Darwin, Northern Territory
In 1997, Charles Darwin University’s Casuarina campus (then known as the Northern Territory University) was a major consumer of electricity in Darwin with a peak electrical demand of 4.8MW and a maximum demand of 5.2MW recorded the year prior.
Located in an area that was undergoing significant development and growth, the university was approached by the local electricity supply authority and offered incentives such as an alternative tariff structure with lower electricity rates to reduce the campus’ maximum electrical demand by 1.5MW.
The reduction could only be achieved by shifting the full chiller load operation to after-hours, or off-peak. To facilitate this change, a large-scale thermal energy storage (TES) tank was constructed.
The system comprises two main features: a chiller plant that generates the chilled water that is then stored in the TES tank; and the site reticulation and pumping system that circulates the chilled water across 80,000m² of air conditioned space.
At the time of commissioning, this was the largest TES system of its kind in the southern hemisphere, with a total tank capacity of some 8.6 megalitres (equivalent to four Olympic-size swimming pools).
In 2011, the university made significant steps to better manage energy consumption by buildings and associated plant and equipment. At the heart of this effort was the rollout of 110 smart energy meters and two high-voltage power quality meters installed at the main intake substation. This humble piece of electronic equipment allows the university to measure, evaluate, action and verify energy consumption. This facility now provides a detailed, accurate reporting facility for energy use at the building level as well as identifying the major energy users within each building. The data from smart meters is used to determine power quality and set benchmarks for each facility.
One year later, Charles Darwin University received a Melaleuca Award for Energy Conservation recognising its commitment to environmental sustainability through reducing energy consumption. Since them, modernising of its BMS has improved air conditioning reliability and lowered operational cost even further.
It is now well over two decades since the TES system was successfully commissioned at Charles Darwin University’s Casuarina campus. The system remains as operationally effective as ever, despite changes to the system over that time and increased demand as a result of a growing campus. The evolution has provided the University a foundation that supports CDU’s research and engineering solutions for managing the integration of PV Solar cells within HVAC systems into the future.