Power to the Kids

AE Smith turnkey trigeneration solution at $1.5b Queensland Children's Hospital (QCH) stars as cover page feature story in Ecolibrium published by AIRAH

1 Oct 2013
 

The new Queensland Children’s Hospital in South Brisbane represents the largest capital investment in children’s health to have ever been made in the Sunshine State. And as Sean McGowan reports, it will all be powered by a world-class central energy plant –

Ecolibrium, Oct 2011

The new Queensland Children’s Hospital (QCH) in South Brisbane represents the largest capital investment in children’s health to have ever been made in the Sunshine State. And as the Australian Institute of Refrigeration, Air conditioning & Heating (AIRAH) reported in the October 2013 issue of Ecolibrium, it will all be powered by a world-class central energy plant.

The new QCH project will bring together the staff and services of Brisbane’s Royal Children’s and Mater Children’s hospitals to provide specialist paediatric care for children from birth to 16 years of age.

This will make it the single biggest specialist children’s hospital in the state, with a total floor area of about 80,000 sq m across 12 clinical levels, as well as a four-level basement carpark and dedicated helipad.

The project also includes the associated QCH Academic and Research Facility (ARF) that will unite children’s health research with the hospital.

World-Class Central Energy

Powering this new health infrastructure will be a world-class central energy plant, housed in its own, five-level purpose designed structure.

Featuring some 4,500 sq m of total floor space, the central energy plant will satisfy the entire power, heating, cooling and steam requirements of the new hospital and research facility, as well as a future building.

AE Smith was appointed by managing contractor Abigroup (now Lend Lease) to provide mechanical and energy services on the central energy plant. It has also been engaged to provide the same services to the QCH and ARF projects, as well as commissioning.

The plant and structure was designed by Floth Sustainable Building Consultants, which was engaged to provide full design and documentation, including construction phase services.

Trigeneration

Ashley Robinson is project director on the Queensland Children’s Hospital project for AE Smith’s Brisbane Construction division.

“Hospitals historically are large energy users, and typically HVAC solutions form the majority of this usage,” Robinson says. “For this reason lowering energy consumption was the main driver for this
energy plant design.”

As a result, energy efficiency became a key driver behind the design of the QCH central energy plant – as did the environmental impact on the surrounding community. The decision was made to install a trigeneration plant.

“The trigeneration plant in this format is the largest of its type in Australia,” Robinson says, “and will prove to be world leading.”

It features two gas-powered 2,400kWe generators combined with hot water heat exchangers providing 5,400kW of heating hot water, and two single-stage lithium bromide absorption chillers of 1,100kWr
each.

Two selective catalytic reduction (SCR) systems are also provided, featuring 15,000L of urea storage providing nitrous oxide (NOx) emission control for each generator.

This will supply most of the QCH’s power, and reduce its demand on the electricity supply by 60 per cent during peak consumption periods (daylight hours).

To provide full power security, the central energy facility also includes a standby power plant consisting of four diesel powered continuous-rated generators of 3.0MVA (2,400kWe) each.

Cooling, Heating and Steam

Along with housing the large trigeneration and standby power sets, the QCH central energy plant also supplies the hospital and research facility with its chilled water and heating hot-water requirements.

Although chilled water for air conditioning is supplied by absorption chillers, this is supplemented by a chilled water plant.

The central-heating hot-water plant consists of seven 1,110kW gas-powered hot-water heating boilers that have been sized to meet the total heating load. These are configured in an redundancy arrangement, and serve air conditioning, heating and dehumidification, as well as domestic hot water.

Other Plant

Along with the trigeneration, chilled water and heating hot-water plant, the QCH central energy plant also provides the entire hospital site with its steam requirements, typically used for cleaning, disinfection and sterilisation. This is achieved by two natural-gas-fired steam boilers of 1,300kW each, configured in a duty/stand-by arrangement.

Furthering the environment credentials of the entire QCH project, the central energy plant facility also accommodates the site’s stormwater treatment and reuse plant.

Plant replacement and maintenance access has also been specifically designed into the central energy plant facility.

The facility features a six-tonne goods lift that serves all five levels, and lifting beams above all major equipment items. Maintenance access corridors, hatches and platforms have also been provided to allow for complete generator, chiller and boiler removal.

All access requirements for the plant have been detailed on drawings to ensure these clearances are maintained for future maintenance access.

Collaboration Critical

Both AE Smith and Floth point to the close collaboration between the two as critical in ensuring the knowledge obtained during the pre-construction phase was transferred through to construction and installation.

It was through this collaboration that AE Smith was also able to assist in optimising the energy plant design in order to facilitate ease of future maintenance and commissioning of the plant.

Although onsite commissioning of the QCH central energy plant has yet to commence, offsite commissioning has seen a wide variety of factory acceptance testing (FATs) conducted. This has included all major equipment items such as chillers and engines, as well as the
software-based generator control systems (GCS) and BMS.

To enable plant commissioning without hospital loads being available, the chilled water, heating-hot-water and steam-load cells have been designed to allow initial performance and operational verification
of the major plant.

The AE Smith commissioning team has been involved with the firm’s engineering and drafting teams to obtain an in-depth understanding of the systems and access required for commissioning.

Once operational, energy performance of the plant will be closely tracked.

“Combining smart equipment selection with an intense tuning strategy will generate long-term energy reductions for this plant in comparison to others,” Robinson says.

“This will enable us to track energy performance of the energy plant by
initially using predictive modelling and then historic data to fault-find and/or improve energy-consumption targets.”

The hospital is slated for completion early next year.

Elderly man smiling broadly while nurse with blond hair smiles and looks at him fondly.
Ecolibrium is the official journal of the Australian Institute of Refrigeration, Air Conditioning and Heating (AIRAH).

AIRAH has a long and proud history of representing an industry of professionals who are of fundamental, and increasing, importance to the comfort, health and safety of the community. Formed in 1920, AIRAH is recognised by government and industry bodies for its expertise across a wide range of issues in the area of engineering services for the built environment.