Beautiful unearthing of subject.
This is an opportunity to take stock of the solutions in competition.
A double flow VMC
worthy of the name represents a considerable investment and requires an irreproachable quality of construction for the result to be convincing. A Double Flux VMC manages all incoming and outgoing air flows. The building must be perfectly
airtight.
The investment for quality equipment (the historical leader is Helios, to my knowledge) represents about 3000 € for the plant and about as much for the pipes and mouths of insufflation / extraction ... It is in any case the budget I spent there 5 years, not poses (made by me).
A heat pump water / air draws calories (or frigories if the heat pump is reversible) in the outside air to return them in a circuit of water as a coolant.
The transmitters are either fan coils or a floor heating / cooling. In the case of a floor, the yield is optimal but the realization of the floor represents the heaviest budget item. The implementation of the floor is very technical and must be performed by very competent professionals under penalty of an inefficient installation ...
The heat pump, although generally overcharged is hardly more expensive than a common wall-mounted gas boiler, but requires much less maintenance (optional, unlike gas or it is imposed by home insurance, under penalty of loss of fire cover).
An alternative to the water / air heat pump is the dual flow VMC is the air / air heat pump that is installed as easily as a satellite TV (an outdoor unit and an indoor unit). There are mounting kits allowing the commissioning without tools specialized very popular DIY and prices start at 500 € for PAC inverter very good quality. I think, unbeatable. there have been achievements documented and described by prominent members of the forum.
The Canadian or Provençal air well is a system that recovers calories or the freshness of the soil. If the principle is known or used for centuries, even millennia, its implementation is less obvious than we think ... It requires a compatible soil (rock or clay, among others, are problematic). The depth of the installation, the permeability of the soil, the watertightness, the drainage of the buried circuit are paramount as well as its maintenance. Specialists consider that in France 40 60% of facilities no longer work or are harmful less than 2 years after their construction (buried network flooded or lined with toxic mold if they are inhaled.
The "hydraulic" Canadian well seems to be a more reliable alternative and less complex to implement. It is offered by manufacturers of double flow CMVs like the
SEWT of Helios. It is mentioned above in the subject that its performance is not so remarkable according to the seasons.
For all geothermal capture (Canadian well or heat pump), the nature of the soil must be compatible (permeability, flexibility, usable depth, exploitable surface, absence of roots, ...).