Sustainable Commericial Hot Water Upgrade

Growthpoint Properties Australia, a leading force in commercial property investment, owns the prominent site at 75 Dorcas Street, South Melbourne. In alignment with the Australian Government's push towards electrification and its commitment to sustainable development, Growthpoint has prioritised reducing the environmental impact of its assets. This initiative supports global Sustainable Development Goals (SDGs).

A key aspect of this strategy is minimising CO₂ emissions and transitioning away from gas dependency to cleaner, renewable energy sources.

To achieve this, Growthpoint partnered with STIEBEL ELTRON to design and propose a sustainable hot water solution that aligns with its environmental objectives. Australian Chillers & HVAC Solutions, recognised for their expertise in large-scale mechanical and plumbing installations, were selected to manage and execute the system upgrade, ensuring the project meets both sustainability goals and high-performance standards.

The building had significant hot water needs across two main zones:

• Level One (End of Trip Facilities): 22 showers and 4 basins, using 4 x 46kW gas continuous flow units with a buffer tank.
• Top Floor (Office Bathrooms): 10 showers and 50 basins, using 2 x 43kW gas storage systems.

These areas were serviced by gas-powered systems, a series of high-capacity continuous flow and storage units. The existing units were approaching the end of their operational life, raising concerns about efficiency and reliability. Their indoor installation also posed logistical challenges for maintenance and replacement. As sustainability and electrification become industry standards, continuing with gas-fired systems is neither environmentally sustainable nor aligned with best practices in commercial property management.

STIEBEL ELTRON proposed replacing the gas systems with WPL-A 07 Premium air source heat pumps. These units offer high temperature output (up to 75°C) and operate efficiently even in low ambient temperatures (down to –25°C), using low-GWP refrigerant.

Tailored systems were proposed for each zone:

• Level One: 3 x 8kW WPL-A heat pumps, 3 x 800L DHW coil tanks, booster cylinder, and weatherproof enclosure.
• Top Floor: 2 x 8kW WPL-A heat pumps, 2 x 800L DHW coil tanks, booster cylinder, and weatherproof enclosure.

Australian Chillers & HVAC Solutions handled the installation of the heat pump systems, including full electrical works. Due to the building’s internal layout and confined service areas, special consideration was given to equipment size and transportability. The selected coil tanks were chosen not only for their capacity—being large enough to meet the hot water demand—but also for their compact dimensions, which allowed them to fit within the building’s limited plant room space and be transported via the elevator. Components were pre-assembled in the car park and strategically moved up the elevator during weekend hours, minimising disruption.

This modular approach avoided costly structural modifications and demonstrated Australian Chillers' capability to execute complex installations in restricted environments. The system was integrated with ISG monitoring, allowing for real-time performance optimisation during the ramp-up phase, as well as ongoing remote access to critical data for STIEBEL’s own monitoring system or BMS integration.

Performance outcomes include:

• Increased system efficiency with strong COPs despite Melbourne’s cool climate.
• Reduced carbon footprint with cleaner, renewable electricity being used.
• Reduced running costs year over year.
• Hot water comfort that is solar-compatible and future-ready.

This project marks a successful shift from traditional gas to sustainable hot water infrastructure. With contributions from STIEBEL ELTRON, Australian Chillers & HVAC Solutions, and Growthpoint’s sustainability vision, the outcome demonstrates the viability of eco-efficient systems in commercial retrofits. The system not only meets current building needs but also aligns with future sustainability goals. Australian Chillers & HVAC Solutions will provide ongoing servicing and maintenance to ensure long-term performance and reliability.

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