Effect of eco-friendly pervious concrete with amorphous metallic fiber on evaporative cooling performance.

Impervious pavements exist in large proportions in most cities owing to the high-impact development of the transportation infrastructure. However, this type of pavement causes environmental issues such as waterlogging, floods, and urban heat islands. Pervious concrete (PC), which is a novel pavement material characterized by a porous structure that allows water to percolate through it, is an important solution to these issues. This study investigates the evaporative cooling performance of eco-friendly PC with blast-furnace slag (BFS) as a cement replacement and amorphous metallic fiber (AMF) that helps to accelerate the evaporative cooling. The thermophysical properties, water permeability, and water absorption capability of the manufactured PC were measured. In addition, a scale model test and thermal conductivity analysis of the manufactured PC were conducted to evaluate the evaporative cooling effect. The results indicate that the physical and mechanical properties of the manufactured PC are typically similar to those of other PCs, and its water absorption rate reaches 1 mm/s. Relatively low water permeability helps the PCs to absorb more water, contributing to accumulate a large amount of water in the material for evaporative cooling. In addition, AMF contributes to increase thermal conductivity of PC, which allow the water inside the PCs to evaporate faster. The result shows that a higher thermal conductivity of the manufactured PC increases the evaporative cooling effect.

Numerical analysis on the hygrothermal behavior of building envelope according to CLT wall assembly considering the hygrothermal-environmental zone in Korea.

As buildings generally have become larger and more airtight, the ventilation rate has decreased further, causing insufficient ventilation which leads to moisture problems such as condensation, mold growth, reduction of thermal insulation performance and corrosion of building materials. In order to prevent moisture problems, it is essential to understand the thermal and hygric status of a climatic region. In this study, the hygrothermal environmental zone considering not only the thermal environment but also the hygric environment was derived by analyzing the climate environment in Korea. The hygrothermal environmental zone has the advantage of being able to take into account the hygrothermal environment of the unexplored regions and to cope with climate change by quantifying the thermal and hygric environmental indexes in each region. Finally, the long-term moisture risk of the building envelopes was evaluated. As the results, it is considered that the proposed hygrothermal environmental zone is appropriate and it is necessary to consider the hygric environment in order to secure the moisture stability of the building envelope.

Design and analysis of phase change material based floor heating system for thermal energy storage.

Pleasant interior space is essential for modern people who spend considerably more time in the buildings than they did in the past. To achieve this, one aspect includes an ambient temperature that maintains the thermal equilibrium of the human body. The construction of wood framed buildings is becoming increasingly popular worldwide, and there have been recent trends toward constructing high-rise wooden houses. In this respect, heating methods appropriate for use in wooden buildings are being studied. Dry floor heating systems are predominantly used in wooden houses, but they provide a poor heat storage performance, which is not conducive to saving energy. In this study, the effects of thermal comfort and energy savings were analyzed after applying a phase change material (PCM) to floor heating, which can be used to reduce the peak temperature and contribute to energy savings. To enable shape stabilization, this study used Macro-Packed PCM (MPPCM), as shape stabilization is necessary when applying PCM. The heat storage performance was improved by applying MPPCM to a dry floor heating system. Paraffin-based PCMs, such as n-octadecane, n-eicosane, and n-docosane, were used to obtain a comfortable floor temperature range. Experimental temperatures ranged from 28 °C to 35 °C, with an entire temperature range of 7 °C. Experimental results showed that the heat storage performance of MPPCM reduced the amount of energy used for heating by 43%, and n-eicosane was the most effective PCM for use in floor heating with respect to obtaining a comfortable floor temperature.

Potential utility of HKUST-1-graphite nanocomposite to endow alkane with high thermal properties and low electrical resistivity.

It is desirable to develop novel multipurpose phase change materials (PCMs) with improved energy storage and release characteristics. In this study, the utility of a nanocomposite composed of a metal-organic framework (MOF) and graphite was explored for shape-stable PCMs. The prepared MOF-integrated graphite featured favorable structural characteristics (such as large specific surface area (550.6 m2/g), increased total pore volume, and dominant mesopore structure). The obtained composite with a high energy storage capacity (111.4 J/g) exhibited an electrical resistivity that was at least 7 orders of magnitude lower than that of the pristine PCM. In addition, the alkane possessed enhanced chemical compatibility with the supporting scaffolds, outstanding shape, and thermal stabilities. The strong structural connectivity, high specific surface area, and pore size distributions (micro/mesopores) of the scaffolds play a remarkable role in large PCM infiltration ratio, high electrical conductivity, and improved thermal properties of as-prepared composites. It was also suggested that the cavities of the MOF, filled with graphite and the π-π interactions between strand ligands, generate favorable pathways in the nanocomposites. Subsequently creates a supramolecular "wire-like" paths and reduce the resistivity of the parent materials. Therefore, this multifunctional material shows the potential for applications in electro/thermal energy management systems.

Infiltration properties of n-alkanes in mesoporous biochar: The capacity of smokeless support for stability and energy storage.

Biochar, also named biocarbon, is a solid particulate material produced from the thermal decomposition of biomass at moderate temperatures. It has progressively become the topic of scientific interest in energy storage and conversion applications due to its affordability, environment friendliness, and structural tunability. In this study, biochar (obtained 600 °C pyrolysis) was introduced as phase change materials (PCMs) support. Three different n-alkanes (such as dodecane, tetradecane, and octadecane) are used as PCMs. The PCMs were infiltrated in the biochar network via the vacuum impregnation method. Among the biochar/n-alkane composites, one from octadecane exhibited a high latent heat storage capacity of 91.5 kJ/kg, 15.7 % and 25.9 % higher than that of dodecane and tetradecane-based composites, respectively. The molecular length of the PCMs and intermolecular interaction between the functional groups play an imperative role. The infiltration ratio of PCM in the biochar reached 50.1 % with improved thermal stability and chemical compatibility. This is attributed to the favorable morphological and structural properties (e.g., large BET surface area and mesopore structure) of the biochar that resides the n-alkanes found in the nanosized chain length. Hence, this report will lay a foundation for the application of biochars in thermal energy management systems.

Spent coffee grounds as supporting materials to produce bio-composite PCM with natural waxes.

Novel kinds of bio composite Phase change materials were prepared by the use of bio-wastes. Of the by-products, coffee wastes, which is currently consumed and abandoned as coffee as a drink, was used as the supporting material for PCM. It was found through chemical composition of FTIR of SCBW, SCPW, SCGW and that the coffee wastes were effectively vacuum impregnated into each natural wax. As a result of TGA, the thermal stability of SCBW, SCPW, SCGW and SCNW was checked. In addition, the DSC results were used to determine the heat storage performance of each material. Micro-morphological analysis with FE-SEM showed whether the impregnation was successful. The use of bio-compatible PCM by-products is economical as well as environmentally friendly and is sufficient for building applications in terms of thermal performance compared to other bio-composites.

Dynamic heat transfer and thermal performance evaluation of PCM-doped hybrid hollow plaster panels for buildings.

The thermal performance of hybrid hollow plaster panels (HHPPs) was analyzed using the amount of phase change material (PCM) injection as a variable according to the size of the hollow area. This study focuses on n-octadecane, an organic PCM that is used for storing latent heat during the phase change range and to improve thermal transmittance using exfoliated graphite nanoplatelets (xGnPs), which have a high thermal conductivity. When xGnP is applied to n-octadecane, the thermal conductivity improves by 225%, and it is confirmed that the thermal storage or release of the phase change material is an active reaction. The thermo-physical properties of the xGnP and n-octadecane composites were analyzed using a thermal conductivity analyzer (TCi) and differential scanning calorimetry (DSC). The thermal stability of PCM was analyzed over a long duration of 10,000 thermal cycles. The thermal performance of the PCM/plaster composite panel using the dynamic heat transfer device was determined. The peak temperature through the HHPP significantly reduced by 3.8 ℃ in an internal room, and the time-lag effect was confirmed to be 1.56 h. The results indicate that up to 36.6 J/m2 of thermal energy was stored in the 26-Px/O, corresponding to approximately 247% of the available thermal energy of the reference panel.

Evaluation of Toluene Adsorption Performance of Mortar Adhesives Using Porous Carbon Material as Adsorbent.

Porous carbon materials are advantageous in adsorbing pollutants due to their wide range of specific surface areas, pore diameter, and pore volume. Among the porous carbon materials in the current study, expanded graphite, xGnP, xGnP C-300, xGnP C-500, and xGnP C-750 were prepared as adsorbent materials. Brunauer-Emmett-Teller (BET) analysis was conducted to select the adsorbent material through the analysis of the specific surface area, pore size, and pore volume of the prepared porous carbon materials. Morphological analysis using SEM was also performed. The xGnP C-500 as adsorbent material was applied to a mortar adhesive that is widely used in the installation of interior building materials. The toluene adsorption performances of the specimens were evaluated using 20 L small chamber. Furthermore, the performance of the mortar adhesive, as indicated by the shear bond strength, length change rate, and water retention rate, was analyzed according to the required test method specified in the Korean standards. It was confirmed that for the mortar adhesives prepared using the xGnP C-500 as adsorbent material, the toluene adsorption performance was excellent and satisfied the required physical properties.

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.

Effect of Mixing Ratio between Pork Loin and Chicken Breast on Textural and Sensory Properties of Emulsion Sausages.

This study is conducted to evaluate the effects of the mixing ratio between pork loin and chicken breast for textural and sensory properties of emulsion sausages. Meat homogenates are prepared by using five mixing ratios between pork loin and chicken breast (100:0, 70:30, 50:50, 30:70, and 0:100), and the emulsion sausages are also formulated with five mixing ratios. The additions of chicken breast increase the salt soluble protein solubility due to high pH levels of chicken breast, thereby resulting in the reduction of cooking losses. In addition, the apparent viscosity of meat homogenates increase with increasing amounts of chicken breast. In terms of emulsion sausages formulated with pork loin and chicken breast, the addition of chicken breast above 50% may contribute to a softer and more flexible texture of emulsion sausages. For sensory evaluations, an increase in the added amount of chicken breast contributes to a rich umami taste and deeper flavor within the emulsion sausages, resulting in the high overall acceptance score for the formulation of 0-30% pork loin and 70-100% chicken breast. Therefore, the optimal mixing ratios between pork loin and chicken breast are 0-30% and 70-100% for enhancing the textural and sensory properties of emulsion sausages.

Effect of glasswort (Salicornia herbacea L.) on the texture of frankfurters.

This study was aimed at evaluation of the effect of glasswort levels (0, 0.5, 1, and 1.5%) on the textural properties of frankfurters formulated with 0.75% NaCl. The addition of glasswort improved protein solubility (P<0.05) and apparent viscosity of frankfurters formulated with 0.75% NaCl, resulting in increased cooking yield and emulsion stability. This phenomenon might be mainly related to salts and dietary fiber within glasswort. In addition, the textural properties of frankfurter prepared with 0.75% NaCl and 1.5% glasswort showed similar properties (P>0.05) compared to those of control (1.5% NaCl). Our result suggests that the use of glasswort can be an effective approach to manufacture reduced-salt meat products. Moreover, the addition of 1.5% glasswort in frankfurters formulated with 0.75% NaCl is the optimum level without adverse effect on the texture.