A review on technical, applications and economic aspect of packed bed solar thermal energy storage system

The development of renewable energy technologies provides a significant solution to deal with the energy crisis, along with resolving the environment related issues. Solar energy is one of the emerging technologies, which has been established as an effective alternative to fossil fuels and is an eco-friendly source for the sustainable development of society, throughout the globe. However, its rapid growth is dealing with many technical barriers like low efficiency, fluctuations in energy supply and economic hindrances. The intermittent nature of solar energy is also one of the major cause of fluctuations in energy supply which can be rectified by installing the storage unit with solar thermal systems. Packed bed storage system is an option for the solar thermal systems to store the energy during its availability and supply that stored energy at the time of requirement. This review is about its technical characteristics and economic feasibility of various applications of solar thermal system for different temperature ranges. Initially, the description of packed bed storage system along with its working principle and design aspects are discussed which is followed by details of its heat transfer fluid and packing element. The various factors affecting the heat transfer involve within a packed bed are described and after that the factors affecting thermal losses and pressure drop are also reported. The review also comprises the various applications of the packed bed storage system for various temperature ranges which is followed its economic aspect.