최근 지구온난화로 인해 폭우, 눈 등 이상기후가 발생하면서 노면 동결(블랙아이스)로 인한 사고 및 인명피해가 늘어나고 있 는 것이 문제가 되고 있다. 이를 최소화하기 위해 본 연구에서는 다공성 골재인 팽창점토에 열저장이 가능한 상변화물질(PCM)을 적용 하였다. PCM은 상변화 과정에서 열에너지를 흡수, 저장, 방출할 수 있는 소재로 온도에 따른 결빙을 최소화할 수 있다. 따라서 본 연 구에서는 시멘트 복합재에 적용되는 PCM 함침이 가능한 경량골재에 진공함침을 실시하고 기계적, 열적 성능 검증 연구를 수행하였다. 열적 성능을 향상시키기 위해 다중벽탄소나노튜브(MWCNT)와 실리카흄을 첨가하였다. 본 연구에서는 물체의 열적 성능을 측정할 수 있는 DSC 실험을 통해 PCM 함침 경량골재 및 콘크리트 복합체의 열적 성능을 검증하였다. 콘크리트 복합체 제작 후 압축강도 시험 과 열적 성능시험을 실시하였다. 이때 열적 성능을 검증하기 위해 항온항습 챔버를 이용하여 시험을 진행하였다. 압축강도 실험을 통 해 MWCNT의 분삭액을 혼입한 PCM 함침 팽창점토가 적용된 콘크리트 복합체의 평균 압축강도는 24MPa 이상으로 구조물에 적용이 가능함을 확인하였다. 열적 성능시험을 통해 PCM 함침 팽창점토가 적용된 콘크리트 복합체는 영하의 외기온도에서도 영상의 온도를 유지할 수 있음을 확인하였다. 이와 같은 결과를 통해 주거 및 상업 건물 및 다양한 구조물에 적용이 가능할 것으로 판단된다.

본 연구에서는 온도 반응형 발열 아스팔트 포장 공법 개발을 위하여 온도 반응형 신소재의 아스팔트 적용 방안과 이를 아스팔트 재 료에 적용하기 위한 기초 연구를 수행하였다. 발열 아스팔트 포장에 적합한 상변화 온도 범위에 따른 PCM 재료 선정 및 아스팔트 재 료에 적용하기 위한 캡슐화 방안을 검토하고 다양한 소재를 활용한 캡슐화된 PCM 신소재(ePCM)를 제작하였다. 이에 대한 발열 특성 및 물리적 특성 평가를 수행하였다.

최근 지구온난화로 인해 발생하는 폭우 및 강설과 같은 비정상적인 기상 패턴으로 인해 도로 표면 결빙(블랙 아이스)으로 인 한 사고와 인명 피해가 증가하고 있으며, 이는 주요 문제로 대두되고 있습니다. 이러한 문제를 완화하기 위해 본 연구에서는 열저장 능력을 갖춘 상변화 물질(PCM)을 시멘트 복합재료에 포함시켰습니다. PCM은 상변화 과정에서 열에너지를 흡수, 저장 및 방출할 수 있어 온도 변동으로 인한 결빙을 최소화할 수 있습니다. PCM은 먼저 미세 캡슐화된 후 시멘트 복합재료에 강화되어 기계적 및 열적 성능 검증 연구가 수행되었습니다. 또한, 열전달 효율과 기계적 특성을 향상시키기 위해 다중벽 탄소나노튜브(CNT)와 실리카 퓸이 추 가되었습니다. 미세 캡슐화된 PCM의 열 성능은 열 거동을 측정하기 위한 재료 실험을 통해 검증되었습니다. 이후, 제조된 시멘트 복 합재의 기계적 및 열적 성능 테스트가 그 효과를 평가하기 위해 수행되었습니다. 이러한 테스트 동안 일정 온도와 습도 챔버를 사용한 열 주기 테스트가 열 성능을 검증하기 위해 수행되었습니다. 기계적 성능 실험에서는 CNT와 실리카 퓸의 포함이 미세 캡슐화된 PCM 의 포함으로 인한 강도 저하를 완화하는 것을 확인하였습니다. 더욱이, 열 주기 테스트를 통해 고효율 열저장 시멘트 복합재가 결빙 조건에서도 영하의 온도를 유지할 수 있음을 보여주었으며, 이는 효율적인 열저장 성능을 입증하였습니다.

PURPOSES : This study aims to determine the type (e.g., melting point, freezing point, latent heat fusion) and optimal content of phase change material (PCM) based on the numerical and experimental analyses evaluating the effects of heat transfer in PCM-modified asphalt pavement systems. METHODS : The effect of PCM on the thermophysical properties of PCM-modified asphalt concrete can be taken as an effective volumetric heat capacity. The volumetric fraction of PCM was calculated using an iterative method. The numerical model was established and computed using the MATLAB 2020 software. The optimum PCM design tool was developed to select the type and contents of the PCM. The PCM was chosen based on the following criteria: black-ice-formation delay time, minimize temperature increase, and increase temperature area. To validate the numerical model, asphalt mixtures were modified with varying PCM contents, and the temperature response of the PCMmodified asphalt samples was examined via temperature test. RESULTS : The numerical results showed that incorporating PCM into the asphalt mixture can slow the cooling rate of the pavement system. The predicted results from the optimum PCM design tool were highly consistent with the measured values from the laboratory temperature test. CONCLUSIONS : The temperature of PCM-modified asphalt pavement can be predicted via numerical method. The effect of PCM on the thermophysical properties can be considered as effective volumetric heat capacity; while the volume fraction of PCM can be calculated via an iterative method. The accuracy of the numerical model was confirmed by a high agreement between the measured and predicted values.

In order to effectively utilize thermal energy, we analyzed the performance of the high efficiency latent heat storage system which can be used for greenhouse heating by using the developed phase change material. The system consists of hot water boiler, heat storage material, heat storage box, heat storage tank, circulation pump, control panel, and storage material. As a result, the latent heat and latent heat temperature of sodium acetate hydrate as latent heat storage material are 231.6 ~ 264.8kJ/kg, 54.95 ~ 55.48℃. As the number of cooling and heating increased, the latent heat temperature showed a slight change, but the latent heat decreased 33.1kJ/kg as the number of repetition increased. In the case of sodium acetate hydrate, large supercooling phenomenon was observed, and it was found that mixing of additives such as nucleating agent, thickener and supercooling agent can control the supercooling more effectively. The consumption of kerosene decreased until the temperature of the heat storage tank was raised to the set temperature by the closed circuit for 4 hours in the initial stage of the boiler operation. The heat exchange rate according to the change of the flow rate was maintained at the set temperature inside the heat storage tank after 4 hours of operation, Consumption was high. As the flow rate increased, the inlet and outlet temperature difference decreased, the heat exchange rate increased, and the heat exchange efficiency was in the range of 57.4 ~ 60.5%.

저밀도 에너지를 효율적으로 축열하기 위해서 현열축열재보다는 상변화 온도 30℃ 수준의 잠열축열재를 이용하는 것이 효과적이다. 이를 위하여 연구를 수행한 결과, SCD에 APS를 0.0~5.0wt% 첨가하여 과냉도를 25.0℃에서 1.5℃ 이하로 조절하였으며, APS의 적정 함량은 3.0wt%였다. SCD에 PSC를 0.0~3.0wt% 첨가하여 상분리량을 70.0%에서 0.0%로 조절하였으며, PSC의 적정 함량은 1.5wt%였다. 축열재 내구성 검증을 위하여 0~1,500회의 상변화 사이클을 수행한 결과 상변화 온도의 변화량이 30±l.0℃ 이하, 잠열량 변화가 54±2.0 Kcal .kg-1 이하로 안정된 값을 보였다. 따라서 축열재의 수명은 10년 정도 보장될 수 있는 것으로 판단되었다

스트론튬계 상전이물질은 특정한 온도에서 물질의 상태가 변함에 따라서 열을 흡수하거나 방출하게 된다. 본 연구의 목적은 스트론튬계 상전이물질의 혼입이 플라이애시 치환 모르타르 및 고로슬래그 치환 모르타르의 수화발열 및 역학적 특성에 미치는 영향을 실험적으로 평가하는 것이다. 스트론튬계 상전이물질의 혼입량은 결합재 질량의 1, 2, 3, 4, 5%로 하였다. 총 12개 수준의 모르타르 배합에 대해서 모르타르 흐름성능, 간이수화열온도상승, 압축 및 휨강도 실험을 각각 수행하였다. 실험결과 본 연구에서 사용한 스트론튬계 상전이물질은 모르타르의 수화열 저감 및 수화지연에 효과적인 것으로 판단된다. 특히 플라이애시 치환 모르타르의 최대온도 상승량은 고로슬래그 치환 모르타르의 최대온도 상승량에 비해 낮게 나타났다. 플라이애시 및 고로슬래그 치환 모르타르의 압축강도는 상전이물질 혼입량이 증가함에 따라 감소하는 것으로 나타났다.

The study was conducted to evaluate the latent heat properties of cement mortar with different contents of phase change material (PCM). The paraffin PCM with melting point of 44℃ used in this study. PCM was added in the mixture with contents ranged from 0 to 30%. Test results indicated that the heat storage performances of cement mortar were improved with increasing the content of PCM.

Phase change material (PCM) has been developed and applied in various fields as construction material. If the application of PCM as the semi-rigid pavement cement grout becomes available, it would be possible to control the occurrence of a micro crack due to the generation of hydration heat in the ultra rapid harding cement, and if the occurrence of a micro crack is reduced, it would be possible to improve the cohesion performance between asphalt matrix and grout as well as to compact the matrix of the pavement material, improving the durability. Therefore, the applicability review of PCM for the purpose of improving the semi-rigid pavement materials through the shrink reduction of ultra rapid harding cement used as the semi-rigid pavement cement grout was carried out in this study.

Phase change material (PCM) has been developed and applied in various fields as construction material. If the application of PCM as the semi-rigid pavement cement grout becomes available, it would be possible to control the occurrence of a micro crack due to the generation of hydration heat in the ultra rapid harding cement, and if the occurrence of a micro crack is reduced, it would be possible to improve the cohesion performance between asphalt matrix and grout as well as to compact the matrix of the pavement material, improving the durability. Therefore, the applicability review of PCM for the purpose of improving the semi-rigid pavement materials through the shrink reduction of ultra rapid harding cement used as the semi-rigid pavement cement grout was carried out in this

This paper describes the hydration heat properties of cement composite different with phase change material (PCM) type. The test results indicated that use of barium materials has more effective to delayed time of hydration of cement composite. On the other hand, strontium based PCM more effective to reduction of hydration heat of cement composite.

For the distribution of fresh produce, the thermoelectric cooling system combined with thermo electric materials (TEM) and phase change material (PCM) was studied. The PCM used this study was produced by in-situ polymerization technology which referred microencapsulation of hydrocarbon (n-tetradecane and n-hexadecane). In this study, quality characteristics of bell peppers in thermoelectric cooling system combined with TEM and PCM were analyzed and control was placed in an EPS (expanded polystyrene) box. As a result of quality characteristics analysis, weight of bell peppers decreased and moisture content of bell peppers was 90.96~94.43% during storage. Vitamin C content of bell pepper decreased during storage and reduction ratio of control was higher than that of BPT-5 treatment(bell pepper in thermoelectric cooling system with PCM which is kept the temperature at 5℃). The result of color value, on 21 day, ΔE value of BPT-5 treatment was 5.05 while that of control was 41.8. On 21 day, total bacteria count of BPT-5 treated bell pepper shown less than that of control. In conclusion, it suggested that the thermoelectric cooling system combined with PCM improved quality of fresh produce during transportation and storage.

A study to apply phase change material(PCM) to rapid hardening cement paste forming semi-rigid pavement was carried out. The characteristics fresh and hardened paste were evaluated through the experiment for a total of 6 mixtures according to the cement type and the substitution of phase change material for acrylate. The fluidity by substituting phase change material for acrylate satisfied the target flow time of 10 to 13 seconds. In case of setting time, it was possible to secure the performance of rapid hardening cement by substituting phase change material, and if the substitution ratio over 60%, the initial set occurred 1 to 2 minutes faster than other mixtures. In case of compressive strength and bond strength, it showed similar strength characteristics with the plain mixture, and it satisfied both the target compressive and bonding strength of 36MPa and 2MPa. The mixture substituting phase change material showed higher resistance to chloride ion penetration than the mixture only using acrylate and the OPC level was insufficient. From the results of physical and mechanical performances of semi-rigid pavement cement paste, the phase change material substitution rate of 20% was effective in the range of this study.

Experimental program was conducted for hydration heat evaluation of concrete using strontium based phase change material (PCM). Adiabatic temperature rise test was investigated for four days. In results, concrete with strontium based PCM has about 20 percent lower hydration heat than ordinary one.

Differential scanning calorimetry of the aggregated impregnated with PCM indicates 4～10 J/g of the amount of heat storage capacity. The results show that it is considered that lightweight aggregate concrete impregnated with PCM may have thermal energy storage capacity.