ravenscroft logoHealthier Air - Energy Saving

Ravenscroft specialises in providing innovative and energy efficient engineering solutions for the heating and ventilating sector. Our customised engineering solutions yield high quality indoor air while reducing HVAC operating costs.  

The refurbished Auckland office tower, 21 Queen St, was the first building in New Zealand to use locally manufactured Halton chilled beams. Installing Halton chilled beams proved to be a very energy efficient choice. It also allowed the Client to make better use of the building space and create more rentable floor area in the building.

chilled beam halton ravenscroft queen st03

The existing building HVAC had console mounted perimeter induction units and constant volume with reheat to the interior zones. The central air handling units were located within the level 13 plant room and eight perimeter risers served the perimeter induction units. One supply and one return air risers served the interior zones.

The Client objectives were to:

  • Increase the vision panel area by removing the console mounted induction units
  • Remove the intrusion of perimeter risers into the tenancy space
  • Raise the ceiling height by 100mm reducing the ceiling void space to 320mm
  • Add an additional office floors to the building

Several HVAC options were reviewed with the chilled beam solution being favored due to the reduced duct requirements.


New central plant rooms were created, one at Level 3 and one at roof level, new supply air risers were created adjacent the core, distributed on each face of the core. The existing return air riser was maintained. This arrangement allowed the previous supply air riser space to be converted to a disabled toilet.

With the local manufacture of the Halton active beams provided additional scope to modify the beams to accommodate the type of Tee rail used, also having the ability to change the paint color from the standard at a small additional cost to the end product. Since the completion of this project the color of the beams can be changed at no additional cost within a certain range of paints available in NZ.

Installation of Halton active chilled beams has proved to be even more energy efficient solution that anticipated with building energy saving in $/m2 being greater than expected.


The Team

Architects: Peddle Thorpe

Mechanical Consultants: Norman Disney & Young
Main Contractor: Fletcher Construction
Mechanical Contractor: Numecon