Stratification
Thermal stratification in is one of the relevant parameters that must be considered to optimize the energetic performance of a storage. For sure also relevant for BILS.
Stratification has mainly to do with the operation of the storage (charging, discharging). It is therefore not yet a focus of our investigations.
Most probably BILS will be divided into several horizontal segments anyway for other reasons. This would simplify the stratification management considerably.
Reverse Stratification
Something that might be interesting is the relation between pressure, temperature, depth and boiling point.
As the static pressure increases with depth, also the boiling point of water will increase. Meaning that the BILS can be operated at higher temperatures at the bottom and store more energy. The hotter part of the storage could be at the bottom: reverse stratification. Of course this is not self-fulfilling, a segregation in horizontal segments would be required.
Relation between lake temperature, depht, static pressure and corresponding boiling point in ().
Temperature versus pressure and boiling point. At 40 m depth the boiling pooint of water is above 150°C.
More to come....