Evaluation of thermal performance of bio-based phase change materials composites using carbon nanomaterials

Paper presented to the 10th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Florida, 14-16 July 2014.Phase change materials (PCMs) have been considered for the latent heat thermal energy storage (LHTES) in buildings. Bio-based PCMs are type of organic fatty acid ester PCMs and significantly less flammable than paraffins so it can be used safely. However, they have a low thermal conductivity which severely reduces their thermal performances. In this study, Bio-based PCMs were prepared by the stirring of carbon nanomaterials such as exfoliated graphite nanoplatelets (xGnP) and carbon nanotubes (CNT) in liquid Bio-based PCMs at different mass fractions (1.0, 3.0 and 5.0 wt%). The micro structures were characterized using scanning electron microscopy (SEM) and it showed well-dispersion of Bio-based PCMs composites. Fourier transform infrared spectroscopy (FT-IR) results showed no chemical interaction between Bio-based PCM and prepared carbon nanomaterials. The thermal conductivity of Bio-based PCMs composites were increased as increasing carbon nanomaterials loading contents. Differential scanning calorimetry (DSC) analysis results indicated that Bio-based PCM/xGnP composites maintained their large latent heat values and suitable phase change temperatures due to large surface area and well-dispersion of carbon nanomaterials. Therefore, Bio-based PCM composites can be considered as suitable candidates for latent heat thermal energy storage.dc201

Thermal efficiency evaluation of silica fume/phase change material composite for application to concrete

Paper presented to the 10th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Florida, 14-16 July 2014.Silica fume has been used as a replacement for cement, due to its high early compressive strength, high tensile and flexural strength, high bond strength, and enhanced durability of concrete. In this study, enhanced thermal performances of silica fume by incorporating organic PCMs were examined, for applying to concrete. Three kinds of organic PCMs were incorporated into the silica fume. The silica fume/PCM composites were prepared by the vacuum impregnation method. Because the silica fume has a high porous structure compared to the cement, it is useful to incorporate the PCM, to enhance its thermal storage performance. 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 analysisdc201

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

Antiosteoarthritic Effects of ChondroT in a Rat Model of Monosodium Iodoacetate-Induced Osteoarthritis

Ganghwaljetongyeum is a traditional Korean herbal medicine used to treat joint pain, limited motion, fever, and swelling; it also inhibits inflammatory processes associated with arthritis. ChondroT, a water extract of Ganghwaljetongyeum, is a new complex herbal medicine. This study investigated the effects of ChondroT using a rat model of monosodium iodoacetate- (MIA-) induced osteoarthritis. Thirty-six rats were randomly divided into three ChondroT groups and a normal, control, and positive control group. Changes in paw edema volume, histopathology, and plantar withdrawal response were analyzed. Further, inflammatory cytokines, arachidonic acids, liver and kidney function, and hematological features were measured. ChondroT significantly decreased paw edema by the 5th day and notably improved articular cartilage damage; it also significantly improved the plantar withdrawal response in terms of both reaction time and force intensity. Moreover, treatment with ChondroT significantly decreased the serum levels of tumor necrosis factor alpha, interleukin-1β, interleukin-6, and prostaglandin E2 and significantly increased serum aspartate aminotransferase and alanine aminotransferase levels. This study demonstrates that ChondroT has anti-inflammatory and analgesic effects in a MIA-induced osteoarthritis rat model. These results support the clinical relevance of ChondroT for future use in patients with osteoarthritis. However, further studies are required to elucidate the corresponding mechanisms