Air Conditioning

In 2010, 4 Mort St, Canberra (Figure 1) was upgraded to significantly improve its energy performance. The retrofit was performed with the dual constraints of a limited budget and the building remaining occupied during the upgrade. This Case Study covers the key factors that enabled this 45 year old commercial office building to achieve a 2.5 star increase to 4.5 star NABERS Energy Rating, including the pathway taken and the technologies used.

Background

The building: ` constructed in 1966 and owned by Trafalgar Platinum Fund ` 5 stories with net lettable area (NLA) of 5,400m2 ` 2 star NABERS Energy Rating, as assessed ` Commonwealth tenants, with single retail tenant leasing part of ground floor, Commonwealth leases were set to expire ` existing HVAC reaching end of operational life, unreliable and expensive to maintain ` difficulty maintaining occupant comfort using existing HVAC system. In order to retain capital asset value the building owner decided to upgrade the building to target a 4.5 star NABERS Energy Rating

The upgrade was also done in the context of:

• requirements to meet the Energy Efficiency in Government Operations Policy requirements for Australian Government tenants1 , and the ACT Environmental Leasing Policy requirements for Territory Government tenants2
• the impending Australian Government Commercial Building Disclosure (CBD) regulations requiring an energy performance rating to be disclosed when advertising for lease or sale3
• minimal disruption to business was also required so that tenants could continue to occupy the building throughout the upgrade
• a limited budget of $1 million, supplemented by $500,000 from the now closed Green Building Fund4 .

Results

Improvement from 2 to 4.5 star NABERS Energy Rating, and aiming to achieve a 5 star NABERS Energy Rating in 2013. ` Improved systems monitoring through the installation of a modern building management system (BMS). ` Annual energy cost saving of $120,000. ` Increase in asset value estimated at $1.4 million. ` 70% reduction in annual greenhouse gas emissions equating to 786 tonnes CO2 -e

Conclusion

4 Mort Street Canberra was in a situation common to many aging commercial buildings. The building was performing poorly (estimated at 2 stars NABERS Energy), the existing HVAC system was nearing the end of its operational life (unreliable and expensive to maintain), energy prices were increasing, and some of the government tenancy leases were due to expire. In order to retain the building’s capital asset value it was necessary for the energy performance of the base building to reach a minimum 4.5 star NABERS Energy Rating in line with the Australian and State and Territory Government leasing policies. Faced with a limited budget for capital expenditure and a requirement that the existing tenants remain in situ throughout the improvements, the task of upgrading the building was not a small one