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Thermal storages are part of highly integrated energy systems. The development of accurate and reduced models is critical for efficient simulations on a system-level and the analysis of the storage design, control, and integration. We present the experimental analysis and numerical modeling of a lab-scale shell and tube latent heat thermal energy storage (LHTES) unit with a (latent) storage capacity of about 10–15 kWh. The phase change material (PCM) is a high density polyethylene (HD-PE) with phase change temperatures between 120 and 135 °C. An efficient 2D numeric storage model is derived which accounts for design and material parameters of PCM, storage, and heat transfer fluid (HTF). Different probability distribution functions are used to model the PCM apparent specific heat capacity. From these functions the state of charge (SOC) can be predicted, which indicates the extent to which a LHTES is charged relative to storeable latent heat. Model predictions are fitted to experimental data from thermophysical measurements and from LHTES operation with partial and full charging/discharging. The storage model agrees well with experimental results. However, thermosphysical material analysis and storage operation indicated that the temperature range of phase transition is noticeable affected by storage loading operating condition, i.e., heating and cooling rates, which is not considered in the model. With this simplification it turns out that the model is limited by the quality of prediction of internal storage PCM temperatures.

Thermochemical energy storage (TCES) is considered a possibility to enhance the energy utilization efficiency of various processes. One promising field is the application of thermochemical redox systems in combination with concentrated solar power (CSP). There, reactions of metal oxides are in the focus of research, because they allow for an increase in the process temperature. The reaction system CuO/Cu2O has been reported as a suitable candidate for TCES. For proper development and modeling of combined CSP–TCES processes, reliable kinetic data are necessary. This work studies the reduction of CuO and the oxidation of Cu2O under isothermal and isokinetic conditions. The reactions are analyzed using a simultaneous thermal analysis (STA) and a lab-scale fixed-bed reactor. The reaction behavior shows significant differences between both analyses. To develop kinetic models, the non-parametric kinetic (NPK) approach is used. This model-free approach is expanded by the Arrhenius correlation to increase the applicable temperature range of the models. The resulting models are evaluated and compared. Furthermore, the cycle stability of the system over 20 cycles is assessed for a small sample mass in the STA and a large sample mass in the fixed-bed reactor.

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The typical exposure caused by wireless LAN applications in public areas has been investigated in a variety of scenarios. Small-sized (internet café) and large-scale (airport) indoor scenarios as well as outdoor scenarios in the environment of access points (AP) supplying for residential areas and public places were considered. The exposure assessment was carried out by numerical GTD/UTD computations based on optical wave propagation, as well as by verifying frequency selective measurements in the considered scenarios under real life conditions. In the small-sized indoor scenario the maximum temporal peak values of power density, spatially averaged over body dimensions, were found to be lower than 20 mW/m(2), corresponding to 0.2% of the reference level according to the European Council Recommendation 1999/519/EC. Local peak values of power density might be 1-2 orders of magnitude higher, spatial and time-averaged values for usual data traffic conditions might be 2-3 orders of magnitude lower, depending on the actual data traffic. In the considered outdoor scenarios, exposure was several orders of magnitude lower than in indoor scenarios due to the usually larger distances to the AP antennas.