HeatTank contains two separate heat exchangers (25-2 and 50-2 versions of the Thermal Battery). One heat exchanger is connected to an external water-air heat exchanger or a separate cooling system to provide free-cooling or more efficient cooling energy for charging. The other heat exchanger is connected to an internal heat exchanger, which cools the interior space and is used for charging the storage in the summer period.

Charging of the Thermal Battery:
Option 1: When the external temperature is lower than the temperature of the phase change material, the cooling potential of the external air can be used through the external heat exchanger to charge the storage (free-cooling).
Option 2: When the external temperature is higher than the temperature of the phase change material, free-cooling is not useable anymore. The internal heat exchanger uses charges the storage with the help of the existing split/DX cooling system, blowing the cold air directly to the internal heat exchanger.
 

Discharging of the Thermal Battery:

The internal circuit cools down the internal cooled space, while Thermal Battery discharges.
If the two separate heat exchangers of the Thermal Battery, operate simultaneously, direct heat exchange is possible between the external and internal circuits, while charging/discharging the HeatTank.
Schematics for an Air duct DX system: as a difference the internal heat exchanger is built in the air handling unit (AHU).