The client’s vision for the building was for it to be a green building that will ensure optimal access to views and daylight while minimising heat loss through the building envelope. The existing 11-storey building was reconfigured by adding a new double glazed façade, creating a new full height glazed atrium and lobby linking the two towers.
There were space constraints due to existing services and down stand beams in the ceiling. Existing tenants had to be accommodated within the building while the existing HVAC Systems were decommissioned and removed. Each tower has nine zones, each with distinctly unique temperature profiles. The totally new façade added extra floor area to the existing office footprint and a full height atrium was added to the building.
Our Approach / Services
WSP | Parsons Brinckerhoff was appointed as the Mechanical Engineers for the refurbishment of the HVAC installation to the existing buildings.
We proposed that two separate systems be utilised for this option namely (a) Internal Zone system and (b) external (Perimeter/Façade) zone system.
Chilled water and hot water variable air volume air-handling units at roof level serve the internal zones and the various zones on the façade. Active chilled beams were used for the perimeter zones. For the Atrium foyer, a dedicated chilled water and hot water variable air volume air-handling unit serves the bottom 2.4m area. The foyer floor is heated by means of hot water underfloor heating. A dedicated Tier 3 grade closed circuit condenser water system was installed to allow tenants with sophisticated Server rooms and small data centres to install water cooling equipment. This allows air-conditioning to tenant’s mission critical areas to operate 24 hours per day.
Four-off new air-cooled chillers were installed on the roof as follow:
• 1 x Ammonia cooling only chiller
• 1 x heat pump Chiller providing simultaneous heating and cooling
• 1 x heat pump chiller providing cooling or heating
• 1 x standard cooling only chiller
Existing tenants were provided with temporary air-conditioning whilst the existing HVAC system was decommissioned and removed.
Completed as scheduled, the building’s glass façade makes it one of the most eye-catching buildings in Sandton.
The suspended glass atrium is a first in South Africa.
The air cooled Ammonia chiller installed is the second of its kind in South Africa.
The building is 4-Star Green Star rated and received the Best Quality Submission Award from the Green Building Council of SA in 2014.
Facts and Figures
Total Cooling ±2400kWcool
Total Heating ±1200kWheat
Client: Liberty Holdings / Pareto Ltd
Project Date: 2013 - 2014
Pieter de Bod