When we think about Ground Source & Geothermal Heat Pumps, we think about high ground temperatures that can deliver very efficient performance.
This can be the case but with the caveat of high civics costs due to the drilling of boreholes and associated works.
There are three methods of ground heat collection:
All three systems offer application benefits to suitable projects and can be configured as primary ground source collector-driven heat pump systems, or air/ground dual-source systems to reduce civil costs where required.
Pipes within the ground at circa 1200 to 1500mm deep run horizontally, with the majority of the thermal collection being solar/surface heat derived due to the shallow collector depth (useful ground temperature starts at 15m depth).
Flow/return pipes running down/up within a single borehole to depths of 150m + (multiple boreholes within a system array).
Water/glycol circulates down to a U at the base of the borehole and returns to the Heat Pump (closed loop collector). The borehole is filled with grout that has good heat transfer capability, which then enables the closed loop collector to gather heat from the ground surrounding the borehole and deliver this to the Heat Pump.
Here, a flow borehole and a separate return borehole circulate ground/aquifer water to the Heat Pump.
Good levels of Heat Pump efficiency are achieved due to the reliable temperatures that can be delivered from aquifer systems.
These systems can also be used where redundant mine workings present a source of water at good usable temperatures.