Royal Darwin Hospital - Building 2 - Replace Air Handling Units 2,3,4 and 23

Three of the AHUs (AHUs 2, 3 & 4) serve operating theatres and the fourth AHU23 has been designed to be used as a temporary supply unit to serve various areas currently served by the above and other AHUs during their replacement (in the future) so that no area will be without air conditioning for more than 24 hours continuously.

AHU 2 serves the Operating Theatres 1, 2 and 3, AHU 3 serves Theatre 4 and AHU 4 serves Operating Theatre 5 (currently the Covid theatre).

AHU23 is currently the plant room cooling unit and is also the main fresh air AHU for the above mentioned AHU’s, within this project AHU23 will be replaced the first and this will be utilised as the plant room cooling and the “temporary” units for all AHUs located in the 2nd floor plant room.

Note that all AHUs have pre-cooling coils to treat the outdoor air. These pre-cooling coils are supplied with cooled water from the Energy Recovery System using exhaust air through a cooling tower.

All existing chilled water valves, STA-D valves, fittings etc up to the flanged connection of the new coils shall be reused and recommissioned. A provision for new insulation will be supplied and fitted as required. Some pipe routes will require alterations to match the new coil dimensions.

This project will consist of 5 stages; Stage 1 AHU23, Stage 2 AHU2, Stage 3 AHU3, Stage 4 AHU 4 and Stage 5 Revert AHU23 to normal operation.