• The Korean Journal of Community Living Science
• /
• v.25 no.4
• /
• pp.549-556
• /
• 2014

This study evaluates the thermal insulation and evaporative resistance of a waterproof and breathable garment system and determines the factors influencing its thermal performance. The experimental garments were composed of underwear (shirts with 100% wool and 100% polyester) and outerwear (jackets and pants with a vapor-permeable membrane and a vapor-impermeable membrane). Data on clothing insulation in a dry condition ($10^{\circ}C$) and a wet condition ($10^{\circ}C$, 40% R.H.), evaporative resistance ($34^{\circ}C$, 40% R.H., and $10^{\circ}C$, 40% R.H.), and microclimate vapor pressure were collected and analyzed. According to the results, the thermal insulation of the experimental garment system ranged 1.27~1.40 in the dry condition and 0.40~0.89 in the wet condition at $10^{\circ}C$. Evaporative resistance ranged $41{\sim}525m^2Pa/W$. A decrease in thermal insulation by wetting underwear ranged 31~67% in the cold condition ($10^{\circ}C$). The breathability of the outer garment influenced the decrease in thermal insulation by wetting. The type of underwear fiber influenced the decrease in thermal insulation only when it was used with breathable outerwear. The vapor-permeable outerwear sample with polyester underwear (P_Perm) showed a larger decrease in insulation than that with wool (W_Perm). The evaporative resistance of the vapor-permeable ensemble showed no effect of underwear in the warm condition ($34^{\circ}C$), but polyester underwear showed lower evaporative resistance than wool in the cold condition ($10^{\circ}C$). The vapor-impermeable ensemble showed no difference in evaporative resistance between polyester underwear and wool underwear in both conditions. Future research should consider various clothing ensemble combinations and environmental conditions and evaluate wear comfort by using human subjects.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2018.11a
• /
• pp.10-11
• /
• 2018

Internal Insulation system is applied to the most apartment building in Korea. However due to the importance of building energy enhanced the interest of the exernal insulation system. The extermal insulation system has better thermal performance because the thermal bridge through the structure are rarely formed. But the thermal bridge around the window decrease the thermal performance of the envelope system. Therefore the technology for reducing the thermal bridge around window improves energy efficiency of the building. In order to this it is necessary to minimize the thermal bridge around window of building. In this study it is aimed to minimize the thermal bridge around the window of building. It was confirmed that the use of thermal bridge barrier imporved the heat transfer rate by 64% or more and the condensation reduction phenomenon by 42% or more compared with the exist technology. These thermal bridge barrier will be used as the main technology to improve the energy efficiency of building.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2018.11a
• /
• pp.92-93
• /
• 2018

This study analyzed the physical properties of insulation materials upon completion of building completion years and found the suitability of the current energy performance analysis methodology to apply the insulation specified in the design drawings to the same thermal conductivity values as the new materials.

• Journal of the Architectural Institute of Korea Structure & Construction
• /
• v.33 no.12
• /
• pp.91-98
• /
• 2017

In this study, the effect of window installation position in the residential building with the external insulation was numerically investigated in terms of insulation performance and heating/cooling energy consumption. For different window positions, 2-D heat transfer simulation was conducted to deduce the linear thermal transmittance, which was inputted to the dynamic energy simulation in order to analyze heating/cooling energy consumption. Simulation results showed that the linear thermal transmittance ranges from 0.05 W/mK to 0.7 W/mK, and is reduced as the window is installed near the external finish line. Indoor surface temperature and TDR analysis showed that the condensation risk is the lowest when the window is installed at the middle of the insulation and wall structure. It was also found that the window installation near the external finish can reduce the annual heating/cooling energy consumption by 12~16%, compared with the window installation near the interior finish. Although the window installation near the external finish can achieve the lowest heating/cooling energy consumption, it might lead to increased condensation risks unless additional insulation is applied. Thus, it can be concluded that the window should be installed near the insulation-wall structure junction, in consideration of the overall performance including energy consumption, condensation prevention and constructability.

• Journal of the Society of Naval Architects of Korea
• /
• v.56 no.6
• /
• pp.515-522
• /
• 2019

Since Liquefied Natural Gas (LNG) is normally carried at 1.1 bar pressure and at -163℃, special Cargo Containment System (CCS) are used. As LNG carrier is becoming larger, typical LNG insulation systems adopt a method to increase the thickness of insulation panel to reduce sloshing load and Boil-off Rate (BOR). However, this will decrease LNG cargo volume and increase insulation material costs. In this paper, silica aerogel, glass bubble were synthesized in polyurethane foam to increase volumetric efficiency by improving mechanical and thermal performance of insulation. In order to increase dispersibility of particles, ultrasonic dispersion was used. Dynamic impact test, quasi-static compression test at room temperature (20℃) and cryogenic temperature (-163℃) was evaluated. To evaluate the thermal performance, the thermal conductivity at room temperature (20℃) was measured. As a result, specimens without ultrasonic dispersion have a little effect on strength under the compressive load, although they show high mechanical performance under the impact load. In contrast, specimens with ultrasonic dispersion have significantly increased impact strength and compressive strength. Recently, as the density of Polyurethane foam (PUF) has been increasing, these results can be a method for improving the mechanical and thermal performance of insulation panel.

• Land and Housing Review
• /
• v.15 no.2
• /
• pp.29-37
• /
• 2024

This study investigates the thermal conductivity and density of expanded polystyrene insulation materials collected from buildings under going energy retrofit projects. Due to the absence of initial thermal conductivity data, determining precise long-term patterns was challenging. Analysis based on design documents revealed that expanded polystyrene insulation maintained consistent performance over ten years. Notably, the thermal conductivity measurements of insulation samples of the same grade and age varied significantly. Additionally, the insulation density was found to be substantially below the standard specified in the design documents. The results of the experiment indicate that performance management during both construction and operation phases is lacking. It is crucial to apply building commissioning, which involves performance verification throughout the building's life cycle, to properly evaluate building energy performance improvements, such as building energy retrofit projects.

• Journal of the Korea Institute of Building Construction
• /
• v.12 no.2
• /
• pp.243-256
• /
• 2012

This study is the experimental study to improve the insulation of the fastening unit system, which has the most vulnerable insulation in the curtain walls. The Fastening Units were designed and fabricated to minimize the connection part of mullions. In addition, slight movements were taken into account and the performance of the middle layer was evaluated by forming an insulation layer with the vibration-proof rubber and the silicon to satisfy the mechanical and thermal performance criteria. A total of 10 experiments were performed under various conditions, such as indoor-outdoor temperature difference, type of insulation material, thickness of insulation material, and others. using the fabricated Fastening Units. As a result, the vibration-proof rubber insulation showed the temperature difference of $2.2^{\circ}C-5.0^{\circ}C$, and the silicon insulation showed the temperature difference of $2.8^{\circ}C-4.5^{\circ}C$, compared to the non-insulated Fasteniirature difference, typesng Units. When these results were compared with the psychometric chart graph, the insulated Fastening Unit designed in this study can be considered to prevent the dew condensation.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.8 no.4
• /
• pp.497-509
• /
• 1996

Evacuated powder insulations have long been known to have better thermal performance than existing commercially available insulators, such as fiber glass and CFC-blown foam. To make a composite powder panel, a series of individually evacuated panels was encapsulated in a rigid closed cell foam matrix. The panels were encapsulated in a thin glass sheet barrier to preserve the vacuum. The thermal conductivity of the individual panel was found to be $0.0062W/m^{\circ}K$ by experiment and the polyurethane foam above had a thermal conductivity of $0.024W/m^{\circ}K$. In this study, numerical analysis using finite element method was carried out to investigate insulation performance of rigid foam/evacuated powder composite panel with respect to panel geometries such as panel pitch, panel aspect ratio and panel area ratio. Numerical analysis has indicated that more optimal vacuum panel geometries, much lower overall thermal conductivities can be achieved.

• Journal of the Korean Solar Energy Society
• /
• v.37 no.4
• /
• pp.35-47
• /
• 2017

Energy efficiency solutions are being pursued as a sustainable approach to reducing energy consumption and related gas emissions across various sectors of the economy. Vacuum Insulation Panel (VIP) is an energy efficient advanced insulation system that facilitates slim but high-performance insulation, based on a porous core material evacuated and encapsulated in a barrier envelope. Although VIP has been applied in buildings for over a decade, it wasn't until recently that efforts have been initiated to propose and adopt a global standard on characterization and testing of VIP. One of the issues regarding VIP is its durability and aging due to pressure and moisture dependent increase of the initial low thermal conductivity with time; more so in building applications. In this paper, the aging of commercially available VIP was investigated experimentally; thermal conductivity was tested in accordance with ISO 8302 standard (guarded hot box method) and long-term durability was estimated based on a non-linear pressure-humidity dependent equation based on study of IEA/ECBCS Annex 39, with the aim of assessing durability of VIP for use in buildings. The center-of-panel thermal conductivity after 25 years based on initial 90% fractile with a confidence level of 90 % for the thermal conductivity (${\lambda}90/90$) ranged from 0.00726-0.00814 (W/m K) for silica core VIP. Significant differences between manufacturer-provided data and measurements of thermal conductivity and internal pressure were observed.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.22 no.6
• /
• pp.404-412
• /
• 2010

The purpose of this study is to accomplished an in-site evaluation method for existing building insulation status using Infra-red camera and to consider improvement performance to prevent condensation and draw the optimum insulation design method for building using simulation tool. The research contents of this study are to evaluate validity and suitability of building insulation defect survey using Infra-red camera for apartment housing with temperature and heat flow pattern analyze method. Based on this research, the three corners, weak part in condensation, were selected in apartment building and conducted simulation by three-dimensional steady state. From the results, it is required to strengthen insulation design, and it is founded that existing insulation system typically applied to most Korean apartment housings have serious insulation defect that insulation is disconnected by structural components at the joints of wall-slab and wall-wall in envelope. Thus, it is considerate to need a concrete technology improvement.