A great deal of thought goes into the design of a GSHP system, firstly the
property itself must be surveyed to see if it meets the required insulation
standards, GSHP is a low intensity heat source so many older, poorly
insulated properties are totally unsuitable for this form of heating.
Next the method of heat gathering must be ascertained, on average a
horizontal looped ground source will need around 50 m² per Kw of heat
demand, a vertical loop will require about 30 m². Bore holes will require very
little space but require an extensive geological survey. (Dealt with on another
page). The nature of the ground itself factors into the decision making, if the
soil is very shallow or rocky the digging of trenches for the loops may not be
practical. Very dry, well drained land will increase the total area required,
where as very wet, marshy land will reduce it. While vertical loop systems
require less surface area they will require significantly deeper trenches than
horizontal loops so a suitable depth of excavate-able soil needs to be
available. If the property in question has a large body of constantly standing
water available then a system can be designed to utilise that as an excellent
heat source.
Once the heat gathering method has been decided upon then the correct
heat pump must be chosen, it must be suitable for the heat gathering method
and able to provide sufficient heat to meet the property’s heat demand. the
nature of the electricity supply to the property must be factored in here as not
all available power supply systems are suitable for all heat pump systems.
Finally the heat distribution method should be designed. Because GSHP is a
low intensity heat gathering system then it follows that a low intensity heat
distribution system is best suited. In-slab or underfloor heating are generally
the choices for this. In-slab heating is a method suitable only for new builds
whereas underfloor heating can be fitted easily to existing properties. The
button below opens an excellent PDF from GSHP.ORG that explains the
process in greater detail.