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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.
Melting of Ice on the Heating Plate with Split Fins
Hiki Hong,Moo Geun Kim 대한설비공학회 2001 International Journal Of Air-Conditioning and Refr Vol.9 No.2
One of the important applications of a contact melting process is a latent thermal energy storage system owing to its high heat flux and small temperature variation. In some previous works, the split fins have been employed in order to enhance the melting rate. In the present work, the direct contact melting was experimentally investigated using an ice as specimen for both split and non-split fins. It was shown that the contact melting by split fins increases the melting rate compared to that of non-split ones.
Improvement of the T-history Method to Measure Heat of Fusion for Phase Change Materials
Hiki Hong,Chang Hyun Park,Ju Hwan Choi,Jong Hyeon Peck 대한설비공학회 2003 International Journal Of Air-Conditioning and Refr Vol.11 No.1
Though conventional calorimetry methods such as differential scanning calorimetry and differential thermal analysis are used generally in measuring heat of fusion, T-history method has advantages of a simple experimental apparatus and no requirements of sampling process, which is particularly useful for measuring thermophyical properties of inhomogeneous phase change materials in sealed tubes. However, the degree of supercooling used in selecting a range of latent heat release and neglecting sensible heat during the phase change process can cause significant errors in determining the heat of fusion. In the present study, it was shown that a 40% discrepancy exists between the original T-history and the present methods when analyzing the same experimental data. As a result, a reasonable modification to the original T-history method is proposed.
홍희기(Hiki Hong),김시환(Sihwan Kim) 대한설비공학회 2010 설비공학 논문집 Vol.22 No.6
Ondol heating, a kind of radiant floor heating, is a main method used in housing units in Korea. Building energy simulation including ondol and relevant facilities has not been performed due to its complexity. For evaluating energy consumption and indoor temperature variation, a new method should be proposed. At the present work, a dynamic simulation on ondol heating was tried by combining TRNSYS and EES. Characteristic functions for a pump, hot water coils and a gas boiler were simutaneouly solved by EES, and calculated flow rates and supply temperature of hot water were provided as inputs of the active layer of TYPE 56 in TRNSYS. The results by the simulation on a typical housing unit in Korea shows a good trend in a viewpoint of actual behavior of ondol heating.
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.
홍희기(Hiki Hong),김시환(Sihwan Kim) 대한설비공학회 2009 대한설비공학회 학술발표대회논문집 Vol.2009 No.-
Ondol heating, a kind of radiant floor heating, is a main method used in housing units in Korea. Building energy simulation including ondol and relevant facilities has not been performed due to its complexity. For evaluating energy consumption and indoor temperature variation, a new method should be proposed. At the present work, a dynamic simulation on ondol heating was tried by combining TRNSYS and EES. Characteristic functions for a pump, hot water coils and a gas boiler were simutaneouly solved by EES, and calculated flow rates and supply temperature of hot water were provided as inputs of the active layer of TYPE 56 in TRNSYS. The results by the simulation on a typical housing unit in Korea shows a good trend in a viewpoint of actual behavior of ondol heating.