Thermally Activated Technologies
Heat Recovery Units (HRUs)
These units capture heat from the prime mover that can then be used to drive an absorption chiller, run a desiccant dehumidifier, or make hot water or steam for heating.
Chillers transfer recovered heat from prime movers to a heat sink through an absorbent fluid and a refrigerant. The chiller accomplishes its cooling effect by absorbing and then releasing water vapor into and out of a lithium bromide solution.
Desiccants use drying agents to remove water from the air being used to condition building space by exposing the desiccant material (such as silica gel, activated alumina, lithium chloride salt, and molecular sieves) to a high relative humidity air stream-allowing it to attract and retain some of the water vapor-and then to a lower relative humidity air stream, which draws the retained moisture from the desiccant.
For more on desiccant technologies, visit NREL's Distributed Thermal Energy Technologies Program site.
ORNL's Heating and Cooling Equipment R&D site also has technical details on CHP applications.