Thermal Energy Storage (TES) is a technology that stores thermal energy by heating or cooling a storage medium, which can be used later for heating, cooling, and power generation. This paper focuses on TES technologies that valorize solar heat and reduce energy demand in buildings. It reviews several energy storage methods, including sensible heat storage (SHS) and latent heat storage (LHS), and discusses the calculation of storage capacities. SHS technologies, such as water tanks, underground storage, and packed-bed storage, are briefly reviewed. LHS systems using phase-change materials (PCMs) for solar heating/cooling, solar water heating, heat-pump systems, and concentrating solar power plants are also discussed. The paper includes information on the performance and costs of TES systems, emphasizing the importance of storage density and the potential of PCMs in increasing energy density and reducing storage volume. The paper highlights the advantages of TES, such as increased efficiency, reliability, and economic benefits, and the environmental benefits of reduced carbon dioxide emissions. It also addresses the challenges and limitations of different TES methods, providing a comprehensive overview of the current state of TES technologies.Thermal Energy Storage (TES) is a technology that stores thermal energy by heating or cooling a storage medium, which can be used later for heating, cooling, and power generation. This paper focuses on TES technologies that valorize solar heat and reduce energy demand in buildings. It reviews several energy storage methods, including sensible heat storage (SHS) and latent heat storage (LHS), and discusses the calculation of storage capacities. SHS technologies, such as water tanks, underground storage, and packed-bed storage, are briefly reviewed. LHS systems using phase-change materials (PCMs) for solar heating/cooling, solar water heating, heat-pump systems, and concentrating solar power plants are also discussed. The paper includes information on the performance and costs of TES systems, emphasizing the importance of storage density and the potential of PCMs in increasing energy density and reducing storage volume. The paper highlights the advantages of TES, such as increased efficiency, reliability, and economic benefits, and the environmental benefits of reduced carbon dioxide emissions. It also addresses the challenges and limitations of different TES methods, providing a comprehensive overview of the current state of TES technologies.