Performance improvement of solar chimneys using phase change materials: A review

Solar energy is an environmentally friendly and renewable energy source which is utilized for electricity generation, domestic water heating and building ventilation. Solar chimney is a solar system that operates as a passive natural ventilation technique for diminishing building's energy consumption and generating electricity from its power plant. However, the solar chimneys suffer from main drawback of non-operative conditions at night when there is no solar energy. Thermal energy storage using phase change materials (PCMs) is considered as an impressive solution for this limitation. Therefore, the present paper provides a literature survey on the incorporation of PCMs for performance improvement of solar chimneys in both buildings and power plant applications. The results obtained from the previous studies showed a great potential of PCM in enhancing the building's thermal comfort, extending the ventilation time, improving the electricity generation of solar chimney power plants, and prolonging the generation period. Moreover, it is also observed that the thermal and geometric characteristics of PCMs have high influence on the overall chimney performance where the paraffins are the most used PCM materials in the available literature. Finally, economic, environmental and exergy analysis was recommended as future research directions beside the PCM's optimal thickness, humidity control and super-cooling reduction.