• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 하계학술발표대회 논문집
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• pp.1155-1160
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• 2008

In the present study investigated the heat dissipation characteristics of the natural convection type radiator by using the latent heat from a solid-liquid PCM(Phase Change Material). Total radiator volume size is $423{\times}295{\times}83\;mm$ and PCM tank size is $398{\times}270{\times}26\;mm$. The objective was elapsed time lower than maximum operating temperature. Experimental condition, in order to study the effects of the phase-change phenomenon, carried out the various mass flow rate, input electric power, and heat of fusion temperature of two type PCMs. For the above experimental conditions, the cooling performance by using the latent heat showed that heat absorption rate performs for about 3 hours from using PCM $38^{\circ}C$. However, cooling performance by using PCM $50^{\circ}C$ showed higher than surface temperature of heater block because of heat of fusion.

• 한국태양에너지학회 논문집
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• 제24권1호
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• pp.7-12
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• 2004

Mixtures type PCM, $H_2O$-NaOH that has relatively large capacity of the latent heat and long duration of phase change temperature was developed and experimentally analyzed for the low temperature storage of the food and medical products. The results could be summarized as follows; 1. Borax as nucleating agent and acrylic polymer as thickening agent were added to $H_2O$ to prevent the supercooling and phase separation. 2. Phase change (solid$\leftrightarrows$liquid) duration of $H_2O$ added with NaOH was prolonged longer 50% than that of pure $H_2O$. 3. Phase change temperature of the latent heat material, $H_2O$-NaOH was $1.5\sim2^{\circ}C$ the maximum latent Heat was 279 kJ/kg at the NaOH addition of 1.3 wt.%. 4. The specific heat of $H_2O$-NaOH at the solid and liquid state was increased in proportion to the wt.% of NaOH, when NaOH of $1.15\sim1.60$ wt.% was added to $H_2O$, the specific heat of the solid state was increased from 3.19 kJ/kg to 5.84 kJ/kg and that of liquid state from 7.8 kJ/kg to 10.28 kJ/kg. 5. When NaOH of $1.15\sim1.60$ wt.% was added to $H_2O$, the total heat storage capacity composed of sensible and latent heat was $313\sim331.3$ kJ/kg and the maximum heat storage capacity was occurred at NaOH addition of 1.30 wt. %.

• 대한기계학회논문집B
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• 제34권2호
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• pp.173-178
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• 2010

빙축열시스템은 저온잠열저장을 위해 물을 사용한다. 그러나 물은 액체에서 고체로 상변화를 하는 과정에서 물의 과냉각 현상에 의하여 냉동기의 냉동용량 증가와 COP감소의 원인이 되고 있다. 본 연구는 저온잠열축열물질로 적용 가능한 TMA(Tri-methyl-amine, $(CH_3)_3N$) 20~25 wt%를 포함하고 있는 TMA-물계 포접화합물(TMA-water clathrate compound)의 냉각특성에 대한 실험적 연구를 수행하였다. 실험적 연구 결과, TMA 질량농도가 높을수록 상변화온도는 증가하였고, 과냉각도와 비열은 감소하였다. 특히, TMA 25wt%를 포함하고 있는 포접화합물은 냉각과정동안 평균 상변화온도 $5.8^{\circ}C$와 과냉각도 $8.0^{\circ}C$, 액상유지시간 651sec 및 비열 3.499 kJ/kgK로서 다른 TMA 농도보다 양호한 냉각특성을 나타내었다. 이와 같이 저온잠열축열물질로서 TMA 25wt%-물계 포접화합물을 적용하는 것이 유리할 것으로 판단된다.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2006년도 하계학술발표대회 논문집
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• pp.122-125
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• 2006

This paper deals with the Ondol, Korean under-floor heating system using latent heat storage materials. It has been recognized that the heating system using the latent heat storage materials are economically efficient and comfortable. For the comparison and analysis to the data of the existing experiment, a repetitive experiment makes sure the ability of Ondol panel.

• 설비공학논문집
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• 제28권8호
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• pp.305-310
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• 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.

• 태양에너지
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• 제8권1호
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• pp.13-21
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• 1988

Heat transfer phenomena in a high-temperature heat storage unit were investigated using molten salts. Carbonate salt, an equimolar mixture of $Li_2CO_3$ and $K_2CO_3$, which melts at $505^{\circ}C$ with a latent heat of 82 cal/g, was selected as the most promising latent heat storage material based on its low cost and excellent thermophysical properties at moderately high temperatures. It was also found that nitrate salts were good candidates of sensible heat storage materials. For the carbonate salt to be utilized commercially, however, several means of enhancing thermal recovery must be explored by promoting heat conduction through the solid salt formed during the heat discharge period. These would be achieved by the additions of aluminum screens and wool, and stainless fins. Finally, experimental results of moving boundary of phase change were well compared with predictied values obtained from the approximate solution.

• 설비공학논문집
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• 제13권12호
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• pp.1223-1229
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• 2001

Though conventional calorimetry methods such as differential scanning calorimetry (DSC) and differential thermal analysis (DTA) are used generally in measuring heat of fusion, T-history method has the advantages of a simple experimental apparatus and no requirements of sampling process, which is particularly useful for measuring thermal properties of inhomogeneous phase change materials (PCMs) in sealed tubes. However, random criteria (a degree of supercooling) used in selecting the range of latent heat release and neglecting sensible heat during the phase change process can cause significant errors in determining the heat of fusion. In the present study, it was shown that a 40% discrepancy exists between the original T-history and the present methods when analyzing the same experimental data. As a result, a reasonable modification to the original T-history method is proposed.

• International Journal of Air-Conditioning and Refrigeration
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• 제11권1호
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• pp.32-39
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• 2003

Though conventional calorimetry methods such as differential scanning calorimetry and differential thermal analysis are used generally in measuring heat of fusion, T-history method has advantages of a simple experimental apparatus and no requirements of sampling process, which is particularly useful for measuring thermophyical properties of in-homogeneous phase change materials in sealed tubes. However, the degree of supercooling used in selecting a range of latent heat release and neglecting sensible heat during the phase change process can cause significant errors in determining the heat of fusion. In the present study, it was shown that a 40% discrepancy exists between the original T-history and the present methods when analyzing the same experimental data. As a result, a reasonable modification to the original T-history method is proposed.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2013년도 춘계 학술논문 발표대회
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• pp.234-235
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• 2013

In order to evaluate the properties of reduced heat of hydrationof concrete mixed with slag, in the present study, we have evaluated by experimental and analytical characteristics of heat of hydration of concrete using the latent heat material and slag.

• 한국태양에너지학회 논문집
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• 제34권6호
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• pp.85-92
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• 2014

This study carried out experimental on the cooling characteristics of clathrate compound including TMA(Tri-Methyl-Amine ; $(CH_3)_3N$) as a low temperature latent heat storage material. And additive was used for subcooling improvement of TMA-water clathrate compound. The conclusion of above study is as following ; TMA 25wt%-water clathrate compound is shown stable phase change and low subcooling degree. The subcooling was improved in the case ethanol($CH_3CH_2OH$) 0.5wt% is added to TMA 25wt%-water clathrate compound.