Su-Gwang Jeong

Application of PCM thermal energy storage system to reduce building energy consumption

The building sector is known to make a large contribution to total energy consumption and CO2 emissions. Phase change materials (PCMs) have been considered for thermal energy storage (TES) in buildings. They can balance out the discrepancies between energy demand and energy supply, which are temporally out of phase. However, traditional PCMs need special latent storage devices or containers to encapsulate the PCM, in order to store and release the latent heat of the PCM. The proper design of TES systems using a PCM requires quantitative information and knowledge about the heat transfer and phase change processes in the PCM. In Korea, radiant floor heating systems, which have traditionally been used in residential buildings, consume approximately 55% of the total residential building energy consumption in heating. This article reviews the development of available latent heat thermal energy storage technologies and discusses PCM application methods for residential building using radiant floor heating systems with the goal of reducing energy consumption.

Preparation and Thermal Properties of Octadecane/xGnP Shape-Stabilized Phase Change Materials to Improve the Heat Storage Performance of Buildings

In this study, a shape-stabilized phase change material (SSPCM) was prepared by octadecane and exfoliated graphite nanoplate (xGnP) in a vacuum, to improve thermal storage performance. The octadecane as an organic phase change material (PCM) is very stable against phase separation of PCM, and has the proper temperature range for thermal comfort in the building; and the xGnP is a porous carbon nano-material. Scanning electron microscope (SEM) and Fourier transformation infrared spectrophotometer (FT-IR) were used to confirm the chemical and physical stability of the Ocatadecane/xGnP SSPCM. In addition, thermal properties were determined by Deferential scanning calorimeter (DSC), and Thermogravimetric analysis (TGA). The specific heat of Octadecane/xGnP SSPCM was at . The melting temperature ranges of melting and freezing were found to be and , respectively. At this time, the latent heats of melting and freezing were 110.9 J/g and 104.5 J/g, respectively. The Octadecane was impregnated into xGnP by as much as about 56.0% of the Octadecane/xGnP SSPCM`s mass fraction.

Formaldehyde emissions from particle board made with phenol–urea–formaldehyde resin prepared by different synthesis methods

This paper suggests the optimum NAF resin preparation to reduce the quantity of pollutant emissions from the particle boards by using PUF resin. The pollutant emissions performance of the prepared NAF resin was evaluated by comparison with eMDI resin. Each PF and PUF resin was made by variation of the molar ratio and synthesis methods according to order of addition of the basic products. In addition, after verifying the properties of the resins, the quantity of pollutant emitted from boards made with the PUF resins were evaluated. Of the cases of boards made with each resin, the formaldehyde emission was the lowest for PB #7. The eMDI resin used in this board showed good quality as an eco-friendly resin, because it had less than half the formaldehyde emission of the other formaldehyde-based resins. In addition, the mechanical properties of the particle board met the KS criteria; therefore, there should be no restriction on use in manufactured goods.

Preparation of thermal-enhanced epoxy resin adhesive with organic PCM for applying wood flooring

Epoxy resins are well-known materials that show beneficial properties, such as high tensile strength and modulus, good adhesive properties, low cost, and ease of processing and environmental advantages. However, epoxy resin adhesive has no characteristic of thermal storage. Latent heat storage is one of the favorable kinds of thermal energy storage methods considered for energy saving and thermal efficiency in various fields, such as solar air conditioning systems and buildings. So we prepared thermal-enhanced epoxy resin adhesive by using PCM. This paper addresses the effects of n-hexadecane and sodium lauryl sulfate on the thermal properties and chemical properties of epoxy resin adhesive and HEAC, using differential scanning calorimetry, thermal gravimetric analysis, and Fourier transform-infrared spectroscopy. Also, we evaluated the applicability of composite epoxy resin adhesive to wood-based flooring using n-hexadecane, through measurement of bonding strength from universal testing machine analysis.

Preparation of Shape Stabilized PCM Using Porous Materials for Application to Buildings

The increase of greenhouse gas emission and decrease of fossil fuel are being caused by the indiscreet consumption of energy by people. Recently, green policy has been globally implemented to reduce energy consumption. This paper studied the research to reduce the energy consumption in buildings, by using the heat storage properties of PCM. PCM has to prevent leakage from the liquid state. Therefore, we prepared form stable PCM, by using the vacuum impregnation method. Three kinds of organic PCMs were impregnated into the structure of porous material. The characteristics of the composites were determined by using SEM, DSC, FTIR and TGA. SEM morphology showed the micro structure of silica fume/PCM. Also, thermal properties were examined by DSC and TGA analyses; and the chemical bonding of the composite was determined by FTIR analysis.

Consideration of Ozone Removal and Control in Built Environment by Building Materials

Recently, residents have been spending almost 90% of their time indoors, which presents a higher risk from inhalation of pollutants than when spending time outdoors. Therefore, controlling indoor air quality became important. It is reported that the lung diseases and mortality for occupants are increased when there is high density of ozone which is one of the pollutants among the indoor air. In addition, the reactions between ozone and building materials produce VOCs and formaldehyde. The studies to eliminate the ozone by building materials have been actively investigated. However, ozone removal and secondary pollutants from ozone reactions with building materials have not been reported in Korea. For this reason, the aim of this study is to introduce ozone removal by HVAC filters, various building materials, and eco-friendly building materials including the quantity of secondary pollutant emissions.

Development of heat storage gypsum board with paraffin-based mixed SSPCM for application to buildings

Abstract Latent heat thermal energy storage using phase change materials (PCMs) is considered to be the method with the most potential to solve the energy shortage problem. In this study, paraffin-based mixed shape-stabilized PCM (SSPCM) (PBMS) was made by vacuum impregnation method. The prepared PBMS was added to gypsum powder as a fine aggregate. In the experiment, the n-hexadecane and n-octadecane was used as the PCM and the materials have latent heat capacities of 254.7 and 247.6 J/g, and melting points of 20.84 and 30.4 °C, respectively. The PBMS was prepared by an impregnation method in a vacuum, following the manufacturing process. The physical and thermal properties of the PBMS gypsum board were analyzed by Fourier transform infrared spectrometry (FTIS), differential scanning calorimetry, enthalpy analysis, and thermogravimetric analysis. From the Fourier transform infrared analysis, PBMS could be maintained in the structure of the gypsum board due to its physical rather than chemical bonding. From the specific heat and enthalpy analysis, the PBMS has high enthalpy and thermal inertia property. In addition, the gypsum board with PBMS has high latent heat capacity and high thermal efficiency.

Empirical Validation of Heat Transfer Performance Simulation of Graphite/PCM Concrete Materials for Thermally Activated Building System

To increase the heat capacity in lightweight construction materials, a phase change material (PCM) can be introduced to building elements. A thermally activated building system (TABS) with graphite/PCM concrete hollow core slab is suggested as an energy-efficient technology to shift and reduce the peak thermal load in buildings. An evaluation of heat storage and dissipation characteristics of TABS in graphite/PCM concrete has been conducted using dynamic simulations, but empirical validation is necessary to acceptably predict the thermal behavior of graphite/PCM concrete. This study aimed to validate the thermal behavior of graphite/PCM concrete through a three-dimensional transient heat transfer simulation. The simulation results were compared to experimental results from previous studies of concrete and graphite/PCM concrete. The overall thermal behavior for both materials was found to be similar to experiment results. Limitations in the simulation modeling, which included determination of the indoor heat transfer coefficient, assumption of constant thermal conductivity with temperature, and assumption of specimen homogeneity, led to slight differences between the measured and simulated results.

Evaluation of the Adsorption Performance and Sustainability of Exfoliated Graphite Nanoplatelets (xGnP) for VOCs

Exfoliated graphite nanoplatelets (xGnP), which combine the layered structure and low price of nanoclays with the superior mechanical, electrical, and thermal properties of carbon nanotubes, are very cost-effective, and can simultaneously provide a multitude of physical and chemical property enhancements. In this study, we evaluated xGnP’s adsorption performance of volatile organic compounds (VOCs) according to thermal extractor (TE) analysis for seven days in order to use the xGnP as an adsorption material of pollutants. In addition, we carried out a sustainability evaluation in order to evaluate its adsorption capacity over 28 days. The results indicate that the adsorption performance of xGnP is higher than for other adsorption materials such as zeolite. Also, we determined that the adsorption performance of xGnP is maintained continuously for 28 days and that its adsorption capacity is large.

Analysis of Hygrothermal Performance for Standard Wood-frame Structures in Korea

본 연구는 WUFI Pro 5.3을 이용하여 한국농어촌공사에서 제시하고 있는 농어촌 표준 목조주택 설계를 기준으로 목조 벽체의 hygrothermal 거동에 대한 평가를 실시하였다. 그 결과, 2010년도에 제시된 벽체보다 2014년도에 개선된 벽체의 Total Water Contents (TWC)가 더 낮게 나타난 것을 확인하였고, 3년간의 평가에서 T...