If you have space around your home, gather energy from the top layers of ground, heated by the sun and connected to a heat exchanger. This method provides a consistent amount of energy all year round, for hot water, heating and cooling.
Works well on larger plots of land
No deep drilling required
Lower installation costs
Mainly solar energy being collected
Very low maintenance
How it works
Our earth has natural heat inside it from solar energy striking the ground, ground water movement and the natural geothermal gradient of heat rising from deep within the Earth. This natural renewable heat can be used to create heat for your own home.
A system of trenches are excavated in adjacent land such as a garden, field or paddocks. Typically, there would be between 2 and 8 trenches typically between 1.2 and 1.8 m in depth depending on the energy loads of the building, ground conditions and the available space. The trenches can be anything between 25 and 125 m in length, depending on the space available, the energy loads and the ground conditions.
Pipes are installed into each trench in a pattern dictated by the design and this could be between 2 and 6 pipes per trench or a slinky arrangement. The trenches are backfilled over the pipes and the area graded. The pipes in each trench allow water to flow along the trench and back again collecting energy. The trench pipework is connected by a manifold system which is connected to the heat pump, creating a closed system. The heat pump process is the same as for vertical borehole or closed systems in lakes or bodies of water. Fluid is circulated through the system and the difference in temperature between leaving and entering the heat pump, along with the refrigeration process, enables conversion into usable heat for the home.
Horizontal Trenched GSHP's provide a consistent amount of energy all year round, for hot water, heating and cooling.
Replacing a poorly designed system and saving 75% running costs
This client contacted us because of constant issues with his aging heat pump system. An early adopter of the technology, he had his heat pump installed in the early 2000s, but it had never lived up to expectations:
Using considerably more power than he had been advised
Producing low ground loop temperatures due to incorrectly sized ground collector and heat pump selection
Creating very high pumping costs because of the poor hydraulic design of the ground loop and considerable ice build-up on the ground loop pipe work in the utility room.
Over the years this customer had operated the system, the original installer had replaced the heat pump several times due to power issues, and had even (at his own expense) installed 3 phase power thinking that bigger was better and that 3 phase would stop the lights from flickering when the heat pump came on. Finally, the heat pump failed completely and the customer was ready to ditch the technology entirely and opt for LPG or oil, or have another go at a ground source heat pump.
The customer asked our advice and we carried out a detailed load calculation for the house, discovering that the heat pump was hugely oversized and the ground loop undersized. The heat pump was operating constantly at 55 degrees Centigrade (above manufacturers guidelines) to maintain the hot water tank temperatures and was cooled down to 35-40 degrees for the underfloor heating and radiators. The heat pump system also took up most of a utility room and a large part of an upstairs cupboard.
Having completed the load calculations, we produced a revised design. The result was a peak load of just 8 kW. The ground loop was replaced with a new system that was hydraulically balanced and correctly sized, the entire utility room pipe work was removed and replaced with new, the heat pump selected was a Mastertherm AQ22i single phase combi unit with an integral 170 litre hot water tank and a small 100 litre buffer fitted in behind the combi. The more compact installation meant that the customer could now have a washing machine in the utility room and gain back the cupboard on the landing.
The running costs for the heating and hot water have been reduced by 75%, the system operates as it should and the customer no longer has to adjust valves or settings to get the system to perform.