In the simplest definition, geothermal heating and cooling is the use of the earth’s temperature to heat and cool your house. Pretty simple, no? Although the systems can be expensive to install (especially on an already existing house), once in place there is a 30-70% reduction in utility bills for heating or cooling. Plus, there is no pollution or burning of fossil fuels, which is incredibly important in today’s day and age.
Below the earth’s surface the temperature tends to stay right around 55 degrees Fahrenheit. No matter what the temperature outside is, that temperature is pretty constant. And geothermal energy uses this stable temperature to cool your house in the summer and heat the house in the winter. Sort of like radiant heating inside for your floor, channels are dug outside into the ground and pipes laid into them circulate water (or refrigerant) throughout the house – one direction during the winter to draw in the warmer water and the other direction in the summer to send the heat outside and bring the cooler temperature water inside.
Geothermal energy has been around for a long time – even the Romans used to use it to heat the water in their bathhouses. Natural hot springs you visit on vacation are the result of geothermal energy. Some places, like Iceland, have water so hot under the surface that they can actually use the steam to power buildings! Of course, this is natural geothermal energy and not the artificial kind we create to use for our houses, but still – you get the idea. From Climate.org, here are some ways that we can access geothermal energy and what forms it comes in:
-in hydrothermal reservoirs of steam or hot water trapped in rock. These reservoirs are concentrated in particular regions as a result of geologic processes.
-in the heat of the shallow ground. Called “earth energy,” this geothermal source is found everywhere and is the normal temperature of the ground at shallow depths. Earth energy is not “enhanced by” geologic process and therefore is not as hot as other geothermal sources.
-in the hot dry rock found everywhere between 5-10 miles beneath the earth’s surface and at even shallower depths in areas of geologic activity.
-in magma, molten or partially molten rock, that can reach temperatures of up to 1200 C or 2192 F. While some magma is found at accessible depths, much of it lies too deep to be reached by current technology.
-in geopressurized brines – hot, pressurized waters containing dissolved methane that are found 10,000 to 20,000 feet below the surface.
Every single house and building in the world (well, where you can use geothermal) should be using this to heat and cool their open spaces. Imagine if every home in your city could be heated and cooled using mainly only the earth’s temperature…there would be less pollution almost immediately! Supposedly, just by estimating for the houses using geothermal in this country as of today, it is like the equivalent of reducing our oil consumption by 21 million barrels of oil per year. That is the the amount that the U.S. consumes in one day, but imagine if every house built from here on out used geothermal energy…we could reduce our dependence on this dirty fossil fuel and reduce pollution in our environment at the same time.