We looked into all the ways possible to heat our new home that we were building in a rural area. We found that one way could actually provide cooling too. If you dig down far enough and pump water through pipes buried deep in a hole, you can extract heat or cold depending on the season. A simple drilled hole in the ground gets you down into the earth where it is a constant temperature. It gives you heat in the cold, and cool when it is hot outside. Drill farther and the advantages and disadvantages of geothermal energy come into play.
You can drill a hole deep enough that you can get to areas of the earth that are closer to the core and therefore hotter. There are geothermal plants that make use of this. If you have ever visited caves or caverns that are deep, you probably noticed the temperature of them is about 52 degrees Fahrenheit on average. If your house was 52 degrees in the summer, you would feel that as being too cold. If you felt 52 degree air blowing out of a vent in the winter, it would feel warm. Then you would only have to heat the room another 18 to 20 degrees for it to be comfortably warm. That is how you can make use of extracting heat and cold from near the surface of the earth.
If you dig deeper, you get into the warmer parts of the earth that can be quite warm. Part of the disadvantages of geothermal energy is losing or gaining temperature, depending on what you are trying to accomplish, as you pipe the heat or cold back up to where you can use it. The simple premise for using geothermal properties to cool your house is to pump water through pipes in the deep hole where it cools to 52 degrees. Then you pump that back up to where it goes through a radiator and you blow air over the cooled pipes. It works the same as an air conditioner with no need for refrigerant.