Fire retardant performance, toxicity and combustion characteristics, and numerical evaluation of core materials for sandwich panels.

According to fire accident statistics, fires in buildings are increasing. The flame-retardant performance of insulation materials is considered an important factor for preventing the spread of fire and ensuring evacuation. This study evaluated the flame-retardant performance and combustion characteristics of four types of organic thermal insulation used as core materials in sandwich panels. The flame-retardant performance evaluation based on total heat release and heat release rate revealed that phenolic foam (PF) satisfied the criteria for non-combustible grade insulation. An analysis of the hazardous gases released while combustion of the four insulation materials indicated that a significant amount of CO was released-an average of 19,000 ppm or higher-in the rigid urethan foam (PIR) and spray-type polyurethane foam (SPU). The fractional effective dose (FED) value was derived from the gas analysis results according to ISO 13344. PIR and SPU had an average FED value of 2.0 or higher and were identified as very dangerous in the case of fire accidents. Moreover, the evacuation time in the case of a fire in a warehouse-type building was comprehensively analyzed considering the material, size, and height for the four types of insulation. PIR was the most vulnerable to fire, and for PF, the danger limit was not reached until the end of the simulation.

Use of biochar co-mediated chitosan mesopores to encapsulate alkane and improve thermal properties.

Phase-change materials (PCMs) plays a significant role in energy conservation and thermal management systems. However, excessive seepage and insufficient thermal conductivity of pristine PCMs are restricting its real-world applications. Herein, "anisotropic-like" biochar with favorable pore characteristics is designed by combining it with chitosan for dodecane encapsulation. The use of biochar could overcome high manufacturing costs and associated environmental issues of PCM supporting materials. Biochar co-mediated chitosan enrich the mesopore proportion (96.5%) and provide interactive synergistic architecture. The prepared composite PCM exhibited outstanding latent heat retention of 95.9% after repeated cycling, high loading ratio, enhanced thermal conductivity (0.373 W/(m·K)), leakage-free, and repeatable utilization properties above the melting point of pristine dodecane. A figure of merit of 33.94 × 106 W2 S/(m4oC) was achieved, far surpassing that measure among reported biochar-based composite PCMs. This study provides insights into next-generation sustainable energy storage development for a key global sustainability goal.

Updated results on the integration of metal-organic framework with functional materials toward n-alkane for latent heat retention and reliability.

Phase change composites are in high demand in thermal management systems. Various supporting materials, including nanocomposites, have been employed to develop shape-stable phase change materials (PCMs). As the reliability of most composite materials has mostly been studied right after the preparation with specific thermal cycling measurements, it is difficult to analyze the long-term leakage-resistance capability and energy retention capacity. Additionally, achieving multifunctional phase change composites is a significant challenge for single supporting materials. Herein, we provide a follow-up report on the thermal performance of hybrid material-supported n-alkane after a storage time of one year and 50 heating/cooling cycles. The interconnected hybrid material composed of a metal-organic framework (MOF) and graphite improved the shape/thermal stability of tetradecane (TD). The as-synthesized MOF/graphite/TD composites exhibited a high latent heat retention capacity of 84.2%, low leakage rate of 1.25%, and high PCM loading capacity, making them suitable for thermal management applications, such as industrial waste heat recovery systems. Furthermore, the intermolecular interactions and capillary forces between the hybrid materials and TD provided high stability and compatibility. Therefore, the as-prepared hybrid material fabricated in this study can be important in the development of multidirectional composite PCMs with comprehensive thermal characteristics.

Passive PM2.5 control plan of educational buildings by using airtight improvement technologies in South Korea.

Modern people spend most of their time indoors. Therefore, controlling indoor air quality is one of the most important factors for health. The indoor fine dust concentration is affected by the outdoor fine dust concentration. When the latter is high, it increases due to immersion. Therefore, improving the sealing performance of a building is an effective strategy to reduce indoor fine dust concentration during periods of severe outdoor fine dust without considering indoor fine dust generating factors. Traditional methods of improving the airtightness of a building have focused on replacing windows or doors. However, for reasons such as constructability and economic feasibility, more diverse technologies need to be considered. Due to this necessity, this study applied technologies such as sealing film, sealing lid, and padding to the educational building, and then derived the airtight performance through the blower door experiment, and measured the fine dust concentration to evaluate the effect. As a result of the experiment, it was analyzed that air leakage was reduced by up to 37% and fine dust by 22%.

Verification of particle matter generation due to deterioration of building materials as the cause of indoor fine dust.

Particles of fine dust are pollutants that adversely affect indoor air quality and exacerbate human respiratory diseases. The aging of the building was pointed out as a source of fine dust indoors. The aging of buildings has various causes of deterioration. During various deterioration, friction adversely affects the building floor finish. In this study, an accelerated friction deterioration device was used to confirm the generation of fine dust particles through the frictional deterioration of floor finishes in buildings. The study found that the concentration of fine dust particles attributed to deteriorating flooring was 327 mg/m3 in PM2.5 and 4828 mg/m3 in PM10 and confirmed that particle distribution differs depending on the surface of the flooring. Particles of 10 µm or less were observed through particle analysis. The study confirmed that fine dust particles did not diffuse in a specific direction and that the detected fine dust particles could be attributed to deterioration. Further research is needed on the detection of fine dust in degraded building finishing materials.

Hazard evaluation of indoor environment based on long-term pollutant emission characteristics of building insulation materials: An empirical study.

Insulation materials are essential components in construction, and their main objective is to increase the efficiency of thermal energy by minimizing internal and external thermal exchange. Accordingly, research and development studies are being actively conducted to increase the thermal resistance of insulation materials, and high-performance insulation materials that use organic chemicals have been developed after industrialization. However, thermal insulation comprising chemicals poses a potential risk of pollutant emissions and can cause health problems. In this study, five types of insulation materials and the contaminants generated from the building materials used in insulation construction were quantitatively analyzed. In addition, an empirical study on the discharge of pollutants was conducted using a test bed, and the effects of the pollutants discharged from the insulation material on the indoor environment were examined by analyzing the pollutant concentration for 90 days. In addition, we analyzed the effect of an insulation material on an indoor environment through the standard specifications. Moreover, the necessity of legal management of the emission of contaminants from insulation materials was proposed based on the empirical research results.

Thermal, hygric, and environmental performance evaluation of thermal insulation materials for their sustainable utilization in buildings.

As energy use in the building sector is increasing worldwide, building materials with characteristics that save energy are becoming increasingly important; in addition, there is an emerging need for high-performance insulation materials with low thermal conductivity. However, thermal insulation should consider thermal conductivity, which is the main performance parameter, in addition to the water adsorption rate, acidity, and deformation and expansion due to drying conditions. This study evaluated the main performance of 21 insulation materials used at construction sites to objectively and clearly evaluate their overall performance, including their thermal conductivity. Thermal conductivity was measured by the heat flow meter method according to ASTM C518 and ISO 8301 standards; it was also evaluated according to the drying conditions. The water absorption rate was evaluated by ISO 2896 to ensure the sustainability and long-term thermal conductivity performance of the material. Acidity was evaluated with ASTM E861 to reduce the environmental load of the buildings and soil. The results of this study reviewed an appropriate method to measure the main performance according to the type of insulation.

Assessment of recycled ceramic-based inorganic insulation for improving energy efficiency and flame retardancy of buildings.

In addition to the mitigation of carbon emissions through the reduction of building energy consumption, the prevention of fire spread in buildings is important an important task globally. Therefore, a growing interest towards building materials that can simultaneously contribute to energy savings and provide good flame-retardant performance in buildings exist. The flame-retardant performances of buildings can be improved through the use of inorganic building materials during construction. Meanwhile, among the different types of construction waste, more than 70% of ceramics can be recycled, which would reduce carbon emissions in the production process. Ceramics are inorganic and non-flammable, and can thus secure the flame-retardant performance of buildings. In this study, recycled ceramic-based inorganic insulation to secure the flame-retardant performance of a building are analyzed for their energy saving values. A case study building was modeled and the flame-retardant performance and building energy consumption were analyzed. Setting the thermal transmittance of the external wall according to the energy conservation design standards in South Korea, the tradeoff between model calculates annual energy consumption fire protection and minimization of material environmental impacts are discussed. As a result of simulation, when a wall constructed according to the energy conservation design standards of buildings, the building energy was saved by 18.6% and fire resistance performance was secured.

Characterization of biocomposite using coconut oil impregnated biochar as latent heat storage insulation.

Objective of this research was to characterize properties of the latent heat storage biocomposite (LHSBC) as a novel material that can be employed as a latent heat storage insulation by using biochar. Biochars produced from waste material pine cone, pine saw dust, and paper mill sludge were vacuum impregnated with a bio-based phase change material (PCM), coconut oil, to prepare LHSBCs. In particular, this paper analyzed the chemical stability, latent heat storage performance, thermal conductivity, and thermal stability of LHSBCs based on results of fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), laser flash method and thermogravimetric analysis (TGA). As a result, the LHSBCs showed a maximum latent heat storage capacity of 74.6 J/g and a low thermal conductivity of 0.030 W/mK at the maximum, confirming that LHSBCs have a high latent heat storage capacity and thermal insulation performance. With a maximum specific heat of 1.69 J/gK, a high, sensible heat storage was confirmed. In addition, all LHSBCs were found to be thermally and chemically stable. The LHSBC could be employed as a material with good thermal insulation performance and heat storage characteristics.

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.

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.

Biochar-red clay composites for energy efficiency as eco-friendly building materials: Thermal and mechanical performance.

Biochar and red clay were used to develop eco-friendly building materials with improved thermal and mechanical performance. Rice husk, coconut shell, and bamboo were prepared by thermally decomposing as biochar. Thermal conductivity measurements, scanning electron microscopy imaging, compressive strength measurements, and an infrared heat transfer experiment were performed, and the results showed that the mixture of biochar tends to lower the thermal conductivity. The compressive strength of specimens mixed with rice husk decreased, but that of specimens mixed with coconut shell and bamboo tended to increase. The infrared heat transfer test showed that the thermal performance of the mixed rice husk specimens was significant, while the specimen mixed with coconut shell and bamboo showed thermal performance improvement. A comprehensive evaluation of the improvement in thermal performance and strength indicated that a 10 wt.% mixture of bamboo was the most effective. Therefore, it was possible to effectively determine the type and weight ratio of biochar to red clay binder an important step in the study of biochar and red clay building materials.

Latent heat storage biocomposites of phase change material-biochar as feasible eco-friendly building materials.

One approach to enhance the energy efficiency of buildings is the integration of construction materials of latent heat storage biocomposites, which are prepared by vacuum impregnating the phase change material into biochar. Biochar is used because it is highly utilized and environmentally-friendly, and the selected phase change materials are fatty acid type which are bio-based material and have a low risk of depletion. Experimental results showed that latent heat storage biocomposite possesses excellent exudation and thermal stability as characterized by 0.1727 W/mK of thermal conductivity comparable to that for a gypsum board, and good chemical compatibility as its amount of latent heat tends to decrease as compared with that of pure phase change material. Results of the numerical analysis showed further that latent heat storage biocomposite efficiently reduced the maximum energy consumption of reference building models by 531.31 kWh per year. Thus, both results validate the claim that latent heat storage biocomposite is a promising building material.