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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℃.
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℃.
TMA 농도에 따른 저온축열물질의 과냉각 특성에 대한 연구
김창오(Chang-Oh Kim),김진흥(Jin-Heung Kim),정낙규(Nak-Kyu Chung) 대한기계학회 2006 대한기계학회 춘추학술대회 Vol.2006 No.11
This study is investigated the supercooling 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 at -5℃, cooling source temperature. The results showed that as the concentration of TMA is increased, phase change temperature is increased, the supercooling and retention time of liquid phase are decreased. Especially, low temperature latent heat storage material containing TMA 25 wt% has the average of phase change temperature of 5.8℃, supercooling degree of 8.0℃, retention time of liquid phase for 10 minutes in the cooling process. Phase change temperature higher than that of water and inhibitory effect against superrcooling can be confirmed through experimental study on cooling characteristics of TMA-water clathrate compound. This can lead to shorten refrigerator operation time of low temperature thermal storage system and improve efficiency of refrigerator COP and overall system.
저온잠열저장을 위한 TMA-물계 포접화합물의 과냉각 특성에 대한 연구
김창오(Kim Chang-Oh),김진흥(Kim Jin-Heung),정낙규(Chung Nak-Kyu) 한국태양에너지학회 2006 한국태양에너지학회 학술대회논문집 Vol.- No.-
Ice storage system that water is used as low temperature latent heat storage material, refrigerator capacity is increased and COP is decreased because refrigerator is operated at low temperature due to supercooling of water in the course of phase change from solid to liquid. This study is investigated 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 at -5℃, cooling source temperature. The results showed that the phase change temperature, the specific heat is increased and the supercooling degree is decreased as the weight concentration of TMA became higher. Especially, low temperature latent heat storage material containing TMA 25 wt% has the average of phase change temperature of 5.8℃, supercooling degree of 8.0℃ and specific heat of 4.099kJ/㎏K inthe cooling process. Phase change temperature higher than that of water and inhibitory effect against supercooling can be confirmed through experimental study on cooling characteristics of TMA-water clathrate compound.
저온잠열저장을 위한 TMA-물계 포접화합물의 과냉각 개선에 대한 연구
김창오(Kim Chang-Oh),김진흥(Kim Jin-Heung),정낙규(Chung Nak-Kyu) 한국태양에너지학회 2007 한국태양에너지학회 학술대회논문집 Vol.- No.-
This study aims to find out cooling characteristics of TMA(Tri-Methyl- Amine, (CH₃)₃N) 25wt%-water clathrate compound with ethanol(CH₃CH₂OH) such as supercooling, phase change temperature and specific heat. For this purpose, ethanol is added as per weight concentration and cooling experiment is performed at -6˜-8℃, cooling heat source temperature, and it leads the following result. (1) Phase change temperature is decreased due to freezing point depression phenomenon. Especially, it is minimized as 3.8℃ according to cooling source temperature in case that 0.5wt% of ethanol is added. (2) If 0.5wt% of ethanol is added, average supercooling degree is 0.9℃ and minimum supercooling is 0.8, 0.7℃ according to cooling heat source temperature. The restraint effect of supercooling is shown. (3) Specific heat shows tendency to decrease if ethanol is added. It is 3.013~3.048 ㎉/㎏℃ according to cooling heat source temperature if 0.5wt% of ethanol is added. Phase change temperature higher than that of water and inhibitory effect against supercooling can be confirmed through experimental study on cooling characteristics of TMA 25wt%-water clathrate compound by adding additive, ethanol. This can lead to shorten refrigerator operation time of low temperature latent heat storage system and improve COP of refrigerator and efficiency of overall system. Therefore energy can be saved and efficiency can be improved much more.