Here's a smaller scale water battery that heats an entire house year round. The water tank itself is placed in the center of the house across all 3 floors and actually makes for a quite nice design element as well. The energy is generated in the warm seasons and the volume of water is large enough to last through the entire winter. It's a German vid but subtitles are quite accurate.
https://www.youtube.com/watch?v=MBLiNHsod8Y