Hello again and happy Friday! Last issue we talked all about how we can use Geothermal to create power, but today we’re going to be talking about a couple other really cool applications for Geothermal.
First up on the list are geothermal heat pumps. Recently there has been a rise in using geothermal as a climate control supplement or alternative for homes. While air temperatures may vary greatly throughout the year, just a few feet below ground temperatures remain fairly consistent year round. In the summer, the ground is cooler than the air, and in the winter, it’s warmer than the air. Depending on the time of year, a heat pump will work in one of two ways.
Let’s start by looking at a typical home in the summer:
Using a standard forced air system, warm air from the home is supplied to a heat exchanger, where cold water will suck the heat out of it. The now cool air is returned to the home, and the now warm water is pumped through a series of underground pipes, where the extra heat will dissipate off. The cold water is then returned to the heat exchanger to remove more heat from the warm supply air, starting the cycle over again (“Geothermal Heat Pumps”).
Now let’s look at the same house in the winter:
With colder air in the home, the cycle just works in reverse. Cold air is supplied to the heat exchanger where warm water will heat it up. The now cold water is pumped underground where it will warm up again and be used to start the cycle again (“Geothermal Heat Pumps”).
Geothermal heat pumps are a great solution to a nearly carbon free heating system. With an alternative of natural gas, biofuels, or electric heating systems (which may or may not be clean energy), geothermal is just another step in the right direction towards a carbon free lifestyle. Pair it with solar to power the system and you have carbon-free climate control!
To explore some other really cool applications of geothermal, let’s take a look at Iceland, a country that has defined their energy sector by geothermal. With over 200 volcanoes and an abundance of hot springs, there is no shortage of hot ground water to go around. The vast majority of homes, hotels, and other businesses get their water directly from underground sources or from water that has been used in a geothermal power plant. This water is used for showers, baths, cleaning or radiators, just to name a few, but it isn’t recommended for cooking or drinking due to some of the several minerals in the water (The Hot Water in Iceland).
Ryan and his friend Andres at Secret Lagoon in Iceland / Image courtesy of Ryan Scerbo
When I took a trip to Iceland in the Spring of 2019, I had the same thought that almost every tourist does when they visit for the first time: wow that hot water smells bad! The horrible, rotten egg smell that exists in Iceland’s hot water is sulphuric dioxide. This, as well as a number of other minerals, comes from basalt lava that the water drips through before being pumped across the country. This makes for some soft, stinky water, but also virtually free hot water for the majority of Iceland’s hot water needs (The Hot Water in Iceland).
Just east of the capital city, Reykjavik, lives the Nesjavellir geothermal power plant. After water is used to produce electricity, it is pumped into an accumulator tank, before gravity flow sends it on a long 27 km (16.7 mi) journey back to Reykjavik, where it will supply up to 40% of the city’s hot water needs. Along the way, it travels through an ultra insulated pipeline, losing only 0.5 degrees Celsius (about 1 degree Fahrenheit) from start to finish! (“Nesjavellir Hot Water Main”)
Personally, I think geothermal is super interesting. Unlike other renewable methods we have talked about, there are plenty of other applications for geothermal, and the two we talked about today are just a sample. Geothermal has been used for hundreds of years for cooking, cleaning, and more, but we are just starting to see its place in the modern world.
Thanks for reading along with us today, next issue we’ll be back with the next chapter in our renewable series: biomass!
Bibliography
“Geothermal Heat Pumps.” Energy.Gov, https://www.energy.gov/energysaver/geothermal-heat-pumps.
“Nesjavellir Hot Water Main I Projects I” Www.Verkis.Com, https://www.verkis.com/projects/utilities/water-supply-systems/nr/982.
The Hot Water in Iceland | Reykjavik Excursions. https://www.re.is/blog/the-hot-water-in-iceland/.
What Is a Geothermal Heat Pump? https://www.energyhomes.org/renewable-technology/howgeoworks.html.