This apartment owner has decided that ground source heat pumps (GSHP) are an excellent investment, and the right environmental choice for lowering emissions. Since GSHPs work best in larger structures, such as this 26-unit, 2044 m2 (22000 sq. ft.) apartment complex, this building is ideally suited for such a system. Also, combined with the fact that this GSHP also integrates solar hot water (SHW), the system is very cost effective as a result, and easily meets all of the building’s heating and cooling needs throughout the year.
The GSHP system is comprised of five 5.4 t (6 tons) systems drawing from fifteen 85 m (280′) wells. These are vertical wells (more efficient than horizontal wells) and surrounded by hard or crushed rock (again, this is more efficient than sand or soil for heat exchange), making this system very effective and efficient. Combined with the SHW system, which adds extra heat storage capabilities to the system, and an efficient building envelope, the owner estimates that the system achieves a coefficient of performance (COP) of 6 to 8, where most GSHP achieve an estimated COP of 4. The system seems to work best during the shoulder seasons (spring and fall). During the time of visit, in July, the system was trapping heat in the ground above 80 °C (176 °F) for use in the winter.
This system provides space heating and cooling for the entire building. The system installation and maintenance costs are recuperated by having these services included in the cost of rent for the tenants.
The owner is also considering adding a wind turbine to the property in the future, so as to lower energy costs even further.
