1. Techniques used

There is a wide range of technical solutions available for harnessing the heat of the earth at shallow depths.

• Canadian and Provençal wells are the oldest techniques. They have recently been rediscovered with the construction of HQE (high environmental quality) buildings, where they are generally favoured for their low cost. They are not techniques capable of heating buildings entirely. They are back-up solutions, used to preheat or cool air, depending on the season. Canadian or Provençal wells can be installed in all types of new buildings, from detached houses to commercial buildings.

• The commercial development of heat pump solutions using horizontal or vertical buried collectors (in this case, vertical geothermal probes) dates back to the early 1990s. These are heating and cooling...