Canberra Grammar School

The Snow Concert Hall project at Canberra Grammar School was designed with a subterranean layout featuring an innovative geothermal heat pump system. STIEBEL ELTRON supplied modular heat pumps for the project, which were located in the central plant room in the basement, about twelve metres below ground level. The project was well-suited for ground source heat pumps for several reasons, with the climate being the primary factor. Canberra's climate requires both heating and cooling, which means longer operating times can help with the business case while also providing a better thermal balance in the ground heat exchanger. The GSHP system eliminated the need for traditional above-ground heat rejection equipment, such as cooling towers and combustion gas flues, which was critical given the heritage status of the adjacent school buildings.

The geothermal system offered energy savings and construction cost savings and aligned with the school's desire to follow the ACT government's push to phase out natural gas use by 2045. The system was able to absorb or reject energy from/to the GHX to produce 55℃ heating and 5℃ cooling water simultaneously, which minimised the total energy drawn from or rejected to the GHX. This enabled the heating and cooling needs of the building to be provided by the geothermal heat pumps, each of which is capable of supplying approximately 85kW at its peak, allowing significant levels of turndown when the building is at minimal load, further improving efficiency during low-load periods.

The geothermal system was installed after being evaluated and validated for the viability of the ground heat exchanger (GHX), and energy modelling was conducted to demonstrate the payback period depending on system size and use. The adoption of a geothermal system also advantaged the overall building design by eliminating the need for a large externally ventilated plant room. This was achieved by locating the "plant room" beneath the level of the adjacent playing fields as well as in the basement of the new building.

In summary, the geothermal heat pumps supplied by STIEBEL ELTRON were a key component in the Snow Concert Hall project, providing a highly efficient and sustainable heating and cooling solution that aligned with the school's goals while meeting the demands of the project's unique design requirements.