Geothermal air conditioning system
Introduction
Geothermal air conditioning is an air conditioning system (heating or cooling) that uses the great thermal inertia of the subsoil, since at about three meters deep it has a constant temperature of between 10 and 16 °C, depending on the latitude (north or south) of the place.[1].
Geothermal heating or cooling should not be confused with geothermal energy, which requires a high temperature in the subsurface, usually associated with volcanic activity.
In 2004 there were more than one million units installed worldwide, providing 12 GW of thermal capacity, with an annual growth rate of 10%.[2].
Concept
Contenido
Existen dos sistemas: de alta entalpía (con bomba de climatización), y de baja entalpía (sin bomba de climatización).
Without heat pump
The low enthalpy one is the simplest and has a lower energy cost.
The subsoil temperature varies much less than the ambient temperature (and may not vary throughout the year if taken at sufficient depth).[3] This stable temperature (heat or cold) can be extracted simply by using a pumped fluid. The liquid is maintained at a cave temperature, which in winter would be apparently warm and in summer apparently cool, although in reality the subsoil temperature does not vary, rather it is the ambient temperature that changes.[1].
This system avoids the complexity and expense of a heat pump and the expense of a water pump is minimal. However, it is less powerful and may be insufficient or it may be necessary to support it with another auxiliary renewable energy system, unless it is used for underfloor heating.
With heat pump
In the high enthalpy system a heat pump is used, and it is very similar in concept to an air conditioner that works for cooling or heating. The difference is that, instead of expelling heat to the outside of the house, the subfloor is used as a sink or as a heat source.