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Abstract This work focuses on the study of heat transfer mechanisms in composites materials which may be used for Latent Heat Thermal Energy Storage applications. These composites contain phase change material (PCM) which can absorb and release energy during thermal cycling. PCM’s used here are paraffins microencapsulated in poly(methylmethacrylate); microencapsulation avoids the flow of paraffin when it is in the liquid state. Samples with different paraffin weight fractions and particles shape and distribution were studied in this work. Scanning Electron Microscopy and Differential Scanning Calorimetry were used to determine morphology and perform measurements of phase changes temperatures, enthalpies and heat capacity respectively. Further, a periodic method (DICO) allowed measuring thermal conductivity (λ) and diffusivity (a) of the composites at temperatures below and above of the paraffin phase change from crystalline solid to isotropic liquid.

Abstract Although most of the parameters affecting spiral jet milling have already been studied, there are no investigations of several parameters and their effects on the flow conditions over the entire cross-section inside the spiral jet mill via non-invasive methods. In order to vary several geometrical and operative parameters and to determine the flow conditions inside the jet mill, a new type of experimental spiral jet mill apparatus was designed and constructed. It has an almost entire optical accessibility and its highly modular construction enables a very convenient variation of the geometric parameters. This paper describes the new type of mill apparatus and preliminary experimental results concerning the flow conditions inside the spiral jet mill as well as grinding effects under different conditions on particle size distributions of barium sulphate micro particles.

Due to the high interest of appropriate characterization of PCM and hybrid PCM composites, different research centres and universities are using several material characterization techniques not commonly used with PCM, to study the structure and morphology of these materials. Likewise, physico-chemical stability is a crucial parameter for the performance of latent storage materials during time and its evaluation has been done by using molecular spectroscopy, chemiluminiscence or calorimetric tests. Atomic force microscopy and nanoindentation are also reported to characterize hybrid PCM composites.

The impact of the length of axially segmented lifters, as used in industrial rotary drums, on their process behavior and in particular the axial solids transport is analyzed in this study. Experime...

Abstract The impact of sectional internals, as often used in industrial rotary drums, on the axial solid transport in rotary drums is investigated experimentally under variation of the operation parameters solid feed rate, drum inclination and rotational speed. Different section numbers and internal-lengths have been analyzed, applying the axial dispersion model, in a fully optically accessible lab scale rotary drum apparatus. The mean residence times are increasing with the section numbers and their length up to 4 times compared to bare drum results. Capacity limits have been detected, resulting in higher back-spillage ratios dependent on the set of operational parameters. The impacts of parameter changes on the axial dispersion are decreasing with section number and length, resulting in a more constant axial dispersion coefficient of about 1 × 10−6 m2/s. A qualitative similarity of the axial solid bed profile proposed by the Saeman-model for bare drums has been found for sectional internals.

The use of thermal energy storage by phase change materials (PCM) is increasing in interest for building applications. For the deployment of the technology, appropriate characterization of PCM and hybrid PCM is essential, but it is not always possible to carry it out with conventional equipment, mainly due to the sample size. This paper shows equipment developed in different research centers and universities to analyze thermophysical properties, such as specific heat, latent heat and melting temperature, and thermal conductivity and diffusivity of PCM and hybrid PCM materials. The work is partially funded by the European Union (COST Action COST TU0802), the Spanish government (ENE2011-28269-C03-01, ENE2011-28269-C03-02 and ENE2011- 22722), TUBITAK (project 110M032), and by Qatar National Foundation through the NPRP No.: 4-465-2-173. The authors would like to thank the Catalan Government for the quality accreditation given to the research group GREA (2009 SGR 534) and their research group DIOPMA (2009 SGR 645), both in Spain. Laia Miró would like to thank the Spanish Government for her research fellowship (BES-2012-051861).

Abstract The effect of sectional internals on the solid bed cross section in rotary drums is investigated with a novel, fully optical accessible rotary drum apparatus for different internal configurations. The impact on mixing behavior is analyzed for different section numbers and filling degrees as well as material configurations. The mixing kinetics is affected positively by the sections, particularly for lower rotational speeds and filling degrees. The goodness of mixing in segregating particulate systems can be improved by sectional internals. Additionally to mixing effects, the impact of sectional internals on phase interfaces of the cross section is analyzed. A mathematical model description of the solid bed cross section is created and validated with the experimental data. The gas/solid interface is increasing logarithmically compared to the bare drum. The solid/inner wall interface is increasing linearly with the number of sections and the solid/outer wall interface is not affected significantly by sectional internals.