The usage of the Earth’s natural heating and cooling abilities are one of the oldest sources of energy known to mankind, and ever since ancient times people have been relying upon the earth’s natural temperature in a number of different ways. From utilizing it as underground shelter in prehistoric ages to adapting its energy for domestic use in ancient Greece geothermal energy has played a major role in human development.
Only in recent years, however, has the process of tapping the earth’s crust for the production of electrical energy been adopted in order to provide clean, renewable power for domestic civilization. Much similar to conventional coal or fossil fuel burning power plants most modern day geothermal power facilities utilize a process of pumping steam into holes drilled into geographic “hot spots” and then forcing the produced steam out of a secondary exhaust hole and into a chamber to power a turbine. Unfortunately although this process is highly effective and can yield massive amounts of energy with little to no environmental impact it is only limited to a few select areas on the Earth where the crust is particularly thin and these are generally inherently unsafe for a number of reasons (primarily the fact that they lie along fault lines and developing volcanoes).
Modern-day trends in geothermal power have led researchers to instead of further overly-focus on conventional hot spots to instead look towards alternative methods for harvesting energy from the Earth’s crust. This has involved research into low-heat power generation facilities, a fusion of both heat and energy generation stations, the development of enhanced geothermal stations and even the utilization of abandoned and exhausted oil pumping stations in order to further try to tap into the potential opened up through previous developments.
Many buildings today are also sporting geothermal heat transfers in order to circulate air and other surface and floor heat through geo”synchs” imbedded into the earth where either water, air or antifreeze is cycled through an enclosed home’s system in order to provide low- to no-cost cooling in the summer and the opposite in the winter. In fact these heat-synch systems alone have been responsible for providing significant drops in energy consumption during winter and summer months in certain areas and are particularly popular in mountainous regions such as the northwest United States and many other rocky, mountainous regions with high volcanic activity such as Iceland.
Although research has been slow in recent years in regards to geothermal power and development due to overwhelming public interest in other alternative energy sources such as solar and wind power a number of scientists working around the world are continuing to try and adapt new technology and develop new methods for tapping the inherent power within the earth. The primary limiting factors at this point are both funding and local regional support, two items that are unfortunately hard to come by in many scientific areas – particularly for large developments such as geothermal plants that require a variety of testing over a wide area that many local governments would much rather dedicate to residential zones or other districts.
You barely touch the realm of mega-watt production found possible by using hot water geothermal sources slightly warmer than hot coffee. Your are valid in noting that it is a heat exchange system like domestic geothermal that uses a refrigerant to boil at these lower tempuratures to run turbines to spin generators. They use the same trick to get the pressure gradiaent across the turbine that is used with steam. That being they spray the cooled liquid (refrigerant in this case, instead of the typicaL water with steam) right behind the turbine to cause the warm flowing gas to return to liquid.
Sincerely, gdm
I should add that I’ve have yet to hear of such systems being appended to present geothermal production facilities that are effectively ~wasting~ the heat in the steam they release into the air; now that this lower tempurature generation method is shown to work. Admittedly the facilty would need more ‘space’ to radiate out the heat at these lower tempuratures; as well at the place to put the turbines and heat exchangers. Though the later two could be put underground if necessary. Yet since many of these facilities are in desert areas they are likely ideally located; as deserts are noted for losing heat to their empty skies, the effect being especially notable at night. [And thus came the word 'desserts' from our forebearers.]
Sincerely, gdm