Te Uru Gallery's HVAC system has proved to have insufficient dehumidification capacity to manage indoor humidity during periods of high ambient load. The building has also proved to be an excessive consumer of energy while dehumidifying.
Investigations have concluded that the fresh air supply system must be replaced with one selected for high latent cooling and at elevated design conditions. Indoor humidity will then be managed via dilution by dry ventilation air. Indoor temperature will chiefly be managed by the zone fan coil units (FCU's) as at present.
This RFP specifies the plant and works required to:
* Replace the fresh air supply system with a new unit to have the same ventilation rate but greater capacity for dehumidification
* Using an energy efficient topology capable of sensible heat recovery
* And make optimisations to ancillary equipment to support effective and efficient operation.
Works required include:
* Mechanical & electrical for mechanical
* Controls
* Building (minor)

In outline the works are:
* Decommission and remove existing CAV DX AHU and two associated outdoor units from L5 plantroom
* Install replacement VAV AHU, a 4-pipe unit within L5 plantroom and adapt supply air ducting to suit
* Install air-source 4-pipe simultaneous heat-pump outdoor at ground level to the west of the building with a new electrical supply from the main switch board
* Make penetrations and install insulated heating and chilled flow and return lines between the heat-pump and AHU
* Modify controls to suit the new AHU and heat-pump
* Modify FCU zone controls to gain automatic control of fan speed
* Move the controlling return air temperature/humidity sensor to the wall in five galleries.