Ground Loops are used as the fuel source for geothermal heat pumps in areas where it is not possible or desirable to use vertical bore holes.
There are a number of different layouts used as every heat pump manufacturer has their own preference but the most widely used method is the slinky, which can be laid horizontally or vertically. Using this method enables the insertion of approximately 250 continuous linear metres of pipe formed into one metre circles at a depth of between 1.5 and 2.0 metres, in a trench 80 metres long and one metre wide.
Where space is difficult an alternative layout enables the insertion of 600 metres of loop in 50 metre sections to be installed in an area 20 metres long and 15 metres wide and at a depth of 60cms. In every case the loops are filled with an antifreeze mixture to protect them against freezing down to a temperature of minus twelve degrees centigrade.
Ground loop lengths are calculated once the makeup of the ground is established but as a rule of thumb each kilowatt of output from the pump will require around 50 metres of ground loop.