Loading...

Modeling and optimization of a multiple (cascading) phase change material solar storage system

Nekoonam, S ; Sharif University of Technology | 2021

262 Viewed
  1. Type of Document: Article
  2. DOI: 10.1016/j.tsep.2021.100873
  3. Publisher: Elsevier Ltd , 2021
  4. Abstract:
  5. Utilization of heat storage units in solar energy systems can resolve the challenge of fluctuation and uncertainty of the solar energy. Phase change materials (PCMs) are used as the storage media for solar energy storage systems. In this research, a system including of a solar collector and a PCM-based cascaded energy storage unit was numerically investigated. Air was used as the heat transfer fluid (HTF) and three paraffin-based materials (RT50, RT65, and RT80) were used as PCM for the energy storage unit. The investigated system mainly operates between 15 °C and 90 °C and considering different PCMs, the selected PCMs were appropriate. Paraffin-based PCMs also present acceptable thermal efficiency and stability regarding the storage application. Developed governing equations were solved using the finite-difference method. The effective heat capacity (EHC) method was integrated into a two-dimensional transient thermal model to determine the temperature distribution within the energy storage unit. The Genetic algorithm (GA) was applied for optimization to achieve the maximum level of stored energy for one entire day. Results showed that phase change temperature (PCT) of the PCM located at the last layer of the cascaded section, is a key element for the level of stored energy. It was observed that the latent heat of phase change (LHPC) is a key factor for the first PCM layer selection (of the cascade). Also, the multiple-PCM energy storage unit at its optimal configuration, improves the charging efficiency of the storage by at least 7%. © 2021
  6. Keywords:
  7. Air ; Finite difference method ; Genetic algorithms ; Heat storage ; Heat transfer ; Paraffins ; Solar energy ; Specific heat ; Storage (materials) ; Charging efficiency ; Energy storage unit ; Governing equations ; Heat storage units ; Modeling and optimization ; Phase change temperature ; Solar energy systems ; Two-dimensional transient ; Phase change materials
  8. Source: Thermal Science and Engineering Progress ; Volume 23 , 2021 ; 24519049 (ISSN)
  9. URL: https://www.sciencedirect.com/science/article/abs/pii/S2451904921000354