환경기체조성하에서 토마토의 호흡속도를 측정하는 실측 실험을 수행한 결과 2$0^{\circ}C$에서 12.7~42.1mg$CO_2$/kg.hr였으며 12$^{\circ}C$에서 2.5~8.2mg$CO_2$/kg.hr로 일반적으로 보고되고 있는 토마토 호흡속도와 일치하는 결과를 나타내었다.

• Proceedings of the KAIS Fall Conference
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• 2010.05b
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• pp.1123-1126
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• 2010

본 연구에서는 외기온습도에 따른 히트펌프 칠러의 난방성능을 조사하고자 하였다. 난방표준 온도조건에서 건구온도 및 습구온도 변화에 따른 히트펌프 칠러의 난방능력과 COP를 획득하기 위하여 항온항습 챔버와 항온수조를 사용하였다. 실험은 건구온도 $7^{\circ}C{\sim}17^{\circ}C$, 상대습도 67%~87%에서 수행하였다. 외기온도가 증가함에 따라 난방능력은 약 27%, COP는 약 28% 증가하였지만, 상대습도 증가에 따른 난방능력과 COP의 변화는 거의 없었다. 따라서 난방운전 시 건구온도의 영향은 크고, 상대습도의 영향은 미미함을 알 수 있었다.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.35S no.10
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• pp.77-84
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• 1998

The temperature difference occurs at the test points of chamber, because the traditional Test Handler consists of a heater and a fan. To reduce the temperature variation at different points in the chamber, we divided the heater to three parts which are controlled independently. First, we identified the chamber's parameter and then designed a LQG controllers by the identification model. RTD sensors and VME system were used to construct the temperature control system. In our experiment for the proposed control system, the temperature variation was reduced from ${\pm}1.5^{\circ}C$ to ${\pm}0.35^{\circ}C$ at 50$^{\circ}C$ ${\cdot}$ 80$^{\circ}C$ and 120$^{\circ}C$.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.4
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• pp.107-113
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• 2008

We investigated the electro-optical characteristics of an ICP(Inductively Coupled Plasma) light source depending on driving temperature, and length of discharge tube. An electro-optical stability of a sample at operating was measured to see a steady state of a sample. In this results, we can see that a stability of power loss and luminous flux of a sample at operating of upper 70[min] was 1.45[%1 and 0.36[%]. We measured the optical characteristics of a sample in a thermal chamber operated at a specific temperature divided into 5 steps. While luminance increased with temperature increasing, the decrement of luminance a eared at u or $46.7[^{\circ}C]$. According to Parchen's and Boyle-Charles' law, we can speculate that a pressure was increased and a higher voltage was needed but a ballaster having a rating power can't support a higher voltage corresponding to a pressure change, 0.02[Torr] at $46.7[^{\circ}C]$. Moreover, we measured an a lied power and current of samples depending to a various length of a discharge tube.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.483.1-483.1
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• 2014

태양광 시스템의 발전량의 증가로 인하여 높은 전위차에 의한 새로운 형태의 태양전지 모듈의 열화 및 출력 감소가 보고되고 있다. Potential induced degradation (PID) 이라고 불리는 이 현상은 고 전위차가 모듈을 구성하는 태양전지와 프레임 사이에 인가되며 발생하는 열화 현상이다. PID의 발생은 태양전지와 프레임 사이의 누설 전류의 크기를 통하여 간접적으로 설명이 되고 있다. 그리고 PID의 해결 방법으로 이 누설 전류를 줄이기 위하여 모듈의 구성 재료를 변화시키는 연구가 보고되고 있다. 하지만 아직 누설 전류와 출력 감소의 연관성에 대한 설명이 부족하고 정확한 발생 원인은 밝혀지지 못한 상황이다. PID가 발생된 이후 태양전지에 발생된 변화를 관찰하기 위하여 항온, 항습 챔버와 고전압 발생 장치에서 PID 시험을 하였다. 서로 다른 두 종류의 태양전지를 사용하여 시간에 따른 PID 현상의 차이점을 살펴보았고 출력 변화를 light IV로 관찰하였다. 또한 시간에 따른 모듈의 전기적 특성의 변화는 dark IV와 electroluminescence (EL)를 이용하여 측정하였다.