• Journal of Biosystems Engineering
• /
• 제26권4호
• /
• pp.385-390
• /
• 2001

The Ondol system using both air-to-water heat pump and PCM(Phase Change Material) was constructed, and the effects of ambient air temperature on COP(Coefficient of Performance) of heat pump, the amount of heat supplied to the Ondol in the heating process, the heat storage in the PCM and the variation of Ondol room temperature were analyzed. The results from this study could be summarized as follows: 1. The COP of the heat pump (3 PS) was in proportion to the ambient air temperature. 2. When the ambient air temperature was varied between -10$^{\circ}C$ and -7$^{\circ}C$, the air temperature in the Ondol room was maintained between 16$^{\circ}C$ and 22$^{\circ}C$. As the results, it was certified that the heat pump-latent heat storage type Ondol system could be a comfortable residential heating system in the winter. 3. The maximum radiation and convection heat transfer from Ondol surface was 206.2 kJ/㎥hr and 82.6 kJ/㎥hr respectively. As the results, it could be confirmed that the radiation was major heat transfer mechanism for the Ondol room heating.

• 설비공학논문집
• /
• 제28권8호
• /
• pp.305-310
• /
• 2016

A thermal storage systems was designed to correspond to the temporal or quantitative variation in the thermal energy demand, and most of its heat is stored using the latent and sensible heat of the heat storage material. The heat storage method using latent heat has a very complex phenomenon for heat transfer and thermal behavior because it is accompanied by a phase change in the course of heating/cooling of the heat storage material. Therefore, many studies have been conducted to produce an experimentally accessible as well as numerical approach to confirm the heat transfer and thermal behavior of phase change materials. The purpose of this study was to investigate the problems encountered during the actual heat transfer from an internal storage tank through simulation of the process of storing and utilizing thermal energy from the thermal storage tank containing charged PCM. This study used analysis methods to investigate the heat transfer characteristics of the PCM with simultaneous heating/cooling conditions in the rectangular space simulating the thermal storage tank. A numerical analysis was carried out in a state considering natural convection using the ANSYS FLUENT(R) program. The result indicates that the slope of the liquid-solid interface in the analysis field changed according to the temperature difference between the heating surface and cooling surface.

• Journal of Biosystems Engineering
• /
• 제31권3호
• /
• pp.168-174
• /
• 2006

The purpose of this study is to develop the cold chain system by developing optimal phase change materials (PCM). There are some benefits from developing this system such as keeping freshness of agriculture products, saving energy, etc. The major results are as follows. To decide a latent heat material, the characteristics of water, sodium, polyacrylate, ethanol and N-tetradecane are analysed. Also, an insulating material is made by mixing water, nucleating agent and latent heat material, using cementing method. In addition, the sensitivity analysis for developed latent heat material($K_l,\;K_2,\;K_3$) is conducted. For $K_l,\;K_2,\;K_3$ which cans keep latent heat temperature, ranging from $0\;to\;5^{\circ}C,\;5\;to\;10^{\circ}C,\;10\;to\;15^{\circ}C$. it can keeps latent heat temperature at radiant heat (5, 12, $17^{\circ}C$) and transportation latent heat container both melting temperature and amount of latent heat of Kl are $-1.6{\pm}1.0^{\circ}C$, 326.51 J/g, respectively and freezing temperature and latent heat are $-7.98{\pm}1.5^{\circ}C$ and 174.18 J/g. and $K_2$ are $7.41{\pm}1.5^{\circ}C$, 89.80 J/g, respectively and freezing temperature and latent heat are $-2.14{\pm}1.5^{\circ}C$ and 83.90 J/g. and $K_3$ are $9.54{\pm}1.0^{\circ}C$, 145.42 J/g, respectively and freezing temperature and latent heat are $0.21{\pm}1.0^{\circ}C$ and 152.48 J/g.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2011년도 춘계 학술논문 발표대회 1부
• /
• pp.5-6
• /
• 2011

CO₂ reduction is the most urgent issue the world is facing. So, there should be a measure to reduce the CO₂ emission in construction industry which has more released CO₂ gas than other industries. CO₂ emission of building depend on using energy. Then efficient energy use process working efficiently at CO₂ reduction. Therefore In this study, author find the technical possibility of saving the building energy using the PCM which is able to control heat, storage heat and potential heat. So, it considered that apply to floor heating type which is major heating system of living space in Korea. And evaluate the Using possibility.

• 한국태양에너지학회 논문집
• /
• 제21권4호
• /
• pp.47-54
• /
• 2001

This study has been conducted to verify the possibility of adaptation of a latent storage type air-conditioning system, shifting the peak load of electronic power to a building. In this paper, an energy equation to evaluate performance of PEM(phase change material) has been suggested and solved, after discretization. As a result, it is confirmed that the results from the energy equation are correspond with those from present studies to analysis of one-dimensional solidification and to analysis of two-dimensional solidification.

• 태양에너지
• /
• 제18권3호
• /
• pp.89-94
• /
• 1998

태양열 응용을 위한 한 방편으로 캡슐화된 PCM을 이용한 유동층 축열조에서 축열 및 방열과정에서 열전달 특성을 살펴보았다. 유동층 축열조는 원통형으로 높이는 40cm, 직경은 5.0cm 이었다. 축열물질은 무기염의 일종인 sodium acetate 였으며, 이것은 파라핀 왁스와 PMMA 로 코팅되었다. 캡슐화된 PCM의 크기는 약 $2{\sim}3mm$였으며, 용융점은 $58^{\circ}C$였다. 축열 및 방열과정시 유동층 축열조의 시간에 따른 온도분포, 순간 열저장 및 방출 속도를 측정하였으며 이로부터 유동층 축열조의 체적 열전달 계수를 도출하였다. 또한 유동층 축열조의 조업변수인 열전달 유체의 유속, 유입온도에 대한 열전달 계수의 영향도 관찰하였다.

• 한국염색가공학회:학술대회논문집
• /
• 한국염색가공학회 2011년도 제45차 학술발표회
• /
• pp.35-35
• /
• 2011

Phase change material(PCM) has thermal energy storage and been attracted attention. Latent heat of the organic PCM can keep maintaining temperature when the change of outside energy conditions influence to PCM. Thus, many researchers have interested to thermal energy storage ability and investigated to applications such as thermal storage of solar energy, bioclimatic building, icebank, medical application, clothing industry and so on. Among the many applications, investigation of the PCM in clothing industry is also important because the people has interest functional factor called health-care in the clothing. In addition, PCM can give them mild environment condition such suitable temperature control or humidity. To fabrics, the PCM has various methods such as microcapsule, padding and modified cross-section formation(Sheath/core). Sheath core PCM fabric has a better benefit of durability than other method. However, PCM sheath/core spinning is difficult. In addition, dyeing property is important to use clothing industry due to visual images. In this study, we investigated dyeing properties of Nylon/PCM sheath/core fabrics. Especially, we observed the relation between dyeing property and PCM including ratio. Various temperature and pH conditions were also studied to optimize dyeing properties as acid dye.

• 공업화학
• /
• 제21권5호
• /
• pp.522-526
• /
• 2010

축열이용기술은 열저장효과를 이용하여 냉난방 부하가 적을 때 남는 열을 저장하였다가 부하가 증가할 때 이용하는 방법으로써, 열저장 물질의 온도이용 특성에 따라 현열축열과 잠열축열로 구분한다. 잠열축열은 특정 온도 범위에서 상변화 할 때 높은 잠열을 갖는 물질을 이용하여 열을 저장하는 방법으로 동일한 열저장을 위해 소요되는 공간 크기가 현열 축열에 비하여 작아지게 되고 일정한 온도범위에서 열의 흡수 및 방출이 가능한 특성이 있다. 본 연구는 건축물의 냉난방시 소요되는 에너지를 절약하기 위하여 상온 상변화물질을 축열재로 사용하여, 건축자재로 범용적으로 사용되고 있는 시멘트, 석고 등에 적용하고자 하였다. 제조된 물질이 에너지절약성능은 물론 건축자재로서 필요한 물성을 갖추기 위하여 최적배합 방법 및 비율을 도출하고자 하였다. 그에 따라 중량비로 3% 들어간 축열모르타르의 냉각지연효과는 약 19%로 나타났다.

• Journal of Biosystems Engineering
• /
• 제19권1호
• /
• pp.62-69
• /
• 1994

This study was designed to seek information on the heat charging and discharging characteristics of a multi-capsule type LTES(Latent Heat of Fusion Thermal Energy Storage) system, and especially prediction equation of outlet water temperature from the system. During heat charging process, the water temperature in the LTES tank increased very slowly in comparison with a predicted one and was kept near the melting point of the PCM for about 25 minutes. During heat discharging process, the latent heat discharging period of the outlet water temperature became longer as the inlet water temperature became higher and/or mass flow rate became lower. The dimensionless temperature of the outlet water was predicted by linking three equations of ${\theta}=1.1Exp(-{\tau}/0.82)$, ${\theta}=-0.06{\tau}+0.3$, ${\theta}=0.8Exp(-{\tau}/1.4)$ ($r^2{\leq}0.88$) depending on discharging period regardless of mass flow rates on the case of the inlet water temperature at $21.5^{\circ}C$.

• 태양에너지
• /
• 제10권1호
• /
• pp.38-46
• /
• 1990

고밀도 잠열축열장치의 최적설계와 효율적인 작동을 위해서는 그 전열특성과 축열효율이 규명되어야 한다. 본 연에서는 수직이중관형 잠열축열장치의 방열과정에서의 전열특성을 이론 및 실험적으로 분석하였으며 두 결과는 잘 일치하였다. 그리고 컴퓨터 시뮬레이션을 통하여 방열효율에 대한 설계 및 작동피라미터의 영향을 분석하였다.