New Performing Arts Building for Mt Maria College




Mt Maria College Mitchelton
Brisbane Catholic Education

Project Summary

Performance Arts Building at secondary college

Project Description

Mt Maria College is a co-educational secondary Catholic school located in Mitchelton, Brisbane. With over 1100 students from Year 7 to Year 12, the school has a mix of heritage-listed buildings and modern classrooms designed for quality educational outcomes.

When the school were designing a new performing arts and learning block, they were seeking a high efficiency air conditioning solution. Alinta Energy Geothermal were introduced to the project through Brisbane Catholic Education who had commenced a program to improve the efficiency of all schools and classrooms across the diocese portfolio of properties. Involvement in the project was post construction commencement which presented challenges in integrating both design and delivery of the project. With the works underway, integration within the construction program was a challenge.

Geothermal System Overview

The 2-storey building design incorporates central areas with 11 interconnecting classrooms including dance studios, practice rooms, technology rooms and general learning areas.

Each room has either a 13kW or 14kW system installed. All units are fully-ducted and connected to individual heat pumps. The GeoAir heat pumps installed are all 580 x 580 x 890H and operate at 51db, enabling them to be located beneath the building and not requiring acoustic treatment or plant enclosures.

Geothermal Loop Field

Each heat pump is connected to individual geothermal loops, each installed to depths of 90m at 8m separations. The geothermal loop field was located adjacent to building in an area with no plans for future building within the schools’ master plan.

Basalt was encountered at depths of approximately 6m with temporary casing used during drilling with down the hole (DTH) methodology applied due to the existence of hard rock.

Locations of installed loops were surveyed for accuracy and future protection. Final locations were detailed on as built drawings.

Each geothermal loop was connected to a GeoAir heat pump through lines installed at 800mm below finished level. Mechanical protection was installed above lines to protect from any future unplanned works.

Internal Installation

All systems are fully ducted with in ceiling fan coil units. Outside air is brought into each room to satisfy BCA requirements. The temperature in each room is controlled through a wall-mounted thermostat.

System Monitoring and Performance

Post installation, monitoring equipment was connected to a classroom deemed to have the highest heat load within the building. GLA4 was selected due to its westerly aspect on the upper flow and its high occupancy rate. Monitoring equipment was configured to read energy consumption, discharge and return temperatures to geothermal ground loops and ambient temperatures, along with room temperature.

Connected in January 2018, monitoring was performed during the school’s first term to capture the hottest months with the highest levels of occupancy.

Data collected was reviewed by Calibre Consulting with the following outcomes produced:

System Capacity (monitored) – 12.75kW
School Operating Days (annual) – 200
System Operating Hours (monitored) – 3.94
System Electrical Input (monitored) – 1.77kWe
System COP (average monitored) – 7.19

Based on an over and above cost of the geothermal system at $1,250 per classroom, it is anticipated that the additional costs associated with the GeoAir system install will be recovered by the school in under 4 years.

For the full Calibre report, click here.

System Benefits

1. High efficiency system with potential cost recovery in approximately 4 years based on monitoring.
2. Reduced peak energy load consumption for school.
3. Reduced plant spatial requirements eliminating need for mechanical plant enclosures.
4. GeoAir heat pumps operating at 51db enabling location under building with no requirements for acoustic enclosures.
5. With less moving parts, geothermal system can potentially reduce maintenance costs compared to conventional air conditioning units.
6. Plant installed to under croft of building offers positive design outcomes to finished building.
7. Safer around children with no external fan on condenser unit.

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