http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
The Effect of Solution Pressure to the Release in a Supercooled Aqueous Solution
Chaedong Kang,Byungseon Kim,Hiki Hong 대한설비공학회 2009 International Journal Of Air-Conditioning and Refr Vol.17 No.1
Supercooled type ice storage system with aqueous solution (or water) may have trouble with non-uniform release of supercooling even though it contributes to the simplicity of system and ecological improvement. The non-uniform release increases the instability of the system because it may cause an ice blockage in pipe or cooling part. In order to suppress the release of the supercooling, a cooling experiment was tried to an ethylene glycol(EG) 3 mass% solution corresponding with pressurization. Also, the frequency ratio of the release of the supercooling was measured to the pressurization from 101 to 505 ㎪. At results, the frequency ratio of supercooling release tends to decrease as the pressure of the aqueous solution increased in each cooling rate. Moreover, it tends to decrease as the cooling rate of the solution decreased in each pressure.
Chaedong Kang,Hyun Seung,Hiki Hong 대한설비공학회 2006 International Journal Of Air-Conditioning and Refr Vol.14 No.3
Ice adhesion or cohesion leads to the decrease of the performance of ice making system, especially to dynamic type ice thermal storage system (DISS) which mainly forms ice from the flow of an aqueous solution. The ice adhesion is influenced by various parameters associated with operating or geometric condition. In this study, the influence on an adhesion of ice to the characteristic of cooling surface and to composition of an aqueous solution was fundamentally observed by using batch type cooling device, a beaker. Three patterns of solution in each beaker were cooled with brine. Moreover, the characteristic of cooling surface on each beaker was distinguished to coating materials. Stirring power as a degree of the ice adhesion was measured. The stirring power to cooling heat transfer rate in each beaker was compared. As a result, the lowest stirring power of 8.9W with non-adhesion of ice, was shown in the case of the aqueous solution of EG(4)+PG(1.5)+1,6HD(1.5) in PE coating beaker.
강채동(Chaedong Kang),이동원(Dong-Won Lee),백종현(Jong-Hyeon Peck),이수양(Soo-Yang Lee),서정식(Jeong-sik Seo) 대한설비공학회 2021 대한설비공학회 학술발표대회논문집 Vol.2021 No.6
Along with the changed power demand system, changes in consumer preferences are further shrinking the thermal energy storage system(TES) market. Moreover, due to the suspension of the subsidy system required for the supply of TES, the related equipment industry is in crisis. On the other hand, variable renewable energy(VRE), i.e., unbalanced power generation by a renewable energy utilization system is gradually increasing, and the need for the development of an energy storage system(ESS) is more urgent due to unbalanced demand. Therefore, the purpose of this study is to examine the domestic and international status of TES and related incentives, and to prepare basic data that can help revitalize the TES industry in the future in line with the national energy supply and demand strategy based on carbon neutral.
Evaluation of heat storage and release in a double shell and tube heat exchanger with a PCM layer
Donggyu Lee,CHAEDONG KANG 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.8
In this study, a thermal storage type heat exchanger that combines heat storage and heat exchange functions has proposed and the heat transfer characteristics of the new type of heat exchanger were analyzed through experiments. The proposed thermal storage type heat exchanger has a shell and tube structure and allows mutual heat transfer between three or more mediums, including a phase change material (PCM). This thermal storage type heat exchanger contains 52.2 kg of a PCM with a phase change temperature of 68.8 °C to provide heat storage function. The heat transfer experiment of the heat exchanger confirmed the effect of the temperature change of the heating medium under the same flow conditions. Furthermore, due to the structural characteristics of the thermal storage type double shell and tube heat exchanger (TSDHE), the phenomenon of three-medium heat exchange (hot watercold water, hot water-PCM, additional water-PCM) was verified during the experimental process. In particular, due to the PCM filled inside the heat exchanger, the cold water received a heat transfer of 3 kW or higher from the PCM for at least 5 min (maximum 33 min), even when the hot water supply (heat source) was stopped. The results of this study will be used as basic data for applying a thermal storage type evaporator to a high temperature heat pump that generates steam using industrial waste heat.
Measurement Methods of Latent Heat for PCM with Low Melting Temperature in Closed Tube
Hong Hiki,Kang Chaedong,Peck Jong Hyeon The Society of Air-Conditioning and Refrigerating 2004 International Journal Of Air-Conditioning and Refr Vol.12 No.4
Cycle test for developed phase change material (PCM) is necessary in order to assess the variation of latent heat, which decreases with time by deterioration. T-history method and measurement using heat-flux meter are appropriate for the cycle test in a tube filled with PCM because they do not need an extraction of sample in measuring heat of fusion. In the present study, these methods were applied to a PCM having a melting point below a room temperature, different to the past studies for PCMs melting above a room temperature. As a result of experiment using pure water as specimen, we can obtained rea-sonable values for heat of fusion.
Measurement Methods of Latent Heat for PCM with Low Melting Temperature in Closed Tube
Hiki Hong,Chaedong Kang,Jong Hyeon Peck 대한설비공학회 2004 International Journal of Air-Conditioning and Refr Vol.12 No.4
Cycle test for developed phase change material(PCM) is necessary in order to assess the variation of latent heat, which decreases with time by deterioration. T-history method and measurement using heat-flux meter are appropriate for the cycle test in a tube filled with PCM because they do not need an extraction of sample in measuring heat of fusion. In the present study, these methods were applied to a PCM having a melting point below a room temperature, different to the past studies for PCMs melting above a room temperature. As a result of experiment using pure water as specimen, we can obtained reasonable values for heat of fusion.