Re:Geothermal's path to relevance: cheap drilling
by dredmorbius on Wednesday October 27, 2021 @02:17AM
(#29010081)
Yes, in much the same way that passive or thermal (e.g., hot-water) solar designs are a form of solar power.
The principle difference, as others have pointed out, is that when converting heat to mechanical energy, or for electrical generation (mechanical + a generator), efficiency greatly increases as the temperature gradient between the hot and cold ends of the process increases.
There's still a lot of utility from lower-grade heat, for space heating (to about 24C/75F), water (about 60C/140F), and cooking (175C/350F). Even a partial boost can assist with other heating methods.
But for large-scale electrical generation, high temperatures, well above boiling point, are what are needed.
Community thermal energy storage is a thing. That can use either geological formations or specially-constructed insulated structures. Thermal potential may be stored as a hot or cold medium, for heating or cooling.
The principle difference, as others have pointed out, is that when converting heat to mechanical energy, or for electrical generation (mechanical + a generator), efficiency greatly increases as the temperature gradient between the hot and cold ends of the process increases.
There's still a lot of utility from lower-grade heat, for space heating (to about 24C/75F), water (about 60C/140F), and cooking (175C/350F). Even a partial boost can assist with other heating methods.
But for large-scale electrical generation, high temperatures, well above boiling point, are what are needed.
Community thermal energy storage is a thing. That can use either geological formations or specially-constructed insulated structures. Thermal potential may be stored as a hot or cold medium, for heating or cooling.