A residence in Brighton (suburb of Melbourne, Victoria) employs Geothermal Heat Pumps. The residence is essentially a new build though utilises the slab and selected structures from the former residence. With a vision for energy savings and latest technology, the owner embraced Geothermal Heat Pumps to supply hydronic slab heating, forced-air heating & cooling, hot-water heating and pool heating for the residence. The building of the house occurred from late 2008 with completion by early 2012.
The building is circa 1800 m² across three levels. 7 x 21 kW Geothermal Heat Pumps are employed to provide the heating and cooling, 1 x 21 kW system to provide pool heating and 1 x 14 kW system to provide the domestic hot-water heating.
The units heat and cool water buffer tanks which then supply the hydronic floor coils and 13 water-fed Fan Coil Units.
Brighton has a typical four-season climate, with hot dry summers and cold wet winters. The temperature ranges from 3 °C to 42 °C, while mean minimum daily temperature ranges from 15°C to 6 °C
Heating and Cooling
The heating & cooling is designed to maintain a comfortable temperature within the range 20 °C to 24 °C and is capable of providing additional heating or cooling if required. During winter, the slab heating remains on for the majority of the time.
Due to their considerable ongoing operational savings Geothermal Heat Pumps were considered as the primary option from the outset of the design of the buildings.
Energy costs and savings are an important part of any air conditioning decision, and they are expected to become more important as energy costs rise.
GHPs cut energy use and operating costs. The total annual energy consumption, covering both heating and cooling cycles, for the GHP system is expected to be circa ½ of that consumed by the alternative option.
The GHP system is nearly twice as efficient as the roof-top package and over three times more efficient than LPG heaters.
The annual cost of operating the GHP air conditioner is commonly less than 50% of the cost of the alternative. The capital cost of the GHP system was higher than that for the alternative by the cost of drilling & ground loops. However, when the capital cost and annual operating costs are considered, the time to pay back the additional capital cost is expected to be within a few years. Energy Price increases will shorten the pay-back period.
Geothermal Heat Pumps are noted for their reliability and long life. Warranties of 20 years on the ground loops and 5 years on the plant have been provided. The ground loops are anticipated to have a life of more than 50 years and the plant a life of up to 25 years or more.
Environmental and Safety Performance
Geothermal Heat Pumps are the best environmental option, considering: