저온저장고 내부의 균일한 온도분포를 위한 3차원 공기유동 분석

고학균 서울대학교 농업개발연구소 1999 농업생명과학연구 Vol.3 No.-

Most of the domestic cold storage rooms are inefficient for agricultural products because of temperature gradients inside the storage rooms. Temperature gradients are developed mainly by improper airflow pattern inside the storage room, which is a main cause of the spoilage of the agricultural products. There proper airflow pattern is essential to minimize these temperature gradients and the spoilage. The performance and characteristics of a clod storage room were determined as a function of airflow pattern and temperature distribution in forced circulation cold storage room. A commercial CFD(computational fluid dynamics) code was used to simulate 3-D airflow in the cold storage room. Solving the flow equations for the storage room, a standard k-ε turbulent model was implemented to calculate steady state turbulent velocity distribution. The CFD prediction results were compared with temperature measurements inside the cold storage room. In case of no storage, internal airflow was circulated without stagnation and consequently temperature distribution was uniform. And in case of pallet storage, Temperature gradients inside pallet storage was reduced because the contact area of cold air expanded through an alley of airflow in storage. But in case of bulk storage, the last temperature of storage considerably rose more than the initial temperature of storage. The reason was that bulk storage didn't include any alley of airflow in storage.

오리엔탈 나리 '시베리아' 절화의 포장내 건식저장 기간별 수분함량과 품질 변화

이정수,이주희,강윤임,최지원,Lee, Jung-Soo,Rhee, JuHee,Kang, Yun-Im,Choi, Ji Weon 한국포장학회 2017 한국포장학회지 Vol.23 No.1

오리엔탈 나리 '시베리아'의 건식저장 기간에 따른 절화 보존 시 수분함량 변화와 절화수명을 구명하고자 하였다. 본 실험에서 저장 기간에 따라 저온 저장($5^{\circ}C$)을 한 다음 절화수명에 관계된 수분 및 품질 변화와 개화 정도를 검토하여 '시베리아' 나리의 절화 수확 후 관리 기술에 관계된 기본적인 자료를 얻고자 하였다. '시베리아' 나리를 채화하여 저온에서 건식저장 기간에 따라 3일, 6일, 12일한 후 절화보존 동안에 생체중 변화, 수분균형, 개화정도 등을 조사하였으며 대조구로서 상온 건식저장과 비교하였다. 저온 건식저장 후에 '시베리아' 나리의 수분함량은 건식저장 기간에 영향을 받아 저장하는 기간이 짧을수록 높아져 저장 3일이 다른 처리구보다 높아지는 경향을 보였다. 꽃의 수분함량은 절화보존 시 지속적으로 증가하는데, 저장 기간이 짧을수록 수분이 높게 유지되었다. 생체중 변화는 건식저장 기간에 영향을 받아 저장 기간이 짧았던 것에서 생체중의 증가 정도가 컸으며 음(-)의 값에 이르는 기간이 늦어지는 것으로 나타났다. 또한 절화보존 시 생체중 변화는 저온 건식저장 3일이 생체중 증가 정도가 완만하게 변하며 수분균형도 8일째에 음(-)의 값에 도달하는 것으로 나타났다. 그러나 저장 온도 차이에 따른 생체중 변화는 상온에서 저장한 절화가 저온저장보다 증감 정도가 더 빠른 것으로 나타났다. 개화정도는 '시베리아' 나리의 건식저장 기간이 길어질수록 개화시기가 빨라지며, 절화가 빨리 시들어 상품으로써 유지 기간이 짧아졌다. 개화상태를 비교해 보면 3일 저온 건식저장이 다른 처리보다 개화하는 속도가 늦었으나 절화수명은 다른 처리구보다 길게 나타났다. '시베리아' 나리의 저온 건식저장은 저장 기간이 짧을수록 저장 후 수분함량이 높고 수분 균형값이 음(-)에 늦게 도달하였으며 개화상태가 좋고 절화수명도 길어지는 것으로 나타났다. '시베리아' 나리는 건식저장을 통한 작물체내 수분 함량 감소가 절화보존 시 개화 특성에도 영향을 미쳐 저장기간이 길수록 절화수명이 감소하여 상품 가치를 떨어뜨렸다. '시베리아' 나리 절화를 소비자가 이용 시, 상품 가치 유지를 위해서는 기존 결과의 6일 동안 저온 건식저장도 절화수명을 단축시키므로 저장 기간을 최소화하는 것이 절화 품질 유지를 위해 바람직하다고 판단된다. In order to determine the relationship between water content and flower qualities of oriental hybrid lily cv. 'Siberia' cut flower, flowers were subjected to dry and cold storage at $5^{\circ}C$ for 3, 6, and 12 days and subsequently exposed to ambient temperature ($26^{\circ}C$) in bottles with water for up to 16 days. Flowers stored at $22^{\circ}C$ in dry condition for 3 days were used as the control. Changes in fresh weight, moisture content, water balance, flowering stages, osmolality and vase life of cut flowers were observed. Flowers treated with cold and dry storage had higher moisture content compared to control sample. However, this trend was evident only for 3-day cold and dry stored sample during the whole storage period. The fresh weight of cut flowers increased gradually when the samples were transferred to ambient temperature in water bottles and then declined steadily before reaching the peak in between 6-8 days of vase life. However, the changes of fresh weight of control sample were substantially faster than samples pre-treated with cold and dry storage. This was also correlated with the water balance of cut flower as it reached the minus (-) value in 6-8 days of vase life at ambient temperature. Cut lily flowers showed high osmolality values corresponding with the duration of dry storage regardless of low or higher temperature. However, osmolality had no effect on vase life since flower stem absorbed water rapidly at the end of dry storage period. Our vase life results suggest that cold and dry storage of lily cut flowers for a certain period could ensure longer vase life at ambient temperature. It was observed that prolonging the storage period at cold and dry condition for more than a week significantly increased bud abortion, reduced longevity of flowers and reduced the vase life of cut flowers. On the other hand, the shorter cold and dry storage treatment delayed the bud opening and senescence of the flowers, thus, slowering the normal maturation and aging. Results indicated that dry and cold storage at $5^{\circ}C$ for 3 days was effective in maintaining and preserving overall quality and vase life at ambient condition of oriental hybrid lily cut flowers.

농산물 산지 저온저장 시설의 운용실태 및 효율적 활용방안

조명기 한국식품유통학회 2004 食品流通硏究 Vol.21 No.4

As agricultural products are living organisms, preserving them in a fresh and safe condition is not simple. Demand and supply are also unstable depending on season and weather. Especially, there is a difficulty in storing agricultural products due to increase of materials during harvest period. It makes cold storage an efficient management tool of agricultural products. The efficient policy alternatives for cold storage facilities can be suggested as below. First, regional cold storage facilities for agricultural products had to be large scale so that mending present facilities is required. The old facilities could be closed or proper size facilities need to be built in regional main producing areas. Second, with cold storage facilities, the equipment like pre-cold system and cold-storage car, grading, packing, and processing equipment have to be installed and modernized. Third, to raise operation ratio of cold-storage facilities, the facilities have to be utilized in consideration of time, item and technology by region, facility, and operating body. Fourth, to prevent overlapping investments, the enterprises associated government agencies should be unified. It would also strengthen connection among regions. Fifth, the insolvent facilities sponsored by the government should be utilized based on working rules that make facility leasing, transfer, acquisition and exchange possible. Sixth, to make exact and reliable statistics for cold-storage facilities, the sample selection by region, operating body, item, and size would be better than current total population survey. Also the should body examination be run as an independent organization instead of being controlled by regional government. Lastly, to build consumers' in cold-stored products, continuous PR, the development of item-specific trust consumer preference ennancement regional situation improvement and experts guide for equipment and management would be necessary.

EXPERIMENTAL STUDY ON PERFORMANCE CHARACTERISTICS OF COLD STORAGE HEAT EXCHANGER FOR ISG VEHICLE

D. W. LEE 한국자동차공학회 2017 International journal of automotive technology Vol.18 No.1

The ISG (Idle Stop and Go) system isvery useful in the automobile industry because it increases fuel consumption and reduces green house gas emissions. However, when the engine is on standby, the air-conditioning system does not work due to compressor inactivity, causing thermal discomfort to passengers. This study examines the thermal storage system, which is a cold storage heat exchanger integrated with a current evaporator. The experiments were conducted for an optimum cold storage heat exchanger design with various fin heights and densities, a number of stacking evaporator plates, refrigerant flow circuits inside the evaporator, and PCMs (Phase Change Materials) in the heat exchanger. The effects of coldness-release performance were examined with various ambient temperatures and air flow volume rates to the cold storage heat exchanger. The visualization of PCM’s freezing and melting was conducted with the cold storage heat exchanger. From the results, we found that the air discharge temperature of the air-conditioning system that was applied to the optimum cold storage heat exchanger was delayed around 540 seconds compared to the current air-conditioning system to reach 24 °C. Thus we can say that the cold storage heat exchanger integrated with an evaporator is an effective solution for ISG vehicles in maintaining thermal comfort in vehicle cabins during short engine stops.

저온저장 음나무 배발생 캘러스로부터 체세포배 유도와 식물체 재생

이나념,최용의,문흥규 한국식물생명공학회 2015 식물생명공학회지 Vol.42 No.4

Somatic embryogenesis is as an excellent technology for potential use in plant mass production, germplasm conservation, or genetic engineering. We examined the effect of cold storage using 3 embryogenic callus lines with different levels of embryogenesis competence derived from immature zygotic embryo cultures of Kalopanax setemlobus. Somatic embryo induction, germination and plant conversion were evaluated after 1, 3 and 6 months storage at 4°C in the dark. Most cold-stored embryogenic calli formed somatic embryos normally even after 6 months; however, the induction rate was gradually decreased by increasing the storage period. The most competent line tended to show a slight decline in somatic embryo induction rate, as compared with other lines after cold storage. In general, cold storage resulted in reduced somatic embryo germination and plant regeneration, although 93% somatic embryo germination and 91% plant conversion were achieved regardless of the storage period. Cold storage led to cell browning and degradation. Additionally, the cell structures were confirmed by the aceto-carmine and evans blue dye evaluation. Collectively, our results showed that embryogenic callus of K. septemlobus could be preserved at 4°C without subculture for 6 months, and suggested the need for storage of relatively more competent embryogenic calli lines to support somatic embryo induction.

처리조건에 따른 조생온주밀감의 저온저장 특성

양영택,송상철,김성학,김지용,고정삼,Yang, Young-Taek,Song, Sang-Cherl,Kim, Seong-Hak,Kim, Ji-Yong,Koh, Jeong-Sam 한국응용생명화학회 1997 Applied Biological Chemistry (Appl Biol Chem) Vol.40 No.2

제주산 궁천조생의 저장조건에 따른 저온저장 특성을 검토하였다. 상온저장에 비해 저온저장 감귤은 저장기간 중 가용성 고형물, 총당, 비타민 C의 변화가 매우 적었으며, 부패율과 중량감소가 각각 10% 이내 수준에서 비교적 신선도를 유지한 상태에서 3월 하순까지 저장이 가능한 것으로 보였다. 또한, 중량감소, 경도의 저하, 당함량의 감소는 저장기간 중에 계속하여 서서히 일어났다. 필름포장과 wax-coating은 중량감소와 외관향상에는 도움을 주었으나 장기간 저장에는 부패율이 증가하였다. 습도조절을 하지 않은 저온저장은 습도조절한 경우와 비교하였을 때 부패율과 중량감소가 컸다. 증산작용으로 인한 껍질수분의 감소에 따라 과육으로부터 수분이동이 발생하여 저장기간 중 과육율이 감소하였으며, 저장 60일 후부터 경도저하가 많이 일어나 조직이 연화됨을 알 수 있었다. 조기수확한 감귤에 비하여 완숙한 감귤이 부패율과 중량감소가 적어 저장 100일간을 기준하여 출하하는 것이 바람직하였다. 상온저장한 감귤에 비해 저온저장한 감귤은 저장 4개월 이후 출고하였을 경우 외관 및 맛에 비교적 우수하였으며, 출고후 필름포장한 감귤의 부패율은 급속히 증가하여 취급에 주의가 필요하였다. 조생온주의 경우 저온에서 장기간 저장이 어려움을 알 수 있어서 저장용 감귤의 특성을 고려하여 저장조건을 설정할 필요가 있었다. The conditions of cold storage of Citrus unshiu Marc. var. miyagawa produced in Cheju were investigated. Compared to the citrus fruits stored at room temperature, the content of soluble solids, total sugar, vitamin C and specific gravity decreased slightly on the fruits stored at $4^{\circ}C$ and 87% relative humidity. Decay ratio and weight loss were below 10% on keeping freshness relatively till late of March during cold storage. Weight loss, decrease of firmness and soluble solids occured gradually during cold storage. Nevertheless seal-packaging with 0.02 mm LDPE film or wax-coating of citrus fruits were effective on weight loss and appearance, decay ratio increased for long-term storage. It was needed to control humidity in cold chamber for preventing from decay and weight loss. Edible part ratio was decreased gradually by respiration, and peel and tissue of fruits were softened slightly by 60 days of cold storage. Decay ratio and weight loss of full-ripened citrus fruits were little during the storage for 100 days, compared to the fruits harvested early. Appearance and taste of citrus fruits stored for 4 month were good relatively, but decay occured rapidly on seal-packaging fruits putting out of cold room for a few days. Because of the difficulty of long-term storage for early variety of Citrus unshiu, the conditions and periods of cold storage would be determined after considering the physicochemical properties of fruits.

Development of Low-cost Refrigerator for Fruits and Vegetable Storage

( Hongsun Yun ),( Mungi Kim ) 한국농업기계학회 2018 한국농업기계학회 학술발표논문집 Vol.23 No.1

Proper cooling and storage of produce is as essential for a quality of produce as growing quality produce is. Efficient cold storage enables farmers to supply fresher produce for a longer period of time. In order to store fresh produce, it should be stored at suitable temperature and relative humidity conditions, depending on the produce. Most fresh produce requires a temperature of 0 to 10 ℃ and a relative humidity of 85 to 95% for cold storage. On the other hand, some agricultural products, such as onions and garlic, require a low relative humidity of 65-75%. The cold store is designed to provide a very innovative technology solution, to address the different temperature and relative humidity requirements, for various produce. The range of produce can be stored using two different conditions. One condition will be cool and dry with a temperature range between 0~5℃ and 65-75% relative humidity. The other condition will be cold and damp with a range of 0~10℃ and 85-95% relative humidity. The dimensions of the cold store were 3.5m x 2.8m and 2.4 m height. Polyurethane panel were selected for the insulation, with a total thermal conductivity of 0.0231W/m.K, and having a thickness 100mm. The total heat load of the store was analyzed. This is composed of field heat, heat from respiration, heat from conduction through the walls and heat generated from electrical components and workers moving in and out. The maximum heat load was determined to be 2.95kW. Using the maximum heat load information, the refrigeration system design was evaluated. The heat transfer coefficient of the cold store is 0.24 W/㎡℃. When cabbage is stored, the average temperature and the average relative humidity in the cold store is 0.0℃ and 88.3% respectively. And, When galic is stored, the average temperature and the average relative humidity in the cold store is 0.9℃ and 68.5% respectively. Supply price of the cold storage system was calculated as $5,600 for high humidity and $4,700 for low humidity.

저장고 내부 위치에 따른 저장환경과 복숭아 ‘Kunika’의 품질 분석

박천완,조세라,최동수,김용훈,김승희,송주희 한국산학기술학회 2023 한국산학기술학회논문지 Vol.24 No.11

This study was carried out to determine the relationship between the environmental characteristics of kunika peach quality in cold storage in varying conditions. To measure the storage environment's temperature and humidity, sensors were installed at 9 points inside a CA storage facility, and peaches were stored in the same position. The results showed that the temperature and humidity changed with periodicity during the cooling, loading, and defrosting operations of the cold storage. During the defrost operation, the temperature at the top of the storage facility rose high, and the relative humidity near the evaporator decreased by 52%. EOF analysis of the temperature and humidity data inside the cold storage showed that the variability in Mode 1 was strongly influenced by humidity. Weight loss was highest at 12.8% at the position where the lowest humidity was measured. Hardness and soluble solids did not differ significantly according to the storage date after 2 weeks. Correlation analysis between quality and position showed a greater difference in the vertical direction than the horizontal direction. The difference between quality and storage-environment variability was also higher in the vertical direction, but more detailed analysis of temperature, humidity, and wind speed individually and collectively is needed.

Prediction of Air Movement and Temperature Distribution at Different Store Methods Using 3-D CFD Simulation in Forced-Air Cooling Facility

Yang, G.M.,Koh, H.K. Korean Society for Agricultural Machinery 2002 Agricultural and Biosystems Engineering Vol.3 No.2

Temperature is the most influential environment parameter which affects the quality change of agricultural products in cold storage. Therefore, it is essential to keep the uniform temperature distribution in the storage room. This study was performed to analyze the air movement and temperature distribution in the forced recirculating cold storage facility and to simulate optimum storage method of green groceries using 3-D CFD(three dimensional computational fluid dynamics) computer simulation which applied the standard $textsc{k}$-$\varepsilon$ turbulence model and FVM(finite volume method). The simulation was validated by the experimental results for onion storage and the simulation model was used to simulate the temperature and velocity distribution in the storage room with reference to the change of storage method such as location of storage, no stores, bulk storage, and pallet storage. In case of no stores, internal airflow was circulated without stagnation and consequently air movement and temperature distribution were uniform. In case of bulk storage, air movement was stagnated so much and temperature distribution of onion was not uniform. Furthermore, the inner temperature of onion roses more than the initial temperature of storage. In case of pallet storage, air movement and temperature distribution of onion were so uniform that the danger of quality change was decreased.

냉동 및 냉장 저장한 돈까스와 햄버거스테이크의 품질특성

이주호(J. H. Lee),이진규(J. K. Lee),정지택(J. T. Jeong),최정석(J. S. Choi),최양일(Y. I. Choi) 충북대학교 동물생명과학연구소 2017 동물생명과학연구 Vol.9 No.-

Freezing of meat products is essential to inhibit the growth of microorganisms and deterioration of quality during distribution. However, eating quality of frozen meat products is decreased due to the water loss by formation of ice crystals. Therefore, this study was conducted to determine the quality and storage characteristics of pork cutlet and hamburger steak which are representative frozen meat products during the 7 days at the 4℃ (Cold) and -16℃ (Frozen) storages. Treatments are as follows. P1(Frozen pork cutlet), P2(Cold pork cutlet), H1(Frozen hamburger steak), and H2(Cold hamburger steak). During the 7 day storages, the frozen meat products had higher moisture contents than those of cold meat products (p<0.05). The cooking and purge losses of cold meat products were lower than frozen meat products (p<0.05). In the storage characteristics, the frozen meat products had lower VBN, TMC, and TBA values than those of cold meat products(p<0.05). In the texture properties, the pork cutlet showed high texture characteristics in cold storage and the hamburger steaks showed high texture characteristics in freezing storage. As results, the pork cutlet is considered to be good in cold distribution, and the hamburger steak is recommended to distribute in frozen state for maintenance of quality.