The project refers to the alterations to an existing office building located at New Plymouth-New Zealand. The building has eight floors, six of which are used for office space and a plant room with services on the levels above. The building was aiming for a NABERSNZ rating and was thus investigated by evaluating three distinct HVAC systems, as well as other considerations with details below:

–HVAC Option 1 – VRF

–HVAC Option 2 – 2 pipe chilled water system

–HVAC Option 3 – 4 pipe chilled water system

The results for the base building using various HVAC systems indicates that, the VRF corresponds to an energy use intensity of 135 kW/m2/yr, whereas a two-pipe chilled water system corresponds to 89 kWh/m2/yr. The average of the four pipe chilled water systems is also 80 kWh/m2/year.

Moreso, the results showed that VRF option will result in higher carbon emissions than the 4-pipe and 2-pipe chilled water systems, respectively.

From the modelling results obtained, the 2-pipe chiller system was recommended as the optimal HVAC system for the project based on cost, ease of installation and the corresponding NABERSNZ rating.