Is there a lower and upper limit to the buffer volume?

The buffer is scalable in length, width and depth. But the lower limit is 85m3. There are two reasons for this. The first is economic: a smaller buffer is technically inefficient in terms of cost (ROI versus reference gas). The second reason is physical: at 85m3 the weight is equal to the buoyancy created by the insulation. A buffer smaller than 85m3 can come up despite the back pressure of the water. The upper limit is determined by the energy requirement and the available surface area. Buffers larger than 1500m3 are preferably placed in cascade.