Geothermal is a branch of geophysical science that is dedicated to the study of the thermal conditions of the Earth. The word is of Greek origin, derived from "geos" which means earth, and from "thermos" which means heat: the heat of the earth. It is used interchangeably to designate both the science that studies the internal thermal phenomena of the planet and the set of industrial processes that try to exploit that heat to produce electrical energy or useful heat for a stove.

One of the most notable fruits of the technique is the extraction of geothermal energy.[1]​.

The thermal energy used consists of part of the permanent flow of heat from the Earth's core, through the mantle and to the surface, where the energy is released into the atmosphere. The other part forms radioactive decay processes that occur naturally in the mantle and release energy.

Geothermal air conditioning is an air conditioning system (heating and/or cooling) that uses the great thermal inertia (constant temperature, depending on the different locations, from 10 to 16 °C) of the shallow subsoil. A heat pump is used, which is a thermal machine that allows energy to be transferred in the form of heat from one environment to another as required. Its operation is very similar to a traditional air conditioner that works for cooling or heating.[2]​ The subsoil is usually at a neutral temperature throughout the year (cooler in summer than the air and warmer in winter), so the performance of the heat pump is very high as it requires less work to transfer energy.

There are many advantages of geothermal energy, but also some challenges that must be overcome in order to fully exploit this natural resource. Geothermal energy is a sustainable and renewable energy source that is still largely untapped. As an environmentally friendly resource, it has the potential to meet future heating, cooling and electricity demands.[3]​.