SHARE
Technology

Dual Purpose Underground Thermal Battery

Topic:

Invention Reference Number

201904321

Related Links

Grid – Below-ground balancing
ORNL researchers have developed a system that stores electricity as thermal energy in underground tanks, allowing homeowners to reduce their electricity purchases during peak periods while helping balance the power grid. Credit: Andy Sproles, Oak Ridge National Laboratory/U.S. Dept. of Energy
ORNL researchers have developed a system that stores electricity as thermal energy in underground tanks, allowing homeowners to reduce their electricity purchases during peak periods while helping balance the power grid. Credit: Andy Sproles, Oak Ridge National Laboratory/U.S. Dept. of Energy

Researchers at ORNL have developed a dual-purpose underground battery that consists of a tank acting as a thermal battery and a reservoir tank that can operate as a low duty cycle geothermal source. The reservoir tank can also recycle energy lost from the thermal battery. The proposed invention can reduce buildings' disturbances to the electric grid while meeting their thermal demands efficiently.

Description

The apparatus consists of a fluid filled battery tank positioned within a fluid-filled reservoir tank which is buried underground. The tanks are to a heat pump and an example building via fluid loops, said heat pump may also charge the fluid filled battery tank and deliver thermal energy (both cold and heat) to the example building. The battery tank serves the purpose of discharging energy to the building either jointly with the heat pump or during periods of peak electricity usage while the heat pump is switched off. Phase change materials designed within the tank or in the adjacent tank wall are used to separate the inner tank and annuals of the battery and to increase thermal energy storage density. 

Applications and Industries

  • Energy storage

Benefits

  • Improved efficiency of electric grid operations
  • Potential cost savings at the building level and grid level

To learn more about this technology, email partnerships@ornl.gov or call 865-574-1051.