Horizontal loop geothermal system
In 2010 and 2011, NGroup installed an innovative geothermal heating and cooling system at a Main Ridge house that was being renovated and doubled in size. Main Ridge is in the hilly hinterland of the Mornington Peninsula south of Melbourne.
The owner told Mark Nicholson he wanted the system to heat and cool his home as well as heat water for the pool and spa. “We currently use LPG for the pool but when I return from a trip, my adult children have been down and used all the gas,” the slightly exasperated owner said.
The project included installing two complex reverse-cycle air-conditioners servicing 13 separately controlled areas of the house, with back-up heating provided by an existing open fireplace.
Mark threw himself into research for the project and, on the way to collect his catamaran in the Caribbean, visited a leading heat pump manufacturer in Miami, Florida – FHP, which had been acquired by the United States subsidiary of Germany company Bosch in 2007.
Meanwhile, the homeowner contacted Professor Ian Johnson of the University of Melbourne. Professor Johnson along with one of his PhD students – Amir Kivi (now a doctor of engineering and founder of GeoFlow) – designed a system with 4.5 km of looped black plastic 25 mm pipes 2 metres below the surface, which is known as a horizontal loop. Systems can also be vertical or diagonal.
Designed for experimental research (Amir Kivi was using the project as part of his PhD), it had 160 temperature sensors in the ground – above, below and beside the pipes to enable close monitoring of the system. A Mitsubishi Electric low-noise heat pump was installed next to the house.
The homeowner allowed the university team to design a far more complex system than was required for a holiday house as he was just as committed to improving ground source heat pump design. “My staff and I gained a great deal of knowledge equipping the holiday home for a client who is a renewable energy pioneer and philanthropist.”