• 제목/요약/키워드: phase change material(PCM)

검색결과 165건 처리시간 0.021초

저온 유통 용기에 따른 소고기의 저장 중 품질평가 (Quality characteristics of fresh beef during storage using cold chain containers)

  • 권기현;김종훈;김병삼;차환수;김지영;김소희
    • 한국식품저장유통학회지
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    • 제22권6호
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    • pp.788-795
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    • 2015
  • 개발한 수배송용기[TEPP-1(250 L), TEPP-2(50 L)]와 기존의 사용되고 있는 스티로폼(EPS) 박스에 소고기를 저장하면서 저장 중 품질특성을 조사하였다. 잠열재, 용기내부, 샘플중심의 온도변화 측정에서 저장기간 동안 수배송용기 TEPP-1가 설정온도 $5^{\circ}C$로 온도유지가 잘 되는 것으로 측정되었고, pH변화 또한 유의적으로 큰 변화 없이 유지하는 경향을 보였다. 소고기 구매에 영향을 주는 색변화는 TEPP-1에 저장 시 가장 적었고, VBN은 저장 7일에 8.39 mg%로 유의적으로 가장 적은 증가율을 나타내었고, TBA역시 TEPP-2보다 적게 증가하는 것으로 측정되었다. 육즙 손실은 저장 7일에 TEPP-1은 0.87%로 큰 변화가 발생하지 않은 반면 TEPP-2는 1.78% 육즙 손실을 나타내었고, 미생물의 변화는 저장 4일까지 두 수 배송용기의 유의적 차이는 없었으나 저장 7일에 TEPP-1 6.65 log CFU/mL, TEPP-2는 7.62 log CFU/mL로 증식하여 유의적 차이를 나타내었다. 기호도 조사 또한 저장 7일째 TEPP-1은 대부분의 항목에서 6.5점 이상의 평가를 받았지만 TEPP-2는 3점 이하의 평가를 받아 소고기가 부패되어 상품성이 상실된 것으로 판단되었다. EPS 박스는 저장 3일 이후 더 이상 실험이 불가능하였고, 모든 분석항목에서 TEPP-1(250 L) 수 배송용기가 TEPP-2(50 L)보다 소고기 신선도 유지에 효과적인 것으로 측정되었고, 저장 7일까지 소고기의 신선도 유지가 가능한 것으로 판단된다.

지역난방 급탕공급 부하균등화를 위한 잠열축열조의 현장 적용 (Field Application of a Latent Heat Storage Tank for Load Shaving of Domestic Hot Water Supply in District Heating)

  • 박성용;유호선
    • 플랜트 저널
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    • 제17권2호
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    • pp.42-47
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    • 2021
  • 지역난방의 운영적 측면에서 특정시간의 피크부하 완화를 통한 효율적인 열생산과 공급 및 지역난방 공급 중단 시 급탕 공급은 난방 대비 대체가 어려워 사용자 측면의 불편함과 공급자 측면의 애로사항을 해결할 수 있는 적용 기술이 요구되고 있다. 본 연구에서는 이러한 문제점을 해결할 수 있는 기술 중 열저장 능력과 급탕공급에 적합한 78℃급 수화물계 잠열축열조를 제작하여 지역난방 사용자 아파트 급탕공급설비에 현장 적용하였다. 본 시스템의 적용 결과 기존 공급방식 대비 급탕온도의 변화가 거의 없이 일정하게 사용자에게 공급됨을 확인하였으며, 피크 열부하는 평균 35% 감소와 비상열원으로서의 활용 가능성을 확인하였다. 또한 부하균등화에 따른 피크부하 감소로 기존 열 공급시설에서 10%의 열공급 여유와 신규 열공급시설 건설비용 및 열사용자의 공사비부담금이 각 5%와 10%가 감소됨을 확인하였다.

가열기구에 따른 조리방법이 닭고기의 품질특성에 미치는 영향 (Effect of Cooking Methods with Various Heating Apparatus on the Quality Characteristics of Chicken)

  • 전기홍;권기현;김은미;김영붕;손동인;최진영
    • 한국조리학회지
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    • 제20권3호
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    • pp.201-213
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    • 2014
  • 본 연구에서는 가열처리방법을 달리하여 기존의 가열처리방법과 열처리용으로 개발된 잠열재 처리와 제작하여 사용하였으며, 닭고기의 가슴살과 다리살의 이화학적 특성과 관능특성을 비교하였다. 일반성분에서 수분은 찌기처리구에서 닭가슴살과 다리살 모두에서 63.6%, 62.1%로 높았으며, 조지방은 삶기처리구에서 1.3%, 8.6%로 가장 낮은 함량을 보였다(p<0.05). 조단백질의 경우, 닭가슴살은 숯불처리구에서 37.9%, 닭다리살은 전기그릴 처리구에서 30.5%로 가장 높게 나타났으며, 조회분 실험결과 닭가슴살은 전기그릴처리구에서 2.4%로 가장 높았으며(p<0.05), 닭다리살은 오븐과 숯불구이처리구에서 1.3%로 가장 높게 나타났다(p<0.05). 가열감량은 닭가슴살과 다리살 모두에서 33.52%, 41.16%로 숯불구이처리구가 오븐구이처리구에 비해 월등히 높았고(p<0.05), 전단력은 전기그릴처리구에서 닭가슴살 $3.53kg/cm^2$, 닭다리살은 $6.80kg/cm^2$으로 가장 높았다. 색도 시험결과 L값은 스팀처리구에서 78.31로 가장 높았고(p<0.05) a 값의 경우, 닭다리살은 오븐구이 처리구에서 10.00으로 가장 높았다(p<0.05). 닭고기 가슴살과 다리살의 관능평가를 9점척도법으로 실시한 결과 전체적인 기호도 항목에서 닭고기 가슴살은 숯불처리구에서 7.25점으로 가장 높았고 삶기와 찌기처리구에서는 6.00점으로 가장 낮은 결과를 보였다(p<0.05). 또한 닭고기 다리살도 숯불구이 처리구에서 7.71점으로 가장 높은 결과를 보였으나 유의적으로는 차이를 보이지 않았다.

설비공학 분야의 최근 연구 동향: 2014년 학회지 논문에 대한 종합적 고찰 (Recent Progress in Air-Conditioning and Refrigeration Research: A Review of Papers Published in the Korean Journal of Air-Conditioning and Refrigeration Engineering in 2014)

  • 이대영;김사량;김현정;김동선;박준석;임병찬
    • 설비공학논문집
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    • 제27권7호
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    • pp.380-394
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    • 2015
  • This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2014. It is intended to understand the status of current research in the areas of heating, cooling, ventilation, sanitation, and indoor environments of buildings and plant facilities. Conclusions are as follows. (1) The research works on the thermal and fluid engineering have been reviewed as groups of heat and mass transfer, cooling and heating, and air-conditioning, the flow inside building rooms, and smoke control on fire. Research issues dealing with duct and pipe were reduced, but flows inside building rooms, and smoke controls were newly added in thermal and fluid engineering research area. (2) Research works on heat transfer area have been reviewed in the categories of heat transfer characteristics, pool boiling and condensing heat transfer and industrial heat exchangers. Researches on heat transfer characteristics included the results for thermal contact resistance measurement of metal interface, a fan coil with an oval-type heat exchanger, fouling characteristics of plate heat exchangers, effect of rib pitch in a two wall divergent channel, semi-empirical analysis in vertical mesoscale tubes, an integrated drying machine, microscale surface wrinkles, brazed plate heat exchangers, numerical analysis in printed circuit heat exchanger. In the area of pool boiling and condensing, non-uniform air flow, PCM applied thermal storage wall system, a new wavy cylindrical shape capsule, and HFC32/HFC152a mixtures on enhanced tubes, were actively studied. In the area of industrial heat exchangers, researches on solar water storage tank, effective design on the inserting part of refrigerator door gasket, impact of different boundary conditions in generating g-function, various construction of SCW type ground heat exchanger and a heat pump for closed cooling water heat recovery were performed. (3) In the field of refrigeration, various studies were carried out in the categories of refrigeration cycle, alternative refrigeration and modelling and controls including energy recoveries from industrial boilers and vehicles, improvement of dehumidification systems, novel defrost systems, fault diagnosis and optimum controls for heat pump systems. It is particularly notable that a substantial number of studies were dedicated for the development of air-conditioning and power recovery systems for electric vehicles in this year. (4) In building mechanical system research fields, seventeen studies were reported for achieving effective design of the mechanical systems, and also for maximizing the energy efficiency of buildings. The topics of the studies included energy performance, HVAC system, ventilation, and renewable energies, piping in the buildings. Proposed designs, performance performance tests using numerical methods and experiments provide useful information and key data which can improve the energy efficiency of the buildings. (5) The field of architectural environment was mostly focused on indoor environment and building energy. The main researches of indoor environment were related to the evaluation of work noise in tunnel construction and the simulation and development of a light-shelf system. The subjects of building energy were worked on the energy saving of office building applied with window blind and phase change material(PCM), a method of existing building energy simulation using energy audit data, the estimation of thermal consumption unit of apartment building and its case studies, dynamic window performance, a writing method of energy consumption report and energy estimation of apartment building using district heating system. The remained studies were related to the improvement of architectural engineering education system for plant engineering industry, estimating cooling and heating degree days for variable base temperature, a prediction method of underground temperature, the comfort control algorithm of car air conditioner, the smoke control performance evaluation of high-rise building, evaluation of thermal energy systems of bio safety laboratory and a development of measuring device of solar heat gain coefficient of fenestration system.

설비공학 분야의 최근 연구 동향 : 2016년 학회지 논문에 대한 종합적 고찰 (Recent Progress in Air-Conditioning and Refrigeration Research : A Review of Papers Published in the Korean Journal of Air-Conditioning and Refrigeration Engineering in 2016)

  • 이대영;김사량;김현정;김동선;박준석;임병찬
    • 설비공학논문집
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    • 제29권6호
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    • pp.327-340
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    • 2017
  • This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2016. It is intended to understand the status of current research in the areas of heating, cooling, ventilation, sanitation, and indoor environments of buildings and plant facilities. Conclusions are as follows. (1) The research works on the thermal and fluid engineering have been reviewed as groups of flow, heat and mass transfer, the reduction of pollutant exhaust gas, cooling and heating, the renewable energy system and the flow around buildings. CFD schemes were used more for all research areas. (2) Research works on heat transfer area have been reviewed in the categories of heat transfer characteristics, pool boiling and condensing heat transfer and industrial heat exchangers. Researches on heat transfer characteristics included the results of the long-term performance variation of the plate-type enthalpy exchange element made of paper, design optimization of an extruded-type cooling structure for reducing the weight of LED street lights, and hot plate welding of thermoplastic elastomer packing. In the area of pool boiling and condensing, the heat transfer characteristics of a finned-tube heat exchanger in a PCM (phase change material) thermal energy storage system, influence of flow boiling heat transfer on fouling phenomenon in nanofluids, and PCM at the simultaneous charging and discharging condition were studied. In the area of industrial heat exchangers, one-dimensional flow network model and porous-media model, and R245fa in a plate-shell heat exchanger were studied. (3) Various studies were published in the categories of refrigeration cycle, alternative refrigeration/energy system, system control. In the refrigeration cycle category, subjects include mobile cold storage heat exchanger, compressor reliability, indirect refrigeration system with $CO_2$ as secondary fluid, heat pump for fuel-cell vehicle, heat recovery from hybrid drier and heat exchangers with two-port and flat tubes. In the alternative refrigeration/energy system category, subjects include membrane module for dehumidification refrigeration, desiccant-assisted low-temperature drying, regenerative evaporative cooler and ejector-assisted multi-stage evaporation. In the system control category, subjects include multi-refrigeration system control, emergency cooling of data center and variable-speed compressor control. (4) In building mechanical system research fields, fifteenth studies were reported for achieving effective design of the mechanical systems, and also for maximizing the energy efficiency of buildings. The topics of the studies included energy performance, HVAC system, ventilation, renewable energies, etc. Proposed designs, performance tests using numerical methods and experiments provide useful information and key data which could be help for improving the energy efficiency of the buildings. (5) The field of architectural environment was mostly focused on indoor environment and building energy. The main researches of indoor environment were related to the analyses of indoor thermal environments controlled by portable cooler, the effects of outdoor wind pressure in airflow at high-rise buildings, window air tightness related to the filling piece shapes, stack effect in core type's office building and the development of a movable drawer-type light shelf with adjustable depth of the reflector. The subjects of building energy were worked on the energy consumption analysis in office building, the prediction of exit air temperature of horizontal geothermal heat exchanger, LS-SVM based modeling of hot water supply load for district heating system, the energy saving effect of ERV system using night purge control method and the effect of strengthened insulation level to the building heating and cooling load.