Experimental Analysis and Numerical Modeling of a Shell and Tube Heat Storage Unit with Phase Change Materials

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• 作者：Tilman Barz ; Christoph Zauner ; Daniel Lager ; Diana C. López Cárdenas ; Florian Hengstberger ; Mariano Nicolás Cruz Bournazou ; Klemens Marx
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2016
• 出版时间：July 27, 2016
• 年：2016
• 卷：55
• 期：29
• 页码：8154-8164
• 全文大小：558K
• 年卷期：0
• ISSN：1520-5045

文摘

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.