In a number of natural or industrial settings, such as magmatic intrusions or geothermal power systems, subsurface porous rocks are flooded by fluid of a different density and composition than the original formation fluid. As the invading fluid migrates through the formation and reacts, its density and composition might change. In turn, this may lead
All buildings require ventilation to keep the indoor air fresh and clean. With underfloor air distribution, fresh air is supplied at a low level, while exhaust air is extracted from the top of a room. If the room contains a heat source, then a temperature stratification develops and occupants are surrounded by fresh air in
Renewable energy sources such as wind and solar are intermittent, and this leads to the need for substantial energy storage. At times of excessive generation, some of the renewable energy might be converted into hydrogen and stored underground. The hydrogen will then be recovered and used when the renewable sources produce insufficient energy. A recent