from National Driller, March 1, 2010, by Greg Ettling - Most people understand the broad concept of what “geothermal” means, but there are distinctions to be made.
As geothermal increasingly has become more mainstream, we need to do a better job of defining what is being discussed. This is no small matter to Ralph Cadwallader, who “just hates the fact that there is confusion, and not enough understanding of what I do and love.” Cadwallader is CEO of Loop Tech Intl., Huntsville, Texas, and he took some time to discuss the issue and share his thoughts:
“I want to help folks understand that the word ‘geothermal,’ in reference to energy, has two very distinct origins,” Cadwallader explains. “There is massive confusion, or should I say little differentiation, of the two very distinct fields of pursuit in the media. I feel it is time to help clear the air.
“On one hand, you have the hot rocks, or ‘Big G,’ which involves the guy who seeks to harness the unlimited high energy source called ‘magma’ found beneath the earth’s relatively thin crust. Magma is a complex, high-temperature (1,300 degrees F to 2,400 degrees F) fluid substance. The Big G is (deep) energy that is brought up to drive electric turbines or used as direct heat. You can read of places where the entire community’s heating system is directly connected to the one source.
“On the other hand, you have the ‘Little G,’ which involves the guy, like myself, who seeks to recycle energy by using the solar energy that is stored in the earth’s shallow depths of 500 feet of subsurface, including bodies of water. The idea of geoexchange (geothermal, ground source heat pump, earth coupled) is that we can capture the energy that already exists and recycle it. Geoexchange is nothing more than circulating water across a hot refrigerant removing the energy from a conditioned space and storing that energy in the ground for winter use. The earth’s thermal mass will store the energy to heat the refrigerant when the reversing valve calls for heating. Reclaiming or recycling energy that already exists is just as important as finding new energy, and that is what I help my clients do.”
"I suppose the word needs to get out that geoexchange describes my industry better. Would there be less confusion between the two if we had labeled one ‘geothermal’ and the other ‘geothermic?’ I prefer ‘geoexchange’ for the recycled stuff, the title given to the industry by the Geothermal Heat Pump Consortium.”