BILS2 experiments

The purpose of a BILS is to store heat, hence the BILS must be heated up. To heat up the storage a mobile electric heater is used. Unfortunately we had only about 11 kW heating power available, where maybe 7-8kW reach the storage.

This is limiting of course the maximum temperature, but still the general behaviour can be studied,  


When heating up, buoyancy increases and the BILS surfaces - as expected. But the position at the surface is now horizontal, and the top (that is the side of the cylinder) is flattened. 

Questions to answer:

  • What is the maximum temperature? (see below)

  • Why horizontal? (explanation to come)

  • Why flattened? (explanation to come)

Maxium temperature


Measurement of the temperature inside the storage and simulated development of the temperature. The simulation requires some assumptions about the volume of the BILS, heat transfer coefficients, thickness of the skin, location of the sensors etc. The message at this point is not that we are able to simulate perfectly the development of the storage, but much more that the simulation tool provides reasonable results with reasonable assumptions.   

Impressions from the first experiments, enjoy