October 21, 2024 in News
Walking the journey together – A.G. Coombs Diversity ...
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540 Wickham Street Fortitude Valley QLD
The Australian commercial building market is on a clear path towards electrification.
So, when it came time for an iconic property in Brisbane to decommission its gas-fired cogeneration plant, the technical expertise of the A.G. Coombs Group was called on to deliver a project close to home.
Role of A.G. Coombs
- Cromwell Property Group engaged the expertise of A.G. Coombs Advisory to assess the environmental impact of their 1900kVa gas-fired cogeneration plant on the building’ environmental ratings.
- A.G. Coombs Advisory were then engaged to draft replacement specifications for the cogeneration plantand provide technical support during the tender process.
- A.G. Coombs were awarded the project under a traditional Design and Construct (D&C) contract. A.G. Coombs Advisory continued to provide technical assistance to the client throughout the project.
Objectives
The project aimed to help reduce the buildings carbon emissions in 3 ways:
- Decommissioning the gas fired cogeneration plant. The owner was able to purchase green power from renewable sources.
- Selecting a more efficient electric chiller to replace the absorption chiller providing low and mid load cooling which is required for about 80% of normal operation.
- A chiller using a hydrofluoroolefin (HFO) refrigerant was selected, with a Global Warming Potential (GWP) of one, HFO is equivalent to carbon dioxide (CO2), unlike similar chillers with refrigerants having a GWP over 1400.
Approach & Methodology
- The investigation considered the plant’s maintenance and life cycle, the building’s standby power demands, the fluctuating energy costs, and a decarbonised electricity grid, especially the upcoming changes to NABERS Energy rating emissions factors.
- A.G. Coombs Advisory found that replacing the cogeneration set with a magnetic bearing, water-cooled electric chiller, and a standby diesel generator for essential services could improve the HQ North tower’s NABERS Energy rating to a market-leading 6 stars. Using HFO (R1233zd) refrigerant further reduced the site’s Scope 1 emissions.
- A waste minimisation strategy ensured many plant components were reused: The gas-powered generator in outback Australia; urea in another trigen plant; lithium bromide in an overseas absorption chiller; and various spare parts to extend other plants’ lives. The absorption chiller, redundant cable, pipework, and flues were also recycled.
Image: Ross Pottinger
Challenges
- The works presented a major logistics challenge to minimise disruption to the building and tenants, and safely remove the heavy plant.
Outcomes
- Careful planning limited service shutdowns, with a temporary generator providing essential standby power until the new diesel generator and systems were complete. A pre-commissioned controls and mechanical electrical board replaced the existing one, addressing arc flash safety by allowing Main Switchroom control from outside, eliminating the risk of switching near 3200Amp circuit breakers.
- The plant’s replacement reduced operational costs and optimised plant room space, benefiting the onsite facility management team. Using a diesel generator for standby power simplified plant operation and maintenance while increasing system reliability.
- The new electric chiller plant will contribute significantly to Cromwell Property Group’s net zero emissions goals, while reducing complexity and providing significant savings in plant maintenance.
