• International Journal of Air-Conditioning and Refrigeration
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• 제15권4호
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• pp.175-181
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• 2007

A computer model of a high efficiency refrigeration system equipped with heat storage for reverse cycle-hot gas defrost (the stored heat is used during defrost cycle of the system) is presented. The model was developed based on both theoretical and empirical equations for the compressor, evaporator, condenser and the heat storage equipment. Simulations of the prototype system were carried out to investigate refrigeration system performance under various operating conditions during refrigeration cycles. The simulations of the evaporator during defrost cycles at 30 and $40^{\circ}C$ hot gas refrigerant temperature were also performed which resulted on shorter defrost time but only slight increase in defrost efficiency. These information on energy efficiency and the defrost time required are important in order to avoid excessive parasitic load and temperature rise of the refrigerated room.

• 설비공학논문집
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• 제22권6호
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• pp.369-374
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• 2010

A refrigerant-subcooling refrigeration system consisted of a typical single vapor-compression refrigeration cycle, a subcooler, and an ice storage tank. The degree of subcooling at the exit of the condenser can be increased by the heat exchange between the subcooler and the ice storage tank. The cold heat in the ice storage tank was stored by using the refrigeration cycle during night time and then used to absorb the heat from the subcooler during daytime. The performance of the refrigerant-subcooling refrigeration system was measured by varying the degree of subcooling. In addition, the performance characteristics of the present system were compared with those of a conventional refrigeration system. The mass flow rate of the present system was higher than that of the conventional system due to the increase in the degree of subcooling. Generally, the refrigerant-subcooling system showed superior performance to the conventional refrigeration system.

• 설비공학논문집
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• 제22권12호
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• pp.845-851
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• 2010

This study was experimentally performed to find the effects of refrigerant subcooling in the refrigeration system and to propose how to get the efficient use of energy. A refrigerant-subcooling refrigeration system consisted of a typical single vapor-compression refrigeration cycle, a subcooler, and an ice storage tank. The degree of subcooling at the exit of the condenser can be increased by the heat transfer between the subcooler and the ice storage tank. The cold heat in the ice storage tank was stored by using the refrigeration cycle during night time and then used to absorb the heat from the subcooler during daytime. The cooling capacity and COP of this system were higher than those of the conventional system due to the increase in the degree of subcooling. Typically, the refrigerant-subcooling system showed superior performance to the conventional refrigeration system and would also contribute to load leveling.

• 설비공학논문집
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• 제23권6호
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• pp.406-412
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• 2011

This paper describes the analysis on freeze and refrigeration capacity of cold storage facilities for fisheries products during the last 15 years. And based on the analysis results, we prospect the number and scale of cold storage facilities in the near future. The main analysis results are summarized by the followings; Under the present conditions, the number and scale of our facilities is 879 and 3,586,824 ton, respectively. In comparison of the present and last 15 years ago, the business number increases about 22%, the accommodation capacity increases approximately 80%. In the reported update reference with the related data during the last 15 years, the capacity of cold storage facilities in 2011 expects to reach up to 4,600,000 ton. The newlyestablished facility in 2011 has the function of a multi-purpose distribution center as well as the existing cold storage, but this facilities converges in the capital area. Therefore, in this paper, we provided the basic reference data for the present situation and prediction of our cold storage facilities. But it is necessary to investigate and analyse widely our cold storage facilities for fisheries products in the near future.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2005년도 동계학술발표대회 논문집
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• pp.585-590
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• 2005

It can be said that refrigeration and air-conditioning technology in Korea dates back to the ancient Shilla dynasty, all the way up to the Sokkuram(700s) and Seokbinggo(1700s). But modem refrigeration and air-conditioning technology was first developed in and introduced to Korea in the 1960s with the modernization of Korea. Today it is at a level which meets that of advanced countries in both the industrial and domestic fields. 62 million units of refrigeration and air-conditioning machinery and equipment were produced in 2003, worth a total of 7.7 trillion won(about 7.7 thousand million US$). As of 2003, there were about 700 companies that owned cold storage / freezing / refrigeration facilities, with cold storage capacity of about 2 million ton and capacity per company of about 3 thousand ton. This facilities most are continuously expanding and automatizing their facilities.

• Journal of Biosystems Engineering
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• 제33권3호
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• pp.167-172
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• 2008

The objective of this study was to investigate the adequate storage method that was able to maintain the high quality of rough rice according to storage methods and period. The quality change of the rough rice during the storage period was evaluated by storage method such as cooling bin using winter cold air, ordinary temperature bin, freezing, refrigeration and indoor storage. Moisture content, brown rice whiteness, hardness, crack ratio and germination ratio were measured in this study. Moisture content of rough rice stored in cooling bin using winter cold air and ordinary temperature bin were decreased by 0.07% and 0.42%, respectively, which were lower than the other storage method. The hardness of brown rice increased in order of storage method such as winter cooling bin, normal bin, freezing storage, refrigeration storage and indoor storage. Crack ratio by indoor and ordinary temperature bin storage were increased by 2.68% and 3.63%, respectively, whereas cooling bin using winter cold air, refrigeration and freezing storage showed below 1.0%. The highest germination rate was found in cooling bin using winter cold air. As a result, cooling bin using winter cold air can be evaluated for the adequate storage method of rough rice.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2009년도 하계학술발표대회 논문집
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• pp.810-814
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• 2009

A experimental study of a high efficiency transport refrigeration system for sliced-raw fish transportation is presented in this paper. The refrigeration system, that is powered by the car engine, is equipped with heat storage for reverse cycle-hot gas defrost; the stored heat is used during defrost cycle of the system. The heat storage has size $400(L){\times}350(W){\times}250(H)\;mm$ and made of fin-tube heat exchanger. System performance and container operating conditions are experimentally investigated and analyzed under cooling and defrosting conditions with heat storage materials. The water is faster about 30% than paraffin in cooling-down time of heat storage materials with load and unload.

• 설비공학논문집
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• 제23권9호
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• pp.587-594
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• 2011

This paper describes the investigation on current state of cold storage facilities, and analysis on the demand prediction in the near future. And based on the analysis results, we prospect the scale of cold storage facilities in the near future. The main analysis results are summarized by the followings ; The present circumstances of cold storage facility are determined by investigating actual loading capacity, average stock amounts, and return number of cold storage facility. From the results, the present situation for cold storage facility is about 3% over. It is found that the average stock amounts increase gradually, and accordingly that the demand of cold storage facility is predicted to be increased, resulting that the capacity of cold storage facilities in 2013 expects to reach up to 5,250,000 ton. It is considered that the results of demand prediction has significant implications on the management of cold storage facility in the near future.

• 대한한의학회지
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• 제39권1호
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• pp.22-34
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• 2018

Objectives: The purpose of this study is to investigate changes of the marker compounds and anti-inflammatory effect of Gamisoyo-san decoction (GMSYS) depending on storage temperature and periods. Methods: GMSYS was stored at room temperature or refrigeration for 12 months. According to storage temperature and periods, pH and sugar content of GMSYS were measured. To determine the marker compounds of GMSYS, high-performance liquid chromatography analysis was performed. To estimate the anti-inflammatory effect of GMSYS, LPS-induced pro-inflammatory mediators and cytokines were measured in RAW 264.7 cells. Results: There was no change in pH and sugar content depending on storage temperature and periods of GMSYS. The contents of gallic acid and mangiferin in both of room temperature and refrigerated decoctions reduced with increasing storage periods. Chlorogenic acid was time-dependently decreased in case of stored at room temperature. GMSYS significantly inhibited the LPS-induced production of nitric oxide, prostaglandin $E_2$ ($PGE_2$) and IL-6 in RAW 264.7 cells. These effects equally maintained up to 3 months at both of room temperature and refrigeration. Since 4 months, the inhibitory effect of GMSYS on LPS-induced $PGE_2$ production was time-dependently reduced, and the decrease in $PGE_2$ inhibitory effect of decoction stored at refrigeration was lower than that of stored at room temperature. Conclusions: Our results indicate that the anti-inflammatory effect of GMSYS are maintained up to 12 months, but it shows optimal efficacy up to 3 months. It is recommended to store in a refrigeration for short periods since some components decrease as storage periods becomes longer.

• 설비공학논문집
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• 제21권6호
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• pp.319-325
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• 2009

The purpose of this study is to investigate the performance characteristics of a bypass two-circuit refrigerator. A bench scale refrigeration system was designed and constructed to estimate possible performance improvement of the bypass two-circuit refrigerator. The experiments were conducted in the bench scale refrigeration system by varying capacity of the condenser and refrigerant charge amount with an adoption of a refrigerant storage vessel. The COPs of the bypass two-circuit refrigeration system in the refrigerator and freezer (RF)-mode and freezer(F) only-mode were increased by 10% and 17%, respectively, with increasing the capacity of the condenser. Besides, the COP of the system in the F only-mode was increased by 10% by adopting the refrigerant storage vessel.