Canadian well as a geothermal energy capture system

Do you know what geothermal energy is? It is a renewable energy source aimed at maximizing the natural heat found inside the Earth. With this underground energy, we can heat the water in our homes, condition the indoor air, and even, with different dry steam techniques, produce electricity. In this article, we will focus on the Canadian well, or Provençal, a geothermal facility that utilizes the inertia of the ground to condition (heat and cool) our buildings.

How does a Canadian well work?

Indeed, the Canadian well allows us to cool our home in summer and keep it warm in winter. How does it achieve this? Its operation is simple: it is based on the basic principle that heat energy moves from warmer bodies to cooler ones.

It involves drilling into the ground and building a series of cavities or ducts through which air will circulate. Since the deeper we go, the warmer it is, we must dig these ducts to the desired depth. These pipes will allow an exchange of energy between the cavity through which the air circulates and the surrounding earth, as we mentioned earlier, heat moves from the warmer surfaces to the cooler ones.

During the winter months, the temperature of the outside air is lower than that of the Earth’s interior. If very cold air circulates through the ducts, the ground will concede its heat and temper this air. Once tempered, we can use this warm air to heat our homes without relying on traditional heating systems.

During the summer months, the opposite happens: the temperature of the outside air is high. If we circulate this hot air inside the tubes, it will concede heat to the surrounding earth and cool down. This cooled air can be used to cool our home.

Practical example

Currently, there are many buildings that use this sustainable and eco-friendly conditioning technique, such as the Schwerzenbacherhof industrial and administrative building in Zurich, Switzerland. This building manages to cool the air inside when the temperature of the outside air exceeds 22°C. Thanks to the Canadian well, on the hottest days of summer, the temperature of the building remains around 24.7°C.

Parts of the system

A Canadian well consists of the following elements:

• Air intake. This is the point where the geothermal installation draws air from the outside.

• Filters. A series of filters are installed at the air intake to prevent dust and dirt from entering the buried ducts.

• Heat exchanger. This is the duct itself, which acts as a heat exchanger between the inside of the pipe and the ground.

• Drainage. A place where water that may be generated inside the ducts is eliminated.

• Element to propel air. This is a component (fan) that draws in the air and makes it circulate.