Methods and systems for thermal energy storage and their use in buildings applications

A system for using thermal energy storage for a building application, the system comprising:

• a plurality of particles;
• a silo;
• a heat pump configured to transfer heat to a first heat transfer fluid;
• a first heat exchanger configured to operate in a charging mode and a discharging mode;
• a conveyor configured to move at least some of the particles from the silo along a particle stream from the first heat exchanger to the silo;
• a phase change material positioned within the silo;
• and
• a particle cooler and a particle heater located along the particle stream downstream from the first heat exchanger, the particle heater and particle cooler configured to cool or heat at least some of the particles before said particles return to the silo;
• wherein:
• during the charging mode, the first heat exchanger is configured to receive at least some of the particles from the silo and facilitate heat transfer between said particles and the first heat transfer fluid,
• during the discharging mode, the first heat exchanger is configured to receive at least some of the particles from the silo and facilitate heat transfer between the said particles and a second heat transfer fluid,
• the system is configured to exchange heat between at least some of the particles and the phase change material during the charging mode and during the discharging mode, and
• the system is configured to exchange heat between the second heat transfer fluid and the building application.