Particulate heat transfer fluid and related system and method

A method for transferring heat comprising:

• i) providing at least one storage vessel containing a particulate heat transfer fluid, the heat transfer fluid comprising a plurality of particles of a metal-containing material having a melting point of greater than 800° C., the heat transfer fluid being substantially free of a liquid component;
• ii) conveying the particulate heat transfer fluid from the storage vessel to an inlet of a tubular receiver positioned to receive heat from a heat source, the tubular receiver comprising one or more enclosed tubes;
• and
• iii) flowing the particulate heat transfer fluid by gravity feed through the enclosed tubes in a dense, unfluidized state, the particulate heat transfer fluid having a particle volume fraction of at least about 25% during said flowing step, the particulate heat transfer fluid absorbing heat from the heat source during said flowing step.