An ecological, economical and ULTRA-sustainable solution

The Canadian well or Provençal well is a surface geothermal heat collector, consisting either of a series of horizontal or vertical tubes buried in the ground. Or a labyrinth of concrete walls buried in the ground through which outside air passes to supply renewable energy to a ventilation monobloc or a heat pump. 

This passive technical element, without any mechanical and mobile elements, allows to preheat the new air in winter and to cool it in summer. All this is free of charge and without polluting emissions. A very simple operation, but it was necessary to think about it. The savings that a Canadian well provides for double-flow ventilation systems (VDF) or for heat pumps is simply exceptional, ultra-durable, reliable and economical.

ERTE has built no less than fifteen Canadian wells in its 37 years of existence. Simple and efficient, our expertise and our installations allow you to make great energy savings and ensure optimal comfort. The Canadian well is a system that is made to last. An ecological solution that lasts for 50 to 100 years, as long as the buildings it supplies.

Even old oil tanks are transformed by ERTE into ingenious and powerful Canadian wells.

Our conclusions

Our experience with Canadian heat sinks leads to the following conclusions:

  • The thermal energy gained is significant, while the electricity consumed specifically to transport the air through the Canadian well is small. The electrothermal gain factor varies from 10 to 50 depending on the season, temperature, intensity of use, air flow rates, and the number and diameter of the tubes. In comparison, this amplification factor varies from 3 to 5 for a heat pump and from 8 to 15 for a double flow ventilation.
  • The energy saving in winter is not fully cumulative with other air energy recovery systems.
  • The global warming and the increasingly strong and long heat waves make the Canadian wells even more interesting for all types of buildings.
  • The operation of a Canadian well is compatible with the MINERGIE standard and positive energy buildings (BEP).
  • The lifespan of a Canadian well is 50 to 100 years, which is incomparable to mechanical systems and appliances, which last between 15 and 25 years.
  • A Canadian well that cannot be worn out for at least 50 years, combined with a solar photovoltaic system that produces solar electricity almost without breakdowns for 35 to 45 years (no mechanical parts), combined with a double flow ventilation monobloc with a life span of 50 years where only the inexpensive moving parts need to be replaced halfway through, combined with a modulating PACAir-Eau which has a 20 to 25 year life span, gives the best, most reliable, most durable overall energy system and the one that harnesses the most solar and geothermal energy with the highest efficiency and annual coefficient of performance available.

No other system can compete with this SUNERGIE® system to produce heat for heating and hot water as cleanly, solarly and elegantly, but also for cooling in summer.

The example of the WMO Canadian well

The WMO (World Meteorological Organisation) Canadian well was installed in the foundations of the underground car park, taking advantage of the excavation required for the latter. It consists of two parallel networks of PE pipes, laid in a lean concrete backfill 15 m below ground level, where the temperature is always around 15°C. The air is sucked in through two vents above the car park and, after passing through the tubes of the Canadian well, it is led to the inlet of the ventilation monoblocks and then to the exchanger with a nominal flow rate of 220,000 m3/h.

During the summer, the coolness of the ground surrounding the tubes is used to cool the offices. At the end of the warm summer season, this huge thermal mass has warmed up to about 25°C and is used to preheat the cold outside air for the winter. In spring, this mass has given up its heat to the air and cooled down to about 3 to 5°C. It should be noted that the greater the temperature differences, the higher the performance of the heat pump. During the summer, the average temperature of the ground in the centre of the heat pump follows the average outdoor temperature quite closely, with a time lag of a few weeks. The characteristic lifetime of the storage can therefore be considered to be of this order of magnitude, which allows fresh air to be gained for cooling mainly in early summer. This period of cooling use can be extended if the control takes the precaution of regenerating the storage by using the night fresh air whenever its temperature is lower than the ground temperature. This function has been planned for the WMO.

In contrast, the winter period is characterised by a stagnation of the ground temperature between 3 and 5°C, clearly above the low outdoor temperatures. It is likely that the extracted heat is regenerated by ground heat from deeper layers, with a phase shift of a few weeks to a few months.