Various forms of geothermal utilization

Geothermy is, literally, the heat energy in the ground at our feet. There are two main methods for its utilization; namely, the direct use of heat or steam as geothermal energy, and the utilization of ground-source heat which makes use of the temperature difference between the subsurface and the air. Aside from power generation, geothermal energy is used for indoor heating and hot water supply, which also includes the hot springs much loved by the Japanese. Other uses include lumber drying, greenhouse cultivation, and fish farming. The utilization of ground-source heat, meanwhile, is a power-saving technology for effectively improving the quality of air conditioning systems by making use of the constant year-round temperature more than 10 to 20 m or so below ground.