• Transactions of the Korean hydrogen and new energy society
• /
• v.28 no.5
• /
• pp.512-520
• /
• 2017

This paper is a numerical study of various methods of applying SOFC hot BOP insulation. The application methods are four cases from case 1 to case 4, and the performance difference between the result of applying powdered insulation and the result of zoning using composite multi-layer insulation was examined. Numerical results show that the thermal stability of composite multi-layer insulation is better than that of powder insulation when the thermal conductivity is 0.04 W/mK. In the future, we will increase the thermal conductivity of the composite multi-layer thermal insulation material and find the greatest value of thermal conductivity with a similar result to that of the powder insulation.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.19 no.4
• /
• pp.469-475
• /
• 2016

Thermal batteries are primary reserve power sources, which are activated upon the melting of eutectic electrolytes by the ignition of heat sources. Therefore, sufficient thermal insulation is absolutely needed for the stable operation of thermal batteries. Currently, excessive amount of heat sources is being used to compensate the heat loss in the cell stack along with the insertion of metal plates and thermal insulators to reserve heat at the both ends of cell stack. However, there is a possibility that the excessive heat flows into the cell stack, causing a thermal runaway at the early stage of discharge. At the same time, the internal temperature of thermal batteries cannot be maintained above the battery operating temperature at the later stage of discharge because of the insufficient insulation. Therefore, the effects of Phase Changing Material(PCM) plates were demonstrated in this study, which can replace the metal and insulating plates, to improve the thermal insulation performance and safety of thermal batteries.

• Progress in Superconductivity and Cryogenics
• /
• v.12 no.3
• /
• pp.49-54
• /
• 2010

This paper presents apparent thermal conductivity of various powder at different vacuum levels for cryogenic insulation. Four kinds of powder insulator are examined by using boil-off calorimetry at pressure range from 50 Torr to 3 mTorr. The first material is perlite which is widely used in cryogenic application. Microsphere is the second one that is recently proposed as a replacement powder for liquid hydrogen storage tanks. It is a hollow sphere made of silica with the diameter in the order of 10 to $100{\mu}m$. Popped rice and polystyrene beads are also selected as candidates for powder insulation even though they are polymers. With their porous elliptic and spherical configuration and light density, they demonstrate fairly good thermal insulation performance at pressure range from 50 Torr to 3 mTorr. According to the experimental investigation in this paper, microsphere and polystyrene beads possess promising insulation characteristic as powder insulators and further study is desired.

• Transactions of the Korean hydrogen and new energy society
• /
• v.32 no.6
• /
• pp.585-591
• /
• 2021

Liquefied hydrogen have advantage which reduces the volume by about 800 times or more compared to hydrogen gas, so it is possible to increase the storage density. However, liquefied hydrogen produced by cryogenic cooling of 20 K or less at normal pressure has a problem of maximizing the insulation effect that blocks heat introduced from the outside. Representative insulation technologies include vacuum insulation and multi-layer insulation materials and in general, heat blocking is attempted by combining insulation technologies. Therefore, in this study, the pressure of the internal vacuum layer was changed to 10^-1, 10^-2, 10^-3 and 10^-4 Torr to confirm the thermal insulation performance of the vacuum jacket valve for transporting liquefied hydrogen. As a result, it was confirmed that the insulation performance improved as the degree of vacuum increased.

• Korean Journal of Agricultural Science
• /
• v.38 no.1
• /
• pp.115-120
• /
• 2011

20% of total energy use to sustain temperature of building inside. In this reasons, researchers effort to improve the thermal insulation capacity with new wall system. Using appropriate materials and consisting new wall system should considered in energy saving design. OSB(Oriented strand board), Larch lining board used to consist wall system. $2{\sim}6$ Larch lining board has tongue & groove shape for preventing moisture. Comparing with gypsum board and green timber lining board as interior sheathing material, temperature difference of Green timber wall system was bigger than temperature difference of gypsum board wall system. This aspects indicate that Green timber wall system was revealed higher thermal insulation property than gypsum board wall system. Gypsum board portion transfer heat easily because temperature difference gradient of gypsum board wall system was smaller than OSB wall system. Total temperature variation shape of G-4-S and G-6-S show similar model but, temperature variation shape in green timber wall portion assume a new aspect. The purpose of this study was that possibility of thermal insulation variation and new composition of wall system identify to improve thermal insulation performance. In the temperature case, this study shows possibility of improving thermal insulation performance. Humidity, sunshine and wind etc. should considered to determine building adiabatic properties.

• Journal of the Korean Solar Energy Society
• /
• v.37 no.5
• /
• pp.65-75
• /
• 2017

In this study, the change of heat loss due to the degree of deterioration of the XPS insulation in KEPCO's office buildings is analyzed. The acceleration aging test of the XPS insulation was carried out according to the test method A of KS M ISO 11561: 2009. The performance of the insulation was analyzed by applying it to the three - dimensional steady state heat transfer analysis program. The acceleration aging test of the XPS insulation, show that the thermal resistance performance decreased by 1.44% at the A regional headquarters, 0.85% at the B regional headquarters, 6.41% at the C branch office, 7.76% at the D regional headquarters, 8.51% at the E branch office, and by 8.54% at the F branch office respectively. Using simulation, we determined that the thermal resistance value of E branch office decreased by 8.04%, while its heat loss increased by 8.52%. At A regional headquarters, the thermal resistance decreased by 1.38%, and the heat loss increased by 1.51%. At D regional headquarters, these value are 6.82% and 7.17%, respectively.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.29 no.2
• /
• pp.89-95
• /
• 2017

This study aimed to compare the primary heating energy consumption of regional apartment houses based on the enhanced thermal insulation performance of building envelope standards. The difference of the heating energy consumption based on the enhanced thermal insulation performance of building envelope standards in the southern region, the largest regional difference in primary heating energy consumption, is $10.3kWh/(m^2{\cdot}year)$. The difference of the heating energy consumption based on the enhanced thermal insulation performance of building envelope standards in the central region is $8.0{\sim}8.5kWh/(m^2{\cdot}year)$ and that of the Jeju region is $0.5kWh/(m^2{\cdot}year)$. These energy consumption differences do not result in building energy efficiency ratings changing. The building energy efficiency ratings have the possibility to be changed.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2016.05a
• /
• pp.105-106
• /
• 2016

The study of the sandwich wall with the increasing interest in building energy consumption have been actively conducted. This study designed exposed sandwich wall in the light of energy saving design standard and thermal bridge of share connection. The heat insulating performance was analyzed U-fator using calculation program provided in passive houses association and KS F 2277 (method of measuring thermal insulation of construction component materials).

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2013.05a
• /
• pp.96-97
• /
• 2013

Research and analysis on thermal insulation status of existing buildings are needed to make data for repair and rehabilitation caused by deterioration in insulating material performance. To do this, we have researched and analyzed the insulation status of existing buildings according to the balcony with measuring instruments in pre-set investigation conditions.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
• /
• v.13 no.4
• /
• pp.21-30
• /
• 2017

Recently, It has increased the importance of building energy saving. Pipe insulation as well as building envelope insulation is to improve energy efficiency and reduce the energy loss. However, there continues to use the old standard for pipe insulation that is one of the most important elements in energy savings in buildings. The purpose of this study is to propose suitable pipe insulation thickness for reducing building energy use. The study also reviews pipe insulation thickness standard in accordance to Korea standard, ASHRAE 90.1 and BS5422 and analyzed through thermal simulation. As a result, it is necessary to apply the performance design method of the pipe insulation thickness to reduce the energy loss of the piping.