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정낙규(Nak Kyu Chung),김진흥(Jin Heung Kim),김창오(Chang Oh Kim) 대한기계학회 2005 대한기계학회 춘추학술대회 Vol.2005 No.5
This study is investigated the supercooling improvement and the cooling characteristics of the TMA clathrate compound including TMA(Tri-methyl-amine, (CH₃)₃N) of 25 wt% with additive as a low temperature storage material at -6℃ heat source. The additive is ethanol of 0.1, 0.3 wt% and 0.5 wt%. The results showed that as the concentration of ethanol is increased, phase change temperature, the supercooling and retention time of liquid phase are decreased. Especially, TMA 25 wt% clathrate compound with ethanol of 0.5 wt% has the average of phase change temperature of 3.8℃ supercooling of 0.9℃ and retention time of liquid phase for 6 minutes in the cooling process. From the results of this study, TMA 25 wt% clathrate compound with ethanol showed higher phase change temperature than water and supercooling repression effect.
정낙규(Nak Kyu Chung),김진흥(Jin Heung Kim),정종헌(Chang Oh Kim),김창오(Jong Hun Chung),강승현(Seung Hyun Kang) 대한기계학회 2004 대한기계학회 춘추학술대회 Vol.2004 No.11
The objective of this study is to investigate the effect of supercooling repression on the clathrate compound by adding additives. For this purpose, phase change temperature and supercooling were measured when additives added to TMA30wt% clathrate for heat source temperature of -6℃. The experimental results show that the phase change temperature with the chloroform of 0.1wt% is higher by 0.3C than TMA30wt% and the supercooling with the surfactant 0.1 wt% is reduced by 9.2℃.
포접화합물의 열물성에 미치는 첨가제의 효과 (Ⅲ) - TMA 물계 포접화합물에 Acetone을 첨가한 경우 -
김진흥(Jin Heung Kim),정낙규(Nak Kyu Chung),김석현(Suk Hyun Kim),김창오(Chang Oh Kim),강승현(Seung Hyeon Kang) 대한설비공학회 2004 설비공학 논문집 Vol.16 No.12
An experimental investigation is conducted to measure phase change temperature and supercooling when acetone is added to TMA 30 wt% clathrate during cooling process in heat source. Also rate of volume change is investigated when acetone is added to TMA 30 wt% clathrate during the cooling process in heat source -8℃. The results show that phase change temperature is about 4.5~5.5℃ when acetone is added to TMA 30 wt% clathrate during the cooling process for heat sink temperature of -6, -7℃ and -8℃. Supercooling is repressed about 2~10℃ when 0.08 wt% acetone is added to it and rate of volume change is decreased about 2.9% when 0.1 wt% acetone is added for the heat sink temperature of -8℃.
김창오(Kim Chang-Oh),정현호(Chung Hyun-Ho),정낙규(Chung Nak-Kyu) 대한기계학회 2010 大韓機械學會論文集B Vol.34 No.2
빙축열시스템은 저온잠열저장을 위해 물을 사용한다. 그러나 물은 액체에서 고체로 상변화를 하는 과정에서 물의 과냉각 현상에 의하여 냉동기의 냉동용량 증가와 COP감소의 원인이 되고 있다. 본 연구는 저온잠열축열물질로 적용 가능한 TMA(Tri-methyl-amine, (CH3)3 N) 20~25 wt%를 포함하고 있는 TMA-물계 포접화합물(TMA-water clathrate compound)의 냉각특성에 대한 실험적 연구를 수행하였다. 실험적 연구 결과, TMA 질량농도가 높을수록 상변화온도는 증가하였고, 과냉각도와 비열은 감소하였다. 특히, TMA 25wt%를 포함하고 있는 포접화합물은 냉각과정동안 평균 상변화온도 5.8℃와 과냉각도 8.0℃, 액상유지시간 651sec 및 비열 3.499 kJ/㎏K로서 다른 TMA 농도보다 양호한 냉각특성을 나타내었다. 이와 같이 저온잠열축열물질로서 TMA 25wt%-물계 포접화합물을 적용하는 것이 유리할 것으로 판단된다. The ice storage system uses water for low temperature latent heat storage. However, a refrigerator capacity are increased and COP are decreased due to supercooling of water in the course of phase change from liquid to solid. This study investigates the cooling characteristics of the TMA-water clathrate compound including TMA (Tri-methyl-amine, (CH3)3N) of 20~25 wt% as a low temperature latent heat storage material. The results showed that the phase change temperature are increased and the supercooling degree and the specific heat are decreased according to the weight concentration of TMA increased. Especially, the clathrate compound containing TMA 25wt% has the average phase change temperature of 5.8℃ and the supercooling degree of 8.0℃, retention time of liquid phase for 651sec and specific heat of 3.499 kJ/㎏K in the cooling process. This expressed good than different concentration of TMA cooling characteristic. Like this, to apply TMA 25wt%-water clathrate compound is determined by advantageous as the low temperature latent heat storage material.