Near surface geothermal energy

Near-surface geothermal energy, such as in sub-soil loop systems and the use of environmental heat through heat pumps makes use of solar energy stored within the top layers of the soil. In winter, the heat pump extracts heat stored in the soil, thereby cooling the soil down. As warmer conditions return, the soil is again heated by the sun and any summer rains. Used correctly, this “energy source,” just like the sun itself, is inexhaustible over human time scales.

The Center for Energy Efficient Design, Virginia, USA (top row) draws on a two-stage heating and cooling system to ensure thermal comfort for occupants. The first stage preconditions incoming fresh air as it enters the ERV with a passive thermal ground loop and/or solar-heated water. The second stage, only necessary for larger groups, employs a ground-source heat pump for extra cooling. Both the Residential and commercial building, in Munich, Germany (bottom left) and the Terraced house at Princedale Road in London, UK (bottom right) use air-to-air subsoil heat exchangers to pre-condition the air coming into the ventilation system (for frost protection in winter and pre-cooling in summer). The Residential and commercial building also employs a wood pellet heating system and solar panels. 

See database entry for the Center for Energy Efficient Design
See database entry for the Residential and commercial building
See database entry for the Terraced house at Princedale 100 (Finalist of Passive House Award 2014)