• 태양에너지
• /
• 제19권4호
• /
• pp.33-43
• /
• 1999

The study on ice thermal storage system is to improve total system performance and increase the economical efficiency in actual all-conditioning facilities. To obtain the high charging and discharging efficiencies in ice thermal storage system, the improvement of thermal stratification is essential, therefore the process flow must be piston flow in the cylindrical type. With the relation of the aspect ratio(H/D) in the storage tank, the stratification is formed better as inlet flow rate is smaller. If the inlet and the outlet port are settled at the upside and downside of the storage tank, higher storage rate could be obtainable. In case that the flow directions inside the thermal storage tank are the upward flow in charging and the downward in discharging, thermal stratification is improved because the thermocline thickness is maitained thin and the degree of stratification increases respectively. In the charging process, in case of inlet flow rate the thermal stratification has a tendency to be improved with the lower flow rate and smaller temperature gradient in case of inlet temperature, the large temperature difference between inflowing water and storage water are influenced from the thermal conduction. The effect of the reference temperature difference is seen differently in comparison with the former study for chilled and hot water. In the discharging process, the thermal stratification is improved by the effect of the thermal stratification of the charging process.

• 수산해양교육연구
• /
• 제18권3호
• /
• pp.293-301
• /
• 2006

연속식 스테인레스 단자 방식의 전해수의 기기특성과 오징어를 담수빙과 산성전해수빙, 염기성전해수빙 저장 중 선도보존 효과 및 표피색변화에 대하여 검토하여, 향후 연안 어류의 전기분해수 빙장 적용기초 자료로 이용하고자 연구한 결과를 요약하면 다음과 같다. 1. 본 연구에서는 TMD에서 개발된 기기에 단자를 구리에서 스테인레스로 교체한 TMD II기기의 성능을 평가하였다.실험결과 전체적으로 동일한 전류를 걸었을때, 산성전해수의 경우 낮은 pH를 유지했으며, 유량을 늘릴수록 산성도가 떨어지는 것을 알 수 있었다.본 장치는 단자부분 재질의 감도를 보다 높이고 전해 촉매제를 사용할수 있다면, 충분히 더 낮은 혹은 더 높은 pH를 확보할 수 있으며 또한 알카리 영역의 경우도 그럴 수 있으리라 예측된다. 2. 먹는물 수질기준에 따른 유속별 생산 전해수의 수질분석 및 미생물검사결과 세균학적인 검사의 경우 모든 검사과정에서 먹는물 기준 이하치를 나타내고 있으나 산성전해수의 경우 미생물학적인 검사에서 음성의 결과를 나타냈으나, 알카리수의 경우 중온성 세균수에 있어서는 먹는물의 수준은 될 수 없음을 알 수 있다. 3. 전해수빙과 담수빙 저장중 오징어의 일반성분과 VBN관찰 결과 수분 함량은 77.65%였으며 단백질 함량은 18.32%, 지질의 함량은 2.41%, 회분 함량은 1.62%로 나타났다. 오징어 빙장 직전 11.2mg/100g이었으며, 저장 초기에 모든 산성 전해수 빙장구에서 VBN 증가가 억제되었다.담수빙 법에서의 VBN 증가가 전해수빙중 산성수빙보다 훨씬 빠르게 진행되었으며 염기성수빙 보다는 느리게 진행되었다. 4. 저장중 오징어의 외관 및 색도 변화를 색차계로 저장시간별로 측정한 결과, 명도(L)는 저장시간별로 감소하는 경향이었으며, 적색도, 황색도는 저장방법에 따른 차이는 있었지만 저장기간에 따라서 증가하는 경향을 보였다. 즉, 저장시간별로 적색에서 녹색으로 청색에서 황색으로 색깔의 변화가 진행됨을 알 수 있었다. 백색도의 경우도 명도와 비슷한 경향 이었다.

• 대한설비공학회:학술대회논문집
• /
• 대한설비공학회 2004년도 하계학술발표 논문집
• /
• pp.94-94
• /
• 2004

• Asian-Australasian Journal of Animal Sciences
• /
• 제29권12호
• /
• pp.1782-1789
• /
• 2016

This study evaluated the effect of vacuum and modified atmosphere (40% $CO_2+60%$ $N_2$, MA) packaging on the chemical composition, physicochemical properties and sensory attributes of chill-stored meat from 10 fallow deer (Dama dama) bucks at 17 to 18 months of age. The animals were hunter-harvested in the forests of north-eastern Poland. During carcass dressing (48 to 54 h post mortem), both musculus longissimus muscles were cut out. Each muscle was divided into seven sections which were allocated to three groups: 0, A, and B. Samples 0 were immediately subjected to laboratory analyses. Samples A were vacuum-packaged, and samples B were packaged in MA. Packaged samples were stored for 7, 14, and 21 days at $2^{\circ}C$. The results of the present study showed that the evaluated packaging systems had no significant effect on the quality of fallow deer meat during chilled storage. However, vacuum-packaged meat samples were characterised by greater drip loss. Vacuum and MA packaging contributed to preserving the desired physicochemical properties and sensory attributes of meat during 21 days of storage. Regardless of the packaging method used, undesirable changes in the colour, water-holding capacity and juiciness of meat, accompanied by tenderness improvement, were observed during chilled storage.

• 대한설비공학회지:설비저널
• /
• 제20권2호
• /
• pp.125-133
• /
• 1991

This paper presents some design guidelines for using cold air/water distribution to cool commercial and industrial buildings. Cold air /water distribution systems provide primary air/water for space conditioning at nominal temperature between $3^{\circ}C$ and $10^{\circ}C$ ($4{\sim}5^{\circ}C$ might be recommendable for better selection). By using lower temperature primary air/water equipment could be downsized, means lower first costs, and often reduce annual energy costs up to 50% less than that of the conventional ($13^{\circ}C$) system. This concept takes full advantages of the $2{\sim}4^{\circ}C$ chilled water (brine) available with ice storate systems.

• 태양에너지
• /
• 제19권2호
• /
• pp.1-8
• /
• 1999

The heat transfer characteristics of ice storage system of falling film type using sprial coil is investigated. The experimental facilities consisted of a water tank, spiral coils located above the tank, an upper water distributor, and a circulating water pump. Water is distributed uniformally over the spiral coils and it forms falling thin films. In the process of freezing, ice is formed on outside of the spiral coils through recirculation of tank water. In the process of melting, ice is melted with return water from the heat load, while the water is chilled again and drops into the tank. The results of falling film type of ice thermal storage system are as follows. The highly efficient shower flowrates for icing is near $3{\ell}/min$. Icing rates on spiral coils is rosed while brine flowrates is increased. Lower brine temperature is not only increased freezing rates but. also become higher total icing weight and overall heat transfer coefficient. Smaller shower flowrates is obtained lower water temperature on outlet for a long time. The amounts of quantity can be detected more accurately by measuring storage tank weight.

• 한국태양에너지학회 논문집
• /
• 제21권4호
• /
• pp.37-46
• /
• 2001

This study describes the experimental study that focuses on the effects that distributor shapes and flow rate variations have an influence on the stratification in a rectangular thermal storage tank. Experiments were carried out under the conditions that the flow rates of working fluid are 20, 10 and $5\ell$/min. The storage tank is initially filled with chilled water of $1^{\circ}C$, and is extracted through the bottom at the same rate as the return warm water from load is entered through the distributor at the top of the tank. The thermo-cline forms at the top of the storage tank as the warm water enters the tank from the load through the distributor and the thermo-cline thickness increases with time. Emphasis is given to the effects of mixing at the inlet that increases the thermo-cline decay Flow rate variation and inlet distributor shapes are the important parameters in deciding the performance of a storage system. Stratification degree increases with decreasing in inlet flow rate under $10\ell$/min. Experiments shows that better thermal stratification can be obtain using the distributor to limit momentum mixing at the inlets and outlets. Also, 12% of improvement in the thermal energy usage has been achieved using the modified distributor discharging same flow rate in each lateral ports.

• 한국식품저장유통학회지
• /
• 제14권6호
• /
• pp.598-604
• /
• 2007

한국의 고유 식품인 깻잎은 위생적, 고품질 및 규격화된 가공방법의 개발이 요구된다. 본 연구에서는 깻잎 절임의 관능적, 위생상 안전성이 향상된 최적조리 조건을 확립하고자 하였다. 그 결과 반응표면분석에서는 저장기간에 따른 성분 조성의 최적값에는 차이가 있으나 저장식품인 경우를 고려할 때 간장 $24{\sim}27g$, 물엿 24 g이 전반적으로 적합한 것으로 나타났다. 깻잎의생균수는 세척전 8.08 cfu/g에서 세척 후 4.27 cfu/g 으로 약 50% 수준으로 감소하였다. 또한 3% 염수에 침지 후 세척한 깻잎은 0.55 cfu/g으로 미생물이 대부분 제거되었다. 이는 가열 조리하는 방법의 밑반찬과는 달리 비열처리되는 반찬이므로 저장성에 효과가 있을 것으로 판단된다. 깻잎 절임의 저장 중 품질 변화에 있어서 배합조건에 대한 큰 차이는 볼 수 없었으나, 전처리 및 세척 방법에 따른 저장성의 차이가 나타났으며, 3% 염수에 1분간 침지 후 수돗물에 헹궈서 이용하는 것이 미생물 생육을 억제하고 저장성에도 가장 효과가 우수하였다.

• 대한설비공학회:학술대회논문집
• /
• 대한설비공학회 2008년도 동계학술발표대회 논문집
• /
• pp.27-32
• /
• 2008

The present study has been conducted economic analysis of heat storage type ground source heat pump system(HSGSHP) and normal ground source heat pump (GSHP) which are installed at the same building in the shared an apartment house. Cost items, such as initial cost, annual energy cost and maintenance cost of each system are considered to analyze life cycle cost (LCC) and simple payback period (SPP) with initial cost different are compared. The initial cost is a rule to the Government basic unit cost of production. LCC applied present value method is used to assess economical profit of both of them. Variables used to LCC analysis are prices escalation rate and interest rate mean values of during latest 10 years. The LCC result shows that HSGSHP (1,050,910,000won) is more profitable than GSHP by 68.9% initial cost. And SPP appeared 3.0 year overcome the different initial cost by different annual energy cost.

• 한국수산과학회지
• /
• 제16권2호
• /
• pp.117-124
• /
• 1983

Qualify changes of the precooked frozen sardine (Sardinops melanosticta) during frozen storage were investigated by measuring extractable protein, expressible drip, available lysine and lipid oxidation as peroxide value. Fresh sardine was dressed, washed in chilled water, cooked in boiling water to have $55^{\circ}C\;and\;70^{\circ}$ at the center of the body, frozen at $-40^{\circ}C$, and finally stored at $-20^{\circ}C$ for 84 days. The quality factor mentioned above were determined in both ordinary and dark muscle at 14 day intervals through the period of storage. When cooked at $70^{\circ}C$, the changes in expressible drip were less than that of raw and the one cooked at $55^{\circ}C$. In observation of the extractability of muscle protein, no great change in extractable sarcoplasmic protein was observed, the extractable myofibrillar protein, however, showed a tendency to decrease during the period of frozen storage, accompanying the increase of the alkali-soluble protein. That was more excessive in ordinary muscle than dark muscle. Lipid oxidation of dark muscle was faster than that of ordinary muscle. Acid value was not changed, and peroxide value of the samples cooked at $70^{\circ}C\;and\;55^{\circ}$ was higher than that of raw at the early stage of the storage, after 40-50 day storage, it became lower than that of raw muscle.