A residence in Caulfield (suburb of Melbourne, Victoria) employs Direct Energy’s 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, architects and builder engaged Direct Energy to supply its Geothermal Heat Pumps to supply hydronic slab heating, forced-air heating & cooling and hot-water heating to the house. The building of the house occurred throughout 2010 with completion by early 2011.
The building is circa 500 m² across two levels. 2 x 14 kW Geothermal Heat Pumps are employed to provide the heating and cooling.
Each unit supplies a direct expansion Fan Coil Unit (one for each level) and also heats water to 40 C to provide the hydronic floor heating and domestic hot water heating.
Caulfield 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: