Geothermal heating a total capacity of 15 GW extracted 88 PJ of heat energy for space heating. Global ground-source heat pump capacity is growing by 10% annually. Hot springs have been used for bathing at least since Paleolithic times. The oldest known spa is a stone pool on China's Mount Li built in the Qin dynasty in the 3rd century BC, at the same site where the Huaqing Chi palace was later built. Geothermal energy supplied channeled district heating for baths and houses in Pompeii around 0 AD. In the first century AD, Romans conquered Aquae Sulis in England and used the
Aquae Sulis ("deiada" "goddess"); "Andagin" - accusative feminine "woman"; "Cuamenai" - locative/dative feminine of "Cuamena" It was the religious settlement, rather than the road junction further north, which was given defensive stone walls, probably in the 3rd century. The area within - of approximately - was largely open ground, but soon began to be filled in. There is some dispute as to whether these new buildings were private dwellings or were associated with servicing the pilgrims to the temple. There was also a ribbon development along the northern road outside the walls and cemeteries beyond. From the later 3rd century on, the