During the XX century, energy consumption was mainly dependent on fossil derivatives, like oil, gas and coal. Characterized by a high energy density, these resources were the most important source of energy.

Unfortunately, these forms of energy are stored in the underground and they aren’t renewable, meaning that it may end. In 1973 this concern was discussed because of the "first oil shock" As a consequence, the energy prices have been raising since then. By other hand, energy production using fossil derivatives leads to an increase of carbon dioxide in atmosphere among other pollutants.

Being heat a major form of energy, the use of alternative forms of heat production may lead to a more environment and cost-friendly solution. Heat Pumps (HP) emerges as an alternative heat source. Unlike common used sources of heat, this technology has the highest efficiency.