PDF Publication Title:
Text from PDF Page: 021
Table 14 Summary of metal matrix studies. as PCM. Different samples of this composite were evaluated. The results showed that the highest effective thermal conductivity of composite PCM was 50.78 W/mK, which was 110 times higher than that of salt powder. Also, it was concluded that the addition of ENG- TSA causes a decrease in latent heat, but there is no remarkable variation in phase change temperature. 3.6. Nanoparticle-encapsulatedPCMs As illustrated in Table 15, most of the research work in the lit- erature was conducted on improving the thermal properties of organic PCMs such as paraffins and fatty acids. Paraffin draws a great attraction to researchers for its desirable characteristics i.e. good heat storage density, melting or solidification compatibly with little or no sub-cooling, being inert to most common chemical reagents and of low cost. The main drawback of these PCMs is their low thermal conductivity, hence the growing interest in dispersing high con- ductive nanoparticles within the PCMs [134]. Wu et al. [146] tested different metal nanoparticles in order to enhance the thermal con- ductivity of paraffin wax. The results concluded that Cu/paraffin composite had a better cooling/heating rate i.e., better thermal con- Table 15 Recent relevant publications concerning nanoparticle-PCM (>2011). ductivity than aluminium, carbon/copper nanoparticle dispersed paraffin composite in the same condition showed in Fig. 21. Additional recent work on nanoparticle PCMs is summarized in Table 15. The review by Kibria et al. [134] illustrates how dispers- ing nanoparticles in PCMs enhance the overall heat capacity, whilst also demonstrating the effects upon the PCM viscosity and subcooling. Major areas of concern remain to be clarified. • Although the thermal conductivity of the PCM increases with increase in concentration of nanoparticles, surface modifica- tion of the nanoparticles might be required. The diameter of the nanoparticles was shown to have a limited effect only. Mostly carbon nano-tubes and fibres, graphite and graphene have been investigated. • Metal and metal oxide nanoparticles show an enhancement in thermal conductivity that varies with their shape, size and con- centrations. The enhancement is also temperature dependent. • The presence of nanoparticles reduces the solidification and melting time of the composition. Too high a concentration of nanoparticles could negatively modify other properties of PCM. Authors Kibria et al. [134] Warzoha et al. [135] Sahan et al. [136] Yu et al. 2014 [137] Jourabian et al. [138] Motahar et al. [139] Cingarapu et al. [140] Sciacovelli et al. [141] Kashani et al. [142] Khodadadi et al. [143] Abolghasemi et al. [144] Guo and Wang [145] Topics H. Zhang et al./Progress in Energy and Combustion Science 53 (2016) 1–40 21 Copper studies Aluminium studies Nickel studies Author Zhao et al. [123] Vadwala [124] Li et al. [125] Bauer and Wirtz [126] Tong et al. [127] Xiao et al. [128] Studied material Copper foam embedded in paraffin RT58 (low temperature storage) Paraffin wax and open cell copper foam (low temperature storage) Copper matrix and sodium nitrate (high temperature storage) Composite developed by plate-like thermally conductive aluminium containing pentaglycerine as PCM Water/aluminium foam composite (low temperature storage) Paraffin/nickel foam composite (low temperature storage) Main conclusions The addition of metal foams with a cell size of 10 PPI and 95% porosity can increase the overall heat transfer rate by 3–10 times. Also, smaller porosities and pore densities produced better heat transfer performance, depending on the metal foam parameters. The equivalent thermal conductivity of a foam-wax composite was found to be 3.8 W/ mK, which was 18 times higher than that of pure paraffin wax, i.e. 0.21 W/mK. Moreover, copper foam reduced the time required to melt approximately the same amount of wax to 36% of that without the use of metal foam. Heat transfer coefficient of the thermal energy storage with copper matrix can be significantly increased up to 28.1 times by heat conduction when the PCM is in the solid phase, and up to 3.1 times by the combination of natural convection and heat conduction when the PCM is in the liquid phase. Hence, both the melting and solidification times are substantially shortened. In addition, it was concluded that porosity plays a more important role to enhancing the heat transfer efficiency in thermal energy storage system than pore density. An increase in aluminium foam metal fraction results in an increase in the effective thermal conductivity of the composite because only about 2% of the heat flow is through the PCM, and the interfacial bond resistance decreases due to increased contact area. The trade-off is a reduced charging time versus a reduced volumetric latent heat storage due to the increasing aluminium foam metal fraction. An increase in the heat transfer rate during melting and freezing of the PCM (water). It was demonstrated that thermal conductivity of the paraffin/nickel foam composite was nearly three times larger than that of pure paraffin, 0.4 and 1.2 W/mK respectively. Fiedler et al. [129] compared a copper and ductivity compared to aluminium matrices. It was found that a further increase is possible using diamond-coated copper matrices. Xiao et al. [128] and Fiedler et al. [129] concluded that copper is an acceptable matrix material. aluminium metal matrix and found that copper matrices achieve approximately an increase of 80% in the effective thermal con- Review of thermophysical properties of nanoparticle-dispersed PCM Temperature-dependent thermal properties of a paraffin PCM embedded with herringbone style graphite nanofibres Improving thermal conductivity PCM: a study of paraffin nanomagnetite composites Influence of nanoparticles and graphite foam on the supercooling of acetamide The expedited melting of PCM through dispersion of nanoparticles in the thermal storage unit A novel PCM containing mesoporous silica nanoparticles for thermal storage: thermal conductivity and viscosity Nanofluids with encapsulated tin nanoparticles for advanced heat transfer and thermal energy storage Melting of PCM in a thermal energy storage unit: Numerical investigation and effect of nanoparticle enhancement Numerical study of solidification of a nano-enhanced PCM in a thermal storage system Thermal conductivity enhancement of nanostructure-based colloidal suspension utilized as PCM for thermal energy storage Heat transfer enhancement of a thermal storage unit consisting of a PCM and nanoparticles Numerical investigation of nanoparticles-enhanced high temperature PCM for solar energy storagePDF Image | Thermal energy storage: Recent developments
PDF Search Title:
Thermal energy storage: Recent developmentsOriginal File Name Searched:
3-Thermal-Energy-storage-recent-developments-and-practical-aspects.pdfDIY PDF Search: Google It | Yahoo | Bing
Turbine and System Plans CAD CAM: Special for this month, any plans are $10,000 for complete Cad/Cam blueprints. License is for one build. Try before you buy a production license. More Info
Waste Heat Power Technology: Organic Rankine Cycle uses waste heat to make electricity, shaft horsepower and cooling. More Info
All Turbine and System Products: Infinity Turbine ORD systems, turbine generator sets, build plans and more to use your waste heat from 30C to 100C. More Info
CO2 Phase Change Demonstrator: CO2 goes supercritical at 30 C. This is a experimental platform which you can use to demonstrate phase change with low heat. Includes integration area for small CO2 turbine, static generator, and more. This can also be used for a GTL Gas to Liquids experimental platform. More Info
Introducing the Infinity Turbine Products Infinity Turbine develops and builds systems for making power from waste heat. It also is working on innovative strategies for storing, making, and deploying energy. More Info
Need Strategy? Use our Consulting and analyst services Infinity Turbine LLC is pleased to announce its consulting and analyst services. We have worked in the renewable energy industry as a researcher, developing sales and markets, along with may inventions and innovations. More Info
Made in USA with Global Energy Millennial Web Engine These pages were made with the Global Energy Web PDF Engine using Filemaker (Claris) software.
Sand Battery Sand and Paraffin for TES Thermo Energy Storage More Info
CONTACT TEL: 608-238-6001 Email: greg@infinityturbine.com (Standard Web Page)