They are using an underground conical tank of 1400cu-m of water, heated by a large array of solar thermal panels. The 20m diameter pool is level at the ground level, but topped with 1/2m of polystyrene, but not insulated underneath. 50% of the heat brought in from the panels stays in the water, and the remainder is an earth charging process, soaking into the surrounding soil for later reclamation. They claim it's a world first, for which I am thankful, because it supports my case for doing it on our house, which may be the first for a Domestic property.
I have also been told by my Wikipedia friend, Engineer Mike SM about an article describing an office conversion project reported in the IEEE journal Sept 2007 in San Jose California (also claiming to be a world first). The architect is David Kaneda. The building is using reverse cycle heat pump, so that in summer, the pump is cooling the building and dumping the heat underground, and in winter, it is getting the heat back from the same place. They are also generating 30kw of rooftop PV, which is easy in the sunshine of San Jose.