Pieu énergétique

Un pieu énergétique - également appelé pieu échangeur de chaleur - est un pieu équipé d’un tube ou réseau de tubes de manière à pouvoir échanger de la chaleur avec le terrain. Ce pieu assure une double fonction : celle de reporter en profondeur les charges d'une construction et celle d’échangeur de chaleur avec le terrain. Les pieux énergétiques sont mis en œuvre soit avec refoulement du sol (voir 'Procédé d'exécution'), soit réalisés par excavation du sol. Le fonctionnement de l'installation se déroule sur un cycle annuel, avec une extraction de la chaleur du terrain pendant la saison de chauffage en hiver (injection de froid) et une extraction de froid pendant la période de climatisation, en été (injection de chaleur dans le terrain).

Construction sequence

The functioning of the installation takes place over an annual cycle.

In winter, with the aid of a heat pump, when the water is colder than the soil, heat is removed from the circulating fluid (and indirectly extracted from the soil) and renders a higher temperature to the heating.

In summer, conversely, when the water is warmer than the soil, heat is dissipated into the soil for cooling

1., 2. & 3. During the screwing-in phase, a soil displacing screw head inserts the guide tube to the correct design depth

4. During the screwing-out phase - as the auger is simultaneously withdrawn while rotating - concrete is pumped into the borehole through the hollow central tube of the auger.

5. & 6. The reinforcement, fitted with integrated heat exchangers in HDPE (‘collector pipes’), is then placed into the concreted pile. A heat exchange fluid, usually simply clear water, circulates in an U-shaped pipe circuit (‘pipe loop’) located between the piles and a heat pump (HP) and is heated or cooled by the surrounding soil.

Fields of application

• "Nearly zero-energy building"

• Ideal solution for heating and cooling of buildings (housing, offices…)

• To be used in combination with a geothermal heat pump

Environmental impact

• Integration with existing components, low maintenance

• Ecological system, not subject to licensing procedures

• Sustainable concept; possible reduction of C02 emissions by approximately 40%

• Energy savings of about 45% possible.

Technical specifications

• The placement of reinforcing cage is required at the level where the exchange of temperature (heating/cooling) should take place.

• The energy pile is equipped with individual or several pipe circuits made out of plastic (polyethylene) so as to exchange heat with the surrounding soil.

• A heat exchange fluid, usually simply clear water, circulates in the pipe circuit (‘pipe loop’) and into a collector supplying one (or more) heat pump(s).