This is the TSS system that is now all underground. It is made of foam insulated panels and 14-18" of spray expanding foam. After it was all put together, it was lined then filled with tubing, a storage tank, and sand making it solid and well insulated. All this is now has been back filled and is underground. The solar panels will feed into this system, as well as our GARN wood boiler which is heating our home, and dad's new building. The storage from this tank will be able to heat the super insulated building for about a month and a half in winter, giving us the flexibility to travel away from home/studio if needed.