Residential Aged Care Geothermal Installation 


Mount Lofty, Toowoomba QLD
Cornubia QLD 

Developer / Owner

Infinite Care

Head Contractor

Woollam Constructions

Mechanical Engineer

Peter Eustace and Associates

Project Completion

February 2019 (Mount Lofty)
June 2019 (Cornubia)

Project Description

Infinite Care is a well-established provider of residential aged care in Australia. With five facilities in South Australia and an expanding portfolio across Queensland, Infinite Care is an industry leader in the delivery of innovative care and services to the ageing community.  With a platform for growth, the Mount Lofty and Cornubia projects in South East Queensland were delivered between 2017 and 2018.

Infinite Care has a commitment to sustainability and resource conservation. Sustainable design initiatives including large solar array and geothermal heating and cooling form a cornerstone of outcomes across both projects. Alinta Energy Geothermal were engaged at early design stages on these projects for the implementation of the geothermal systems.

With a future focus, Infinite Care were seeking solutions that would deliver long term and ongoing energy savings to the facilities.  The HVAC solution across both sites is a combination of conventional VRF for accommodation rooms with the geothermal systems providing heating and cooling for common areas.

Alinta Energy Geothermal’s involvement commenced in the early stages of both projects as significant upfront design co-ordination was required. The confined sites required geothermal loop fields to be installed below building and car park, requiring co-ordination with all inground services and an allowance for works within head contractor programme. 

Waste heat recovery from geothermal heat pumps required co-ordination with hydraulic engineer and hot water plant manufacturers.

A building management system was installed providing a high-level interface from all mechanical plant. Geothermal heat pumps were configured to provide full access for control and monitoring. 

Project Highlights

  1. New state-of-the-art aged care facilities in Toowoomba and Cornubia.
  2. Geothermal systems were installed to common areas at both facilities – 440kW at Mount Lofty and 355kW at Cornubia.
  3. Systems are fully integrated with building management system providing full control and system monitoring and performance.
  4. Waste heat from geothermal plant is used as pre heat for potable hot water for facilities.

Infinite Care Mount Lofty

Infinite Care Mount Lofty is a 134-bed care facility located in Toowoomba, QLD.  Architecturally designed around its elevated position, this state-of-the-art facility takes full advantage of spectacular natural views afforded by the stunning Mount Lofty Ranges surrounding the site.

Total capacity of geothermal plant installed was 440kW.  All geothermal loops were installed below the building and car park. Twenty-five (25) geothermal heat pumps were installed; all within the basement plant room.

Infinite Care Cornubia

Infinite Care Cornubia is a 133-bed aged care facility in the Loganlea-Carbrook area south of Brisbane.  Architecturally designed, this state-of-the-art facility sits in an elevated and prominent position and enjoys spectacular views of surrounding hillside, offering residents the spoils of open green space.

Total capacity of geothermal plant installed was 440kW.  All geothermal loops were installed below the building and car park.  Twenty-two (22) geothermal heat pumps were installed; all within the basement plant room.

Installation Overview

Twenty-two (22) GeoAir units installed in the plant room at Infinite Care Cornubia

Geothermal Loop Field

Geothermal loops for both sites were installed below the building footprint requiring detailed upfront design for co-ordination with inground services and builder works. Allowance within construction programme was required and two Alinta Energy Geothermal drilling rigs were deployed for works. Interconnecting lines between geothermal loops and the heat pumps were installed within shared trenches (where practical) to limit inground works.

Geothermal Heat Pumps

Operating at 51db and not requiring airflow, geothermal heat pumps were installed within basement plant rooms.  Connecting lines from loop field were brought into plant room at ceiling level to eliminate pipework.

Potable Hot Water Recovery

Geothermal heat pumps are configured to produce hot water passively when in operation. With the desuperheat loop connected to heat exchangers and integrated within the hydraulic plant, hot water storage tanks retain heat when the geothermal plant is operational.  This heated water acts as a preheat to hot water plant which is finished off by gas boilers.

Internal Installation

A third party mechanical contractor was responsible for all internal installation. Alinta Energy Geothermal supplied all fan coil units. Geothermal was used for common areas with VRF for all accommodation rooms.


Geothermal plant is controlled and monitored by building management system. High level interface provides both system control and monitoring.

Geothermal Overview

Geothermal systems, also known as Ground Source Heat Pumps (GSHP) use the earth as a heat source in the winter and as a heat storage source in the summer. Ground temperatures below the earth’s surface, stay relatively constant throughout the year. This allows the geothermal system to provide extremely efficient heating or cooling all year-long in virtually any climate.

Sometimes the term “environmental comfort system” is used to describe a geothermal heat pump. This happens because a heat pump absorbs or rejects heat from the earth, has absolutely no impact on the environment and is not impacted by varying air temperatures.

Cooling Mode

GeoAir™ circulates a hot refrigerant vapor into the earth through installed geothermal loops to absorb the naturally cooler, and stable sub surface temperatures.  With excess heat removed, this cooled refrigerant condenses into a liquid. This liquid is expanded through an expansion device at the heat pump, lowering the pressure, causing the temperature to reduce even further.  This refrigerant is then circulated through the fan coil unit installed within the building, absorbing excess heat from the air. This causes the refrigerant to heat and expand back into a vapor. The cycle then repeats.

Heating Mode

When operating in Heating Mode, cold refrigerant is circulated within the geothermal loop, absorbing the heat naturally supplied by the earth. This heated refrigerant vapor is compressed and circulated through the fan coil unit, heating the home. This process removes the heat from the refrigerant, cooling it again. The cycle repeats.

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